From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

When module text memory will be allocated with ROX permissions, the
memory at the actual address where the module will live will contain
invalid instructions and there will be a writable copy that contains the
actual module code.

Update relocations and alternatives patching to deal with it.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/um/kernel/um_arch.c           |  11 +-
 arch/x86/entry/vdso/vma.c          |   3 +-
 arch/x86/include/asm/alternative.h |  14 +--
 arch/x86/kernel/alternative.c      | 160 +++++++++++++++++------------
 arch/x86/kernel/ftrace.c           |  30 +++---
 arch/x86/kernel/module.c           |  45 +++++---
 include/linux/module.h             |  16 ++-
 7 files changed, 161 insertions(+), 118 deletions(-)

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index f8de31a0c5d1..e8e8b54b3037 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -435,24 +435,25 @@ void __init arch_cpu_finalize_init(void)
 	os_check_bugs();
 }
 
-void apply_seal_endbr(s32 *start, s32 *end)
+void apply_seal_endbr(s32 *start, s32 *end, struct module *mod)
 {
 }
 
-void apply_retpolines(s32 *start, s32 *end)
+void apply_retpolines(s32 *start, s32 *end, struct module *mod)
 {
 }
 
-void apply_returns(s32 *start, s32 *end)
+void apply_returns(s32 *start, s32 *end, struct module *mod)
 {
 }
 
 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
-		   s32 *start_cfi, s32 *end_cfi)
+		   s32 *start_cfi, s32 *end_cfi, struct module *mod)
 {
 }
 
-void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
+			struct module *mod)
 {
 }
 
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index b8fed8b8b9cc..ed21151923c3 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -54,7 +54,8 @@ 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 ca9ae606aab9..dc03a647776d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -96,16 +96,16 @@ extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
  * instructions were patched in already:
  */
 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_seal_endbr(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, struct module *mod);
 extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine,
-			  s32 *start_cfi, s32 *end_cfi);
-
-struct module;
+			  s32 *start_cfi, s32 *end_cfi, struct module *mod);
 
 struct callthunk_sites {
 	s32				*call_start, *call_end;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index d17518ca19b8..3b3fa93af3b1 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -392,8 +392,10 @@ EXPORT_SYMBOL(BUG_func);
  * Rewrite the "call BUG_func" replacement to point to the target of the
  * indirect pv_ops call "call *disp(%ip)".
  */
-static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
+static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a,
+			    struct module *mod)
 {
+	u8 *wr_instr = module_writable_address(mod, instr);
 	void *target, *bug = &BUG_func;
 	s32 disp;
 
@@ -403,14 +405,14 @@ static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
 	}
 
 	if (a->instrlen != 6 ||
-	    instr[0] != CALL_RIP_REL_OPCODE ||
-	    instr[1] != CALL_RIP_REL_MODRM) {
+	    wr_instr[0] != CALL_RIP_REL_OPCODE ||
+	    wr_instr[1] != CALL_RIP_REL_MODRM) {
 		pr_err("ALT_FLAG_DIRECT_CALL set for unrecognized indirect call\n");
 		BUG();
 	}
 
 	/* Skip CALL_RIP_REL_OPCODE and CALL_RIP_REL_MODRM */
-	disp = *(s32 *)(instr + 2);
+	disp = *(s32 *)(wr_instr + 2);
 #ifdef CONFIG_X86_64
 	/* ff 15 00 00 00 00   call   *0x0(%rip) */
 	/* target address is stored at "next instruction + disp". */
@@ -448,7 +450,8 @@ 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;
@@ -477,6 +480,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 	 */
 	for (a = start; a < end; a++) {
 		int insn_buff_sz = 0;
+		u8 *wr_instr, *wr_replacement;
 
 		/*
 		 * In case of nested ALTERNATIVE()s the outer alternative might
@@ -490,7 +494,11 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 		}
 
 		instr = instr_va(a);
+		wr_instr = module_writable_address(mod, instr);
+
 		replacement = (u8 *)&a->repl_offset + a->repl_offset;
+		wr_replacement = module_writable_address(mod, replacement);
+
 		BUG_ON(a->instrlen > sizeof(insn_buff));
 		BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
 
@@ -501,9 +509,9 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 		 *   patch if feature is *NOT* present.
 		 */
 		if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) {
-			memcpy(insn_buff, instr, a->instrlen);
+			memcpy(insn_buff, wr_instr, a->instrlen);
 			optimize_nops(instr, insn_buff, a->instrlen);
-			text_poke_early(instr, insn_buff, a->instrlen);
+			text_poke_early(wr_instr, insn_buff, a->instrlen);
 			continue;
 		}
 
@@ -513,11 +521,12 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 			instr, instr, a->instrlen,
 			replacement, a->replacementlen, a->flags);
 
-		memcpy(insn_buff, replacement, a->replacementlen);
+		memcpy(insn_buff, wr_replacement, a->replacementlen);
 		insn_buff_sz = a->replacementlen;
 
 		if (a->flags & ALT_FLAG_DIRECT_CALL) {
-			insn_buff_sz = alt_replace_call(instr, insn_buff, a);
+			insn_buff_sz = alt_replace_call(instr, insn_buff, a,
+							mod);
 			if (insn_buff_sz < 0)
 				continue;
 		}
@@ -527,11 +536,11 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 
 		apply_relocation(insn_buff, instr, a->instrlen, replacement, a->replacementlen);
 
-		DUMP_BYTES(ALT, instr, a->instrlen, "%px:   old_insn: ", instr);
+		DUMP_BYTES(ALT, wr_instr, a->instrlen, "%px:   old_insn: ", instr);
 		DUMP_BYTES(ALT, replacement, a->replacementlen, "%px:   rpl_insn: ", replacement);
 		DUMP_BYTES(ALT, insn_buff, insn_buff_sz, "%px: final_insn: ", instr);
 
-		text_poke_early(instr, insn_buff, insn_buff_sz);
+		text_poke_early(wr_instr, insn_buff, insn_buff_sz);
 	}
 
 	kasan_enable_current();
@@ -722,18 +731,20 @@ 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;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		struct insn insn;
 		int len, ret;
 		u8 bytes[16];
 		u8 op1, op2;
 
-		ret = insn_decode_kernel(&insn, addr);
+		ret = insn_decode_kernel(&insn, wr_addr);
 		if (WARN_ON_ONCE(ret < 0))
 			continue;
 
@@ -761,9 +772,9 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
 		len = patch_retpoline(addr, &insn, bytes);
 		if (len == insn.length) {
 			optimize_nops(addr, bytes, len);
-			DUMP_BYTES(RETPOLINE, ((u8*)addr),  len, "%px: orig: ", addr);
+			DUMP_BYTES(RETPOLINE, ((u8*)wr_addr),  len, "%px: orig: ", addr);
 			DUMP_BYTES(RETPOLINE, ((u8*)bytes), len, "%px: repl: ", addr);
-			text_poke_early(addr, bytes, len);
+			text_poke_early(wr_addr, bytes, len);
 		}
 	}
 }
@@ -799,7 +810,8 @@ 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;
 
@@ -808,12 +820,13 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
 
 	for (s = start; s < end; s++) {
 		void *dest = NULL, *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		struct insn insn;
 		int len, ret;
 		u8 bytes[16];
 		u8 op;
 
-		ret = insn_decode_kernel(&insn, addr);
+		ret = insn_decode_kernel(&insn, wr_addr);
 		if (WARN_ON_ONCE(ret < 0))
 			continue;
 
@@ -833,32 +846,35 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
 
 		len = patch_return(addr, &insn, bytes);
 		if (len == insn.length) {
-			DUMP_BYTES(RET, ((u8*)addr),  len, "%px: orig: ", addr);
+			DUMP_BYTES(RET, ((u8*)wr_addr),  len, "%px: orig: ", addr);
 			DUMP_BYTES(RET, ((u8*)bytes), len, "%px: repl: ", addr);
-			text_poke_early(addr, bytes, len);
+			text_poke_early(wr_addr, bytes, len);
 		}
 	}
 }
 #else
-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 */
 
 #ifdef CONFIG_X86_KERNEL_IBT
 
-static void poison_cfi(void *addr);
+static void poison_cfi(void *addr, void *wr_addr);
 
-static void __init_or_module poison_endbr(void *addr, bool warn)
+static void __init_or_module poison_endbr(void *addr, void *wr_addr, bool warn)
 {
 	u32 endbr, poison = gen_endbr_poison();
 
-	if (WARN_ON_ONCE(get_kernel_nofault(endbr, addr)))
+	if (WARN_ON_ONCE(get_kernel_nofault(endbr, wr_addr)))
 		return;
 
 	if (!is_endbr(endbr)) {
@@ -873,7 +889,7 @@ static void __init_or_module poison_endbr(void *addr, bool warn)
 	 */
 	DUMP_BYTES(ENDBR, ((u8*)addr), 4, "%px: orig: ", addr);
 	DUMP_BYTES(ENDBR, ((u8*)&poison), 4, "%px: repl: ", addr);
-	text_poke_early(addr, &poison, 4);
+	text_poke_early(wr_addr, &poison, 4);
 }
 
 /*
@@ -882,22 +898,23 @@ static void __init_or_module poison_endbr(void *addr, bool warn)
  * Seal the functions for indirect calls by clobbering the ENDBR instructions
  * and the kCFI hash value.
  */
-void __init_or_module noinline apply_seal_endbr(s32 *start, s32 *end)
+void __init_or_module noinline apply_seal_endbr(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 
-		poison_endbr(addr, true);
+		poison_endbr(addr, wr_addr, true);
 		if (IS_ENABLED(CONFIG_FINEIBT))
-			poison_cfi(addr - 16);
+			poison_cfi(addr - 16, wr_addr - 16);
 	}
 }
 
 #else
 
-void __init_or_module apply_seal_endbr(s32 *start, s32 *end) { }
+void __init_or_module apply_seal_endbr(s32 *start, s32 *end, struct module *mod) { }
 
 #endif /* CONFIG_X86_KERNEL_IBT */
 
@@ -1119,7 +1136,7 @@ static u32 decode_caller_hash(void *addr)
 }
 
 /* .retpoline_sites */
-static int cfi_disable_callers(s32 *start, s32 *end)
+static int cfi_disable_callers(s32 *start, s32 *end, struct module *mod)
 {
 	/*
 	 * Disable kCFI by patching in a JMP.d8, this leaves the hash immediate
@@ -1131,6 +1148,7 @@ static int cfi_disable_callers(s32 *start, s32 *end)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		addr -= fineibt_caller_size;
@@ -1138,13 +1156,13 @@ static int cfi_disable_callers(s32 *start, s32 *end)
 		if (!hash) /* nocfi callers */
 			continue;
 
-		text_poke_early(addr, jmp, 2);
+		text_poke_early(wr_addr, jmp, 2);
 	}
 
 	return 0;
 }
 
-static int cfi_enable_callers(s32 *start, s32 *end)
+static int cfi_enable_callers(s32 *start, s32 *end, struct module *mod)
 {
 	/*
 	 * Re-enable kCFI, undo what cfi_disable_callers() did.
@@ -1154,6 +1172,7 @@ static int cfi_enable_callers(s32 *start, s32 *end)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		addr -= fineibt_caller_size;
@@ -1161,19 +1180,20 @@ static int cfi_enable_callers(s32 *start, s32 *end)
 		if (!hash) /* nocfi callers */
 			continue;
 
-		text_poke_early(addr, mov, 2);
+		text_poke_early(wr_addr, mov, 2);
 	}
 
 	return 0;
 }
 
 /* .cfi_sites */
-static int cfi_rand_preamble(s32 *start, s32 *end)
+static int cfi_rand_preamble(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		hash = decode_preamble_hash(addr);
@@ -1182,18 +1202,19 @@ static int cfi_rand_preamble(s32 *start, s32 *end)
 			return -EINVAL;
 
 		hash = cfi_rehash(hash);
-		text_poke_early(addr + 1, &hash, 4);
+		text_poke_early(wr_addr + 1, &hash, 4);
 	}
 
 	return 0;
 }
 
-static int cfi_rewrite_preamble(s32 *start, s32 *end)
+static int cfi_rewrite_preamble(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		hash = decode_preamble_hash(addr);
@@ -1201,59 +1222,62 @@ static int cfi_rewrite_preamble(s32 *start, s32 *end)
 			 addr, addr, 5, addr))
 			return -EINVAL;
 
-		text_poke_early(addr, fineibt_preamble_start, fineibt_preamble_size);
+		text_poke_early(wr_addr, fineibt_preamble_start, fineibt_preamble_size);
 		WARN_ON(*(u32 *)(addr + fineibt_preamble_hash) != 0x12345678);
-		text_poke_early(addr + fineibt_preamble_hash, &hash, 4);
+		text_poke_early(wr_addr + fineibt_preamble_hash, &hash, 4);
 	}
 
 	return 0;
 }
 
-static void cfi_rewrite_endbr(s32 *start, s32 *end)
+static void cfi_rewrite_endbr(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 
-		poison_endbr(addr+16, false);
+		poison_endbr(addr+16, wr_addr, false);
 	}
 }
 
 /* .retpoline_sites */
-static int cfi_rand_callers(s32 *start, s32 *end)
+static int cfi_rand_callers(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		addr -= fineibt_caller_size;
 		hash = decode_caller_hash(addr);
 		if (hash) {
 			hash = -cfi_rehash(hash);
-			text_poke_early(addr + 2, &hash, 4);
+			text_poke_early(wr_addr + 2, &hash, 4);
 		}
 	}
 
 	return 0;
 }
 
-static int cfi_rewrite_callers(s32 *start, s32 *end)
+static int cfi_rewrite_callers(s32 *start, s32 *end, struct module *mod)
 {
 	s32 *s;
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
+		void *wr_addr = module_writable_address(mod, addr);
 		u32 hash;
 
 		addr -= fineibt_caller_size;
 		hash = decode_caller_hash(addr);
 		if (hash) {
-			text_poke_early(addr, fineibt_caller_start, fineibt_caller_size);
+			text_poke_early(wr_addr, fineibt_caller_start, fineibt_caller_size);
 			WARN_ON(*(u32 *)(addr + fineibt_caller_hash) != 0x12345678);
-			text_poke_early(addr + fineibt_caller_hash, &hash, 4);
+			text_poke_early(wr_addr + fineibt_caller_hash, &hash, 4);
 		}
 		/* rely on apply_retpolines() */
 	}
@@ -1262,8 +1286,9 @@ static int cfi_rewrite_callers(s32 *start, s32 *end)
 }
 
 static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
-			    s32 *start_cfi, s32 *end_cfi, bool builtin)
+			    s32 *start_cfi, s32 *end_cfi, struct module *mod)
 {
+	bool builtin = mod ? false : true;
 	int ret;
 
 	if (WARN_ONCE(fineibt_preamble_size != 16,
@@ -1281,7 +1306,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
 	 * rewrite them. This disables all CFI. If this succeeds but any of the
 	 * later stages fails, we're without CFI.
 	 */
-	ret = cfi_disable_callers(start_retpoline, end_retpoline);
+	ret = cfi_disable_callers(start_retpoline, end_retpoline, mod);
 	if (ret)
 		goto err;
 
@@ -1292,11 +1317,11 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
 			cfi_bpf_subprog_hash = cfi_rehash(cfi_bpf_subprog_hash);
 		}
 
-		ret = cfi_rand_preamble(start_cfi, end_cfi);
+		ret = cfi_rand_preamble(start_cfi, end_cfi, mod);
 		if (ret)
 			goto err;
 
-		ret = cfi_rand_callers(start_retpoline, end_retpoline);
+		ret = cfi_rand_callers(start_retpoline, end_retpoline, mod);
 		if (ret)
 			goto err;
 	}
@@ -1308,7 +1333,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
 		return;
 
 	case CFI_KCFI:
-		ret = cfi_enable_callers(start_retpoline, end_retpoline);
+		ret = cfi_enable_callers(start_retpoline, end_retpoline, mod);
 		if (ret)
 			goto err;
 
@@ -1318,17 +1343,17 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
 
 	case CFI_FINEIBT:
 		/* place the FineIBT preamble at func()-16 */
-		ret = cfi_rewrite_preamble(start_cfi, end_cfi);
+		ret = cfi_rewrite_preamble(start_cfi, end_cfi, mod);
 		if (ret)
 			goto err;
 
 		/* rewrite the callers to target func()-16 */
-		ret = cfi_rewrite_callers(start_retpoline, end_retpoline);
+		ret = cfi_rewrite_callers(start_retpoline, end_retpoline, mod);
 		if (ret)
 			goto err;
 
 		/* now that nobody targets func()+0, remove ENDBR there */
-		cfi_rewrite_endbr(start_cfi, end_cfi);
+		cfi_rewrite_endbr(start_cfi, end_cfi, mod);
 
 		if (builtin)
 			pr_info("Using FineIBT CFI\n");
@@ -1347,7 +1372,7 @@ static inline void poison_hash(void *addr)
 	*(u32 *)addr = 0;
 }
 
-static void poison_cfi(void *addr)
+static void poison_cfi(void *addr, void *wr_addr)
 {
 	switch (cfi_mode) {
 	case CFI_FINEIBT:
@@ -1359,8 +1384,8 @@ static void poison_cfi(void *addr)
 		 *	ud2
 		 * 1:	nop
 		 */
-		poison_endbr(addr, false);
-		poison_hash(addr + fineibt_preamble_hash);
+		poison_endbr(addr, wr_addr, false);
+		poison_hash(wr_addr + fineibt_preamble_hash);
 		break;
 
 	case CFI_KCFI:
@@ -1369,7 +1394,7 @@ static void poison_cfi(void *addr)
 		 *	movl	$0, %eax
 		 *	.skip	11, 0x90
 		 */
-		poison_hash(addr + 1);
+		poison_hash(wr_addr + 1);
 		break;
 
 	default:
@@ -1380,22 +1405,21 @@ static void poison_cfi(void *addr)
 #else
 
 static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
-			    s32 *start_cfi, s32 *end_cfi, bool builtin)
+			    s32 *start_cfi, s32 *end_cfi, struct module *mod)
 {
 }
 
 #ifdef CONFIG_X86_KERNEL_IBT
-static void poison_cfi(void *addr) { }
+static void poison_cfi(void *addr, void *wr_addr) { }
 #endif
 
 #endif
 
 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
-		   s32 *start_cfi, s32 *end_cfi)
+		   s32 *start_cfi, s32 *end_cfi, struct module *mod)
 {
 	return __apply_fineibt(start_retpoline, end_retpoline,
-			       start_cfi, end_cfi,
-			       /* .builtin = */ false);
+			       start_cfi, end_cfi, mod);
 }
 
 #ifdef CONFIG_SMP
@@ -1692,16 +1716,16 @@ void __init alternative_instructions(void)
 	paravirt_set_cap();
 
 	__apply_fineibt(__retpoline_sites, __retpoline_sites_end,
-			__cfi_sites, __cfi_sites_end, true);
+			__cfi_sites, __cfi_sites_end, NULL);
 
 	/*
 	 * 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);
 
-	apply_alternatives(__alt_instructions, __alt_instructions_end);
+	apply_alternatives(__alt_instructions, __alt_instructions_end, NULL);
 
 	/*
 	 * Now all calls are established. Apply the call thunks if
@@ -1712,7 +1736,7 @@ void __init alternative_instructions(void)
 	/*
 	 * Seal all functions that do not have their address taken.
 	 */
-	apply_seal_endbr(__ibt_endbr_seal, __ibt_endbr_seal_end);
+	apply_seal_endbr(__ibt_endbr_seal, __ibt_endbr_seal_end, NULL);
 
 #ifdef CONFIG_SMP
 	/* Patch to UP if other cpus not imminent. */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8da0e66ca22d..b498897b213c 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -118,10 +118,13 @@ ftrace_modify_code_direct(unsigned long ip, const char *old_code,
 		return ret;
 
 	/* replace the text with the new text */
-	if (ftrace_poke_late)
+	if (ftrace_poke_late) {
 		text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL);
-	else
-		text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE);
+	} else {
+		mutex_lock(&text_mutex);
+		text_poke((void *)ip, new_code, MCOUNT_INSN_SIZE);
+		mutex_unlock(&text_mutex);
+	}
 	return 0;
 }
 
@@ -318,7 +321,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 	unsigned const char op_ref[] = { 0x48, 0x8b, 0x15 };
 	unsigned const char retq[] = { RET_INSN_OPCODE, INT3_INSN_OPCODE };
 	union ftrace_op_code_union op_ptr;
-	int ret;
+	void *ret;
 
 	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
 		start_offset = (unsigned long)ftrace_regs_caller;
@@ -349,15 +352,15 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 	npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
 
 	/* Copy ftrace_caller onto the trampoline memory */
-	ret = copy_from_kernel_nofault(trampoline, (void *)start_offset, size);
-	if (WARN_ON(ret < 0))
+	ret = text_poke_copy(trampoline, (void *)start_offset, size);
+	if (WARN_ON(!ret))
 		goto fail;
 
 	ip = trampoline + size;
 	if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
 		__text_gen_insn(ip, JMP32_INSN_OPCODE, ip, x86_return_thunk, JMP32_INSN_SIZE);
 	else
-		memcpy(ip, retq, sizeof(retq));
+		text_poke_copy(ip, retq, sizeof(retq));
 
 	/* No need to test direct calls on created trampolines */
 	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
@@ -365,8 +368,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 		ip = trampoline + (jmp_offset - start_offset);
 		if (WARN_ON(*(char *)ip != 0x75))
 			goto fail;
-		ret = copy_from_kernel_nofault(ip, x86_nops[2], 2);
-		if (ret < 0)
+		if (!text_poke_copy(ip, x86_nops[2], 2))
 			goto fail;
 	}
 
@@ -379,7 +381,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 	 */
 
 	ptr = (unsigned long *)(trampoline + size + RET_SIZE);
-	*ptr = (unsigned long)ops;
+	text_poke_copy(ptr, &ops, sizeof(unsigned long));
 
 	op_offset -= start_offset;
 	memcpy(&op_ptr, trampoline + op_offset, OP_REF_SIZE);
@@ -395,7 +397,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 	op_ptr.offset = offset;
 
 	/* put in the new offset to the ftrace_ops */
-	memcpy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
+	text_poke_copy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
 
 	/* put in the call to the function */
 	mutex_lock(&text_mutex);
@@ -405,9 +407,9 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 	 * the depth accounting before the call already.
 	 */
 	dest = ftrace_ops_get_func(ops);
-	memcpy(trampoline + call_offset,
-	       text_gen_insn(CALL_INSN_OPCODE, trampoline + call_offset, dest),
-	       CALL_INSN_SIZE);
+	text_poke_copy_locked(trampoline + call_offset,
+	      text_gen_insn(CALL_INSN_OPCODE, trampoline + call_offset, dest),
+	      CALL_INSN_SIZE, false);
 	mutex_unlock(&text_mutex);
 
 	/* ALLOC_TRAMP flags lets us know we created it */
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 837450b6e882..8984abd91c00 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -146,18 +146,21 @@ static int __write_relocate_add(Elf64_Shdr *sechdrs,
 		}
 
 		if (apply) {
-			if (memcmp(loc, &zero, size)) {
+			void *wr_loc = module_writable_address(me, loc);
+
+			if (memcmp(wr_loc, &zero, size)) {
 				pr_err("x86/modules: Invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
 				       (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
 				return -ENOEXEC;
 			}
-			write(loc, &val, size);
+			write(wr_loc, &val, size);
 		} else {
 			if (memcmp(loc, &val, size)) {
 				pr_warn("x86/modules: Invalid relocation target, existing value does not match expected value for type %d, loc %p, val %Lx\n",
 					(int)ELF64_R_TYPE(rel[i].r_info), loc, val);
 				return -ENOEXEC;
 			}
+			/* FIXME: needs care for ROX module allocations */
 			write(loc, &zero, size);
 		}
 	}
@@ -224,7 +227,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
 		    struct module *me)
 {
-	const Elf_Shdr *s, *alt = NULL, *locks = NULL,
+	const Elf_Shdr *s, *alt = NULL,
 		*orc = NULL, *orc_ip = NULL,
 		*retpolines = NULL, *returns = NULL, *ibt_endbr = NULL,
 		*calls = NULL, *cfi = NULL;
@@ -233,8 +236,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
 		if (!strcmp(".altinstructions", secstrings + s->sh_name))
 			alt = s;
-		if (!strcmp(".smp_locks", secstrings + s->sh_name))
-			locks = s;
 		if (!strcmp(".orc_unwind", secstrings + s->sh_name))
 			orc = s;
 		if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
@@ -265,20 +266,20 @@ int module_finalize(const Elf_Ehdr *hdr,
 			csize = cfi->sh_size;
 		}
 
-		apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize);
+		apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize, me);
 	}
 	if (retpolines) {
 		void *rseg = (void *)retpolines->sh_addr;
-		apply_retpolines(rseg, rseg + retpolines->sh_size);
+		apply_retpolines(rseg, rseg + retpolines->sh_size, 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 (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 (calls || alt) {
 		struct callthunk_sites cs = {};
@@ -297,8 +298,28 @@ int module_finalize(const Elf_Ehdr *hdr,
 	}
 	if (ibt_endbr) {
 		void *iseg = (void *)ibt_endbr->sh_addr;
-		apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size);
+		apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size, me);
 	}
+
+	if (orc && orc_ip)
+		unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+				   (void *)orc->sh_addr, orc->sh_size);
+
+	return 0;
+}
+
+int module_post_finalize(const Elf_Ehdr *hdr,
+			 const Elf_Shdr *sechdrs,
+			 struct module *me)
+{
+	const Elf_Shdr *s, *locks = NULL;
+	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
+		if (!strcmp(".smp_locks", secstrings + s->sh_name))
+			locks = s;
+	}
+
 	if (locks) {
 		void *lseg = (void *)locks->sh_addr;
 		void *text = me->mem[MOD_TEXT].base;
@@ -308,10 +329,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 					    text, text_end);
 	}
 
-	if (orc && orc_ip)
-		unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
-				   (void *)orc->sh_addr, orc->sh_size);
-
 	return 0;
 }
 
diff --git a/include/linux/module.h b/include/linux/module.h
index 7039f609c6ef..2c1a24ba99a3 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -376,15 +376,6 @@ struct module_memory {
 #endif
 };
 
-#ifdef CONFIG_MODULES
-void *module_writable_address(struct module *mod, void *loc);
-#else
-static inline void *module_writable_address(struct module *mod, void *loc)
-{
-	return loc;
-}
-#endif
-
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 /* Only touch one cacheline for common rbtree-for-core-layout case. */
 #define __module_memory_align ____cacheline_aligned
@@ -778,6 +769,8 @@ static inline bool is_livepatch_module(struct module *mod)
 
 void set_module_sig_enforced(void);
 
+void *module_writable_address(struct module *mod, void *loc);
+
 #else /* !CONFIG_MODULES... */
 
 static inline struct module *__module_address(unsigned long addr)
@@ -885,6 +878,11 @@ static inline bool module_is_coming(struct module *mod)
 {
 	return false;
 }
+
+static inline void *module_writable_address(struct module *mod, void *loc)
+{
+	return loc;
+}
 #endif /* CONFIG_MODULES */
 
 #ifdef CONFIG_SYSFS
-- 
2.43.0

Hi Mike,

On Wed, Oct 09, 2024 at 09:08:14PM +0300, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> 
> When module text memory will be allocated with ROX permissions, the
> memory at the actual address where the module will live will contain
> invalid instructions and there will be a writable copy that contains the
> actual module code.
> 
> Update relocations and alternatives patching to deal with it.
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

I bisected a boot failure that I see with CONFIG_CFI_CLANG enabled to
this change as commit be712757cabd ("x86/module: perpare module loading
for ROX allocations of text") in -next.

  $ echo CONFIG_CFI_CLANG=y >arch/x86/configs/cfi.config

  $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 mrproper defconfig cfi.config bzImage

  $ curl -LSs https://github.com/ClangBuiltLinux/boot-utils/releases/download/20230707-182910/x86_64-rootfs.cpio.zst | zstd -d >rootfs.cpio

  $ qemu-system-x86_64 \
      -display none \
      -nodefaults \
      -M q35 \
      -d unimp,guest_errors \
      -append 'console=ttyS0 earlycon=uart8250,io,0x3f8' \
      -kernel arch/x86/boot/bzImage \
      -initrd rootfs.cpio \
      -cpu host \
      -enable-kvm \
      -m 512m \
      -smp 8 \
      -serial mon:stdio
  [    0.000000] Linux version 6.12.0-rc2-00140-gbe712757cabd (nathan@n3-xlarge-x86) (ClangBuiltLinux clang version 19.1.0 (https://github.com/llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4), ClangBuiltLinux LLD 19.1.0 (https://github.com/llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)) #1 SMP PREEMPT_DYNAMIC Thu Oct 10 22:42:57 UTC 2024
  ...
  [    0.092204] Speculative Store Bypass: Mitigation: Speculative Store Bypass disabled via prctl
  [    0.093207] TAA: Mitigation: TSX disabled
  [    0.093711] MMIO Stale Data: Mitigation: Clear CPU buffers
  [    0.094228] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
  [    0.095203] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
  [    0.096203] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
  [    0.097203] x86/fpu: Supporting XSAVE feature 0x020: 'AVX-512 opmask'
  [    0.098003] x86/fpu: Supporting XSAVE feature 0x040: 'AVX-512 Hi256'
  [    0.098203] x86/fpu: Supporting XSAVE feature 0x080: 'AVX-512 ZMM_Hi256'
  [    0.099203] x86/fpu: Supporting XSAVE feature 0x200: 'Protection Keys User registers'
  [    0.100204] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256
  [    0.101204] x86/fpu: xstate_offset[5]:  832, xstate_sizes[5]:   64
  [    0.102203] x86/fpu: xstate_offset[6]:  896, xstate_sizes[6]:  512
  [    0.103204] x86/fpu: xstate_offset[7]: 1408, xstate_sizes[7]: 1024
  [    0.104051] x86/fpu: xstate_offset[9]: 2432, xstate_sizes[9]:    8
  [    0.104204] x86/fpu: Enabled xstate features 0x2e7, context size is 2440 bytes, using 'compacted' format.

then nothing after that. Boot is successful if CFI is not enabled (the
initrd will just shutdown the machine after printing the version string).

If there is any further information I can provide or patches I can test,
I am more than happy to do so.

Cheers,
Nathan

On Thu, Oct 10, 2024 at 03:54:11PM -0700, Nathan Chancellor wrote:
> Hi Mike,
> 
> On Wed, Oct 09, 2024 at 09:08:14PM +0300, Mike Rapoport wrote:
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> > 
> > When module text memory will be allocated with ROX permissions, the
> > memory at the actual address where the module will live will contain
> > invalid instructions and there will be a writable copy that contains the
> > actual module code.
> > 
> > Update relocations and alternatives patching to deal with it.
> > 
> > Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> 
> I bisected a boot failure that I see with CONFIG_CFI_CLANG enabled to
> this change as commit be712757cabd ("x86/module: perpare module loading
> for ROX allocations of text") in -next.
 
>   [    0.000000] Linux version 6.12.0-rc2-00140-gbe712757cabd (nathan@n3-xlarge-x86) (ClangBuiltLinux clang version 19.1.0 (https://github.com/llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4), ClangBuiltLinux LLD 19.1.0 (https://github.com/llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)) #1 SMP PREEMPT_DYNAMIC Thu Oct 10 22:42:57 UTC 2024
>   ...
>   [    0.092204] Speculative Store Bypass: Mitigation: Speculative Store Bypass disabled via prctl
>   [    0.093207] TAA: Mitigation: TSX disabled
>   [    0.093711] MMIO Stale Data: Mitigation: Clear CPU buffers
>   [    0.094228] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
>   [    0.095203] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
>   [    0.096203] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
>   [    0.097203] x86/fpu: Supporting XSAVE feature 0x020: 'AVX-512 opmask'
>   [    0.098003] x86/fpu: Supporting XSAVE feature 0x040: 'AVX-512 Hi256'
>   [    0.098203] x86/fpu: Supporting XSAVE feature 0x080: 'AVX-512 ZMM_Hi256'
>   [    0.099203] x86/fpu: Supporting XSAVE feature 0x200: 'Protection Keys User registers'
>   [    0.100204] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256
>   [    0.101204] x86/fpu: xstate_offset[5]:  832, xstate_sizes[5]:   64
>   [    0.102203] x86/fpu: xstate_offset[6]:  896, xstate_sizes[6]:  512
>   [    0.103204] x86/fpu: xstate_offset[7]: 1408, xstate_sizes[7]: 1024
>   [    0.104051] x86/fpu: xstate_offset[9]: 2432, xstate_sizes[9]:    8
>   [    0.104204] x86/fpu: Enabled xstate features 0x2e7, context size is 2440 bytes, using 'compacted' format.
> 
> then nothing after that. Boot is successful if CFI is not enabled (the
> initrd will just shutdown the machine after printing the version string).
> 
> If there is any further information I can provide or patches I can test,
> I am more than happy to do so.

I overlooked how cfi_*_callers routines update addr.
This patch should fix it:

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3b3fa93af3b1..cf782f431110 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1148,11 +1148,13 @@ static int cfi_disable_callers(s32 *start, s32 *end, struct module *mod)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
-		void *wr_addr = module_writable_address(mod, addr);
+		void *wr_addr;
 		u32 hash;
 
 		addr -= fineibt_caller_size;
-		hash = decode_caller_hash(addr);
+		wr_addr = module_writable_address(mod, addr);
+		hash = decode_caller_hash(wr_addr);
+
 		if (!hash) /* nocfi callers */
 			continue;
 
@@ -1172,11 +1174,12 @@ static int cfi_enable_callers(s32 *start, s32 *end, struct module *mod)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
-		void *wr_addr = module_writable_address(mod, addr);
+		void *wr_addr;
 		u32 hash;
 
 		addr -= fineibt_caller_size;
-		hash = decode_caller_hash(addr);
+		wr_addr = module_writable_address(mod, addr);
+		hash = decode_caller_hash(wr_addr);
 		if (!hash) /* nocfi callers */
 			continue;
 
@@ -1249,11 +1252,12 @@ static int cfi_rand_callers(s32 *start, s32 *end, struct module *mod)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
-		void *wr_addr = module_writable_address(mod, addr);
+		void *wr_addr;
 		u32 hash;
 
 		addr -= fineibt_caller_size;
-		hash = decode_caller_hash(addr);
+		wr_addr = module_writable_address(mod, addr);
+		hash = decode_caller_hash(wr_addr);
 		if (hash) {
 			hash = -cfi_rehash(hash);
 			text_poke_early(wr_addr + 2, &hash, 4);
@@ -1269,14 +1273,15 @@ static int cfi_rewrite_callers(s32 *start, s32 *end, struct module *mod)
 
 	for (s = start; s < end; s++) {
 		void *addr = (void *)s + *s;
-		void *wr_addr = module_writable_address(mod, addr);
+		void *wr_addr;
 		u32 hash;
 
 		addr -= fineibt_caller_size;
-		hash = decode_caller_hash(addr);
+		wr_addr = module_writable_address(mod, addr);
+		hash = decode_caller_hash(wr_addr);
 		if (hash) {
 			text_poke_early(wr_addr, fineibt_caller_start, fineibt_caller_size);
-			WARN_ON(*(u32 *)(addr + fineibt_caller_hash) != 0x12345678);
+			WARN_ON(*(u32 *)(wr_addr + fineibt_caller_hash) != 0x12345678);
 			text_poke_early(wr_addr + fineibt_caller_hash, &hash, 4);
 		}
 		/* rely on apply_retpolines() */
 
> Cheers,
> Nathan

-- 
Sincerely yours,
Mike.

On Fri, Oct 11, 2024 at 03:58:04PM +0300, Mike Rapoport wrote:
> I overlooked how cfi_*_callers routines update addr.
> This patch should fix it:

Thanks, can confirm. My boot is working again and LKDTM's
CFI_FORWARD_PROTO test properly fails.

> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 3b3fa93af3b1..cf782f431110 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -1148,11 +1148,13 @@ static int cfi_disable_callers(s32 *start, s32 *end, struct module *mod)
>  
>  	for (s = start; s < end; s++) {
>  		void *addr = (void *)s + *s;
> -		void *wr_addr = module_writable_address(mod, addr);
> +		void *wr_addr;
>  		u32 hash;
>  
>  		addr -= fineibt_caller_size;
> -		hash = decode_caller_hash(addr);
> +		wr_addr = module_writable_address(mod, addr);
> +		hash = decode_caller_hash(wr_addr);
> +
>  		if (!hash) /* nocfi callers */
>  			continue;
>  
> @@ -1172,11 +1174,12 @@ static int cfi_enable_callers(s32 *start, s32 *end, struct module *mod)
>  
>  	for (s = start; s < end; s++) {
>  		void *addr = (void *)s + *s;
> -		void *wr_addr = module_writable_address(mod, addr);
> +		void *wr_addr;
>  		u32 hash;
>  
>  		addr -= fineibt_caller_size;
> -		hash = decode_caller_hash(addr);
> +		wr_addr = module_writable_address(mod, addr);
> +		hash = decode_caller_hash(wr_addr);
>  		if (!hash) /* nocfi callers */
>  			continue;
>  
> @@ -1249,11 +1252,12 @@ static int cfi_rand_callers(s32 *start, s32 *end, struct module *mod)
>  
>  	for (s = start; s < end; s++) {
>  		void *addr = (void *)s + *s;
> -		void *wr_addr = module_writable_address(mod, addr);
> +		void *wr_addr;
>  		u32 hash;
>  
>  		addr -= fineibt_caller_size;
> -		hash = decode_caller_hash(addr);
> +		wr_addr = module_writable_address(mod, addr);
> +		hash = decode_caller_hash(wr_addr);
>  		if (hash) {
>  			hash = -cfi_rehash(hash);
>  			text_poke_early(wr_addr + 2, &hash, 4);
> @@ -1269,14 +1273,15 @@ static int cfi_rewrite_callers(s32 *start, s32 *end, struct module *mod)
>  
>  	for (s = start; s < end; s++) {
>  		void *addr = (void *)s + *s;
> -		void *wr_addr = module_writable_address(mod, addr);
> +		void *wr_addr;
>  		u32 hash;
>  
>  		addr -= fineibt_caller_size;
> -		hash = decode_caller_hash(addr);
> +		wr_addr = module_writable_address(mod, addr);
> +		hash = decode_caller_hash(wr_addr);
>  		if (hash) {
>  			text_poke_early(wr_addr, fineibt_caller_start, fineibt_caller_size);
> -			WARN_ON(*(u32 *)(addr + fineibt_caller_hash) != 0x12345678);
> +			WARN_ON(*(u32 *)(wr_addr + fineibt_caller_hash) != 0x12345678);
>  			text_poke_early(wr_addr + fineibt_caller_hash, &hash, 4);
>  		}
>  		/* rely on apply_retpolines() */
>  
> > Cheers,
> > Nathan
> 
> -- 
> Sincerely yours,
> Mike.

> +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, struct module *mod);
>  extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine,
> -			  s32 *start_cfi, s32 *end_cfi);
> -
> -struct module;
> +			  s32 *start_cfi, s32 *end_cfi, struct module *mod);

Please drop all the pointless externs while you're at it.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>