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* [PATCH 43/48] objtool: Add insn_sym() helper
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Alternative replacement instructions awkwardly have insn->sym set to the
function they get patched to rather than the symbol (or rather lack
thereof) they belong to in the file.

This makes it difficult to know where a given instruction actually
lives.

Add a new insn_sym() helper which preserves the existing semantic of
insn->sym.  Rename insn->sym to insn->_sym, which contains the actual
ELF binary symbol (or NULL, for alternative replacements) an instruction
lives in.

The private insn->_sym value will be needed for a subsequent patch.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c                 | 31 ++++++++++++---------------
 tools/objtool/disas.c                 | 22 +++++++++----------
 tools/objtool/include/objtool/check.h | 19 ++++++++++++++--
 tools/objtool/include/objtool/warn.h  |  6 +++---
 tools/objtool/trace.c                 |  8 +++----
 5 files changed, 48 insertions(+), 38 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index ae047be919c5..410061aeed26 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -495,7 +495,7 @@ static int decode_instructions(struct objtool_file *file)
 			}
 
 			sym_for_each_insn(file, func, insn) {
-				insn->sym = func;
+				insn->_sym = func;
 				if (is_func_sym(func) &&
 				    insn->type == INSN_ENDBR &&
 				    list_empty(&insn->call_node)) {
@@ -859,15 +859,14 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)
 	list_for_each_entry(insn, &file->endbr_list, call_node) {
 
 		int *site = (int *)sec->data->d_buf + idx;
-		struct symbol *sym = insn->sym;
+		struct symbol *func = insn_func(insn);
 		*site = 0;
 
-		if (opts.module && sym && is_func_sym(sym) &&
-		    insn->offset == sym->offset &&
-		    (!strcmp(sym->name, "init_module") ||
-		     !strcmp(sym->name, "cleanup_module"))) {
+		if (opts.module && func && insn->offset == func->offset &&
+		    (!strcmp(func->name, "init_module") ||
+		     !strcmp(func->name, "cleanup_module"))) {
 			ERROR("%s(): Magic init_module() function name is deprecated, use module_init(fn) instead",
-			      sym->name);
+			      func->name);
 			return -1;
 		}
 
@@ -1581,7 +1580,7 @@ static int add_jump_destinations(struct objtool_file *file)
 		}
 
 		if (!dest_sym || is_sec_sym(dest_sym)) {
-			dest_sym = dest_insn->sym;
+			dest_sym = insn_sym(dest_insn);
 			if (!dest_sym)
 				goto set_jump_dest;
 		}
@@ -1597,7 +1596,7 @@ static int add_jump_destinations(struct objtool_file *file)
 			continue;
 		}
 
-		if (!insn->sym || insn->sym->pfunc == dest_sym->pfunc)
+		if (!insn_sym(insn) || insn_sym(insn)->pfunc == dest_sym->pfunc)
 			goto set_jump_dest;
 
 		/*
@@ -1770,7 +1769,6 @@ static int handle_group_alt(struct objtool_file *file,
 		nop->offset = special_alt->new_off + special_alt->new_len;
 		nop->len = special_alt->orig_len - special_alt->new_len;
 		nop->type = INSN_NOP;
-		nop->sym = orig_insn->sym;
 		nop->alt_group = new_alt_group;
 		nop->fake = 1;
 	}
@@ -1789,7 +1787,6 @@ static int handle_group_alt(struct objtool_file *file,
 
 		last_new_insn = insn;
 
-		insn->sym = orig_insn->sym;
 		insn->alt_group = new_alt_group;
 
 		/*
@@ -2432,12 +2429,12 @@ static int __annotate_late(struct objtool_file *file, int type, struct instructi
 		break;
 
 	case ANNOTYPE_NOCFI:
-		sym = insn->sym;
+		sym = insn_sym(insn);
 		if (!sym) {
 			ERROR_INSN(insn, "dodgy NOCFI annotation");
 			return -1;
 		}
-		insn->sym->nocfi = 1;
+		insn_sym(insn)->nocfi = 1;
 		break;
 
 	default:
@@ -2538,7 +2535,7 @@ static void mark_holes(struct objtool_file *file)
 	 * favour of a regular symbol, but leaves the code in place.
 	 */
 	for_each_insn(file, insn) {
-		if (insn->sym || !find_symbol_hole_containing(insn->sec, insn->offset)) {
+		if (insn_sym(insn) || !find_symbol_hole_containing(insn->sec, insn->offset)) {
 			in_hole = false;
 			continue;
 		}
@@ -2982,7 +2979,7 @@ static int update_cfi_state(struct instruction *insn,
 			}
 
 			if (op->dest.reg == CFI_BP && op->src.reg == CFI_SP &&
-			    insn->sym->frame_pointer) {
+			    insn_sym(insn)->frame_pointer) {
 				/* addi.d fp,sp,imm on LoongArch */
 				if (cfa->base == CFI_SP && cfa->offset == op->src.offset) {
 					cfa->base = CFI_BP;
@@ -2994,7 +2991,7 @@ static int update_cfi_state(struct instruction *insn,
 			if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
 				/* addi.d sp,fp,imm on LoongArch */
 				if (cfa->base == CFI_BP && cfa->offset == 0) {
-					if (insn->sym->frame_pointer) {
+					if (insn_sym(insn)->frame_pointer) {
 						cfa->base = CFI_SP;
 						cfa->offset = -op->src.offset;
 					}
@@ -4171,7 +4168,7 @@ static int validate_retpoline(struct objtool_file *file)
 	 * broken.
 	 */
 	list_for_each_entry(insn, &file->retpoline_call_list, call_node) {
-		struct symbol *sym = insn->sym;
+		struct symbol *sym = insn_sym(insn);
 
 		if (sym && (is_notype_sym(sym) ||
 			    is_func_sym(sym)) && !sym->nocfi) {
diff --git a/tools/objtool/disas.c b/tools/objtool/disas.c
index 59090234af19..e6a54a83605c 100644
--- a/tools/objtool/disas.c
+++ b/tools/objtool/disas.c
@@ -210,7 +210,7 @@ static bool disas_print_addr_alt(bfd_vma addr, struct disassemble_info *dinfo)
 	offset = addr - alt_group->first_insn->offset;
 
 	addr = orig_first_insn->offset + offset;
-	sym = orig_first_insn->sym;
+	sym = insn_sym(orig_first_insn);
 
 	disas_print_addr_sym(orig_first_insn->sec, sym, addr, dinfo);
 
@@ -222,15 +222,13 @@ static void disas_print_addr_noreloc(bfd_vma addr,
 {
 	struct disas_context *dctx = dinfo->application_data;
 	struct instruction *insn = dctx->insn;
-	struct symbol *sym = NULL;
+	struct symbol *sym = insn_sym(insn);
 
 	if (disas_print_addr_alt(addr, dinfo))
 		return;
 
-	if (insn->sym && addr >= insn->sym->offset &&
-	    addr < insn->sym->offset + insn->sym->len) {
-		sym = insn->sym;
-	}
+	if (sym && (addr < sym->offset || addr >= sym->offset + sym->len))
+		sym = NULL;
 
 	disas_print_addr_sym(insn->sec, sym, addr, dinfo);
 }
@@ -291,9 +289,9 @@ static void disas_print_address(bfd_vma addr, struct disassemble_info *dinfo)
 	 * up. So check it first.
 	 */
 	jump_dest = insn->jump_dest;
-	if (jump_dest && jump_dest->sym && jump_dest->offset == addr) {
+	if (jump_dest && insn_sym(jump_dest) && jump_dest->offset == addr) {
 		if (!disas_print_addr_alt(addr, dinfo))
-			disas_print_addr_sym(jump_dest->sec, jump_dest->sym,
+			disas_print_addr_sym(jump_dest->sec, insn_sym(jump_dest),
 					     addr, dinfo);
 		return;
 	}
@@ -768,8 +766,8 @@ static int disas_alt_jump(struct disas_alt *dalt)
 		if (orig_insn->len == 5)
 			suffix[0] = 'q';
 		str = strfmt("jmp%-3s %lx <%s+0x%lx>", suffix,
-			     dest_insn->offset, dest_insn->sym->name,
-			     dest_insn->offset - dest_insn->sym->offset);
+			     dest_insn->offset, insn_sym(dest_insn)->name,
+			     dest_insn->offset - insn_sym(dest_insn)->offset);
 		nops = 0;
 	} else {
 		str = strfmt("nop%d", orig_insn->len);
@@ -794,8 +792,8 @@ static int disas_alt_extable(struct disas_alt *dalt)
 
 	alt_insn = dalt->alt->insn;
 	str = strfmt("resume at 0x%lx <%s+0x%lx>",
-		     alt_insn->offset, alt_insn->sym->name,
-		     alt_insn->offset - alt_insn->sym->offset);
+		     alt_insn->offset, insn_sym(alt_insn)->name,
+		     alt_insn->offset - insn_sym(alt_insn)->offset);
 	if (!str)
 		return -1;
 
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index eea64728d39b..0c53476528a8 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -94,14 +94,29 @@ struct instruction {
 		};
 	};
 	struct alternative *alts;
-	struct symbol *sym;
+	struct symbol *_sym;
 	struct stack_op *stack_ops;
 	struct cfi_state *cfi;
 };
 
+/*
+ * Return the symbol associated with an instruction.  For alternative
+ * replacements, return the symbol of the original code being replaced rather
+ * than NULL.  insn->_sym reflects the actual location in the ELF file.
+ */
+static inline struct symbol *insn_sym(struct instruction *insn)
+{
+	struct symbol *sym = insn->_sym;
+
+	if (!sym && insn->alt_group && insn->alt_group->orig_group)
+		sym = insn->alt_group->orig_group->first_insn->_sym;
+
+	return sym;
+}
+
 static inline struct symbol *insn_func(struct instruction *insn)
 {
-	struct symbol *sym = insn->sym;
+	struct symbol *sym = insn_sym(insn);
 
 	if (sym && sym->type != STT_FUNC)
 		sym = NULL;
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index a9936d60980c..870e147f3a56 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -77,13 +77,13 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 #define WARN_INSN(insn, format, ...)					\
 ({									\
 	struct instruction *_insn = (insn);				\
-	if (!_insn->sym || !_insn->sym->warned)	{			\
+	if (!insn_sym(_insn) || !insn_sym(_insn)->warned)	{	\
 		WARN_FUNC(_insn->sec, _insn->offset, format,		\
 			  ##__VA_ARGS__);				\
 		BT_INSN(_insn, "");					\
 	}								\
-	if (_insn->sym)							\
-		_insn->sym->warned = 1;					\
+	if (insn_sym(_insn))						\
+		insn_sym(_insn)->warned = 1;				\
 })
 
 #define BT_INSN(insn, format, ...)				\
diff --git a/tools/objtool/trace.c b/tools/objtool/trace.c
index 5dec44dab781..61c6aa302bc3 100644
--- a/tools/objtool/trace.c
+++ b/tools/objtool/trace.c
@@ -169,8 +169,8 @@ void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
 		 */
 		TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s for instruction at 0x%lx <%s+0x%lx>",
 				      alt_name,
-				      orig_insn->offset, orig_insn->sym->name,
-				      orig_insn->offset - orig_insn->sym->offset);
+				      orig_insn->offset, insn_sym(orig_insn)->name,
+				      orig_insn->offset - insn_sym(orig_insn)->offset);
 	} else {
 		TRACE_ALT_INFO_NOADDR(orig_insn, "/ ", "%s", alt_name);
 	}
@@ -185,8 +185,8 @@ void trace_alt_begin(struct instruction *orig_insn, struct alternative *alt,
 		if (orig_insn->type == INSN_NOP) {
 			suffix[0] = (orig_insn->len == 5) ? 'q' : '\0';
 			TRACE_ADDR(orig_insn, "jmp%-3s %lx <%s+0x%lx>", suffix,
-				   alt_insn->offset, alt_insn->sym->name,
-				   alt_insn->offset - alt_insn->sym->offset);
+				   alt_insn->offset, insn_sym(alt_insn)->name,
+				   alt_insn->offset - insn_sym(alt_insn)->offset);
 		} else {
 			TRACE_ADDR(orig_insn, "nop%d", orig_insn->len);
 			trace_depth--;
-- 
2.53.0


^ permalink raw reply related

* [PATCH 42/48] objtool/klp: Add correlation debugging output
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Add debugging messages to show how duplicate symbols get correlated, and
split the --debug feature into --debug-correlate and --debug-clone.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/include/objtool/warn.h | 16 +++++++----
 tools/objtool/klp-diff.c             | 42 ++++++++++++++++++++++------
 tools/objtool/objtool.c              |  3 --
 3 files changed, 45 insertions(+), 16 deletions(-)

diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index 595ee8009667..a9936d60980c 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -109,7 +109,7 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 #define ERROR_FUNC(sec, offset, format, ...) __WARN_FUNC(ERROR_STR, sec, offset, format, ##__VA_ARGS__)
 #define ERROR_INSN(insn, format, ...) ERROR_FUNC(insn->sec, insn->offset, format, ##__VA_ARGS__)
 
-extern bool debug;
+extern bool debug, debug_correlate, debug_clone;
 extern int indent;
 
 static inline void unindent(int *unused) { indent--; }
@@ -148,15 +148,21 @@ static inline void unindent(int *unused) { indent--; }
 		      (unsigned long long)checksum);			\
 })
 
-#define __dbg_indent(format, ...)					\
+#define dbg_correlate(args...)						\
 ({									\
-	if (unlikely(debug))						\
+	if (unlikely(debug_correlate))					\
+		__dbg(args);						\
+})
+
+#define __dbg_clone(format, ...)					\
+({									\
+	if (unlikely(debug_clone))					\
 		__dbg("%*s" format, indent * 8, "", ##__VA_ARGS__);	\
 })
 
-#define dbg_indent(args...)						\
+#define dbg_clone(args...)						\
 	int __cleanup(unindent) __dummy_##__COUNTER__;			\
-	__dbg_indent(args);						\
+	__dbg_clone(args);						\
 	indent++
 
 #endif /* _WARN_H */
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 6d7fbb16e59c..acb76aefd04f 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -33,6 +33,9 @@ struct export {
 	char *mod, *sym;
 };
 
+bool debug, debug_correlate, debug_clone;
+int indent;
+
 static const char * const klp_diff_usage[] = {
 	"objtool klp diff [<options>] <in1.o> <in2.o> <out.o>",
 	NULL,
@@ -40,7 +43,9 @@ static const char * const klp_diff_usage[] = {
 
 static const struct option klp_diff_options[] = {
 	OPT_GROUP("Options:"),
-	OPT_BOOLEAN('d', "debug", &debug, "enable debug output"),
+	OPT_BOOLEAN('d', "debug", &debug, "enable all debug output"),
+	OPT_BOOLEAN(0, "debug-correlate", &debug_correlate, "enable correlation debug output"),
+	OPT_BOOLEAN(0, "debug-clone", &debug_clone, "enable cloning debug output"),
 	OPT_END(),
 };
 
@@ -543,6 +548,14 @@ static struct symbol *find_twin(struct elfs *e, struct symbol *sym1)
 	else if (csum_orig == 1 && csum_patched == 1)
 		match = csum_last;
 
+	if (!match)
+		return NULL;
+
+	if (name_orig != 1 || name_patched != 1)
+		dbg_correlate("find_twin(): %s%s -> %s%s",
+			      sym1->name, is_func_sym(sym1) ? "()" : "",
+			      match->name, is_func_sym(match) ? "()" : "");
+
 	return match;
 }
 
@@ -638,10 +651,14 @@ static struct symbol *find_twin_suffixed(struct elf *elf, struct symbol *sym1)
 		match = sym2;
 	}
 
-	if (count == 1)
-		return match;
+	if (count != 1)
+		return NULL;
 
-	return NULL;
+	dbg_correlate("find_suffixed_twin(): %s%s -> %s%s",
+		      sym1->name, is_func_sym(sym1) ? "()" : "",
+		      match->name, is_func_sym(match) ? "()" : "");
+
+	return match;
 }
 
 /*
@@ -688,6 +705,10 @@ static struct symbol *find_twin_positional(struct elfs *e, struct symbol *sym1)
 	if (idx_orig != idx_patched)
 		return NULL;
 
+	dbg_correlate("find_twin_positional(): %s%s -> %s%s",
+	    sym1->name, is_func_sym(sym1) ? "()" : "",
+	    match->name, is_func_sym(match) ? "()" : "");
+
 	return match;
 }
 
@@ -944,7 +965,7 @@ static struct symbol *clone_symbol(struct elfs *e, struct symbol *patched_sym,
 	if (patched_sym->clone)
 		return patched_sym->clone;
 
-	dbg_indent("%s%s", patched_sym->name, data_too ? " [+DATA]" : "");
+	dbg_clone("%s%s", patched_sym->name, data_too ? " [+DATA]" : "");
 
 	/* Make sure the prefix gets cloned first */
 	if (is_func_sym(patched_sym) && data_too) {
@@ -1324,7 +1345,7 @@ static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc,
 
 	klp_sym = find_symbol_by_name(e->out, sym_name);
 	if (!klp_sym) {
-		__dbg_indent("%s", sym_name);
+		__dbg_clone("%s", sym_name);
 
 		/* STB_WEAK: avoid modpost undefined symbol warnings */
 		klp_sym = elf_create_symbol(e->out, sym_name, NULL,
@@ -1375,7 +1396,7 @@ static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc,
 }
 
 #define dbg_clone_reloc(sec, offset, patched_sym, addend, export, klp)			\
-	dbg_indent("%s+0x%lx: %s%s0x%lx [%s%s%s%s%s%s]",				\
+	dbg_clone("%s+0x%lx: %s%s0x%lx [%s%s%s%s%s%s]",				\
 		   sec->name, offset, patched_sym->name,				\
 		   addend >= 0 ? "+" : "-", labs(addend),				\
 		   sym_type(patched_sym),						\
@@ -1437,7 +1458,7 @@ static int clone_reloc(struct elfs *e, struct reloc *patched_reloc,
 	if (is_string_sec(patched_sym->sec)) {
 		const char *str = patched_sym->sec->data->d_buf + addend;
 
-		__dbg_indent("\"%s\"", escape_str(str));
+		__dbg_clone("\"%s\"", escape_str(str));
 
 		addend = elf_add_string(e->out, out_sym->sec, str);
 		if (addend == -1)
@@ -2077,6 +2098,11 @@ int cmd_klp_diff(int argc, const char **argv)
 	if (argc != 3)
 		usage_with_options(klp_diff_usage, klp_diff_options);
 
+	if (debug) {
+		debug_correlate = true;
+		debug_clone = true;
+	}
+
 	objname = argv[0];
 
 	e.orig = elf_open_read(argv[0], O_RDONLY);
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 1c3622117c33..a4e139dee7e9 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -16,9 +16,6 @@
 #include <objtool/objtool.h>
 #include <objtool/warn.h>
 
-bool debug;
-int indent;
-
 static struct objtool_file file;
 
 struct objtool_file *objtool_open_read(const char *filename)
-- 
2.53.0


^ permalink raw reply related

* [PATCH 41/48] objtool/klp: Rewrite symbol correlation algorithm
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Rewrite the symbol correlation code, using a tiered list of
deterministic strategies in a loop.  For duplicately named symbols, each
tier applies a filter with the goal of finding a 1:1 deterministic
correlation between the original and patched version of the symbol.

Overall this works much better than the existing algorithm, particularly
with LTO kernels.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/klp-diff.c | 482 ++++++++++++++++++++++++++++-----------
 1 file changed, 346 insertions(+), 136 deletions(-)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 8d64d4c691cb..6d7fbb16e59c 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -393,78 +393,319 @@ static bool dont_correlate(struct symbol *sym)
 	       is_special_section_aux(sym->sec);
 }
 
-/*
- * When there is no full name match, try match demangled_name. This would
- * match original foo.llvm.123 to patched foo.llvm.456.
- *
- * Note that, in very rare cases, it is possible to have multiple
- * foo.llvm.<hash> in the same kernel. When this happens, report error and
- * fail the diff.
- */
-static int find_global_symbol_by_demangled_name(struct elf *elf, struct symbol *sym,
-						struct symbol **out_sym)
+static const char *llvm_suffix(const char *name)
 {
-	struct symbol *sym2, *result = NULL;
-	int count = 0;
+	return strstr(name, ".llvm.");
+}
 
-	for_each_sym_by_demangled_name(elf, sym->demangled_name, sym2) {
-		if (is_local_sym(sym2) || sym2->twin)
+static bool is_llvm_sym(struct symbol *sym)
+{
+	return llvm_suffix(sym->name);
+}
+
+/*
+ * Determine if two symbols have compatible source file origins:
+ *
+ *   - If both symbols are local, only return true if they belong to the same
+ *     ELF file symbol.
+ *
+ *   - If both symbols are global, always return true, as globals don't have
+ *     file associations.
+ *
+ *   - If they have different scopes, also return true, as the patch might have
+ *     changed the symbol's scope.
+ *
+ * Works for both same-ELF (direct pointer compare) and cross-ELF
+ * (compare via file->twin) cases.
+ */
+static bool maybe_same_file(struct symbol *sym1, struct symbol *sym2)
+{
+	if (!sym1->file || !sym2->file)
+		return true;
+	if (sym1->file == sym2->file)
+		return true;
+	return sym1->file->twin == sym2->file;
+}
+
+/*
+ * Similar to maybe_same_file(), but strict: no scope changes allowed.
+ *
+ * Works for both same-ELF (direct pointer compare) and cross-ELF
+ * (compare via file->twin) cases.
+ */
+static bool same_file(struct symbol *sym1, struct symbol *sym2)
+{
+	if (llvm_suffix(sym1->name) && llvm_suffix(sym2->name))
+		return true;
+	if (!sym1->file && !sym2->file)
+		return true;
+	if (!sym1->file || !sym2->file)
+		return false;
+	if (sym1->file == sym2->file)
+		return true;
+	return sym1->file->twin == sym2->file;
+}
+
+/*
+ * Is it a local symbol, or at least was it local in the translation unit
+ * before LLVM promoted it?
+ */
+static bool is_tu_local_sym(struct symbol *sym)
+{
+	return is_local_sym(sym) || is_llvm_sym(sym);
+}
+
+/*
+ * Try to find sym1's twin in patched using deterministic matching.
+ *
+ * Multiple symbols can share a demangled name (e.g., static functions in
+ * different TUs).  This function counts same-named candidates through a
+ * funnel of progressively tighter filters.  Each level is a strict subset
+ * of the previous one.
+ *
+ * The widest level that yields a 1:1 match wins.  Narrower levels are only
+ * needed when the wider level is ambiguous (count > 1).
+ */
+static struct symbol *find_twin(struct elfs *e, struct symbol *sym1)
+{
+	struct symbol *name_last = NULL, *scope_last = NULL,
+		      *file_last = NULL, *csum_last = NULL;
+	unsigned int name_orig = 0, name_patched = 0;
+	unsigned int scope_orig = 0, scope_patched = 0;
+	unsigned int file_orig = 0, file_patched = 0;
+	unsigned int csum_orig = 0, csum_patched = 0;
+	struct symbol *sym2, *match = NULL;
+
+	/* Count orig candidates */
+	for_each_sym_by_demangled_name(e->orig, sym1->demangled_name, sym2) {
+		if (sym2->twin || sym1->type != sym2->type || dont_correlate(sym2) ||
+		    (!maybe_same_file(sym1, sym2)))
 			continue;
 
-		count++;
-		result = sym2;
+		/* Level 1: name match (widest filter)  */
+		name_orig++;
+
+		/* Level 2: scope (scope changes allowed) */
+		if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2))
+			continue;
+		scope_orig++;
+
+		/* Level 3: file (scope changes disallowed) */
+		if (!same_file(sym1, sym2))
+			continue;
+		file_orig++;
+
+		/* Level 4: checksum (unchanged symbols) */
+		if (sym1->len != sym2->len || !sym1->csum.checksum ||
+		    sym1->csum.checksum != sym2->csum.checksum)
+			continue;
+		csum_orig++;
 	}
 
-	if (count > 1) {
-		ERROR("Multiple (%d) correlation candidates for %s", count, sym->name);
-		return -1;
+	/* Count patched candidates */
+	for_each_sym_by_demangled_name(e->patched, sym1->demangled_name, sym2) {
+		if (sym2->twin || sym1->type != sym2->type || dont_correlate(sym2))
+			continue;
+
+		/* Level 1 */
+		if (!maybe_same_file(sym1, sym2))
+			continue;
+		name_patched++;
+		name_last = sym2;
+
+		/* Level 2 */
+		if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2))
+			continue;
+		scope_patched++;
+		scope_last = sym2;
+
+		/* Level 3 */
+		if (!same_file(sym1, sym2))
+			continue;
+		file_patched++;
+		file_last = sym2;
+
+		/* Level 4 */
+		if (sym1->len != sym2->len || !sym1->csum.checksum ||
+		    sym1->csum.checksum != sym2->csum.checksum)
+			continue;
+		csum_patched++;
+		csum_last = sym2;
+	}
+
+	/* Return the widest level that yields a unique (1:1) match */
+	if (name_orig == 1 && name_patched == 1)
+		match = name_last;
+	else if (scope_orig == 1 && scope_patched == 1)
+		match = scope_last;
+	else if (file_orig == 1 && file_patched == 1)
+		match = file_last;
+	else if (csum_orig == 1 && csum_patched == 1)
+		match = csum_last;
+
+	return match;
+}
+
+struct llvm_suffix_pair {
+	struct hlist_node hash;
+	const char *orig;
+	const char *patched;
+};
+
+static DECLARE_HASHTABLE(suffix_map, 7);
+
+/*
+ * Build a mapping of known orig-to-patched LLVM suffixes based on
+ * already-correlated symbol pairs.  All promoted symbols from the same TU
+ * share the same .llvm.<hash> suffix, so one correlated pair seeds the map
+ * for the entire TU.
+ */
+static int update_suffix_map(struct elf *elf)
+{
+	struct llvm_suffix_pair *entry;
+	struct symbol *sym;
+
+	for_each_sym(elf, sym) {
+		const char *s1, *s2;
+		bool found;
+
+		if (!sym->twin)
+			continue;
+
+		s1 = llvm_suffix(sym->name);
+		s2 = llvm_suffix(sym->twin->name);
+
+		if (!s1 || !s2)
+			continue;
+
+		found = false;
+		hash_for_each_possible(suffix_map, entry, hash, str_hash(s1)) {
+			if (!strcmp(entry->orig, s1)) {
+				found = true;
+				break;
+			}
+		}
+		if (found)
+			continue;
+
+		entry = calloc(1, sizeof(*entry));
+		if (!entry) {
+			ERROR_GLIBC("calloc");
+			return -1;
+		}
+
+		entry->orig = s1;
+		entry->patched = s2;
+		hash_add(suffix_map, &entry->hash, str_hash(s1));
 	}
 
-	*out_sym = result;
 	return 0;
 }
 
 /*
- * For each symbol in the original kernel, find its corresponding "twin" in the
- * patched kernel.
+ * Match by translating the symbol's .llvm.<hash> suffix through the suffix
+ * map to find the corresponding hash suffix for the patched object.
+ */
+static struct symbol *find_twin_suffixed(struct elf *elf, struct symbol *sym1)
+{
+	const char *suffix, *patched_suffix = NULL;
+	struct symbol *sym2, *match = NULL;
+	char name[SYM_NAME_LEN];
+	struct llvm_suffix_pair *entry;
+	int count = 0;
+
+	suffix = llvm_suffix(sym1->name);
+	if (!suffix)
+		return NULL;
+
+	hash_for_each_possible(suffix_map, entry, hash, str_hash(suffix)) {
+		if (!strcmp(entry->orig, suffix)) {
+			patched_suffix = entry->patched;
+			break;
+		}
+	}
+	if (!patched_suffix)
+		return NULL;
+
+	if (snprintf_check(name, SYM_NAME_LEN, "%s%s",
+			   sym1->demangled_name, patched_suffix))
+		return NULL;
+
+	for_each_sym_by_name(elf, name, sym2) {
+		if (sym2->twin || sym1->type != sym2->type || dont_correlate(sym2))
+			continue;
+		count++;
+		match = sym2;
+	}
+
+	if (count == 1)
+		return match;
+
+	return NULL;
+}
+
+/*
+ * Last-resort positional matching.
+ *
+ * Finds a symbol with the same position in the symbol table among
+ * same-demangled-name candidates, similar to livepatch sympos.  Note that
+ * LLVM-promoted symbols are globals, which come after locals in the symbol
+ * table, so we have to be careful not to compare different scopes.
+ *
+ * This is a bit less deterministic than the other matching strategies, so it
+ * should be done last.
+ */
+static struct symbol *find_twin_positional(struct elfs *e, struct symbol *sym1)
+{
+	unsigned int idx_orig = 0, idx_patched = 0;
+	unsigned int sym1_pos = 0;
+	struct symbol *sym2, *match = NULL;
+
+	for_each_sym_by_demangled_name(e->orig, sym1->demangled_name, sym2) {
+		if (sym2->twin || sym1->type != sym2->type || dont_correlate(sym2) ||
+		    !maybe_same_file(sym1, sym2))
+			continue;
+		if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2) ||
+		    is_llvm_sym(sym1) != is_llvm_sym(sym2))
+			continue;
+		if (sym1 == sym2)
+			sym1_pos = idx_orig;
+		idx_orig++;
+	}
+
+	for_each_sym_by_demangled_name(e->patched, sym1->demangled_name, sym2) {
+		if (sym2->twin || sym1->type != sym2->type || dont_correlate(sym2) ||
+		    !maybe_same_file(sym1, sym2))
+			continue;
+		if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2) ||
+		    is_llvm_sym(sym1) != is_llvm_sym(sym2))
+			continue;
+		if (idx_patched == sym1_pos)
+			match = sym2;
+		idx_patched++;
+	}
+
+	if (idx_orig != idx_patched)
+		return NULL;
+
+	return match;
+}
+
+/*
+ * Correlate symbols between the orig and patched objects.  This is a
+ * prerequisite for detecting changed functions, as well as for properly
+ * translating relocations so they point to the correct symbol.
  */
 static int correlate_symbols(struct elfs *e)
 {
 	struct symbol *file1_sym, *file2_sym;
 	struct symbol *sym1, *sym2;
+	bool progress;
 
+	/* Correlate FILE symbols */
 	file1_sym = first_file_symbol(e->orig);
 	file2_sym = first_file_symbol(e->patched);
 
-	/*
-	 * Correlate any locals before the first FILE symbol.  This has been
-	 * seen when LTO inexplicably strips the initramfs_data.o FILE symbol
-	 * due to the file only containing data and no code.
-	 */
-	for_each_sym(e->orig, sym1) {
-		if (sym1 == file1_sym || !is_local_sym(sym1))
-			break;
-
-		if (dont_correlate(sym1))
-			continue;
-
-		for_each_sym(e->patched, sym2) {
-			if (sym2 == file2_sym || !is_local_sym(sym2))
-				break;
-
-			if (sym2->twin || dont_correlate(sym2))
-				continue;
-
-			if (strcmp(sym1->demangled_name, sym2->demangled_name))
-				continue;
-
-			sym1->twin = sym2;
-			sym2->twin = sym1;
-			break;
-		}
-	}
-
-	/* Correlate locals after the first FILE symbol */
 	for (; ; file1_sym = next_file_symbol(e->orig, file1_sym),
 		 file2_sym = next_file_symbol(e->patched, file2_sym)) {
 
@@ -488,92 +729,52 @@ static int correlate_symbols(struct elfs *e)
 
 		file1_sym->twin = file2_sym;
 		file2_sym->twin = file1_sym;
-
-		sym1 = file1_sym;
-
-		for_each_sym_continue(e->orig, sym1) {
-			if (is_file_sym(sym1) || !is_local_sym(sym1))
-				break;
-
-			if (dont_correlate(sym1))
-				continue;
-
-			sym2 = file2_sym;
-			for_each_sym_continue(e->patched, sym2) {
-				if (is_file_sym(sym2) || !is_local_sym(sym2))
-					break;
-
-				if (sym2->twin || dont_correlate(sym2))
-					continue;
-
-				if (strcmp(sym1->demangled_name, sym2->demangled_name))
-					continue;
-
-				sym1->twin = sym2;
-				sym2->twin = sym1;
-				break;
-			}
-		}
 	}
 
-	/* Correlate globals */
-	for_each_sym(e->orig, sym1) {
-		if (sym1->bind == STB_LOCAL)
-			continue;
-
-		sym2 = find_global_symbol_by_name(e->patched, sym1->name);
-		if (sym2 && !sym2->twin) {
-			sym1->twin = sym2;
-			sym2->twin = sym1;
-		}
-	}
 
 	/*
-	 * Correlate globals with demangled_name.
-	 * A separate loop is needed because we want to finish all the
-	 * full name correlations first.
+	 * Correlate in two phases: loop deterministic levels until no more
+	 * progress, then use positional fallback for the rest.  This prevents
+	 * the nondeterministic positional matching from stealing symbols that
+	 * have deterministic matches.
 	 */
+	hash_init(suffix_map);
+	do {
+		progress = false;
+		for_each_sym(e->orig, sym1) {
+			if (sym1->twin || dont_correlate(sym1))
+				continue;
+			sym2 = find_twin(e, sym1);
+			if (!sym2)
+				continue;
+			sym1->twin = sym2;
+			sym2->twin = sym1;
+			progress = true;
+		}
+
+		if (update_suffix_map(e->orig))
+			return -1;
+
+		for_each_sym(e->orig, sym1) {
+			if (sym1->twin || dont_correlate(sym1))
+				continue;
+			sym2 = find_twin_suffixed(e->patched, sym1);
+			if (!sym2)
+				continue;
+			sym1->twin = sym2;
+			sym2->twin = sym1;
+			progress = true;
+		}
+	} while (progress);
+
 	for_each_sym(e->orig, sym1) {
-		if (sym1->bind == STB_LOCAL || sym1->twin)
+		if (sym1->twin || dont_correlate(sym1))
 			continue;
-
-		if (find_global_symbol_by_demangled_name(e->patched, sym1, &sym2))
-			return -1;
-
-		if (sym2 && !sym2->twin) {
-			sym1->twin = sym2;
-			sym2->twin = sym1;
-		}
-	}
-
-	/* Correlate original locals with patched globals */
-	for_each_sym(e->orig, sym1) {
-		if (sym1->twin || dont_correlate(sym1) || !is_local_sym(sym1))
+		sym2 = find_twin_positional(e, sym1);
+		if (!sym2)
 			continue;
-
-		sym2 = find_global_symbol_by_name(e->patched, sym1->name);
-		if (!sym2 && find_global_symbol_by_demangled_name(e->patched, sym1, &sym2))
-			return -1;
-
-		if (sym2 && !sym2->twin) {
-			sym1->twin = sym2;
-			sym2->twin = sym1;
-		}
-	}
-
-	/* Correlate original globals with patched locals */
-	for_each_sym(e->patched, sym2) {
-		if (sym2->twin || dont_correlate(sym2) || !is_local_sym(sym2))
-			continue;
-
-		sym1 = find_global_symbol_by_name(e->orig, sym2->name);
-		if (!sym1 && find_global_symbol_by_demangled_name(e->orig, sym2, &sym1))
-			return -1;
-
-		if (sym1 && !sym1->twin) {
-			sym2->twin = sym1;
-			sym1->twin = sym2;
-		}
+		sym1->twin = sym2;
+		sym2->twin = sym1;
 	}
 
 	for_each_sym(e->orig, sym1) {
@@ -785,19 +986,24 @@ static void mark_included_function(struct symbol *func)
  */
 static int mark_changed_functions(struct elfs *e)
 {
-	struct symbol *sym_orig, *patched_sym;
+	struct symbol *orig_sym, *patched_sym;
 	bool changed = false;
 
 	/* Find changed functions */
-	for_each_sym(e->orig, sym_orig) {
-		if (!is_func_sym(sym_orig) || dont_correlate(sym_orig))
+	for_each_sym(e->orig, orig_sym) {
+		if (dont_correlate(orig_sym))
 			continue;
 
-		patched_sym = sym_orig->twin;
+		patched_sym = orig_sym->twin;
 		if (!patched_sym)
 			continue;
 
-		if (sym_orig->csum.checksum != patched_sym->csum.checksum) {
+		if (orig_sym->csum.checksum != patched_sym->csum.checksum) {
+			if (!is_func_sym(orig_sym)) {
+				ERROR("changed data: %s", orig_sym->name);
+				return -1;
+			}
+
 			patched_sym->changed = 1;
 			mark_included_function(patched_sym);
 			changed = true;
@@ -822,7 +1028,7 @@ static int mark_changed_functions(struct elfs *e)
 			printf("%s: changed function: %s\n", objname, patched_sym->name);
 	}
 
-	return !changed ? -1 : 0;
+	return !changed ? 1 : 0;
 }
 
 static int clone_included_functions(struct elfs *e)
@@ -1865,6 +2071,7 @@ static int copy_import_ns(struct elfs *e)
 int cmd_klp_diff(int argc, const char **argv)
 {
 	struct elfs e = {0};
+	int ret;
 
 	argc = parse_options(argc, argv, klp_diff_options, klp_diff_usage, 0);
 	if (argc != 3)
@@ -1891,7 +2098,10 @@ int cmd_klp_diff(int argc, const char **argv)
 	if (correlate_symbols(&e))
 		return -1;
 
-	if (mark_changed_functions(&e))
+	ret = mark_changed_functions(&e);
+	if (ret < 0)
+		return -1;
+	if (ret > 0)
 		return 0;
 
 	e.out = elf_create_file(&e.orig->ehdr, argv[2]);
-- 
2.53.0


^ permalink raw reply related

* [PATCH 40/48] objtool/klp: Calculate object checksums
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Start checksumming data objects in preparation for revamping the
correlation algorithm.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/include/objtool/checksum.h | 43 ++++++++----
 tools/objtool/include/objtool/warn.h     | 29 ++++----
 tools/objtool/klp-checksum.c             | 88 +++++++++++++++++++-----
 tools/objtool/klp-diff.c                 |  2 +-
 4 files changed, 115 insertions(+), 47 deletions(-)

diff --git a/tools/objtool/include/objtool/checksum.h b/tools/objtool/include/objtool/checksum.h
index be4eb7dfe6f2..ccaf57c7df38 100644
--- a/tools/objtool/include/objtool/checksum.h
+++ b/tools/objtool/include/objtool/checksum.h
@@ -6,28 +6,43 @@
 
 #ifdef BUILD_KLP
 
-static inline void checksum_init(struct symbol *func)
+static inline void checksum_init(struct symbol *sym)
 {
-	if (func && !func->csum.state) {
-		func->csum.state = XXH3_createState();
-		XXH3_64bits_reset(func->csum.state);
+	if (sym && !sym->csum.state) {
+		sym->csum.state = XXH3_createState();
+		XXH3_64bits_reset(sym->csum.state);
 	}
 }
 
-static inline void checksum_update(struct symbol *func,
-				   struct instruction *insn,
-				   const void *data, size_t size)
+static inline void __checksum_update(struct symbol *sym, const void *data,
+				     size_t size)
 {
-	XXH3_64bits_update(func->csum.state, data, size);
-	dbg_checksum(func, insn, XXH3_64bits_digest(func->csum.state));
+	XXH3_64bits_update(sym->csum.state, data, size);
 }
 
-static inline void checksum_finish(struct symbol *func)
+static inline void __checksum_update_insn(struct symbol *sym,
+					  struct instruction *insn,
+					  const void *data, size_t size)
 {
-	if (func && func->csum.state) {
-		func->csum.checksum = XXH3_64bits_digest(func->csum.state);
-		XXH3_freeState(func->csum.state);
-		func->csum.state = NULL;
+	__checksum_update(sym, data, size);
+	dbg_checksum_insn(sym, insn, XXH3_64bits_digest(sym->csum.state));
+}
+
+static inline void __checksum_update_object(struct symbol *sym,
+					    unsigned long offset,
+					    const char *what, const void *data,
+					    size_t size)
+{
+	__checksum_update(sym, data, size);
+	dbg_checksum_object(sym, offset, what, XXH3_64bits_digest(sym->csum.state));
+}
+
+static inline void checksum_finish(struct symbol *sym)
+{
+	if (sym && sym->csum.state) {
+		sym->csum.checksum = XXH3_64bits_digest(sym->csum.state);
+		XXH3_freeState(sym->csum.state);
+		sym->csum.state = NULL;
 	}
 }
 
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index fa8b7d292e83..595ee8009667 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -130,10 +130,22 @@ static inline void unindent(int *unused) { indent--; }
 		objname ? ": " : "",					\
 		##__VA_ARGS__)
 
-#define dbg(args...)							\
+#define dbg_checksum_insn(func, insn, checksum)				\
 ({									\
-	if (unlikely(debug))						\
-		__dbg(args);						\
+	if (unlikely(func->debug_checksum)) {				\
+		char *insn_off = offstr(insn->sec, insn->offset);	\
+		__dbg("checksum: %s(): %s %016llx",			\
+		      func->name, insn_off, (unsigned long long)checksum);\
+		free(insn_off);						\
+	}								\
+})
+
+#define dbg_checksum_object(sym, offset, what, checksum)		\
+({									\
+	if (unlikely(sym->debug_checksum))				\
+		__dbg("checksum: %s+0x%lx: %s %016llx",			\
+		      sym->name, offset, what,				\
+		      (unsigned long long)checksum);			\
 })
 
 #define __dbg_indent(format, ...)					\
@@ -147,15 +159,4 @@ static inline void unindent(int *unused) { indent--; }
 	__dbg_indent(args);						\
 	indent++
 
-#define dbg_checksum(func, insn, checksum)				\
-({									\
-	if (unlikely(insn->sym && insn->sym->pfunc &&			\
-		     insn->sym->pfunc->debug_checksum)) {		\
-		char *insn_off = offstr(insn->sec, insn->offset);	\
-		__dbg("checksum: %s %s %016llx",			\
-		      func->name, insn_off, (unsigned long long)checksum);\
-		free(insn_off);						\
-	}								\
-})
-
 #endif /* _WARN_H */
diff --git a/tools/objtool/klp-checksum.c b/tools/objtool/klp-checksum.c
index e4a910f3211c..adfd02447a45 100644
--- a/tools/objtool/klp-checksum.c
+++ b/tools/objtool/klp-checksum.c
@@ -35,7 +35,7 @@ static int checksum_debug_init(struct objtool_file *file)
 			*comma = '\0';
 
 		for_each_sym_by_name(file->elf, s, sym) {
-			if (!is_func_sym(sym))
+			if (!is_func_sym(sym) && !is_object_sym(sym))
 				continue;
 			sym->debug_checksum = 1;
 			found = true;
@@ -66,14 +66,14 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 	if (insn->fake)
 		return;
 
-	checksum_update(func, insn, insn->sec->data->d_buf + insn->offset, insn->len);
+	__checksum_update_insn(func, insn, insn->sec->data->d_buf + insn->offset, insn->len);
 
 	if (!reloc) {
 		struct symbol *call_dest = insn_call_dest(insn);
 
 		if (call_dest)
-			checksum_update(func, insn, call_dest->demangled_name,
-					strlen(call_dest->demangled_name));
+			__checksum_update_insn(func, insn, call_dest->demangled_name,
+					       strlen(call_dest->demangled_name));
 		goto alts;
 	}
 
@@ -84,7 +84,7 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 		char *str;
 
 		str = sym->sec->data->d_buf + sym->offset + offset;
-		checksum_update(func, insn, str, strlen(str));
+		__checksum_update_insn(func, insn, str, strlen(str));
 		goto alts;
 	}
 
@@ -96,8 +96,9 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 		offset -= sym->offset;
 	}
 
-	checksum_update(func, insn, sym->demangled_name, strlen(sym->demangled_name));
-	checksum_update(func, insn, &offset, sizeof(offset));
+	__checksum_update_insn(func, insn, sym->demangled_name,
+			       strlen(sym->demangled_name));
+	__checksum_update_insn(func, insn, &offset, sizeof(offset));
 
 alts:
 	for (alt = insn->alts; alt; alt = alt->next) {
@@ -108,12 +109,13 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 			break;
 		in_alt = true;
 
-		checksum_update(func, insn, &alt->type, sizeof(alt->type));
+		__checksum_update_insn(func, insn, &alt->type,
+				       sizeof(alt->type));
 
 		if (alt_group && alt_group->orig_group) {
 			struct instruction *alt_insn;
 
-			checksum_update(func, insn, &alt_group->feature, sizeof(alt_group->feature));
+			__checksum_update_insn(func, insn, &alt_group->feature,sizeof(alt_group->feature));
 
 			for (alt_insn = alt->insn; alt_insn; alt_insn = next_insn_same_sec(file, alt_insn)) {
 				checksum_update_insn(file, func, alt_insn);
@@ -128,31 +130,81 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 	}
 }
 
+static void checksum_update_object(struct objtool_file *file, struct symbol *sym)
+{
+	struct reloc *reloc;
+
+	__checksum_update_object(sym, 0, "len", &sym->len, sizeof(sym->len));
+
+	if (sym->sec->data->d_buf)
+		__checksum_update_object(sym, 0, "data",
+					 sym->sec->data->d_buf + sym->offset,
+					 sym->len);
+
+	sym_for_each_reloc(file->elf, sym, reloc) {
+		struct symbol *target = reloc->sym;
+		s64 offset;
+
+		offset = reloc_addend(reloc);
+
+		if (is_string_sec(target->sec)) {
+			char *str;
+
+			str = target->sec->data->d_buf + target->offset + offset;
+			__checksum_update_object(sym, reloc_offset(reloc),
+						 "reloc string", str, strlen(str));
+			continue;
+		}
+
+		if (is_sec_sym(target)) {
+			target = find_symbol_containing(reloc->sym->sec, offset);
+			if (!target)
+				continue;
+
+			offset -= target->offset;
+		}
+
+		__checksum_update_object(sym, reloc_offset(reloc), "reloc name",
+					 target->demangled_name,
+					 strlen(target->demangled_name));
+		__checksum_update_object(sym, reloc_offset(reloc), "reloc addend",
+					 &offset, sizeof(offset));
+	}
+}
+
 int calculate_checksums(struct objtool_file *file)
 {
 	struct instruction *insn;
-	struct symbol *func;
+	struct symbol *sym;
 
 	if (checksum_debug_init(file))
 		return -1;
 
-	for_each_sym(file->elf, func) {
+	for_each_sym(file->elf, sym) {
+
 		/*
 		 * Skip cold subfunctions and aliases: they share the
 		 * parent's checksum via func_for_each_insn() which
 		 * follows func->cfunc into the cold subfunction.
 		 */
-		if (!is_func_sym(func) || is_cold_func(func) ||
-		    is_alias_sym(func) || !func->len)
+		if (is_cold_func(sym) || is_alias_sym(sym) || !sym->len ||
+		    !sym->sec || !sym->sec->data)
 			continue;
 
-		checksum_init(func);
+		if (is_func_sym(sym)) {
+			checksum_init(sym);
+			func_for_each_insn(file, sym, insn)
+				checksum_update_insn(file, sym, insn);
+			checksum_finish(sym);
 
-		func_for_each_insn(file, func, insn)
-			checksum_update_insn(file, func, insn);
+		} else if (is_object_sym(sym)) {
+			checksum_init(sym);
+			checksum_update_object(file, sym);
+			checksum_finish(sym);
+		}
 
-		checksum_finish(func);
 	}
+
 	return 0;
 }
 
@@ -213,7 +265,7 @@ int cmd_klp_checksum(int argc, const char **argv)
 	int ret;
 
 	const struct option options[] = {
-		OPT_STRING(0,	"debug-checksum", &opts.debug_checksum,	"funcs", "enable checksum debug output"),
+		OPT_STRING(0,	"debug-checksum", &opts.debug_checksum,	"syms", "enable checksum debug output"),
 		OPT_BOOLEAN(0,	"dry-run", &opts.dryrun, "don't write modifications"),
 		OPT_END(),
 	};
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 33e401b85001..8d64d4c691cb 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -201,7 +201,7 @@ static int read_sym_checksums(struct elf *elf)
 			return -1;
 		}
 
-		if (is_func_sym(sym))
+		if (is_func_sym(sym) || is_object_sym(sym))
 			sym->csum.checksum = sym_checksum->checksum;
 	}
 
-- 
2.53.0


^ permalink raw reply related

* [PATCH 39/48] objtool: Replace iterator callbacks with for_each_sym_by_*()
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Convert the callback-based iterate_sym_by_name() and
iterate_sym_by_demangled_name() callers to use new
for_each_sym_by[_demangled]_name() macros.  This eliminates the callback
structs and functions and makes the code more compact and readable.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/elf.c                 | 80 ++++++-----------------------
 tools/objtool/include/objtool/elf.h | 40 ++++++++++++---
 tools/objtool/klp-checksum.c        | 20 +++-----
 tools/objtool/klp-diff.c            | 42 +++++----------
 4 files changed, 73 insertions(+), 109 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 8a6e1338af97..8d823e96b7c9 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -27,27 +27,16 @@
 
 static ssize_t demangled_name_len(const char *name);
 
-static inline u32 str_hash(const char *str)
-{
-	return jhash(str, strlen(str), 0);
-}
-
-static inline u32 str_hash_demangled(const char *str)
+u32 str_hash_demangled(const char *str)
 {
 	return jhash(str, demangled_name_len(str), 0);
 }
 
-#define __elf_table(name)	(elf->name##_hash)
-#define __elf_bits(name)	(elf->name##_bits)
-
-#define __elf_table_entry(name, key) \
-	__elf_table(name)[hash_min(key, __elf_bits(name))]
-
 #define elf_hash_add(name, node, key)					\
 ({									\
 	struct elf_hash_node *__node = node;				\
-	__node->next = __elf_table_entry(name, key);			\
-	__elf_table_entry(name, key) = __node;				\
+	__node->next = __elf_table_entry(elf, name, key);		\
+	__elf_table_entry(elf, name, key) = __node;			\
 })
 
 static inline void __elf_hash_del(struct elf_hash_node *node,
@@ -69,30 +58,20 @@ static inline void __elf_hash_del(struct elf_hash_node *node,
 }
 
 #define elf_hash_del(name, node, key) \
-	__elf_hash_del(node, &__elf_table_entry(name, key))
-
-#define elf_list_entry(ptr, type, member)				\
-({									\
-	typeof(ptr) __ptr = (ptr);					\
-	__ptr ? container_of(__ptr, type, member) : NULL;		\
-})
-
-#define elf_hash_for_each_possible(name, obj, member, key)		\
-	for (obj = elf_list_entry(__elf_table_entry(name, key), typeof(*obj), member); \
-	     obj;							\
-	     obj = elf_list_entry(obj->member.next, typeof(*(obj)), member))
+	__elf_hash_del(node, &__elf_table_entry(elf, name, key))
 
 #define elf_alloc_hash(name, size)					\
 ({									\
-	__elf_bits(name) = max(10, ilog2(size));			\
-	__elf_table(name) = mmap(NULL, sizeof(struct elf_hash_node *) << __elf_bits(name), \
+	__elf_bits(elf, name) = max(10, ilog2(size));			\
+	__elf_table(elf, name) = mmap(NULL,				\
+				 sizeof(struct elf_hash_node *) << __elf_bits(elf, name), \
 				 PROT_READ|PROT_WRITE,			\
 				 MAP_PRIVATE|MAP_ANON, -1, 0);		\
-	if (__elf_table(name) == (void *)-1L) {				\
+	if (__elf_table(elf, name) == (void *)-1L) {			\
 		ERROR_GLIBC("mmap fail " #name);			\
-		__elf_table(name) = NULL;				\
+		__elf_table(elf, name) = NULL;				\
 	}								\
-	__elf_table(name);						\
+	__elf_table(elf, name);						\
 })
 
 static inline unsigned long __sym_start(struct symbol *s)
@@ -141,7 +120,7 @@ struct section *find_section_by_name(const struct elf *elf, const char *name)
 {
 	struct section *sec;
 
-	elf_hash_for_each_possible(section_name, sec, name_hash, str_hash(name)) {
+	elf_hash_for_each_possible(elf, section_name, sec, name_hash, str_hash(name)) {
 		if (!strcmp(sec->name, name))
 			return sec;
 	}
@@ -154,7 +133,7 @@ static struct section *find_section_by_index(struct elf *elf,
 {
 	struct section *sec;
 
-	elf_hash_for_each_possible(section, sec, hash, idx) {
+	elf_hash_for_each_possible(elf, section, sec, hash, idx) {
 		if (sec->idx == idx)
 			return sec;
 	}
@@ -166,7 +145,7 @@ static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(symbol, sym, hash, idx) {
+	elf_hash_for_each_possible(elf, symbol, sym, hash, idx) {
 		if (sym->idx == idx)
 			return sym;
 	}
@@ -285,7 +264,7 @@ struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(name)) {
+	elf_hash_for_each_possible(elf, symbol_name, sym, name_hash, str_hash(name)) {
 		if (!strcmp(sym->name, name))
 			return sym;
 	}
@@ -300,7 +279,7 @@ static struct symbol *find_local_symbol_by_file_and_name(const struct elf *elf,
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash_demangled(name)) {
+	elf_hash_for_each_possible(elf, symbol_name, sym, name_hash, str_hash_demangled(name)) {
 		if (sym->bind == STB_LOCAL && sym->file == file &&
 		    !strcmp(sym->name, name)) {
 			return sym;
@@ -314,7 +293,7 @@ struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *nam
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash_demangled(name)) {
+	elf_hash_for_each_possible(elf, symbol_name, sym, name_hash, str_hash_demangled(name)) {
 		if (!strcmp(sym->name, name) && !is_local_sym(sym))
 			return sym;
 	}
@@ -322,31 +301,6 @@ struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *nam
 	return NULL;
 }
 
-void iterate_global_symbol_by_demangled_name(const struct elf *elf,
-					     const char *demangled_name,
-					     void (*process)(struct symbol *sym, void *data),
-					     void *data)
-{
-	struct symbol *sym;
-
-	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(demangled_name)) {
-		if (!strcmp(sym->demangled_name, demangled_name) && !is_local_sym(sym))
-			process(sym, data);
-	}
-}
-
-void iterate_sym_by_name(const struct elf *elf, const char *name,
-			 void (*process)(struct symbol *sym, void *data),
-			 void *data)
-{
-	struct symbol *sym;
-
-	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash_demangled(name)) {
-		if (!strcmp(sym->name, name))
-			process(sym, data);
-	}
-}
-
 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
 				     unsigned long offset, unsigned int len)
 {
@@ -359,7 +313,7 @@ struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *se
 		return NULL;
 
 	for_offset_range(o, offset, offset + len) {
-		elf_hash_for_each_possible(reloc, reloc, hash,
+		elf_hash_for_each_possible(elf, reloc, reloc, hash,
 					   sec_offset_hash(rsec, o)) {
 			if (reloc->sec != rsec)
 				continue;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 82b9fb05af26..ba13dd67cf26 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -21,6 +21,13 @@
 #define SEC_NAME_LEN		1024
 #define SYM_NAME_LEN		512
 
+static inline u32 str_hash(const char *str)
+{
+	return jhash(str, strlen(str), 0);
+}
+
+u32 str_hash_demangled(const char *str);
+
 #define bswap_if_needed(elf, val) __bswap_if_needed(&elf->ehdr, val)
 
 #ifdef LIBELF_USE_DEPRECATED
@@ -129,6 +136,23 @@ struct elf {
 	struct symbol *symbol_data;
 };
 
+#define __elf_table(elf, name)	((elf)->name##_hash)
+#define __elf_bits(elf, name)	((elf)->name##_bits)
+
+#define __elf_table_entry(elf, name, key) \
+	__elf_table(elf, name)[hash_min(key, __elf_bits(elf, name))]
+
+#define elf_list_entry(ptr, type, member)				\
+({									\
+	typeof(ptr) __ptr = (ptr);					\
+	__ptr ? container_of(__ptr, type, member) : NULL;		\
+})
+
+#define elf_hash_for_each_possible(elf, name, obj, member, key)		\
+	for (obj = elf_list_entry(__elf_table_entry(elf, name, key), typeof(*obj), member); \
+	     obj;							\
+	     obj = elf_list_entry(obj->member.next, typeof(*(obj)), member))
+
 struct elf *elf_open_read(const char *name, int flags);
 struct elf *elf_create_file(GElf_Ehdr *ehdr, const char *name);
 
@@ -185,12 +209,6 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
 struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *name);
-void iterate_global_symbol_by_demangled_name(const struct elf *elf, const char *demangled_name,
-					     void (*process)(struct symbol *sym, void *data),
-					     void *data);
-void iterate_sym_by_name(const struct elf *elf, const char *name,
-			 void (*process)(struct symbol *sym, void *data),
-			 void *data);
 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
 int find_symbol_hole_containing(const struct section *sec, unsigned long offset);
 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
@@ -485,6 +503,16 @@ static inline void set_sym_next_reloc(struct reloc *reloc, struct reloc *next)
 #define for_each_sym_continue(elf, sym)					\
 	list_for_each_entry_continue(sym, &elf->symbols, global_list)
 
+#define for_each_sym_by_name(elf, _name, sym)				\
+	elf_hash_for_each_possible(elf, symbol_name, sym, name_hash,	\
+				   str_hash_demangled(_name))		\
+		if (!strcmp(sym->name, _name))
+
+#define for_each_sym_by_demangled_name(elf, name, sym)			\
+	elf_hash_for_each_possible(elf, symbol_name, sym, name_hash,	\
+				   str_hash(name))			\
+		if (!strcmp(sym->demangled_name, name))
+
 #define rsec_next_reloc(rsec, reloc)					\
 	reloc_idx(reloc) < sec_num_entries(rsec) - 1 ? reloc + 1 : NULL
 
diff --git a/tools/objtool/klp-checksum.c b/tools/objtool/klp-checksum.c
index 4edd29028bff..e4a910f3211c 100644
--- a/tools/objtool/klp-checksum.c
+++ b/tools/objtool/klp-checksum.c
@@ -11,17 +11,6 @@
 #include <objtool/warn.h>
 #include <objtool/checksum.h>
 
-static void enable_debug_checksum_cb(struct symbol *sym, void *d)
-{
-	bool *found = d;
-
-	if (!is_func_sym(sym))
-		return;
-
-	sym->debug_checksum = 1;
-	*found = true;
-}
-
 static int checksum_debug_init(struct objtool_file *file)
 {
 	char *dup, *s;
@@ -38,13 +27,20 @@ static int checksum_debug_init(struct objtool_file *file)
 	s = dup;
 	while (*s) {
 		bool found = false;
+		struct symbol *sym;
 		char *comma;
 
 		comma = strchr(s, ',');
 		if (comma)
 			*comma = '\0';
 
-		iterate_sym_by_name(file->elf, s, enable_debug_checksum_cb, &found);
+		for_each_sym_by_name(file->elf, s, sym) {
+			if (!is_func_sym(sym))
+				continue;
+			sym->debug_checksum = 1;
+			found = true;
+		}
+
 		if (!found)
 			WARN("--debug-checksum: can't find '%s'", s);
 
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index c903aa65d4b6..33e401b85001 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -46,11 +46,6 @@ static const struct option klp_diff_options[] = {
 
 static DEFINE_HASHTABLE(exports, 15);
 
-static inline u32 str_hash(const char *str)
-{
-	return jhash(str, strlen(str), 0);
-}
-
 static char *escape_str(const char *orig)
 {
 	size_t len = 0;
@@ -398,22 +393,6 @@ static bool dont_correlate(struct symbol *sym)
 	       is_special_section_aux(sym->sec);
 }
 
-struct process_demangled_name_data {
-	struct symbol *ret;
-	int count;
-};
-
-static void process_demangled_name(struct symbol *sym, void *d)
-{
-	struct process_demangled_name_data *data = d;
-
-	if (sym->twin)
-		return;
-
-	data->count++;
-	data->ret = sym;
-}
-
 /*
  * When there is no full name match, try match demangled_name. This would
  * match original foo.llvm.123 to patched foo.llvm.456.
@@ -425,16 +404,23 @@ static void process_demangled_name(struct symbol *sym, void *d)
 static int find_global_symbol_by_demangled_name(struct elf *elf, struct symbol *sym,
 						struct symbol **out_sym)
 {
-	struct process_demangled_name_data data = {};
+	struct symbol *sym2, *result = NULL;
+	int count = 0;
 
-	iterate_global_symbol_by_demangled_name(elf, sym->demangled_name,
-						process_demangled_name,
-						&data);
-	if (data.count > 1) {
-		ERROR("Multiple (%d) correlation candidates for %s", data.count, sym->name);
+	for_each_sym_by_demangled_name(elf, sym->demangled_name, sym2) {
+		if (is_local_sym(sym2) || sym2->twin)
+			continue;
+
+		count++;
+		result = sym2;
+	}
+
+	if (count > 1) {
+		ERROR("Multiple (%d) correlation candidates for %s", count, sym->name);
 		return -1;
 	}
-	*out_sym = data.ret;
+
+	*out_sym = result;
 	return 0;
 }
 
-- 
2.53.0


^ permalink raw reply related

* [PATCH 38/48] klp-build: Validate short-circuit prerequisites
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

The --short-circuit option implicitly requires that certain directories
are already in klp-tmp.  Enforce that to prevent confusing errors.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index eda690b297cc..b44924d097a5 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -440,6 +440,20 @@ do_init() {
 	[[ ! "$SRC" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
 	[[ ! "$OBJ" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
 
+	if (( SHORT_CIRCUIT >= 2 )); then
+		[[ -f "$ORIG_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_DIR"
+		if (( SHORT_CIRCUIT >= 3 )); then
+			[[ -f "$PATCHED_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_DIR"
+			if (( SHORT_CIRCUIT >= 4 )); then
+				[[ -f "$ORIG_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $ORIG_CSUM_DIR"
+				[[ -f "$PATCHED_CSUM_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $PATCHED_CSUM_DIR"
+				if (( SHORT_CIRCUIT >= 5 )); then
+					[[ -f "$DIFF_DIR/.complete" ]] || die "-S $SHORT_CIRCUIT requires completed $DIFF_DIR"
+				fi
+			fi
+		fi
+	fi
+
 	(( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR"
 	mkdir -p "$TMP_DIR"
 
@@ -601,6 +615,7 @@ copy_orig_objects() {
 
 	mv -f "$TMP_DIR/build.log" "$ORIG_DIR"
 	touch "$TIMESTAMP"
+	touch "$ORIG_DIR/.complete"
 }
 
 # Copy all changed objects to $PATCHED_DIR
@@ -639,6 +654,7 @@ copy_patched_objects() {
 	(( found == 0 )) && die "no changes detected"
 
 	mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
+	touch "$PATCHED_DIR/.complete"
 }
 
 # Copy .o files to a separate directory and run "objtool klp checksum" on each
@@ -720,6 +736,8 @@ diff_objects() {
 				die "objtool klp diff failed"
 		)
 	done
+
+	touch "$DIFF_DIR/.complete"
 }
 
 # For each changed object, run "objtool klp checksum" with --debug-checksum to
-- 
2.53.0


^ permalink raw reply related

* [PATCH 37/48] objtool/klp: Remove "objtool --checksum"
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

The checksum functionality has been moved to "objtool klp checksum"
which is now used by klp-build.  Remove the now-dead --checksum and
--debug-checksum options from the default objtool command.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build   |  3 +++
 tools/objtool/builtin-check.c | 17 +----------------
 tools/objtool/check.c         | 10 ----------
 3 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index d29ef3022556..eda690b297cc 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -277,6 +277,9 @@ validate_config() {
 		[[ "$CONFIG_AS_VERSION" -lt 200000 ]] &&	\
 		die "Clang assembler version < 20 not supported"
 
+	"$SRC/tools/objtool/objtool" klp 2>&1 | command grep -q "not implemented" && \
+		die "objtool not built with KLP support; install xxhash-devel/libxxhash-dev (version >= 0.8) and recompile"
+
 	return 0
 }
 
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index b780df513715..ec7f10a5ef19 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -73,7 +73,6 @@ static int parse_hacks(const struct option *opt, const char *str, int unset)
 
 static const struct option check_options[] = {
 	OPT_GROUP("Actions:"),
-	OPT_BOOLEAN(0,		 "checksum", &opts.checksum, "generate per-function checksums"),
 	OPT_BOOLEAN(0,		 "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
 	OPT_STRING_OPTARG('d',	 "disas", &opts.disas, "function-pattern", "disassemble functions", "*"),
 	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
@@ -95,7 +94,6 @@ static const struct option check_options[] = {
 	OPT_GROUP("Options:"),
 	OPT_BOOLEAN(0,		 "backtrace", &opts.backtrace, "unwind on error"),
 	OPT_BOOLEAN(0,		 "backup", &opts.backup, "create backup (.orig) file on warning/error"),
-	OPT_STRING(0,		 "debug-checksum", &opts.debug_checksum,  "funcs", "enable checksum debug output"),
 	OPT_BOOLEAN(0,		 "dry-run", &opts.dryrun, "don't write modifications"),
 	OPT_BOOLEAN(0,		 "link", &opts.link, "object is a linked object"),
 	OPT_BOOLEAN(0,		 "module", &opts.module, "object is part of a kernel module"),
@@ -165,20 +163,7 @@ static bool opts_valid(void)
 		return false;
 	}
 
-#ifndef BUILD_KLP
-	if (opts.checksum) {
-		ERROR("--checksum not supported; install xxhash-devel/libxxhash-dev (version >= 0.8) and recompile");
-		return false;
-	}
-#endif
-
-	if (opts.debug_checksum && !opts.checksum) {
-		ERROR("--debug-checksum requires --checksum");
-		return false;
-	}
-
-	if (opts.checksum		||
-	    opts.disas			||
+	if (opts.disas			||
 	    opts.hack_jump_label	||
 	    opts.hack_noinstr		||
 	    opts.ibt			||
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 3e5d335d0e29..ae047be919c5 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -18,7 +18,6 @@
 #include <objtool/special.h>
 #include <objtool/trace.h>
 #include <objtool/warn.h>
-#include <objtool/checksum.h>
 #include <objtool/util.h>
 
 #include <linux/objtool_types.h>
@@ -4946,15 +4945,6 @@ int check(struct objtool_file *file)
 	if (opts.noabs)
 		warnings += check_abs_references(file);
 
-	if (opts.checksum) {
-		ret = calculate_checksums(file);
-		if (ret)
-			goto out;
-		ret = create_sym_checksum_section(file);
-		if (ret)
-			goto out;
-	}
-
 	if (opts.orc && nr_insns) {
 		ret = orc_create(file);
 		if (ret)
-- 
2.53.0


^ permalink raw reply related

* [PATCH 36/48] klp-build: Use "objtool klp checksum" subcommand
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Use the new "objtool klp checksum" subcommand instead of injecting
--checksum into every objtool invocation via OBJTOOL_ARGS during the
kernel build.

This decouples checksum generation from the build, running it in
separate post-build passes, making the code (and the patch generation
pipeline itself) more modular.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 93 +++++++++++++++++++++++++------------
 1 file changed, 64 insertions(+), 29 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 84053e8aadd3..d29ef3022556 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -39,10 +39,12 @@ OBJ="$(pwd)"
 CONFIG="$OBJ/.config"
 TMP_DIR="$OBJ/klp-tmp"
 
-ORIG_DIR="$TMP_DIR/orig"
-PATCHED_DIR="$TMP_DIR/patched"
-DIFF_DIR="$TMP_DIR/diff"
-KMOD_DIR="$TMP_DIR/kmod"
+ORIG_DIR="$TMP_DIR/1-orig"
+PATCHED_DIR="$TMP_DIR/2-patched"
+ORIG_CSUM_DIR="$TMP_DIR/3-checksum-orig"
+PATCHED_CSUM_DIR="$TMP_DIR/3-checksum-patched"
+DIFF_DIR="$TMP_DIR/4-diff"
+KMOD_DIR="$TMP_DIR/5-kmod"
 
 STASH_DIR="$TMP_DIR/stash"
 TIMESTAMP="$TMP_DIR/timestamp"
@@ -138,10 +140,11 @@ Options:
 Advanced Options:
    -d, --debug			Show symbol/reloc cloning decisions
    -S, --short-circuit=STEP	Start at build step (requires prior --keep-tmp)
-				   1|orig	Build original kernel (default)
-				   2|patched	Build patched kernel
-				   3|diff	Diff objects
-				   4|kmod	Build patch module
+				   1|orig		Build original kernel (default)
+				   2|patched		Build patched kernel
+				   3|checksum		Generate checksums
+				   4|diff		Diff objects
+				   5|kmod		Build patch module
    -T, --keep-tmp		Preserve tmp dir on exit
 
 EOF
@@ -205,10 +208,11 @@ process_args() {
 				[[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir"
 				keep_tmp=1
 				case "$2" in
-					1 | orig)	SHORT_CIRCUIT=1; ;;
-					2 | patched)	SHORT_CIRCUIT=2; ;;
-					3 | diff)	SHORT_CIRCUIT=3; ;;
-					4 | mod)	SHORT_CIRCUIT=4; ;;
+					1 | orig)		SHORT_CIRCUIT=1; ;;
+					2 | patched)		SHORT_CIRCUIT=2; ;;
+					3 | checksum)		SHORT_CIRCUIT=3; ;;
+					4 | diff)		SHORT_CIRCUIT=4; ;;
+					5 | kmod)		SHORT_CIRCUIT=5; ;;
 					*)		die "invalid short-circuit step '$2'" ;;
 				esac
 				shift 2
@@ -519,11 +523,8 @@ clean_kernel() {
 build_kernel() {
 	local build="$1"
 	local log="$TMP_DIR/build.log"
-	local objtool_args=()
 	local cmd=()
 
-	objtool_args=("--checksum")
-
 	cmd=("make")
 
 	# When a patch to a kernel module references a newly created unexported
@@ -550,7 +551,6 @@ build_kernel() {
 	fi
 	cmd+=("-j$JOBS")
 	cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
-	cmd+=("OBJTOOL_ARGS=${objtool_args[*]}")
 	cmd+=("vmlinux")
 	cmd+=("modules")
 
@@ -582,7 +582,7 @@ copy_orig_objects() {
 
 	find_objects | mapfile -t files
 
-	xtrace_save "copying orig objects"
+	xtrace_save "copying original objects"
 	for _file in "${files[@]}"; do
 		local rel_file="${_file/.ko/.o}"
 		local file="$OBJ/$rel_file"
@@ -638,6 +638,35 @@ copy_patched_objects() {
 	mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
 }
 
+# Copy .o files to a separate directory and run "objtool klp checksum" on each
+# copy.  The checksums are written to a .discard.sym_checksum section.
+#
+# If match_dir is given, only process files which also exist there.
+generate_checksums() {
+	local src_dir="$1"
+	local dest_dir="$2"
+	local match_dir="${3:-}"
+	local files=()
+	local file
+
+	rm -rf "$dest_dir"
+	mkdir -p "$dest_dir"
+
+	find "$src_dir" -type f -name "*.o" | mapfile -t files
+	for file in "${files[@]}"; do
+		local rel="${file#"$src_dir"/}"
+		local dest="$dest_dir/$rel"
+
+		[[ -n "$match_dir" && ! -f "$match_dir/$rel" ]] && continue
+
+		mkdir -p "$(dirname "$dest")"
+		cp -f "$file" "$dest"
+		"$SRC/tools/objtool/objtool" klp checksum "$dest"
+	done
+
+	touch "$dest_dir/.complete"
+}
+
 # Diff changed objects, writing output object to $DIFF_DIR
 diff_objects() {
 	local log="$KLP_DIFF_LOG"
@@ -647,16 +676,16 @@ diff_objects() {
 	rm -rf "$DIFF_DIR"
 	mkdir -p "$DIFF_DIR"
 
-	find "$PATCHED_DIR" -type f -name "*.o" | mapfile -t files
+	find "$PATCHED_CSUM_DIR" -type f -name "*.o" | mapfile -t files
 	[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
 
 	[[ -v DEBUG_CLONE ]] && opts=("--debug")
 
 	# Diff all changed objects
 	for file in "${files[@]}"; do
-		local rel_file="${file#"$PATCHED_DIR"/}"
+		local rel_file="${file#"$PATCHED_CSUM_DIR"/}"
 		local orig_file="$rel_file"
-		local patched_file="$PATCHED_DIR/$rel_file"
+		local patched_file="$PATCHED_CSUM_DIR/$rel_file"
 		local out_file="$DIFF_DIR/$rel_file"
 		local filter=()
 		local cmd=()
@@ -680,7 +709,7 @@ diff_objects() {
 		fi
 
 		(
-			cd "$ORIG_DIR"
+			cd "$ORIG_CSUM_DIR"
 			[[ -v VERBOSE ]] && echo "${cmd[@]}"
 			"${cmd[@]}"							\
 				1> >(tee -a "$log")					\
@@ -690,9 +719,9 @@ diff_objects() {
 	done
 }
 
-# For each changed object, run objtool with --debug-checksum to get the
-# per-instruction checksums, and then diff those to find the first changed
-# instruction for each function.
+# For each changed object, run "objtool klp checksum" with --debug-checksum to
+# get the per-instruction checksums, and then diff those to find the first
+# changed instruction for each function.
 diff_checksums() {
 	local orig_log="$ORIG_DIR/checksum.log"
 	local patched_log="$PATCHED_DIR/checksum.log"
@@ -717,8 +746,7 @@ diff_checksums() {
 	done
 
 	cmd=("$SRC/tools/objtool/objtool")
-	cmd+=("--checksum")
-	cmd+=("--link")
+	cmd+=("klp" "checksum")
 	cmd+=("--dry-run")
 
 	for file in "${!funcs[@]}"; do
@@ -727,11 +755,11 @@ diff_checksums() {
 		(
 			cd "$ORIG_DIR"
 			"${cmd[@]}" "$opt" "$file" &> "$orig_log" || \
-				( cat "$orig_log" >&2; die "objtool --debug-checksum failed" )
+				( cat "$orig_log" >&2; die "objtool klp checksum failed" )
 
 			cd "$PATCHED_DIR"
 			"${cmd[@]}" "$opt" "$file" &> "$patched_log" ||	\
-				( cat "$patched_log" >&2; die "objtool --debug-checksum failed" )
+				( cat "$patched_log" >&2; die "objtool klp checksum failed" )
 		)
 
 		for func in ${funcs[$file]}; do
@@ -872,6 +900,13 @@ if (( SHORT_CIRCUIT <= 2 )); then
 fi
 
 if (( SHORT_CIRCUIT <= 3 )); then
+	status "Generating original checksums"
+	generate_checksums "$ORIG_DIR" "$ORIG_CSUM_DIR" "$PATCHED_DIR"
+	status "Generating patched checksums"
+	generate_checksums "$PATCHED_DIR" "$PATCHED_CSUM_DIR"
+fi
+
+if (( SHORT_CIRCUIT <= 4 )); then
 	status "Diffing objects"
 	diff_objects
 	if [[ -v DIFF_CHECKSUM ]]; then
@@ -880,7 +915,7 @@ if (( SHORT_CIRCUIT <= 3 )); then
 	fi
 fi
 
-if (( SHORT_CIRCUIT <= 4 )); then
+if (( SHORT_CIRCUIT <= 5 )); then
 	status "Building patch module: $OUTFILE"
 	build_patch_module
 fi
-- 
2.53.0


^ permalink raw reply related

* [PATCH 35/48] objtool/klp: Add "objtool klp checksum" subcommand
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Move the checksum functionality out of the main objtool command into a
new "objtool klp checksum" subcommand.

This has the benefit of making the code (and the patch generation
process itself) more modular.

For bisectability, both "objtool --checksum" and "objtool klp checksum"
work for now.  The former will be removed after klp-build has been
converted to use the new subcommand.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/Build                      |   2 +-
 tools/objtool/builtin-klp.c              |   1 +
 tools/objtool/check.c                    | 209 +-----------------
 tools/objtool/include/objtool/check.h    |   6 +
 tools/objtool/include/objtool/checksum.h |   4 +
 tools/objtool/include/objtool/klp.h      |   1 +
 tools/objtool/klp-checksum.c             | 257 +++++++++++++++++++++++
 tools/objtool/klp-diff.c                 |   2 +-
 8 files changed, 273 insertions(+), 209 deletions(-)
 create mode 100644 tools/objtool/klp-checksum.c

diff --git a/tools/objtool/Build b/tools/objtool/Build
index 600da051af12..93a37b0dfd31 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -12,7 +12,7 @@ objtool-$(BUILD_DISAS) += disas.o
 objtool-$(BUILD_DISAS) += trace.o
 
 objtool-$(BUILD_ORC) += orc_gen.o orc_dump.o
-objtool-$(BUILD_KLP) += builtin-klp.o klp-diff.o klp-post-link.o
+objtool-$(BUILD_KLP) += builtin-klp.o klp-checksum.o klp-diff.o klp-post-link.o
 
 objtool-y += libstring.o
 objtool-y += libctype.o
diff --git a/tools/objtool/builtin-klp.c b/tools/objtool/builtin-klp.c
index 56d5a5b92f72..58c3b9bda3eb 100644
--- a/tools/objtool/builtin-klp.c
+++ b/tools/objtool/builtin-klp.c
@@ -13,6 +13,7 @@ struct subcmd {
 };
 
 static struct subcmd subcmds[] = {
+	{ "checksum",		"Generate per-function checksums",			cmd_klp_checksum, },
 	{ "diff",		"Generate binary diff of two object files",		cmd_klp_diff, },
 	{ "post-link",		"Finalize klp symbols/relocs after module linking",	cmd_klp_post_link, },
 };
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 17cb9265973d..3e5d335d0e29 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -64,8 +64,8 @@ struct instruction *next_insn_same_sec(struct objtool_file *file,
 	return insn;
 }
 
-static struct instruction *next_insn_same_func(struct objtool_file *file,
-					       struct instruction *insn)
+struct instruction *next_insn_same_func(struct objtool_file *file,
+				       struct instruction *insn)
 {
 	struct instruction *next = next_insn_same_sec(file, insn);
 	struct symbol *func = insn_func(insn);
@@ -113,10 +113,6 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file,
 		for_each_sec(file->elf, __sec)				\
 			sec_for_each_insn(file, __sec, insn)
 
-#define func_for_each_insn(file, func, insn)				\
-	for (insn = find_insn(file, func->sec, func->offset);		\
-	     insn;							\
-	     insn = next_insn_same_func(file, insn))
 
 #define sym_for_each_insn(file, sym, insn)				\
 	for (insn = find_insn(file, sym->sec, sym->offset);		\
@@ -1023,56 +1019,6 @@ static int create_direct_call_sections(struct objtool_file *file)
 	return 0;
 }
 
-#ifdef BUILD_KLP
-static int create_sym_checksum_section(struct objtool_file *file)
-{
-	struct section *sec;
-	struct symbol *sym;
-	unsigned int idx = 0;
-	struct sym_checksum *checksum;
-	size_t entsize = sizeof(struct sym_checksum);
-
-	sec = find_section_by_name(file->elf, ".discard.sym_checksum");
-	if (sec) {
-		if (!opts.dryrun)
-			WARN("file already has .discard.sym_checksum section, skipping");
-
-		return 0;
-	}
-
-	for_each_sym(file->elf, sym)
-		if (sym->csum.checksum)
-			idx++;
-
-	sec = elf_create_section_pair(file->elf, ".discard.sym_checksum", entsize,
-				      idx, idx);
-	if (!sec)
-		return -1;
-
-	idx = 0;
-	for_each_sym(file->elf, sym) {
-		if (!sym->csum.checksum)
-			continue;
-
-		if (!elf_init_reloc(file->elf, sec->rsec, idx, idx * entsize,
-				    sym, 0, R_TEXT64))
-			return -1;
-
-		checksum = (struct sym_checksum *)sec->data->d_buf + idx;
-		checksum->addr = 0; /* reloc */
-		checksum->checksum = sym->csum.checksum;
-
-		mark_sec_changed(file->elf, sec, true);
-
-		idx++;
-	}
-
-	return 0;
-}
-#else
-static int create_sym_checksum_section(struct objtool_file *file) { return -EINVAL; }
-#endif
-
 /*
  * Warnings shouldn't be reported for ignored functions.
  */
@@ -3672,157 +3618,6 @@ static bool skip_alt_group(struct instruction *insn)
 	return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
 }
 
-#ifdef BUILD_KLP
-static void enable_debug_checksum_cb(struct symbol *sym, void *d)
-{
-	bool *found = d;
-
-	if (!is_func_sym(sym))
-		return;
-
-	sym->debug_checksum = 1;
-	*found = true;
-}
-
-static int checksum_debug_init(struct objtool_file *file)
-{
-	char *dup, *s;
-
-	if (!opts.debug_checksum)
-		return 0;
-
-	dup = strdup(opts.debug_checksum);
-	if (!dup) {
-		ERROR_GLIBC("strdup");
-		return -1;
-	}
-
-	s = dup;
-	while (*s) {
-		bool found = false;
-		char *comma;
-
-		comma = strchr(s, ',');
-		if (comma)
-			*comma = '\0';
-
-		iterate_sym_by_name(file->elf, s, enable_debug_checksum_cb, &found);
-		if (!found)
-			WARN("--debug-checksum: can't find '%s'", s);
-
-		if (!comma)
-			break;
-
-		s = comma + 1;
-	}
-
-	free(dup);
-	return 0;
-}
-
-static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
-				 struct instruction *insn)
-{
-	struct reloc *reloc = insn_reloc(file, insn);
-	struct alternative *alt;
-	unsigned long offset;
-	struct symbol *sym;
-	static bool in_alt;
-
-	if (insn->fake)
-		return;
-
-	checksum_update(func, insn, insn->sec->data->d_buf + insn->offset, insn->len);
-
-	if (!reloc) {
-		struct symbol *call_dest = insn_call_dest(insn);
-
-		if (call_dest)
-			checksum_update(func, insn, call_dest->demangled_name,
-					strlen(call_dest->demangled_name));
-		goto alts;
-	}
-
-	sym = reloc->sym;
-	offset = arch_insn_adjusted_addend(insn, reloc);
-
-	if (is_string_sec(sym->sec)) {
-		char *str;
-
-		str = sym->sec->data->d_buf + sym->offset + offset;
-		checksum_update(func, insn, str, strlen(str));
-		goto alts;
-	}
-
-	if (is_sec_sym(sym)) {
-		sym = find_symbol_containing(reloc->sym->sec, offset);
-		if (!sym)
-			goto alts;
-
-		offset -= sym->offset;
-	}
-
-	checksum_update(func, insn, sym->demangled_name, strlen(sym->demangled_name));
-	checksum_update(func, insn, &offset, sizeof(offset));
-
-alts:
-	for (alt = insn->alts; alt; alt = alt->next) {
-		struct alt_group *alt_group = alt->insn->alt_group;
-
-		/* Prevent __ex_table recursion, e.g. LOAD_SEGMENT() */
-		if (in_alt)
-			break;
-		in_alt = true;
-
-		checksum_update(func, insn, &alt->type, sizeof(alt->type));
-
-		if (alt_group && alt_group->orig_group) {
-			struct instruction *alt_insn;
-
-			checksum_update(func, insn, &alt_group->feature, sizeof(alt_group->feature));
-
-			for (alt_insn = alt->insn; alt_insn; alt_insn = next_insn_same_sec(file, alt_insn)) {
-				checksum_update_insn(file, func, alt_insn);
-				if (!alt_group->last_insn || alt_insn == alt_group->last_insn)
-					break;
-			}
-		} else {
-			checksum_update_insn(file, func, alt->insn);
-		}
-
-		in_alt = false;
-	}
-}
-
-static int calculate_checksums(struct objtool_file *file)
-{
-	struct instruction *insn;
-	struct symbol *func;
-
-	if (checksum_debug_init(file))
-		return -1;
-
-	for_each_sym(file->elf, func) {
-		/*
-		 * Skip cold subfunctions and aliases: they share the
-		 * parent's checksum via func_for_each_insn() which
-		 * follows func->cfunc into the cold subfunction.
-		 */
-		if (!is_func_sym(func) || is_cold_func(func) ||
-		    is_alias_sym(func) || !func->len)
-			continue;
-
-		checksum_init(func);
-
-		func_for_each_insn(file, func, insn)
-			checksum_update_insn(file, func, insn);
-
-		checksum_finish(func);
-	}
-	return 0;
-}
-#endif /* BUILD_KLP */
-
 static int validate_branch(struct objtool_file *file, struct symbol *func,
 			   struct instruction *insn, struct insn_state state);
 static int do_validate_branch(struct objtool_file *file, struct symbol *func,
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 6489e52ea2f2..eea64728d39b 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -144,6 +144,12 @@ struct instruction *find_insn(struct objtool_file *file,
 			      struct section *sec, unsigned long offset);
 
 struct instruction *next_insn_same_sec(struct objtool_file *file, struct instruction *insn);
+struct instruction *next_insn_same_func(struct objtool_file *file, struct instruction *insn);
+
+#define func_for_each_insn(file, func, insn)				\
+	for (insn = find_insn(file, func->sec, func->offset);		\
+	     insn;							\
+	     insn = next_insn_same_func(file, insn))
 
 #define sec_for_each_insn(file, _sec, insn)				\
 	for (insn = find_insn(file, _sec, 0);				\
diff --git a/tools/objtool/include/objtool/checksum.h b/tools/objtool/include/objtool/checksum.h
index 3f25df90305d..be4eb7dfe6f2 100644
--- a/tools/objtool/include/objtool/checksum.h
+++ b/tools/objtool/include/objtool/checksum.h
@@ -31,9 +31,13 @@ static inline void checksum_finish(struct symbol *func)
 	}
 }
 
+int calculate_checksums(struct objtool_file *file);
+int create_sym_checksum_section(struct objtool_file *file);
+
 #else /* !BUILD_KLP */
 
 static inline int calculate_checksums(struct objtool_file *file) { return -ENOSYS; }
+static inline int create_sym_checksum_section(struct objtool_file *file) { return -EINVAL; }
 
 #endif /* !BUILD_KLP */
 
diff --git a/tools/objtool/include/objtool/klp.h b/tools/objtool/include/objtool/klp.h
index e32e5e8bc631..6f60cf05db86 100644
--- a/tools/objtool/include/objtool/klp.h
+++ b/tools/objtool/include/objtool/klp.h
@@ -29,6 +29,7 @@ struct klp_reloc {
 	u32 type;
 };
 
+int cmd_klp_checksum(int argc, const char **argv);
 int cmd_klp_diff(int argc, const char **argv);
 int cmd_klp_post_link(int argc, const char **argv);
 
diff --git a/tools/objtool/klp-checksum.c b/tools/objtool/klp-checksum.c
new file mode 100644
index 000000000000..4edd29028bff
--- /dev/null
+++ b/tools/objtool/klp-checksum.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+#include <subcmd/parse-options.h>
+
+#include <objtool/arch.h>
+#include <objtool/builtin.h>
+#include <objtool/check.h>
+#include <objtool/elf.h>
+#include <objtool/klp.h>
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+#include <objtool/checksum.h>
+
+static void enable_debug_checksum_cb(struct symbol *sym, void *d)
+{
+	bool *found = d;
+
+	if (!is_func_sym(sym))
+		return;
+
+	sym->debug_checksum = 1;
+	*found = true;
+}
+
+static int checksum_debug_init(struct objtool_file *file)
+{
+	char *dup, *s;
+
+	if (!opts.debug_checksum)
+		return 0;
+
+	dup = strdup(opts.debug_checksum);
+	if (!dup) {
+		ERROR_GLIBC("strdup");
+		return -1;
+	}
+
+	s = dup;
+	while (*s) {
+		bool found = false;
+		char *comma;
+
+		comma = strchr(s, ',');
+		if (comma)
+			*comma = '\0';
+
+		iterate_sym_by_name(file->elf, s, enable_debug_checksum_cb, &found);
+		if (!found)
+			WARN("--debug-checksum: can't find '%s'", s);
+
+		if (!comma)
+			break;
+
+		s = comma + 1;
+	}
+
+	free(dup);
+	return 0;
+}
+
+static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
+				 struct instruction *insn)
+{
+	struct reloc *reloc = insn_reloc(file, insn);
+	struct alternative *alt;
+	unsigned long offset;
+	struct symbol *sym;
+	static bool in_alt;
+
+	if (insn->fake)
+		return;
+
+	checksum_update(func, insn, insn->sec->data->d_buf + insn->offset, insn->len);
+
+	if (!reloc) {
+		struct symbol *call_dest = insn_call_dest(insn);
+
+		if (call_dest)
+			checksum_update(func, insn, call_dest->demangled_name,
+					strlen(call_dest->demangled_name));
+		goto alts;
+	}
+
+	sym = reloc->sym;
+	offset = arch_insn_adjusted_addend(insn, reloc);
+
+	if (is_string_sec(sym->sec)) {
+		char *str;
+
+		str = sym->sec->data->d_buf + sym->offset + offset;
+		checksum_update(func, insn, str, strlen(str));
+		goto alts;
+	}
+
+	if (is_sec_sym(sym)) {
+		sym = find_symbol_containing(reloc->sym->sec, offset);
+		if (!sym)
+			goto alts;
+
+		offset -= sym->offset;
+	}
+
+	checksum_update(func, insn, sym->demangled_name, strlen(sym->demangled_name));
+	checksum_update(func, insn, &offset, sizeof(offset));
+
+alts:
+	for (alt = insn->alts; alt; alt = alt->next) {
+		struct alt_group *alt_group = alt->insn->alt_group;
+
+		/* Prevent __ex_table recursion, e.g. LOAD_SEGMENT() */
+		if (in_alt)
+			break;
+		in_alt = true;
+
+		checksum_update(func, insn, &alt->type, sizeof(alt->type));
+
+		if (alt_group && alt_group->orig_group) {
+			struct instruction *alt_insn;
+
+			checksum_update(func, insn, &alt_group->feature, sizeof(alt_group->feature));
+
+			for (alt_insn = alt->insn; alt_insn; alt_insn = next_insn_same_sec(file, alt_insn)) {
+				checksum_update_insn(file, func, alt_insn);
+				if (!alt_group->last_insn || alt_insn == alt_group->last_insn)
+					break;
+			}
+		} else {
+			checksum_update_insn(file, func, alt->insn);
+		}
+
+		in_alt = false;
+	}
+}
+
+int calculate_checksums(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct symbol *func;
+
+	if (checksum_debug_init(file))
+		return -1;
+
+	for_each_sym(file->elf, func) {
+		/*
+		 * Skip cold subfunctions and aliases: they share the
+		 * parent's checksum via func_for_each_insn() which
+		 * follows func->cfunc into the cold subfunction.
+		 */
+		if (!is_func_sym(func) || is_cold_func(func) ||
+		    is_alias_sym(func) || !func->len)
+			continue;
+
+		checksum_init(func);
+
+		func_for_each_insn(file, func, insn)
+			checksum_update_insn(file, func, insn);
+
+		checksum_finish(func);
+	}
+	return 0;
+}
+
+int create_sym_checksum_section(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *sym;
+	unsigned int idx = 0;
+	struct sym_checksum *checksum;
+	size_t entsize = sizeof(struct sym_checksum);
+
+	sec = find_section_by_name(file->elf, ".discard.sym_checksum");
+	if (sec) {
+		if (!opts.dryrun)
+			WARN("file already has .discard.sym_checksum section, skipping");
+
+		return 0;
+	}
+
+	for_each_sym(file->elf, sym)
+		if (sym->csum.checksum)
+			idx++;
+
+	sec = elf_create_section_pair(file->elf, ".discard.sym_checksum", entsize,
+				      idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	for_each_sym(file->elf, sym) {
+		if (!sym->csum.checksum)
+			continue;
+
+		if (!elf_init_reloc(file->elf, sec->rsec, idx, idx * entsize,
+				    sym, 0, R_TEXT64))
+			return -1;
+
+		checksum = (struct sym_checksum *)sec->data->d_buf + idx;
+		checksum->addr = 0; /* reloc */
+		checksum->checksum = sym->csum.checksum;
+
+		mark_sec_changed(file->elf, sec, true);
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static const char * const klp_checksum_usage[] = {
+	"objtool klp checksum [<options>] file.o",
+	NULL,
+};
+
+int cmd_klp_checksum(int argc, const char **argv)
+{
+	struct objtool_file *file;
+	int ret;
+
+	const struct option options[] = {
+		OPT_STRING(0,	"debug-checksum", &opts.debug_checksum,	"funcs", "enable checksum debug output"),
+		OPT_BOOLEAN(0,	"dry-run", &opts.dryrun, "don't write modifications"),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, options, klp_checksum_usage, 0);
+	if (argc != 1)
+		usage_with_options(klp_checksum_usage, options);
+
+	opts.checksum = true;
+
+	objname = argv[0];
+
+	file = objtool_open_read(objname);
+	if (!file)
+		return 1;
+
+	ret = decode_file(file);
+	if (ret)
+		goto out;
+
+	ret = calculate_checksums(file);
+	if (ret)
+		goto out;
+
+	ret = create_sym_checksum_section(file);
+
+out:
+	free_insns(file);
+
+	if (ret)
+		return ret;
+
+	if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
+		return 1;
+
+	return elf_close(file->elf);
+}
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 266f0d2ba4fe..c903aa65d4b6 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -171,7 +171,7 @@ static int read_sym_checksums(struct elf *elf)
 
 	sec = find_section_by_name(elf, ".discard.sym_checksum");
 	if (!sec) {
-		ERROR("'%s' missing .discard.sym_checksum section, file not processed by 'objtool --checksum'?",
+		ERROR("'%s' missing .discard.sym_checksum section, file not processed by 'objtool klp checksum'?",
 		      elf->name);
 		return -1;
 	}
-- 
2.53.0


^ permalink raw reply related

* [PATCH 34/48] objtool: Consolidate file decoding into decode_file()
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

decode_sections() relies on CFI and cfi_hash initialization done
separately in check(), making it unusable outside of check().

Consolidate the initialization into decode_sections() and rename it to
decode_file(), and make it global along with free_insns() and
insn_reloc() for use by other objtool components -- namely, the checksum
code which will be moving to another file.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c                 | 36 +++++++++++++--------------
 tools/objtool/include/objtool/check.h |  5 ++++
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index c8208caa4b2c..17cb9265973d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1346,7 +1346,7 @@ __weak bool arch_is_embedded_insn(struct symbol *sym)
 	return false;
 }
 
-static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
+struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
 {
 	struct reloc *reloc;
 
@@ -2633,8 +2633,21 @@ static bool alts_needed(void)
 	       opts.checksum;
 }
 
-static int decode_sections(struct objtool_file *file)
+int decode_file(struct objtool_file *file)
 {
+	arch_initial_func_cfi_state(&initial_func_cfi);
+	init_cfi_state(&init_cfi);
+	init_cfi_state(&func_cfi);
+	set_func_state(&func_cfi);
+	init_cfi_state(&force_undefined_cfi);
+	force_undefined_cfi.force_undefined = true;
+
+	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3)))
+		return -1;
+
+	cfi_hash_add(&init_cfi);
+	cfi_hash_add(&func_cfi);
+
 	file->klp = is_livepatch_module(file);
 
 	mark_rodata(file);
@@ -5002,7 +5015,7 @@ struct insn_chunk {
  * which can trigger more allocations for .debug_* sections whose data hasn't
  * been read yet.
  */
-static void free_insns(struct objtool_file *file)
+void free_insns(struct objtool_file *file)
 {
 	struct instruction *insn;
 	struct insn_chunk *chunks = NULL, *chunk;
@@ -5049,22 +5062,7 @@ int check(struct objtool_file *file)
 		objtool_disas_ctx = disas_ctx;
 	}
 
-	arch_initial_func_cfi_state(&initial_func_cfi);
-	init_cfi_state(&init_cfi);
-	init_cfi_state(&func_cfi);
-	set_func_state(&func_cfi);
-	init_cfi_state(&force_undefined_cfi);
-	force_undefined_cfi.force_undefined = true;
-
-	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3))) {
-		ret = -1;
-		goto out;
-	}
-
-	cfi_hash_add(&init_cfi);
-	cfi_hash_add(&func_cfi);
-
-	ret = decode_sections(file);
+	ret = decode_file(file);
 	if (ret)
 		goto out;
 
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 5f2f77bd9b41..6489e52ea2f2 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -155,6 +155,11 @@ struct instruction *next_insn_same_sec(struct objtool_file *file, struct instruc
 	     insn && insn->offset < sym->offset + sym->len;		\
 	     insn = next_insn_same_sec(file, insn))
 
+struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn);
+
+int decode_file(struct objtool_file *file);
+void free_insns(struct objtool_file *file);
+
 const char *objtool_disas_insn(struct instruction *insn);
 
 extern size_t sym_name_max_len;
-- 
2.53.0


^ permalink raw reply related

* [PATCH 33/48] objtool/klp: Extricate checksum calculation from validate_branch()
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

In preparation for porting the checksum code to other arches, make its
functionality independent from the CFG reverse engineering code.

Move it into a standalone calculate_checksums() function which iterates
all functions and instructions directly, rather than being called inline
from do_validate_branch().

Since checksum_update_insn() is no longer called during CFG traversal,
it needs to manually iterate the alternatives.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c                    | 106 +++++++++++++++++------
 tools/objtool/include/objtool/checksum.h |   6 +-
 2 files changed, 80 insertions(+), 32 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4ed27c53c718..c8208caa4b2c 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1350,10 +1350,7 @@ static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *i
 {
 	struct reloc *reloc;
 
-	if (insn->no_reloc)
-		return NULL;
-
-	if (!file)
+	if (!file || insn->no_reloc || insn->fake)
 		return NULL;
 
 	reloc = find_reloc_by_dest_range(file->elf, insn->sec,
@@ -2622,9 +2619,17 @@ static void mark_holes(struct objtool_file *file)
 
 static bool validate_branch_enabled(void)
 {
-	return opts.stackval ||
-	       opts.orc ||
-	       opts.uaccess ||
+	return opts.stackval	||
+	       opts.orc		||
+	       opts.uaccess;
+}
+
+static bool alts_needed(void)
+{
+	return validate_branch_enabled()	||
+	       opts.noinstr			||
+	       opts.hack_jump_label		||
+	       opts.disas			||
 	       opts.checksum;
 }
 
@@ -2658,7 +2663,7 @@ static int decode_sections(struct objtool_file *file)
 	 * Must be before add_jump_destinations(), which depends on 'func'
 	 * being set for alternatives, to enable proper sibling call detection.
 	 */
-	if (validate_branch_enabled() || opts.noinstr || opts.hack_jump_label || opts.disas) {
+	if (alts_needed()) {
 		if (add_special_section_alts(file))
 			return -1;
 	}
@@ -3654,6 +3659,7 @@ static bool skip_alt_group(struct instruction *insn)
 	return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
 }
 
+#ifdef BUILD_KLP
 static void enable_debug_checksum_cb(struct symbol *sym, void *d)
 {
 	bool *found = d;
@@ -3705,8 +3711,10 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 				 struct instruction *insn)
 {
 	struct reloc *reloc = insn_reloc(file, insn);
+	struct alternative *alt;
 	unsigned long offset;
 	struct symbol *sym;
+	static bool in_alt;
 
 	if (insn->fake)
 		return;
@@ -3719,7 +3727,7 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 		if (call_dest)
 			checksum_update(func, insn, call_dest->demangled_name,
 					strlen(call_dest->demangled_name));
-		return;
+		goto alts;
 	}
 
 	sym = reloc->sym;
@@ -3730,21 +3738,78 @@ static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
 
 		str = sym->sec->data->d_buf + sym->offset + offset;
 		checksum_update(func, insn, str, strlen(str));
-		return;
+		goto alts;
 	}
 
 	if (is_sec_sym(sym)) {
 		sym = find_symbol_containing(reloc->sym->sec, offset);
 		if (!sym)
-			return;
+			goto alts;
 
 		offset -= sym->offset;
 	}
 
 	checksum_update(func, insn, sym->demangled_name, strlen(sym->demangled_name));
 	checksum_update(func, insn, &offset, sizeof(offset));
+
+alts:
+	for (alt = insn->alts; alt; alt = alt->next) {
+		struct alt_group *alt_group = alt->insn->alt_group;
+
+		/* Prevent __ex_table recursion, e.g. LOAD_SEGMENT() */
+		if (in_alt)
+			break;
+		in_alt = true;
+
+		checksum_update(func, insn, &alt->type, sizeof(alt->type));
+
+		if (alt_group && alt_group->orig_group) {
+			struct instruction *alt_insn;
+
+			checksum_update(func, insn, &alt_group->feature, sizeof(alt_group->feature));
+
+			for (alt_insn = alt->insn; alt_insn; alt_insn = next_insn_same_sec(file, alt_insn)) {
+				checksum_update_insn(file, func, alt_insn);
+				if (!alt_group->last_insn || alt_insn == alt_group->last_insn)
+					break;
+			}
+		} else {
+			checksum_update_insn(file, func, alt->insn);
+		}
+
+		in_alt = false;
+	}
 }
 
+static int calculate_checksums(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct symbol *func;
+
+	if (checksum_debug_init(file))
+		return -1;
+
+	for_each_sym(file->elf, func) {
+		/*
+		 * Skip cold subfunctions and aliases: they share the
+		 * parent's checksum via func_for_each_insn() which
+		 * follows func->cfunc into the cold subfunction.
+		 */
+		if (!is_func_sym(func) || is_cold_func(func) ||
+		    is_alias_sym(func) || !func->len)
+			continue;
+
+		checksum_init(func);
+
+		func_for_each_insn(file, func, insn)
+			checksum_update_insn(file, func, insn);
+
+		checksum_finish(func);
+	}
+	return 0;
+}
+#endif /* BUILD_KLP */
+
 static int validate_branch(struct objtool_file *file, struct symbol *func,
 			   struct instruction *insn, struct insn_state state);
 static int do_validate_branch(struct objtool_file *file, struct symbol *func,
@@ -4026,9 +4091,6 @@ static int do_validate_branch(struct objtool_file *file, struct symbol *func,
 		insn->trace = 0;
 		next_insn = next_insn_to_validate(file, insn);
 
-		if (opts.checksum && func && insn->sec)
-			checksum_update_insn(file, func, insn);
-
 		if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
 			/* Ignore KCFI type preambles, which always fall through */
 			if (is_prefix_func(func))
@@ -4094,9 +4156,6 @@ static int validate_unwind_hint(struct objtool_file *file,
 		struct symbol *func = insn_func(insn);
 		int ret;
 
-		if (opts.checksum)
-			checksum_init(func);
-
 		ret = validate_branch(file, func, insn, *state);
 		if (ret)
 			BT_INSN(insn, "<=== (hint)");
@@ -4539,9 +4598,6 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
 
 	func = insn_func(insn);
 
-	if (opts.checksum)
-		checksum_init(func);
-
 	if (opts.trace && !fnmatch(opts.trace, sym->name, 0)) {
 		trace_enable();
 		TRACE("%s: validation begin\n", sym->name);
@@ -4554,9 +4610,6 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
 	TRACE("%s: validation %s\n\n", sym->name, ret ? "failed" : "end");
 	trace_disable();
 
-	if (opts.checksum)
-		checksum_finish(func);
-
 	return ret;
 }
 
@@ -5011,10 +5064,6 @@ int check(struct objtool_file *file)
 	cfi_hash_add(&init_cfi);
 	cfi_hash_add(&func_cfi);
 
-	ret = checksum_debug_init(file);
-	if (ret)
-		goto out;
-
 	ret = decode_sections(file);
 	if (ret)
 		goto out;
@@ -5105,6 +5154,9 @@ int check(struct objtool_file *file)
 		warnings += check_abs_references(file);
 
 	if (opts.checksum) {
+		ret = calculate_checksums(file);
+		if (ret)
+			goto out;
 		ret = create_sym_checksum_section(file);
 		if (ret)
 			goto out;
diff --git a/tools/objtool/include/objtool/checksum.h b/tools/objtool/include/objtool/checksum.h
index 0bd16fe9168b..3f25df90305d 100644
--- a/tools/objtool/include/objtool/checksum.h
+++ b/tools/objtool/include/objtool/checksum.h
@@ -33,11 +33,7 @@ static inline void checksum_finish(struct symbol *func)
 
 #else /* !BUILD_KLP */
 
-static inline void checksum_init(struct symbol *func) {}
-static inline void checksum_update(struct symbol *func,
-				   struct instruction *insn,
-				   const void *data, size_t size) {}
-static inline void checksum_finish(struct symbol *func) {}
+static inline int calculate_checksums(struct objtool_file *file) { return -ENOSYS; }
 
 #endif /* !BUILD_KLP */
 
-- 
2.53.0


^ permalink raw reply related

* [PATCH 32/48] objtool: Add is_cold_func() helper
From: Josh Poimboeuf @ 2026-04-23  4:04 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Add an is_cold_func() helper.  The sym->cold bit is redundant and can be
removed.

No functional changes intended.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c               | 6 +++---
 tools/objtool/elf.c                 | 9 +++++----
 tools/objtool/include/objtool/elf.h | 6 +++++-
 tools/objtool/klp-diff.c            | 3 ++-
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4c18d6e7f6c3..4ed27c53c718 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2614,7 +2614,7 @@ static void mark_holes(struct objtool_file *file)
 		if (insn->jump_dest) {
 			struct symbol *dest_func = insn_func(insn->jump_dest);
 
-			if (dest_func && dest_func->cold)
+			if (dest_func && is_cold_func(dest_func))
 				dest_func->ignore = true;
 		}
 	}
@@ -4426,8 +4426,8 @@ static int create_prefix_symbol(struct objtool_file *file, struct symbol *func)
 	char name[SYM_NAME_LEN];
 	struct cfi_state *cfi;
 
-	if (!is_func_sym(func) || is_prefix_func(func) ||
-	    func->cold || func->static_call_tramp)
+	if (!is_func_sym(func) || is_prefix_func(func) || is_cold_func(func) ||
+	    func->static_call_tramp)
 		return 0;
 
 	if ((strlen(func->name) + sizeof("__pfx_") > SYM_NAME_LEN)) {
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 00c2389f345f..8a6e1338af97 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -586,8 +586,11 @@ static int elf_add_symbol(struct elf *elf, struct symbol *sym)
 	if (strstarts(sym->name, ".klp.sym"))
 		sym->klp = 1;
 
+	sym->pfunc = sym->cfunc = sym;
+
 	if (!sym->klp && !is_sec_sym(sym) && strstr(sym->name, ".cold")) {
-		sym->cold = 1;
+		/* Tell read_symbols() this is a cold subfunction */
+		sym->pfunc = NULL;
 
 		/*
 		 * Clang doesn't mark cold subfunctions as STT_FUNC, which
@@ -596,8 +599,6 @@ static int elf_add_symbol(struct elf *elf, struct symbol *sym)
 		sym->type = STT_FUNC;
 	}
 
-	sym->pfunc = sym->cfunc = sym;
-
 	return 0;
 }
 
@@ -695,7 +696,7 @@ static int read_symbols(struct elf *elf)
 			char *pname;
 			size_t pnamelen;
 
-			if (!sym->cold)
+			if (sym->pfunc)
 				continue;
 
 			coldstr = strstr(sym->name, ".cold");
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 3abe4cbc584c..82b9fb05af26 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -83,7 +83,6 @@ struct symbol {
 	u8 frame_pointer     : 1;
 	u8 ignore	     : 1;
 	u8 nocfi             : 1;
-	u8 cold		     : 1;
 	u8 prefix	     : 1;
 	u8 debug_checksum    : 1;
 	u8 changed	     : 1;
@@ -289,6 +288,11 @@ static inline bool is_prefix_func(struct symbol *sym)
 	return sym->prefix;
 }
 
+static inline bool is_cold_func(struct symbol *sym)
+{
+	return sym->pfunc != sym;
+}
+
 static inline bool is_reloc_sec(struct section *sec)
 {
 	return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 1951a8b2df44..266f0d2ba4fe 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -1718,7 +1718,8 @@ static int create_klp_sections(struct elfs *e)
 		unsigned long sympos;
 		void *func_data;
 
-		if (!is_func_sym(sym) || sym->cold || !sym->clone || !sym->clone->changed)
+		if (!is_func_sym(sym) || is_cold_func(sym) ||
+		    !sym->clone || !sym->clone->changed)
 			continue;
 
 		/* allocate klp_func_ext */
-- 
2.53.0


^ permalink raw reply related

* [PATCH 31/48] objtool: Add is_alias_sym() helper
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Improve readability with a new is_alias_sym() helper.

No functional changes intended.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c               | 6 +++---
 tools/objtool/include/objtool/elf.h | 5 +++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 54ceac857979..4c18d6e7f6c3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -491,7 +491,7 @@ static int decode_instructions(struct objtool_file *file)
 				return -1;
 			}
 
-			if (func->embedded_insn || func->alias != func)
+			if (func->embedded_insn || is_alias_sym(func))
 				continue;
 
 			if (!find_insn(file, sec, func->offset)) {
@@ -2229,7 +2229,7 @@ static int add_jump_table_alts(struct objtool_file *file)
 		return 0;
 
 	for_each_sym(file->elf, func) {
-		if (!is_func_sym(func) || func->alias != func)
+		if (!is_func_sym(func) || is_alias_sym(func))
 			continue;
 
 		mark_func_jump_tables(file, func);
@@ -4527,7 +4527,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
 		return 1;
 	}
 
-	if (sym->pfunc != sym || sym->alias != sym)
+	if (sym->pfunc != sym || is_alias_sym(sym))
 		return 0;
 
 	insn = find_insn(file, sec, sym->offset);
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index cd5844c7b4e2..3abe4cbc584c 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -279,6 +279,11 @@ static inline bool is_local_sym(struct symbol *sym)
 	return sym->bind == STB_LOCAL;
 }
 
+static inline bool is_alias_sym(struct symbol *sym)
+{
+	return sym->alias != sym;
+}
+
 static inline bool is_prefix_func(struct symbol *sym)
 {
 	return sym->prefix;
-- 
2.53.0


^ permalink raw reply related

* [PATCH 30/48] objtool/klp: Handle Clang .data..Lanon anonymous data sections
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Clang generates anonymous data sections named .data..Lanon.<hash>.
These need section-symbol references in the same way as .data..Lubsan
(GCC) and .data..L__unnamed_ (Clang UBSAN) sections.  Without this,
convert_reloc_sym() fails when processing relocations that reference
these sections.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/klp-diff.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 57d2af98a33c..1951a8b2df44 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -873,9 +873,10 @@ static bool section_reference_needed(struct section *sec)
 	if (strstarts(sec->name, ".rodata"))
 		return true;
 
-	/* UBSAN anonymous data */
+	/* Anonymous data (UBSAN, Clang anonymous constants, etc.) */
 	if (strstarts(sec->name, ".data..Lubsan") ||	/* GCC */
-	    strstarts(sec->name, ".data..L__unnamed_"))	/* Clang */
+	    strstarts(sec->name, ".data..L__unnamed_") ||	/* Clang */
+	    strstarts(sec->name, ".data..Lanon."))	/* Clang */
 		return true;
 
 	return false;
-- 
2.53.0


^ permalink raw reply related

* [PATCH 29/48] klp-build: Print "objtool klp diff" command in verbose mode
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Print the full objtool command line when '--verbose' is given to help
with debugging.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 48abbe43f1c9..84053e8aadd3 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -681,6 +681,7 @@ diff_objects() {
 
 		(
 			cd "$ORIG_DIR"
+			[[ -v VERBOSE ]] && echo "${cmd[@]}"
 			"${cmd[@]}"							\
 				1> >(tee -a "$log")					\
 				2> >(tee -a "$log" | "${filter[@]}" >&2) ||		\
-- 
2.53.0


^ permalink raw reply related

* [PATCH 28/48] objtool/klp: Create empty checksum sections for function-less object files
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

If an object file has no functions, objtool has nothing to checksum, so
it doesn't create the .discard.sym_checksum symbol.

Then when 'objtool klp diff' reads symbol checksums, it errors out due
to the missing .discard.sym_checksum section.

Instead, just create an empty checksum section to signal to
read_sym_checksums() that the file has been processed.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/check.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f14212a8c179..54ceac857979 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1044,9 +1044,6 @@ static int create_sym_checksum_section(struct objtool_file *file)
 		if (sym->csum.checksum)
 			idx++;
 
-	if (!idx)
-		return 0;
-
 	sec = elf_create_section_pair(file->elf, ".discard.sym_checksum", entsize,
 				      idx, idx);
 	if (!sec)
-- 
2.53.0


^ permalink raw reply related

* [PATCH 27/48] objtool: Include libsubcmd headers directly from source tree
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Instead of installing libsubcmd headers to a build output directory and
including from there, include directly from tools/lib/ where they
already exist.  This fixes clangd indexing which otherwise can't find
libsubcmd headers.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index b71d1886022e..a4484fd22a96 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -58,7 +58,7 @@ INCLUDES := -I$(srctree)/tools/include \
 	    -I$(srctree)/tools/arch/$(SRCARCH)/include	\
 	    -I$(srctree)/tools/objtool/include \
 	    -I$(srctree)/tools/objtool/arch/$(SRCARCH)/include \
-	    -I$(LIBSUBCMD_OUTPUT)/include
+	    -I$(srctree)/tools/lib
 
 OBJTOOL_CFLAGS  := -std=gnu11 -fomit-frame-pointer -O2 -g $(WARNINGS)	\
 		   $(INCLUDES) $(LIBELF_FLAGS) $(LIBXXHASH_CFLAGS) $(HOSTCFLAGS)
@@ -135,7 +135,7 @@ $(LIBSUBCMD): fixdep $(LIBSUBCMD_OUTPUT) FORCE
 	$(Q)$(MAKE) -C $(LIBSUBCMD_DIR) O=$(LIBSUBCMD_OUTPUT) \
 		DESTDIR=$(LIBSUBCMD_OUTPUT) prefix= subdir= \
 		$(HOST_OVERRIDES) EXTRA_CFLAGS="$(OBJTOOL_CFLAGS)" \
-		$@ install_headers
+		$@
 
 $(LIBSUBCMD)-clean:
 	$(call QUIET_CLEAN, libsubcmd)
-- 
2.53.0


^ permalink raw reply related

* [PATCH 26/48] objtool/klp: Don't set sym->file for section symbols
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Section symbols aren't grouped after their corresponding FILE symbols.
Their sym->file should really be NULL rather than whatever random FILE
happened to be last.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 tools/objtool/elf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c4cb371e72b2..00c2389f345f 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -680,7 +680,7 @@ static int read_symbols(struct elf *elf)
 
 		if (is_file_sym(sym))
 			file = sym;
-		else if (sym->bind == STB_LOCAL)
+		else if (sym->bind == STB_LOCAL && !is_sec_sym(sym))
 			sym->file = file;
 	}
 
-- 
2.53.0


^ permalink raw reply related

* [PATCH 25/48] klp-build: Reject patches to realmode
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Realmode code is compiled as a separate 16-bit binary and embedded into
the kernel image via rmpiggy.S.  It can't be livepatched.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index deb1723b70de..48abbe43f1c9 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -357,7 +357,7 @@ check_unsupported_patches() {
 
 		for file in "${files[@]}"; do
 			case "$file" in
-				lib/*|*/vdso/*|*.S)
+				lib/*|*/vdso/*|*/realmode/rm/*|*.S)
 					die "${patch}: unsupported patch to $file"
 					;;
 			esac
-- 
2.53.0


^ permalink raw reply related

* [PATCH 24/48] klp-build: Reject patches to vDSO
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

vDSO code runs in userspace and can't be livepatched.  Such patches also
cause spurious "new function" errors due to generated files like
vdso*-image.c having unstable line numbers across builds.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 60231cf49e5c..deb1723b70de 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -357,7 +357,7 @@ check_unsupported_patches() {
 
 		for file in "${files[@]}"; do
 			case "$file" in
-				lib/*|*.S)
+				lib/*|*/vdso/*|*.S)
 					die "${patch}: unsupported patch to $file"
 					;;
 			esac
-- 
2.53.0


^ permalink raw reply related

* [PATCH 23/48] klp-build: Fix patch cleanup on interrupt
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

If a build error occurs and the user hits Ctrl-C while a large patch is
being reverted during cleanup, the cleanup EXIT trap gets re-triggered
and tries to re-revert the already partially-reverted patch.  That
causes 'patch -R' to repeatedly prompt

  "Unreversed patch detected!  Ignore -R? [n]"

for each already-reverted hunk, with no way to break out.

Fix it by adding '--force' to the patch revert command in
revert_patch(), which causes it to silently ignore already-reverted
hunks.  And ignore errors, as the cleanup is always best-effort.

For similar reasons, add to APPLIED_PATCHES before (rather than after)
applying the patch in apply_patch() so an interrupted apply will also
get cleaned up.

Fixes: d36a7343f4ba ("livepatch/klp-build: switch to GNU patch and recountdiff")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index a7f571df7813..60231cf49e5c 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -384,15 +384,15 @@ apply_patch() {
 		warn "${patch} applied with fuzz"
 	fi
 
-	patch -d "$SRC" -p1 --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" --silent < "$patch"
 	APPLIED_PATCHES+=("$patch")
+	patch -d "$SRC" -p1 --no-backup-if-mismatch -r /dev/null "${extra_args[@]}" --silent < "$patch"
 }
 
 revert_patch() {
 	local patch="$1"
 	local tmp=()
 
-	patch -d "$SRC" -p1 -R --silent --no-backup-if-mismatch -r /dev/null < "$patch"
+	patch -d "$SRC" -p1 -R --force --no-backup-if-mismatch -r /dev/null &> /dev/null < "$patch" || true
 
 	for p in "${APPLIED_PATCHES[@]}"; do
 		[[ "$p" == "$patch" ]] && continue
-- 
2.53.0


^ permalink raw reply related

* [PATCH 22/48] klp-build: Suppress excessive fuzz output by default
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

When a patch applies with fuzz, the detailed output from the patch tool
can be very noisy, especially for big patches.

Suppress the fuzz details by default, while keeping the "applied with
fuzz" warning.  The noise can be restored with '--verbose'.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 115f68db49c9..a7f571df7813 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -19,12 +19,11 @@ set -o nounset
 # This helps keep execution in pipes so pipefail+errexit can catch errors.
 shopt -s lastpipe
 
-unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP XTRACE
+unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP VERBOSE XTRACE
 
 REPLACE=1
 SHORT_CIRCUIT=0
 JOBS="$(getconf _NPROCESSORS_ONLN)"
-VERBOSE="-s"
 shopt -o xtrace | grep -q 'on' && XTRACE=1
 
 # Avoid removing the previous $TMP_DIR until args have been fully processed.
@@ -194,7 +193,7 @@ process_args() {
 				shift
 				;;
 			-v | --verbose)
-				VERBOSE="V=1"
+				VERBOSE=1
 				shift
 				;;
 			-d | --debug)
@@ -381,7 +380,7 @@ apply_patch() {
 		echo "$output" >&2
 		die "$patch did not apply"
 	elif [[ "$output" =~ $drift_regex ]]; then
-		echo "$output" >&2
+		[[ -v VERBOSE ]] && echo "$output" >&2
 		warn "${patch} applied with fuzz"
 	fi
 
@@ -544,7 +543,11 @@ build_kernel() {
 	#
 	cmd+=("KBUILD_MODPOST_WARN=1")
 
-	cmd+=("$VERBOSE")
+	if [[ -v VERBOSE ]]; then
+		cmd+=("V=1")
+	else
+		cmd+=("-s")
+	fi
 	cmd+=("-j$JOBS")
 	cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
 	cmd+=("OBJTOOL_ARGS=${objtool_args[*]}")
@@ -805,7 +808,11 @@ build_patch_module() {
 	[[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE")
 
 	cmd=("make")
-	cmd+=("$VERBOSE")
+	if [[ -v VERBOSE ]]; then
+		cmd+=("V=1")
+	else
+		cmd+=("-s")
+	fi
 	cmd+=("-j$JOBS")
 	cmd+=("--directory=.")
 	cmd+=("M=$KMOD_DIR")
-- 
2.53.0


^ permalink raw reply related

* [PATCH 21/48] klp-build: Validate patch file existence
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

Make sure all patch files actually exist.  Otherwise there can be
confusing errors later.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index e2f0eb8fdc7f..115f68db49c9 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -157,6 +157,7 @@ process_args() {
 	local short
 	local long
 	local args
+	local patch
 
 	short="hfj:o:vdS:T"
 	long="help,show-first-changed,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
@@ -235,6 +236,10 @@ process_args() {
 
 	KEEP_TMP="$keep_tmp"
 	PATCHES=("$@")
+
+	for patch in "${PATCHES[@]}"; do
+		[[ -f "$patch" ]] || die "$patch doesn't exist"
+	done
 }
 
 # temporarily disable xtrace for especially verbose code
-- 
2.53.0


^ permalink raw reply related

* [PATCH 20/48] klp-build: Don't use errexit
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

The errtrace option (combined with the ERR trap) already serves the same
function (and more) as errexit, so errexit is redundant.  And it has
more pitfalls.  Remove it.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 1 -
 1 file changed, 1 deletion(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 2b8b3c338a87..e2f0eb8fdc7f 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -11,7 +11,6 @@ if (( BASH_VERSINFO[0]  < 4 || \
 	exit 1
 fi
 
-set -o errexit
 set -o errtrace
 set -o pipefail
 set -o nounset
-- 
2.53.0


^ permalink raw reply related

* [PATCH 19/48] klp-build: Fix checksum comparison for changed offsets
From: Josh Poimboeuf @ 2026-04-23  4:03 UTC (permalink / raw)
  To: x86
  Cc: linux-kernel, live-patching, Peter Zijlstra, Joe Lawrence,
	Song Liu, Miroslav Benes, Petr Mladek
In-Reply-To: <cover.1776916871.git.jpoimboe@kernel.org>

The klp-build -f/--show-first-changed feature uses diff to compare
checksum log lines between original and patched objects.  However, diff
compares entire lines, including the offset field.  When a function is
at a different section offset, the offset field differs even though the
instruction checksum is identical, causing the wrong instruction to be
printed.

Only compare the checksum field when looking for the first changed
instruction.  Also print both the original and patched offsets when they
differ.

Fixes: 78be9facfb5e ("livepatch/klp-build: Add --show-first-changed option to show function divergence")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 scripts/livepatch/klp-build | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 81b35fc10877..2b8b3c338a87 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -727,13 +727,29 @@ diff_checksums() {
 		)
 
 		for func in ${funcs[$file]}; do
-			diff <( grep0 -E "^DEBUG: .*checksum: $func " "$orig_log"    | sed "s|$ORIG_DIR/||")	\
-			     <( grep0 -E "^DEBUG: .*checksum: $func " "$patched_log" | sed "s|$PATCHED_DIR/||")	\
-				| gawk '/^< DEBUG: / {
-					gsub(/:/, "")
-					printf "%s: %s: %s\n", $3, $5, $6
-					exit
-			}' || true
+			local -a orig patched
+			paste <(grep0 -E "^DEBUG: .*checksum: $func " "$orig_log") \
+			      <(grep0 -E "^DEBUG: .*checksum: $func " "$patched_log") |
+			while IFS=$'\t' read -r orig patched; do
+				read -ra orig <<< "$orig"
+				read -ra patched <<< "$patched"
+
+				if [[ ${#patched[@]} -eq 0 ]]; then
+					printf "%s: %s: %s (removed)\n" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}"
+					break
+				elif [[ ${#orig[@]} -eq 0 ]]; then
+					printf "%s: %s: %s (added)\n" "${patched[1]%:}" "${patched[3]}" "${patched[-2]}"
+					break
+				fi
+
+				[[ "${orig[-1]}" == "${patched[-1]}" ]] && continue
+
+				printf "%s: %s: %s" "${orig[1]%:}" "${orig[3]}" "${orig[-2]}"
+				[[ "${orig[-2]}" != "${patched[-2]}" ]] && \
+					printf " (patched: %s)" "${patched[-2]}"
+				printf "\n"
+				break
+			done || true
 		done
 	done
 }
-- 
2.53.0


^ permalink raw reply related

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