[RFC PATCH 32/56] x86/alternative: Add module param

[David Kaplan <david.kaplan@amd.com>]

Add a struct module* param to the apply_alternatives(), apply_returns(),
and apply_retpolines() functions.  This will later be used to help store
the old instruction bytes to support re-patching.

Signed-off-by: David Kaplan <david.kaplan@amd.com>
---
 arch/x86/entry/vdso/vma.c          |  2 +-
 arch/x86/include/asm/alternative.h | 11 ++++++-----
 arch/x86/kernel/alternative.c      | 19 ++++++++++---------
 arch/x86/kernel/module.c           |  6 +++---
 4 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index afe105b2f907..2451a8007854 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -42,7 +42,7 @@ int __init init_vdso_image(const struct vdso_image *image)
 
 	apply_alternatives((struct alt_instr *)(image->data + image->alt),
 			   (struct alt_instr *)(image->data + image->alt +
-						image->alt_len));
+						image->alt_len), NULL);
 
 	return 0;
 }
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 15bc07a5ebb3..73fd8ebdf8d9 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -95,16 +95,17 @@ extern s32 __smp_locks[],	__smp_locks_end[];
  */
 extern int alternatives_patched;
 
+struct module;
+
 extern void alternative_instructions(void);
-extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
-extern void apply_retpolines(s32 *start, s32 *end);
-extern void apply_returns(s32 *start, s32 *end);
+extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
+		struct module *mod);
+extern void apply_retpolines(s32 *start, s32 *end, struct module *mod);
+extern void apply_returns(s32 *start, s32 *end, struct module *mod);
 extern void apply_seal_endbr(s32 *start, s32 *end);
 extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine,
 			  s32 *start_cfi, s32 *end_cfi);
 
-struct module;
-
 struct callthunk_sites {
 	s32				*call_start, *call_end;
 };
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 7a1f17078581..9fbec219e98e 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -615,7 +615,8 @@ static inline u8 * instr_va(struct alt_instr *i)
  * to refetch changed I$ lines.
  */
 void __init_or_module noinline apply_alternatives(struct alt_instr *start,
-						  struct alt_instr *end)
+						  struct alt_instr *end,
+						  struct module *mod)
 {
 	u8 insn_buff[MAX_PATCH_LEN];
 	u8 *instr, *replacement;
@@ -972,7 +973,7 @@ static int patch_retpoline(void *addr, struct insn *insn, u8 *bytes)
 /*
  * Generated by 'objtool --retpoline'.
  */
-void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
@@ -1076,7 +1077,7 @@ static int patch_return(void *addr, struct insn *insn, u8 *bytes)
 	return i;
 }
 
-void __init_or_module noinline apply_returns(s32 *start, s32 *end)
+void __init_or_module noinline apply_returns(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
@@ -1117,13 +1118,13 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
 	}
 }
 #else /* !CONFIG_MITIGATION_RETHUNK: */
-void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
+void __init_or_module noinline apply_returns(s32 *start, s32 *end, struct module *mod) { }
 #endif /* !CONFIG_MITIGATION_RETHUNK */
 
 #else /* !CONFIG_MITIGATION_RETPOLINE || !CONFIG_OBJTOOL */
 
-void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
-void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end, struct module *mod) { }
+void __init_or_module noinline apply_returns(s32 *start, s32 *end, struct module *mod) { }
 
 #endif /* !CONFIG_MITIGATION_RETPOLINE || !CONFIG_OBJTOOL */
 
@@ -2407,8 +2408,8 @@ void __init alternative_instructions(void)
 	 * Rewrite the retpolines, must be done before alternatives since
 	 * those can rewrite the retpoline thunks.
 	 */
-	apply_retpolines(__retpoline_sites, __retpoline_sites_end);
-	apply_returns(__return_sites, __return_sites_end);
+	apply_retpolines(__retpoline_sites, __retpoline_sites_end, NULL);
+	apply_returns(__return_sites, __return_sites_end, NULL);
 
 	its_fini_core();
 
@@ -2418,7 +2419,7 @@ void __init alternative_instructions(void)
 	 */
 	callthunks_patch_builtin_calls();
 
-	apply_alternatives(__alt_instructions, __alt_instructions_end);
+	apply_alternatives(__alt_instructions, __alt_instructions_end, NULL);
 
 	/*
 	 * Seal all functions that do not have their address taken.
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 0ffbae902e2f..0765d2360a33 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -286,14 +286,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 	}
 	if (retpolines) {
 		void *rseg = (void *)retpolines->sh_addr;
-		apply_retpolines(rseg, rseg + retpolines->sh_size);
+		apply_retpolines(rseg, rseg + retpolines->sh_size, me);
 	}
 
 	its_fini_mod(me);
 
 	if (returns) {
 		void *rseg = (void *)returns->sh_addr;
-		apply_returns(rseg, rseg + returns->sh_size);
+		apply_returns(rseg, rseg + returns->sh_size, me);
 	}
 	if (calls) {
 		struct callthunk_sites cs = {};
@@ -306,7 +306,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 	if (alt) {
 		/* patch .altinstructions */
 		void *aseg = (void *)alt->sh_addr;
-		apply_alternatives(aseg, aseg + alt->sh_size);
+		apply_alternatives(aseg, aseg + alt->sh_size, me);
 	}
 	if (ibt_endbr) {
 		void *iseg = (void *)ibt_endbr->sh_addr;
-- 
2.34.1