[PATCH v1 00/14] x86/alternatives: Nest them

[PATCH v1 00/14] x86/alternatives: Nest them

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Hi,

here's the next revision

  [ v1 - the last one was v0 even if not denoted as such:
    https://lore.kernel.org/r/20240531123512.21427-1-bp@kernel.org ]

of the alternatives nesting patchset.

All feedback has been incorporated and testing with it still looks good.

Thx.

Changelog:

v0:
---

this is basically peterz's idea to nest the alternative macros with
a fix to an issue I encountered while testing.

For ease of bisection, the old macros are converted to the new, nested
variants in a step-by-step manner so that in case an issue is
encountered during testing, one can pinpoint the place where it fails
easier. Because debugging alternatives is a serious pain.

Testing here on my farm looks good but who knows what happens out there,
in the wild.

Thx.

Borislav Petkov (AMD) (13):
  x86/alternative: Zap alternative_ternary()
  x86/alternative: Convert alternative()
  x86/alternative: Convert alternative_2()
  x86/alternative: Convert alternative_input()
  x86/alternative: Convert alternative_io()
  x86/alternative: Convert alternative_call()
  x86/alternative: Convert alternative_call_2()
  x86/alternative: Convert ALTERNATIVE_TERNARY()
  x86/alternative: Convert ALTERNATIVE_3()
  x86/alternative: Convert the asm ALTERNATIVE() macro
  x86/alternative: Convert the asm ALTERNATIVE_2() macro
  x86/alternative: Convert the asm ALTERNATIVE_3() macro
  x86/alternative: Replace the old macros

Peter Zijlstra (1):
  x86/alternatives: Add nested alternatives macros

 arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
 arch/x86/kernel/alternative.c      |  20 ++-
 arch/x86/kernel/fpu/xstate.h       |  14 +-
 tools/objtool/arch/x86/special.c   |  23 +++
 tools/objtool/special.c            |  16 +-
 5 files changed, 125 insertions(+), 173 deletions(-)

-- 
2.43.0

[PATCH v1 01/14] x86/alternative: Zap alternative_ternary()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Unused.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba99ef75f56c..6db78909180a 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -271,9 +271,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-#define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory")
-
 /*
  * Alternative inline assembly with input.
  *
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Zap alternative_ternary()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     9cbf2643b3ec7866e688df35d5b28c8b07ecbe6c
Gitweb:        https://git.kernel.org/tip/9cbf2643b3ec7866e688df35d5b28c8b07ecbe6c
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:48 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 17:07:35 +02:00

x86/alternative: Zap alternative_ternary()

Unused.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-2-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba99ef7..6db7890 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -271,9 +271,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-#define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory")
-
 /*
  * Alternative inline assembly with input.
  *

[PATCH v1 02/14] x86/alternatives: Add nested alternatives macros

[Borislav Petkov]

From: Peter Zijlstra <peterz@infradead.org>

Instead of making increasingly complicated ALTERNATIVE_n()
implementations, use a nested alternative expression.

The only difference between:

  ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2)

and

  ALTERNATIVE(ALTERNATIVE(oldinst, newinst1, flag1),
              newinst2, flag2)

is that the outer alternative can add additional padding when the inner
alternative is the shorter one, which then results in
alt_instr::instrlen being inconsistent.

However, this is easily remedied since the alt_instr entries will be
consecutive and it is trivial to compute the max(alt_instr::instrlen) at
runtime while patching.

Specifically, after this the ALTERNATIVE_2 macro, after CPP expansion
(and manual layout), looks like this:

  .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
  740:
  740: \oldinstr ;
  741: .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;
  742: .pushsection .altinstructions,"a" ;
  	altinstr_entry 740b,743f,\ft_flags1,742b-740b,744f-743f ;
  .popsection ;
  .pushsection .altinstr_replacement,"ax" ;
  743: \newinstr1 ;
  744: .popsection ; ;
  741: .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;
  742: .pushsection .altinstructions,"a" ;
  altinstr_entry 740b,743f,\ft_flags2,742b-740b,744f-743f ;
  .popsection ;
  .pushsection .altinstr_replacement,"ax" ;
  743: \newinstr2 ;
  744: .popsection ;
  .endm

The only label that is ambiguous is 740, however they all reference the
same spot, so that doesn't matter.

NOTE: obviously only @oldinstr may be an alternative; making @newinstr
an alternative would mean patching .altinstr_replacement which very
likely isn't what is intended, also the labels will be confused in that
case.

  [ bp: Debug an issue where it would match the wrong two insns and
    and consider them nested due to the same signed offsets in the
    .alternative section and use instr_va() to compare the full virtual
    addresses instead.

    - Use new labels to denote that the new, nested
    alternatives are being used when staring at preprocessed output.

    - Use the %c constraint everywhere instead of %P and document the
      difference for future reference. ]

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lkml.kernel.org/r/20230628104952.GA2439977@hirez.programming.kicks-ass.net
---
 arch/x86/include/asm/alternative.h | 120 ++++++++++++++++++++++++++++-
 arch/x86/kernel/alternative.c      |  20 ++++-
 tools/objtool/arch/x86/special.c   |  23 ++++++
 tools/objtool/special.c            |  16 ++--
 4 files changed, 167 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6db78909180a..7d9ebc516bde 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -161,8 +161,13 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 #define alt_end_marker		"663"
 #define alt_slen		"662b-661b"
+#define n_alt_slen		"772b-771b"
+
 #define alt_total_slen		alt_end_marker"b-661b"
+#define n_alt_total_slen	"773b-771b"
+
 #define alt_rlen(num)		e_replacement(num)"f-"b_replacement(num)"f"
+#define n_alt_rlen		"775f-774f"
 
 #define OLDINSTR(oldinstr, num)						\
 	"# ALT: oldnstr\n"						\
@@ -172,6 +177,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
 		"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"		\
 	alt_end_marker ":\n"
 
+#define N_OLDINSTR(oldinstr)						\
+	"# N_ALT: oldinstr\n"						\
+	"771:\n\t" oldinstr "\n772:\n"					\
+	"# N_ALT: padding\n"						\
+	".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * "		\
+		"((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n"		\
+	"773:\n"
+
 /*
  * gas compatible max based on the idea from:
  * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
@@ -209,10 +222,25 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	" .byte " alt_total_slen "\n"			/* source len      */ \
 	" .byte " alt_rlen(num) "\n"			/* replacement len */
 
+#define N_ALTINSTR_ENTRY(ft_flags)					      \
+	".pushsection .altinstructions,\"a\"\n"				      \
+	" .long 771b - .\n"				/* label           */ \
+	" .long 774f - .\n"				/* new instruction */ \
+	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
+	" .byte " n_alt_total_slen "\n"			/* source len      */ \
+	" .byte " n_alt_rlen "\n"			/* replacement len */ \
+	".popsection\n"
+
 #define ALTINSTR_REPLACEMENT(newinstr, num)		/* replacement */	\
 	"# ALT: replacement " #num "\n"						\
 	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
 
+#define N_ALTINSTR_REPLACEMENT(newinstr)		/* replacement */	\
+	".pushsection .altinstr_replacement, \"ax\"\n"				\
+	"# N_ALT: replacement\n"						\
+	"774:\n\t" newinstr "\n775:\n"						\
+	".popsection\n"
+
 /* alternative assembly primitive: */
 #define ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
 	OLDINSTR(oldinstr, 1)						\
@@ -223,6 +251,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	ALTINSTR_REPLACEMENT(newinstr, 1)				\
 	".popsection\n"
 
+/* Nested alternatives macro variant */
+#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
+	N_OLDINSTR(oldinstr)						\
+	N_ALTINSTR_ENTRY(ft_flags)					\
+	N_ALTINSTR_REPLACEMENT(newinstr)
+
 #define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	OLDINSTR_2(oldinstr, 1, 2)					\
 	".pushsection .altinstructions,\"a\"\n"				\
@@ -234,11 +268,21 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	ALTINSTR_REPLACEMENT(newinstr2, 2)				\
 	".popsection\n"
 
+#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2)	\
+	N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1),		\
+		      newinst2, flag2)
+
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
 		      newinstr_yes, ft_flags)
 
+/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
+#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
+	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
+		      newinstr_yes, ft_flags)
+
+
 #define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
 			newinsn3, ft_flags3)				\
 	OLDINSTR_3(oldinsn, 1, 2, 3)					\
@@ -253,6 +297,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	ALTINSTR_REPLACEMENT(newinsn3, 3)				\
 	".popsection\n"
 
+
+#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2,	\
+		      newinst3, flag3)					\
+	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
+		      newinst3, flag3)
+
 /*
  * Alternative instructions for different CPU types or capabilities.
  *
@@ -271,6 +321,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
+#define n_alternative(oldinstr, newinstr, ft_flags)			\
+	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+
+#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
+	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+
 /*
  * Alternative inline assembly with input.
  *
@@ -288,11 +344,32 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
-/* Like alternative_io, but for replacing a direct call with another one. */
+#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
+	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+		: output : "i" (0), ## input)
+
+/*
+ * Like alternative_io, but for replacing a direct call with another one.
+ *
+ * Use the %c operand modifier which is the generic way to print a bare
+ * constant expression with all syntax-specific punctuation omitted. %P
+ * is the x86-specific variant which can handle constants too, for
+ * historical reasons, but it should be used primarily for PIC
+ * references: i.e., if used for a function, it would add the PLT
+ * suffix.
+ */
 #define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
 	asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
+#define n_alternative_input(oldinstr, newinstr, ft_flags, input...)	\
+	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+		: : "i" (0), ## input)
+
+#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
+	asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
+
 /*
  * Like alternative_call, but there are two features and respective functions.
  * If CPU has feature2, function2 is used.
@@ -307,6 +384,15 @@ static inline int alternatives_text_reserved(void *start, void *end)
 		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		\
 		  [new2] "i" (newfunc2), ## input)
 
+#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,   \
+			   output, input...)				      \
+	asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
+		"call %c[new2]", ft_flags2)				      \
+		: output, ASM_CALL_CONSTRAINT				      \
+		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
+		  [new2] "i" (newfunc2), ## input)
+
+
 /*
  * use this macro(s) if you need more than one output parameter
  * in alternative_io
@@ -403,6 +489,27 @@ void nop_func(void);
 	.popsection
 .endm
 
+#define __N_ALTERNATIVE(oldinst, newinst, flag)				\
+740:									\
+	oldinst	;							\
+741:									\
+	.skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90	;\
+742:									\
+	.pushsection .altinstructions,"a" ;				\
+	altinstr_entry 740b,743f,flag,742b-740b,744f-743f ;		\
+	.popsection ;							\
+	.pushsection .altinstr_replacement,"ax"	;			\
+743:									\
+	newinst	;							\
+744:									\
+	.popsection ;
+
+
+.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+	__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+.endm
+
+
 #define old_len			141b-140b
 #define new_len1		144f-143f
 #define new_len2		145f-144f
@@ -417,7 +524,6 @@ void nop_func(void);
 #define alt_max_2(a, b)		((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
 #define alt_max_3(a, b, c)	(alt_max_2(alt_max_2(a, b), c))
 
-
 /*
  * Same as ALTERNATIVE macro above but for two alternatives. If CPU
  * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
@@ -445,6 +551,11 @@ void nop_func(void);
 	.popsection
 .endm
 
+.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
+	__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+		      \newinstr2, \ft_flags2)
+.endm
+
 .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
 140:
 	\oldinstr
@@ -470,6 +581,11 @@ void nop_func(void);
 	.popsection
 .endm
 
+.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
+	__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+		      \newinstr3, \ft_flags3)
+.endm
+
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 89de61243272..37596a417094 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -432,6 +432,11 @@ static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
 	return 5;
 }
 
+static inline u8 * instr_va(struct alt_instr *i)
+{
+	return (u8 *)&i->instr_offset + i->instr_offset;
+}
+
 /*
  * Replace instructions with better alternatives for this CPU type. This runs
  * before SMP is initialized to avoid SMP problems with self modifying code.
@@ -447,7 +452,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 {
 	u8 insn_buff[MAX_PATCH_LEN];
 	u8 *instr, *replacement;
-	struct alt_instr *a;
+	struct alt_instr *a, *b;
 
 	DPRINTK(ALT, "alt table %px, -> %px", start, end);
 
@@ -473,7 +478,18 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 	for (a = start; a < end; a++) {
 		int insn_buff_sz = 0;
 
-		instr = (u8 *)&a->instr_offset + a->instr_offset;
+		/*
+		 * In case of nested ALTERNATIVE()s the outer alternative might
+		 * add more padding. To ensure consistent patching find the max
+		 * padding for all alt_instr entries for this site (nested
+		 * alternatives result in consecutive entries).
+		 */
+		for (b = a+1; b < end && instr_va(b) == instr_va(a); b++) {
+			u8 len = max(a->instrlen, b->instrlen);
+			a->instrlen = b->instrlen = len;
+		}
+
+		instr = instr_va(a);
 		replacement = (u8 *)&a->repl_offset + a->repl_offset;
 		BUG_ON(a->instrlen > sizeof(insn_buff));
 		BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 4134d27c696b..4ea0f9815fda 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -9,6 +9,29 @@
 
 void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
 {
+	static struct special_alt *group, *prev;
+
+	/*
+	 * Recompute orig_len for nested ALTERNATIVE()s.
+	 */
+	if (group && group->orig_sec == alt->orig_sec &&
+	             group->orig_off == alt->orig_off) {
+
+		struct special_alt *iter = group;
+		for (;;) {
+			unsigned int len = max(iter->orig_len, alt->orig_len);
+			iter->orig_len = alt->orig_len = len;
+
+			if (iter == prev)
+				break;
+
+			iter = list_next_entry(iter, list);
+		}
+
+	} else group = alt;
+
+	prev = alt;
+
 	switch (feature) {
 	case X86_FEATURE_SMAP:
 		/*
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index 91b1950f5bd8..097a69db82a0 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -84,6 +84,14 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
 						  entry->new_len);
 	}
 
+	orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
+	if (!orig_reloc) {
+		WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
+		return -1;
+	}
+
+	reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);
+
 	if (entry->feature) {
 		unsigned short feature;
 
@@ -94,14 +102,6 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
 		arch_handle_alternative(feature, alt);
 	}
 
-	orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
-	if (!orig_reloc) {
-		WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
-		return -1;
-	}
-
-	reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);
-
 	if (!entry->group || alt->new_len) {
 		new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
 		if (!new_reloc) {
-- 
2.43.0

[PATCH v1 03/14] x86/alternative: Convert alternative()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Split conversion deliberately into minimal pieces to ease bisection
because debugging alternatives is a nightmare.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 7d9ebc516bde..c05bff2e3626 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -316,14 +316,11 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * without volatile and memory clobber.
  */
 #define alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-#define n_alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
-
 #define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     b94c1fe10be544070f53e4a1e5164087e446945c
Gitweb:        https://git.kernel.org/tip/b94c1fe10be544070f53e4a1e5164087e446945c
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:50 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 17:14:26 +02:00

x86/alternative: Convert alternative()

Split conversion deliberately into minimal pieces to ease bisection
because debugging alternatives is a nightmare.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-4-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 7d9ebc5..c05bff2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -316,14 +316,11 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * without volatile and memory clobber.
  */
 #define alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-#define n_alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
-
 #define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 

[PATCH v1 04/14] x86/alternative: Convert alternative_2()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index c05bff2e3626..21ead5dea15a 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -319,9 +319,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
-
-#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
 /*
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative_2()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     8cb1f14b707d3d9b7d2b330c0acd62537576c6a7
Gitweb:        https://git.kernel.org/tip/8cb1f14b707d3d9b7d2b330c0acd62537576c6a7
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:51 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:06:58 +02:00

x86/alternative: Convert alternative_2()

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-5-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index c05bff2..21ead5d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -319,9 +319,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
-
-#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
 /*

[PATCH v1 05/14] x86/alternative: Convert alternative_input()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 21ead5dea15a..428d6efeb333 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -330,7 +330,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Leaving an unused argument 0 to keep API compatibility.
  */
 #define alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
 		: : "i" (0), ## input)
 
 /* Like alternative_input, but with a single output argument */
@@ -356,10 +356,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
-#define n_alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
-		: : "i" (0), ## input)
-
 #define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
 	asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative_input()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     bb91576965e79d17e8e23fccdef91c4bf09d1a74
Gitweb:        https://git.kernel.org/tip/bb91576965e79d17e8e23fccdef91c4bf09d1a74
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:52 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:09:27 +02:00

x86/alternative: Convert alternative_input()

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-6-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 21ead5d..428d6ef 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -330,7 +330,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Leaving an unused argument 0 to keep API compatibility.
  */
 #define alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
 		: : "i" (0), ## input)
 
 /* Like alternative_input, but with a single output argument */
@@ -356,10 +356,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
-#define n_alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
-		: : "i" (0), ## input)
-
 #define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
 	asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

[PATCH v1 06/14] x86/alternative: Convert alternative_io()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 428d6efeb333..6a746811c602 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -335,11 +335,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* Like alternative_input, but with a single output argument */
 #define alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
-		: output : "i" (0), ## input)
-
-#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
 /*
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative_io()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     ad36085ee3563001cf1720eeb93c2e85715eb5cd
Gitweb:        https://git.kernel.org/tip/ad36085ee3563001cf1720eeb93c2e85715eb5cd
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:53 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:12:29 +02:00

x86/alternative: Convert alternative_io()

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-7-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 428d6ef..6a74681 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -335,11 +335,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* Like alternative_input, but with a single output argument */
 #define alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
-		: output : "i" (0), ## input)
-
-#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
 /*

[PATCH v1 07/14] x86/alternative: Convert alternative_call()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6a746811c602..b6597574fa43 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -349,11 +349,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * suffix.
  */
 #define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
-		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
-
-#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+	asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
 /*
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative_call()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     a880f9ef6bf7edc36753a9e40388d42ae8d7e099
Gitweb:        https://git.kernel.org/tip/a880f9ef6bf7edc36753a9e40388d42ae8d7e099
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:54 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:15:03 +02:00

x86/alternative: Convert alternative_call()

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-8-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6a74681..b659757 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -349,11 +349,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * suffix.
  */
 #define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
-		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
-
-#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+	asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
 /*

[PATCH v1 08/14] x86/alternative: Convert alternative_call_2()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index b6597574fa43..bc260f27d7f1 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -358,23 +358,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Otherwise, if CPU has feature1, function1 is used.
  * Otherwise, old function is used.
  */
-#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
-			   output, input...)				\
-	asm_inline volatile (ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
-		"call %c[new2]", ft_flags2)				\
-		: output, ASM_CALL_CONSTRAINT				\
-		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		\
+#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,		\
+			   output, input...)						\
+	asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
+		"call %c[new2]", ft_flags2)						\
+		: output, ASM_CALL_CONSTRAINT						\
+		: [old] "i" (oldfunc), [new1] "i" (newfunc1),				\
 		  [new2] "i" (newfunc2), ## input)
 
-#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,   \
-			   output, input...)				      \
-	asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
-		"call %c[new2]", ft_flags2)				      \
-		: output, ASM_CALL_CONSTRAINT				      \
-		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
-		  [new2] "i" (newfunc2), ## input)
-
-
 /*
  * use this macro(s) if you need more than one output parameter
  * in alternative_io
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert alternative_call_2()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     719ac02347ee5f94a9f3d5c2fe84640f855432a9
Gitweb:        https://git.kernel.org/tip/719ac02347ee5f94a9f3d5c2fe84640f855432a9
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:55 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:17:10 +02:00

x86/alternative: Convert alternative_call_2()

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-9-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index b659757..bc260f2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -358,23 +358,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Otherwise, if CPU has feature1, function1 is used.
  * Otherwise, old function is used.
  */
-#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
-			   output, input...)				\
-	asm_inline volatile (ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
-		"call %c[new2]", ft_flags2)				\
-		: output, ASM_CALL_CONSTRAINT				\
-		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		\
+#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,		\
+			   output, input...)						\
+	asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
+		"call %c[new2]", ft_flags2)						\
+		: output, ASM_CALL_CONSTRAINT						\
+		: [old] "i" (oldfunc), [new1] "i" (newfunc1),				\
 		  [new2] "i" (newfunc2), ## input)
 
-#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,   \
-			   output, input...)				      \
-	asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
-		"call %c[new2]", ft_flags2)				      \
-		: output, ASM_CALL_CONSTRAINT				      \
-		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
-		  [new2] "i" (newfunc2), ## input)
-
-
 /*
  * use this macro(s) if you need more than one output parameter
  * in alternative_io

[PATCH v1 09/14] x86/alternative: Convert ALTERNATIVE_TERNARY()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

The C macro.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bc260f27d7f1..007baab32c14 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -274,15 +274,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-		      newinstr_yes, ft_flags)
-
-/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
 		      newinstr_yes, ft_flags)
 
-
 #define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
 			newinsn3, ft_flags3)				\
 	OLDINSTR_3(oldinsn, 1, 2, 3)					\
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert ALTERNATIVE_TERNARY()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     d2d302b1bbe28dba3bd8da855ac9c16aa5dbd00e
Gitweb:        https://git.kernel.org/tip/d2d302b1bbe28dba3bd8da855ac9c16aa5dbd00e
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:56 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:20:41 +02:00

x86/alternative: Convert ALTERNATIVE_TERNARY()

The C macro.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-10-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bc260f2..007baab 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -274,15 +274,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-		      newinstr_yes, ft_flags)
-
-/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
 		      newinstr_yes, ft_flags)
 
-
 #define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
 			newinsn3, ft_flags3)				\
 	OLDINSTR_3(oldinsn, 1, 2, 3)					\

[PATCH v1 10/14] x86/alternative: Convert ALTERNATIVE_3()

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Zap the hack of using an ALTERNATIVE_3() internal label, as suggested by
bgerst:

  https://lore.kernel.org/r/CAMzpN2i4oJ-Dv0qO46Fd-DxNv5z9=x%2BvO%2B8g=47NiiAf8QEJYA@mail.gmail.com

in favor of a label local to this macro only, as it should be done.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 24 ++++--------------------
 arch/x86/kernel/fpu/xstate.h       | 14 +++++---------
 2 files changed, 9 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 007baab32c14..fba12ad237e2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -277,26 +277,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
 		      newinstr_yes, ft_flags)
 
-#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
-			newinsn3, ft_flags3)				\
-	OLDINSTR_3(oldinsn, 1, 2, 3)					\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags1, 1)					\
-	ALTINSTR_ENTRY(ft_flags2, 2)					\
-	ALTINSTR_ENTRY(ft_flags3, 3)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinsn1, 1)				\
-	ALTINSTR_REPLACEMENT(newinsn2, 2)				\
-	ALTINSTR_REPLACEMENT(newinsn3, 3)				\
-	".popsection\n"
-
-
-#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2,	\
-		      newinst3, flag3)					\
-	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
-		      newinst3, flag3)
-
+#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
+			newinstr3, ft_flags3)				\
+	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+		      newinstr3, ft_flags3)
 /*
  * Alternative instructions for different CPU types or capabilities.
  *
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 05df04f39628..2ee0b9c53dcc 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -106,21 +106,17 @@ static inline u64 xfeatures_mask_independent(void)
  * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
  * supports modified optimization which is not supported by XSAVE.
  *
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
  */
 #define XSTATE_XSAVE(st, lmask, hmask, err)				\
-	asm volatile(ALTERNATIVE_3(XSAVE,				\
+	asm volatile("1: " ALTERNATIVE_3(XSAVE,				\
 				   XSAVEOPT, X86_FEATURE_XSAVEOPT,	\
 				   XSAVEC,   X86_FEATURE_XSAVEC,	\
 				   XSAVES,   X86_FEATURE_XSAVES)	\
 		     "\n"						\
 		     "xor %[err], %[err]\n"				\
 		     "3:\n"						\
-		     _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+		     _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
 		     : [err] "=r" (err)					\
 		     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)	\
 		     : "memory")
@@ -130,11 +126,11 @@ static inline u64 xfeatures_mask_independent(void)
  * XSAVE area format.
  */
 #define XSTATE_XRESTORE(st, lmask, hmask)				\
-	asm volatile(ALTERNATIVE(XRSTOR,				\
+	asm volatile("1: " ALTERNATIVE(XRSTOR,				\
 				 XRSTORS, X86_FEATURE_XSAVES)		\
 		     "\n"						\
 		     "3:\n"						\
-		     _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE)	\
+		     _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE)	\
 		     :							\
 		     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)	\
 		     : "memory")
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert ALTERNATIVE_3()

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     93694129c6e84d3013f5b2787e2ff88dd706c4f0
Gitweb:        https://git.kernel.org/tip/93694129c6e84d3013f5b2787e2ff88dd706c4f0
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:57 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:22:41 +02:00

x86/alternative: Convert ALTERNATIVE_3()

Zap the hack of using an ALTERNATIVE_3() internal label, as suggested by
bgerst:

  https://lore.kernel.org/r/CAMzpN2i4oJ-Dv0qO46Fd-DxNv5z9=x%2BvO%2B8g=47NiiAf8QEJYA@mail.gmail.com

in favor of a label local to this macro only, as it should be done.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-11-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 24 ++++--------------------
 arch/x86/kernel/fpu/xstate.h       | 14 +++++---------
 2 files changed, 9 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 007baab..fba12ad 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -277,26 +277,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
 		      newinstr_yes, ft_flags)
 
-#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
-			newinsn3, ft_flags3)				\
-	OLDINSTR_3(oldinsn, 1, 2, 3)					\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags1, 1)					\
-	ALTINSTR_ENTRY(ft_flags2, 2)					\
-	ALTINSTR_ENTRY(ft_flags3, 3)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinsn1, 1)				\
-	ALTINSTR_REPLACEMENT(newinsn2, 2)				\
-	ALTINSTR_REPLACEMENT(newinsn3, 3)				\
-	".popsection\n"
-
-
-#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2,	\
-		      newinst3, flag3)					\
-	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
-		      newinst3, flag3)
-
+#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
+			newinstr3, ft_flags3)				\
+	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+		      newinstr3, ft_flags3)
 /*
  * Alternative instructions for different CPU types or capabilities.
  *
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 05df04f..2ee0b9c 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -106,21 +106,17 @@ static inline u64 xfeatures_mask_independent(void)
  * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
  * supports modified optimization which is not supported by XSAVE.
  *
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
  */
 #define XSTATE_XSAVE(st, lmask, hmask, err)				\
-	asm volatile(ALTERNATIVE_3(XSAVE,				\
+	asm volatile("1: " ALTERNATIVE_3(XSAVE,				\
 				   XSAVEOPT, X86_FEATURE_XSAVEOPT,	\
 				   XSAVEC,   X86_FEATURE_XSAVEC,	\
 				   XSAVES,   X86_FEATURE_XSAVES)	\
 		     "\n"						\
 		     "xor %[err], %[err]\n"				\
 		     "3:\n"						\
-		     _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+		     _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
 		     : [err] "=r" (err)					\
 		     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)	\
 		     : "memory")
@@ -130,11 +126,11 @@ static inline u64 xfeatures_mask_independent(void)
  * XSAVE area format.
  */
 #define XSTATE_XRESTORE(st, lmask, hmask)				\
-	asm volatile(ALTERNATIVE(XRSTOR,				\
+	asm volatile("1: " ALTERNATIVE(XRSTOR,				\
 				 XRSTORS, X86_FEATURE_XSAVES)		\
 		     "\n"						\
 		     "3:\n"						\
-		     _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE)	\
+		     _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE)	\
 		     :							\
 		     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)	\
 		     : "memory")

[PATCH v1 11/14] x86/alternative: Convert the asm ALTERNATIVE() macro

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index fba12ad237e2..31b9a47b9df9 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -422,24 +422,6 @@ void nop_func(void);
  * @newinstr. ".skip" directive takes care of proper instruction padding
  * in case @newinstr is longer than @oldinstr.
  */
-.macro ALTERNATIVE oldinstr, newinstr, ft_flags
-140:
-	\oldinstr
-141:
-	.skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr
-144:
-	.popsection
-.endm
-
 #define __N_ALTERNATIVE(oldinst, newinst, flag)				\
 740:									\
 	oldinst	;							\
@@ -455,12 +437,10 @@ void nop_func(void);
 744:									\
 	.popsection ;
 
-
-.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+.macro ALTERNATIVE oldinstr, newinstr, ft_flags
 	__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
 .endm
 
-
 #define old_len			141b-140b
 #define new_len1		144f-143f
 #define new_len2		145f-144f
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE() macro

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     a6c7a6a18b10a4ac0913e7abdbdce928a2601bdb
Gitweb:        https://git.kernel.org/tip/a6c7a6a18b10a4ac0913e7abdbdce928a2601bdb
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:58 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:25:00 +02:00

x86/alternative: Convert the asm ALTERNATIVE() macro

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-12-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index fba12ad..31b9a47 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -422,24 +422,6 @@ void nop_func(void);
  * @newinstr. ".skip" directive takes care of proper instruction padding
  * in case @newinstr is longer than @oldinstr.
  */
-.macro ALTERNATIVE oldinstr, newinstr, ft_flags
-140:
-	\oldinstr
-141:
-	.skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr
-144:
-	.popsection
-.endm
-
 #define __N_ALTERNATIVE(oldinst, newinst, flag)				\
 740:									\
 	oldinst	;							\
@@ -455,12 +437,10 @@ void nop_func(void);
 744:									\
 	.popsection ;
 
-
-.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+.macro ALTERNATIVE oldinstr, newinstr, ft_flags
 	__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
 .endm
 
-
 #define old_len			141b-140b
 #define new_len1		144f-143f
 #define new_len2		145f-144f

[PATCH v1 12/14] x86/alternative: Convert the asm ALTERNATIVE_2() macro

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 31b9a47b9df9..28e07a038964 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -461,28 +461,6 @@ void nop_func(void);
  * @feature2, it replaces @oldinstr with @feature2.
  */
 .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-140:
-	\oldinstr
-141:
-	.skip -((alt_max_2(new_len1, new_len2) - (old_len)) > 0) * \
-		(alt_max_2(new_len1, new_len2) - (old_len)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
-	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr1
-144:
-	\newinstr2
-145:
-	.popsection
-.endm
-
-.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
 	__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
 		      \newinstr2, \ft_flags2)
 .endm
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE_2() macro

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     08a621fcf4a4a4d765315ffe6a28f5d31e8237b2
Gitweb:        https://git.kernel.org/tip/08a621fcf4a4a4d765315ffe6a28f5d31e8237b2
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:16:59 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:27:14 +02:00

x86/alternative: Convert the asm ALTERNATIVE_2() macro

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-13-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 31b9a47..28e07a0 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -461,28 +461,6 @@ void nop_func(void);
  * @feature2, it replaces @oldinstr with @feature2.
  */
 .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-140:
-	\oldinstr
-141:
-	.skip -((alt_max_2(new_len1, new_len2) - (old_len)) > 0) * \
-		(alt_max_2(new_len1, new_len2) - (old_len)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
-	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr1
-144:
-	\newinstr2
-145:
-	.popsection
-.endm
-
-.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
 	__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
 		      \newinstr2, \ft_flags2)
 .endm

[PATCH v1 13/14] x86/alternative: Convert the asm ALTERNATIVE_3() macro

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 28e07a038964..5278cfb1f745 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -466,31 +466,6 @@ void nop_func(void);
 .endm
 
 .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-140:
-	\oldinstr
-141:
-	.skip -((alt_max_3(new_len1, new_len2, new_len3) - (old_len)) > 0) * \
-		(alt_max_3(new_len1, new_len2, new_len3) - (old_len)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
-	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
-	altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr1
-144:
-	\newinstr2
-145:
-	\newinstr3
-146:
-	.popsection
-.endm
-
-.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
 	__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
 		      \newinstr3, \ft_flags3)
 .endm
-- 
2.43.0

[tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE_3() macro

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     1a6ade825079243f08846870561aca0e1fdfb803
Gitweb:        https://git.kernel.org/tip/1a6ade825079243f08846870561aca0e1fdfb803
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:17:00 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:29:26 +02:00

x86/alternative: Convert the asm ALTERNATIVE_3() macro

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-14-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 28e07a0..5278cfb 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -466,31 +466,6 @@ void nop_func(void);
 .endm
 
 .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-140:
-	\oldinstr
-141:
-	.skip -((alt_max_3(new_len1, new_len2, new_len3) - (old_len)) > 0) * \
-		(alt_max_3(new_len1, new_len2, new_len3) - (old_len)),0x90
-142:
-
-	.pushsection .altinstructions,"a"
-	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
-	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
-	altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f
-	.popsection
-
-	.pushsection .altinstr_replacement,"ax"
-143:
-	\newinstr1
-144:
-	\newinstr2
-145:
-	\newinstr3
-146:
-	.popsection
-.endm
-
-.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
 	__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
 		      \newinstr3, \ft_flags3)
 .endm

[PATCH v1 14/14] x86/alternative: Replace the old macros

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Now that the new macros have been gradually put in place, replace the
old ones. Leave the new label numbers starting at 7xx as a hint that the
new nested alternatives are being used now.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/alternative.h | 144 +++++++----------------------
 1 file changed, 32 insertions(+), 112 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 5278cfb1f745..4973edbe9289 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -156,131 +156,51 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 #define ALT_CALL_INSTR		"call BUG_func"
 
-#define b_replacement(num)	"664"#num
-#define e_replacement(num)	"665"#num
+#define alt_slen		"772b-771b"
+#define alt_total_slen		"773b-771b"
+#define alt_rlen		"775f-774f"
 
-#define alt_end_marker		"663"
-#define alt_slen		"662b-661b"
-#define n_alt_slen		"772b-771b"
-
-#define alt_total_slen		alt_end_marker"b-661b"
-#define n_alt_total_slen	"773b-771b"
-
-#define alt_rlen(num)		e_replacement(num)"f-"b_replacement(num)"f"
-#define n_alt_rlen		"775f-774f"
-
-#define OLDINSTR(oldinstr, num)						\
-	"# ALT: oldnstr\n"						\
-	"661:\n\t" oldinstr "\n662:\n"					\
-	"# ALT: padding\n"						\
-	".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * "		\
-		"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"		\
-	alt_end_marker ":\n"
-
-#define N_OLDINSTR(oldinstr)						\
-	"# N_ALT: oldinstr\n"						\
+#define OLDINSTR(oldinstr)						\
+	"# ALT: oldinstr\n"						\
 	"771:\n\t" oldinstr "\n772:\n"					\
-	"# N_ALT: padding\n"						\
-	".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * "		\
-		"((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n"		\
+	"# ALT: padding\n"						\
+	".skip -(((" alt_rlen ")-(" alt_slen ")) > 0) * "		\
+		"((" alt_rlen ")-(" alt_slen ")),0x90\n"		\
 	"773:\n"
 
-/*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_short(a, b)	"((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
-
-/*
- * Pad the second replacement alternative with additional NOPs if it is
- * additionally longer than the first replacement alternative.
- */
-#define OLDINSTR_2(oldinstr, num1, num2) \
-	"# ALT: oldinstr2\n"									\
-	"661:\n\t" oldinstr "\n662:\n"								\
-	"# ALT: padding2\n"									\
-	".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * "	\
-		"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n"	\
-	alt_end_marker ":\n"
-
-#define OLDINSTR_3(oldinsn, n1, n2, n3)								\
-	"# ALT: oldinstr3\n"									\
-	"661:\n\t" oldinsn "\n662:\n"								\
-	"# ALT: padding3\n"									\
-	".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
-		" - (" alt_slen ")) > 0) * "							\
-		"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
-		" - (" alt_slen ")), 0x90\n"							\
-	alt_end_marker ":\n"
-
-#define ALTINSTR_ENTRY(ft_flags, num)					      \
-	" .long 661b - .\n"				/* label           */ \
-	" .long " b_replacement(num)"f - .\n"		/* new instruction */ \
-	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
-	" .byte " alt_total_slen "\n"			/* source len      */ \
-	" .byte " alt_rlen(num) "\n"			/* replacement len */
-
-#define N_ALTINSTR_ENTRY(ft_flags)					      \
+#define ALTINSTR_ENTRY(ft_flags)					      \
 	".pushsection .altinstructions,\"a\"\n"				      \
 	" .long 771b - .\n"				/* label           */ \
 	" .long 774f - .\n"				/* new instruction */ \
 	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
-	" .byte " n_alt_total_slen "\n"			/* source len      */ \
-	" .byte " n_alt_rlen "\n"			/* replacement len */ \
+	" .byte " alt_total_slen "\n"			/* source len      */ \
+	" .byte " alt_rlen "\n"				/* replacement len */ \
 	".popsection\n"
 
-#define ALTINSTR_REPLACEMENT(newinstr, num)		/* replacement */	\
-	"# ALT: replacement " #num "\n"						\
-	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
-
-#define N_ALTINSTR_REPLACEMENT(newinstr)		/* replacement */	\
-	".pushsection .altinstr_replacement, \"ax\"\n"				\
-	"# N_ALT: replacement\n"						\
-	"774:\n\t" newinstr "\n775:\n"						\
+#define ALTINSTR_REPLACEMENT(newinstr)		/* replacement */	\
+	".pushsection .altinstr_replacement, \"ax\"\n"			\
+	"# ALT: replacement\n"						\
+	"774:\n\t" newinstr "\n775:\n"					\
 	".popsection\n"
 
 /* alternative assembly primitive: */
 #define ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
-	OLDINSTR(oldinstr, 1)						\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags, 1)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinstr, 1)				\
-	".popsection\n"
-
-/* Nested alternatives macro variant */
-#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
-	N_OLDINSTR(oldinstr)						\
-	N_ALTINSTR_ENTRY(ft_flags)					\
-	N_ALTINSTR_REPLACEMENT(newinstr)
+	OLDINSTR(oldinstr)						\
+	ALTINSTR_ENTRY(ft_flags)					\
+	ALTINSTR_REPLACEMENT(newinstr)
 
 #define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	OLDINSTR_2(oldinstr, 1, 2)					\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags1, 1)					\
-	ALTINSTR_ENTRY(ft_flags2, 2)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinstr1, 1)				\
-	ALTINSTR_REPLACEMENT(newinstr2, 2)				\
-	".popsection\n"
-
-#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2)	\
-	N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1),		\
-		      newinst2, flag2)
+	ALTERNATIVE(ALTERNATIVE(oldinstr, newinstr1, ft_flags1), newinstr2, ft_flags2)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-		      newinstr_yes, ft_flags)
+	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, newinstr_yes, ft_flags)
 
 #define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
 			newinstr3, ft_flags3)				\
-	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+	ALTERNATIVE(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
 		      newinstr3, ft_flags3)
+
 /*
  * Alternative instructions for different CPU types or capabilities.
  *
@@ -294,10 +214,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * without volatile and memory clobber.
  */
 #define alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
 /*
  * Alternative inline assembly with input.
@@ -308,12 +228,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Leaving an unused argument 0 to keep API compatibility.
  */
 #define alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
 		: : "i" (0), ## input)
 
 /* Like alternative_input, but with a single output argument */
 #define alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
 /*
@@ -327,7 +247,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * suffix.
  */
 #define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+	asm_inline volatile(ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
 /*
@@ -338,7 +258,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  */
 #define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,		\
 			   output, input...)						\
-	asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
+	asm_inline volatile(ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
 		"call %c[new2]", ft_flags2)						\
 		: output, ASM_CALL_CONSTRAINT						\
 		: [old] "i" (oldfunc), [new1] "i" (newfunc1),				\
@@ -422,7 +342,7 @@ void nop_func(void);
  * @newinstr. ".skip" directive takes care of proper instruction padding
  * in case @newinstr is longer than @oldinstr.
  */
-#define __N_ALTERNATIVE(oldinst, newinst, flag)				\
+#define __ALTERNATIVE(oldinst, newinst, flag)				\
 740:									\
 	oldinst	;							\
 741:									\
@@ -438,7 +358,7 @@ void nop_func(void);
 	.popsection ;
 
 .macro ALTERNATIVE oldinstr, newinstr, ft_flags
-	__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+	__ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
 .endm
 
 #define old_len			141b-140b
@@ -461,12 +381,12 @@ void nop_func(void);
  * @feature2, it replaces @oldinstr with @feature2.
  */
 .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-	__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+	__ALTERNATIVE(__ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
 		      \newinstr2, \ft_flags2)
 .endm
 
 .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-	__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+	__ALTERNATIVE(ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
 		      \newinstr3, \ft_flags3)
 .endm
 
-- 
2.43.0

Re: [PATCH v1 14/14] x86/alternative: Replace the old macros

[Peter Zijlstra]

On Fri, Jun 07, 2024 at 01:17:01PM +0200, Borislav Petkov wrote:
> From: "Borislav Petkov (AMD)" <bp@alien8.de>
> 
> Now that the new macros have been gradually put in place, replace the
> old ones. Leave the new label numbers starting at 7xx as a hint that the
> new nested alternatives are being used now.

You forgot to kill alt_max_[23]().

[tip: x86/alternatives] x86/alternative: Replace the old macros

[tip-bot2 for Borislav Petkov (AMD)]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     f776e41fdcc4141876ef6f297318ab04c2382eb7
Gitweb:        https://git.kernel.org/tip/f776e41fdcc4141876ef6f297318ab04c2382eb7
Author:        Borislav Petkov (AMD) <bp@alien8.de>
AuthorDate:    Fri, 07 Jun 2024 13:17:01 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Tue, 11 Jun 2024 18:33:23 +02:00

x86/alternative: Replace the old macros

Now that the new macros have been gradually put in place, replace the
old ones. Leave the new label numbers starting at 7xx as a hint that the
new nested alternatives are being used now.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-15-bp@kernel.org
---
 arch/x86/include/asm/alternative.h | 153 +++++-----------------------
 1 file changed, 32 insertions(+), 121 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 5278cfb..89fa50d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -156,131 +156,51 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 #define ALT_CALL_INSTR		"call BUG_func"
 
-#define b_replacement(num)	"664"#num
-#define e_replacement(num)	"665"#num
+#define alt_slen		"772b-771b"
+#define alt_total_slen		"773b-771b"
+#define alt_rlen		"775f-774f"
 
-#define alt_end_marker		"663"
-#define alt_slen		"662b-661b"
-#define n_alt_slen		"772b-771b"
-
-#define alt_total_slen		alt_end_marker"b-661b"
-#define n_alt_total_slen	"773b-771b"
-
-#define alt_rlen(num)		e_replacement(num)"f-"b_replacement(num)"f"
-#define n_alt_rlen		"775f-774f"
-
-#define OLDINSTR(oldinstr, num)						\
-	"# ALT: oldnstr\n"						\
-	"661:\n\t" oldinstr "\n662:\n"					\
-	"# ALT: padding\n"						\
-	".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * "		\
-		"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"		\
-	alt_end_marker ":\n"
-
-#define N_OLDINSTR(oldinstr)						\
-	"# N_ALT: oldinstr\n"						\
+#define OLDINSTR(oldinstr)						\
+	"# ALT: oldinstr\n"						\
 	"771:\n\t" oldinstr "\n772:\n"					\
-	"# N_ALT: padding\n"						\
-	".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * "		\
-		"((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n"		\
+	"# ALT: padding\n"						\
+	".skip -(((" alt_rlen ")-(" alt_slen ")) > 0) * "		\
+		"((" alt_rlen ")-(" alt_slen ")),0x90\n"		\
 	"773:\n"
 
-/*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_short(a, b)	"((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
-
-/*
- * Pad the second replacement alternative with additional NOPs if it is
- * additionally longer than the first replacement alternative.
- */
-#define OLDINSTR_2(oldinstr, num1, num2) \
-	"# ALT: oldinstr2\n"									\
-	"661:\n\t" oldinstr "\n662:\n"								\
-	"# ALT: padding2\n"									\
-	".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * "	\
-		"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n"	\
-	alt_end_marker ":\n"
-
-#define OLDINSTR_3(oldinsn, n1, n2, n3)								\
-	"# ALT: oldinstr3\n"									\
-	"661:\n\t" oldinsn "\n662:\n"								\
-	"# ALT: padding3\n"									\
-	".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
-		" - (" alt_slen ")) > 0) * "							\
-		"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
-		" - (" alt_slen ")), 0x90\n"							\
-	alt_end_marker ":\n"
-
-#define ALTINSTR_ENTRY(ft_flags, num)					      \
-	" .long 661b - .\n"				/* label           */ \
-	" .long " b_replacement(num)"f - .\n"		/* new instruction */ \
-	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
-	" .byte " alt_total_slen "\n"			/* source len      */ \
-	" .byte " alt_rlen(num) "\n"			/* replacement len */
-
-#define N_ALTINSTR_ENTRY(ft_flags)					      \
+#define ALTINSTR_ENTRY(ft_flags)					      \
 	".pushsection .altinstructions,\"a\"\n"				      \
 	" .long 771b - .\n"				/* label           */ \
 	" .long 774f - .\n"				/* new instruction */ \
 	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
-	" .byte " n_alt_total_slen "\n"			/* source len      */ \
-	" .byte " n_alt_rlen "\n"			/* replacement len */ \
+	" .byte " alt_total_slen "\n"			/* source len      */ \
+	" .byte " alt_rlen "\n"				/* replacement len */ \
 	".popsection\n"
 
-#define ALTINSTR_REPLACEMENT(newinstr, num)		/* replacement */	\
-	"# ALT: replacement " #num "\n"						\
-	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
-
-#define N_ALTINSTR_REPLACEMENT(newinstr)		/* replacement */	\
-	".pushsection .altinstr_replacement, \"ax\"\n"				\
-	"# N_ALT: replacement\n"						\
-	"774:\n\t" newinstr "\n775:\n"						\
+#define ALTINSTR_REPLACEMENT(newinstr)		/* replacement */	\
+	".pushsection .altinstr_replacement, \"ax\"\n"			\
+	"# ALT: replacement\n"						\
+	"774:\n\t" newinstr "\n775:\n"					\
 	".popsection\n"
 
 /* alternative assembly primitive: */
 #define ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
-	OLDINSTR(oldinstr, 1)						\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags, 1)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinstr, 1)				\
-	".popsection\n"
-
-/* Nested alternatives macro variant */
-#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
-	N_OLDINSTR(oldinstr)						\
-	N_ALTINSTR_ENTRY(ft_flags)					\
-	N_ALTINSTR_REPLACEMENT(newinstr)
+	OLDINSTR(oldinstr)						\
+	ALTINSTR_ENTRY(ft_flags)					\
+	ALTINSTR_REPLACEMENT(newinstr)
 
 #define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	OLDINSTR_2(oldinstr, 1, 2)					\
-	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(ft_flags1, 1)					\
-	ALTINSTR_ENTRY(ft_flags2, 2)					\
-	".popsection\n"							\
-	".pushsection .altinstr_replacement, \"ax\"\n"			\
-	ALTINSTR_REPLACEMENT(newinstr1, 1)				\
-	ALTINSTR_REPLACEMENT(newinstr2, 2)				\
-	".popsection\n"
-
-#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2)	\
-	N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1),		\
-		      newinst2, flag2)
+	ALTERNATIVE(ALTERNATIVE(oldinstr, newinstr1, ft_flags1), newinstr2, ft_flags2)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
-	N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-		      newinstr_yes, ft_flags)
+	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, newinstr_yes, ft_flags)
 
 #define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
 			newinstr3, ft_flags3)				\
-	N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+	ALTERNATIVE(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
 		      newinstr3, ft_flags3)
+
 /*
  * Alternative instructions for different CPU types or capabilities.
  *
@@ -294,10 +214,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * without volatile and memory clobber.
  */
 #define alternative(oldinstr, newinstr, ft_flags)			\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
 #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
-	asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
 /*
  * Alternative inline assembly with input.
@@ -308,12 +228,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Leaving an unused argument 0 to keep API compatibility.
  */
 #define alternative_input(oldinstr, newinstr, ft_flags, input...)	\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
 		: : "i" (0), ## input)
 
 /* Like alternative_input, but with a single output argument */
 #define alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
-	asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
+	asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
 /*
@@ -327,7 +247,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * suffix.
  */
 #define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
-	asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+	asm_inline volatile(ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
 /*
@@ -338,7 +258,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  */
 #define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,		\
 			   output, input...)						\
-	asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
+	asm_inline volatile(ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,	\
 		"call %c[new2]", ft_flags2)						\
 		: output, ASM_CALL_CONSTRAINT						\
 		: [old] "i" (oldfunc), [new1] "i" (newfunc1),				\
@@ -422,7 +342,7 @@ void nop_func(void);
  * @newinstr. ".skip" directive takes care of proper instruction padding
  * in case @newinstr is longer than @oldinstr.
  */
-#define __N_ALTERNATIVE(oldinst, newinst, flag)				\
+#define __ALTERNATIVE(oldinst, newinst, flag)				\
 740:									\
 	oldinst	;							\
 741:									\
@@ -438,7 +358,7 @@ void nop_func(void);
 	.popsection ;
 
 .macro ALTERNATIVE oldinstr, newinstr, ft_flags
-	__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+	__ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
 .endm
 
 #define old_len			141b-140b
@@ -447,26 +367,17 @@ void nop_func(void);
 #define new_len3		146f-145f
 
 /*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_2(a, b)		((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
-#define alt_max_3(a, b, c)	(alt_max_2(alt_max_2(a, b), c))
-
-/*
  * Same as ALTERNATIVE macro above but for two alternatives. If CPU
  * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
  * @feature2, it replaces @oldinstr with @feature2.
  */
 .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-	__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+	__ALTERNATIVE(__ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
 		      \newinstr2, \ft_flags2)
 .endm
 
 .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-	__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+	__ALTERNATIVE(ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
 		      \newinstr3, \ft_flags3)
 .endm
 

Re: [PATCH v1 00/14] x86/alternatives: Nest them

[Peter Zijlstra]

On Fri, Jun 07, 2024 at 01:16:47PM +0200, Borislav Petkov wrote:

> Borislav Petkov (AMD) (13):
>   x86/alternative: Zap alternative_ternary()
>   x86/alternative: Convert alternative()
>   x86/alternative: Convert alternative_2()
>   x86/alternative: Convert alternative_input()
>   x86/alternative: Convert alternative_io()
>   x86/alternative: Convert alternative_call()
>   x86/alternative: Convert alternative_call_2()
>   x86/alternative: Convert ALTERNATIVE_TERNARY()
>   x86/alternative: Convert ALTERNATIVE_3()
>   x86/alternative: Convert the asm ALTERNATIVE() macro
>   x86/alternative: Convert the asm ALTERNATIVE_2() macro
>   x86/alternative: Convert the asm ALTERNATIVE_3() macro
>   x86/alternative: Replace the old macros
> 
> Peter Zijlstra (1):
>   x86/alternatives: Add nested alternatives macros
> 
>  arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
>  arch/x86/kernel/alternative.c      |  20 ++-
>  arch/x86/kernel/fpu/xstate.h       |  14 +-
>  tools/objtool/arch/x86/special.c   |  23 +++
>  tools/objtool/special.c            |  16 +-
>  5 files changed, 125 insertions(+), 173 deletions(-)

The whole back and forth with the n_foo things ia weird, but sure, have
at.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Re: [PATCH v1 00/14] x86/alternatives: Nest them

[Borislav Petkov]

On June 11, 2024 3:26:09 PM GMT+02:00, Peter Zijlstra <peterz@infradead.org> wrote:
>On Fri, Jun 07, 2024 at 01:16:47PM +0200, Borislav Petkov wrote:
>
>> Borislav Petkov (AMD) (13):
>>   x86/alternative: Zap alternative_ternary()
>>   x86/alternative: Convert alternative()
>>   x86/alternative: Convert alternative_2()
>>   x86/alternative: Convert alternative_input()
>>   x86/alternative: Convert alternative_io()
>>   x86/alternative: Convert alternative_call()
>>   x86/alternative: Convert alternative_call_2()
>>   x86/alternative: Convert ALTERNATIVE_TERNARY()
>>   x86/alternative: Convert ALTERNATIVE_3()
>>   x86/alternative: Convert the asm ALTERNATIVE() macro
>>   x86/alternative: Convert the asm ALTERNATIVE_2() macro
>>   x86/alternative: Convert the asm ALTERNATIVE_3() macro
>>   x86/alternative: Replace the old macros
>> 
>> Peter Zijlstra (1):
>>   x86/alternatives: Add nested alternatives macros
>> 
>>  arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
>>  arch/x86/kernel/alternative.c      |  20 ++-
>>  arch/x86/kernel/fpu/xstate.h       |  14 +-
>>  tools/objtool/arch/x86/special.c   |  23 +++
>>  tools/objtool/special.c            |  16 +-
>>  5 files changed, 125 insertions(+), 173 deletions(-)
>
>The whole back and forth with the n_foo things ia weird, but sure, have
>at.
>
>Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Thanks, yeah it is in the 0th mail:

"For ease of bisection, the old macros are converted to the new, nested
variants in a step-by-step manner so that in case an issue is
encountered during testing, one can pinpoint the place where it fails
easier. Because debugging alternatives is a serious pain."

If you remember, your original patch had this issue where it would confuse two back-to-back .altinstr entries for nested because you were comparing only the offsets and they happened to be equal, by l

Now debugging *that* was insane and I managed to find the issue only when I started converting each place one-by-one and booting each one step.

That's why this superficial split is all about. We will appreciate it later. I hope not but if something explodes, bisection will be a lot easier this way.

I hope this makes sense.


-- 
Sent from a small device: formatting sucks and brevity is inevitable.