From abaad3592be593a134c987f3f04708dbc918bae7 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 10 Mar 2025 22:29:44 +0000 Subject: [PATCH] FROMLIST: cfi: add C CFI type macro Currently x86 and riscv open-code 4 instances of the same logic to define a u32 variable with the KCFI typeid of a given function. Replace the duplicate logic with a common macro. Signed-off-by: Mark Rutland Co-Developed-by: Maxwell Bland Signed-off-by: Maxwell Bland Co-Developed-by: Sami Tolvanen Signed-off-by: Sami Tolvanen Bug: 397882638 Link: https://lore.kernel.org/lkml/20250310222942.1988975-5-samitolvanen@google.com/ Change-Id: I2c0a90b06f978c1fa8e70fb974b6cdaad123b3aa Signed-off-by: Dao Huang --- arch/riscv/kernel/cfi.c | 35 +++-------------------------------- arch/x86/kernel/alternative.c | 35 +++-------------------------------- include/linux/cfi_types.h | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+), 64 deletions(-) diff --git a/arch/riscv/kernel/cfi.c b/arch/riscv/kernel/cfi.c index 64bdd3e1ab8c..e7aec5f36dd5 100644 --- a/arch/riscv/kernel/cfi.c +++ b/arch/riscv/kernel/cfi.c @@ -4,6 +4,7 @@ * * Copyright (C) 2023 Google LLC */ +#include #include #include @@ -82,41 +83,11 @@ struct bpf_insn; /* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */ extern unsigned int __bpf_prog_runX(const void *ctx, const struct bpf_insn *insn); - -/* - * Force a reference to the external symbol so the compiler generates - * __kcfi_typid. - */ -__ADDRESSABLE(__bpf_prog_runX); - -/* u32 __ro_after_init cfi_bpf_hash = __kcfi_typeid___bpf_prog_runX; */ -asm ( -" .pushsection .data..ro_after_init,\"aw\",@progbits \n" -" .type cfi_bpf_hash,@object \n" -" .globl cfi_bpf_hash \n" -" .p2align 2, 0x0 \n" -"cfi_bpf_hash: \n" -" .word __kcfi_typeid___bpf_prog_runX \n" -" .size cfi_bpf_hash, 4 \n" -" .popsection \n" -); +DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); /* Must match bpf_callback_t */ extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); - -__ADDRESSABLE(__bpf_callback_fn); - -/* u32 __ro_after_init cfi_bpf_subprog_hash = __kcfi_typeid___bpf_callback_fn; */ -asm ( -" .pushsection .data..ro_after_init,\"aw\",@progbits \n" -" .type cfi_bpf_subprog_hash,@object \n" -" .globl cfi_bpf_subprog_hash \n" -" .p2align 2, 0x0 \n" -"cfi_bpf_subprog_hash: \n" -" .word __kcfi_typeid___bpf_callback_fn \n" -" .size cfi_bpf_subprog_hash, 4 \n" -" .popsection \n" -); +DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); u32 cfi_get_func_hash(void *func) { diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index d17518ca19b8..9e81bef6bad1 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-only #define pr_fmt(fmt) "SMP alternatives: " fmt +#include #include #include #include @@ -917,41 +918,11 @@ struct bpf_insn; /* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */ extern unsigned int __bpf_prog_runX(const void *ctx, const struct bpf_insn *insn); - -/* - * Force a reference to the external symbol so the compiler generates - * __kcfi_typid. - */ -__ADDRESSABLE(__bpf_prog_runX); - -/* u32 __ro_after_init cfi_bpf_hash = __kcfi_typeid___bpf_prog_runX; */ -asm ( -" .pushsection .data..ro_after_init,\"aw\",@progbits \n" -" .type cfi_bpf_hash,@object \n" -" .globl cfi_bpf_hash \n" -" .p2align 2, 0x0 \n" -"cfi_bpf_hash: \n" -" .long __kcfi_typeid___bpf_prog_runX \n" -" .size cfi_bpf_hash, 4 \n" -" .popsection \n" -); +DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); /* Must match bpf_callback_t */ extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); - -__ADDRESSABLE(__bpf_callback_fn); - -/* u32 __ro_after_init cfi_bpf_subprog_hash = __kcfi_typeid___bpf_callback_fn; */ -asm ( -" .pushsection .data..ro_after_init,\"aw\",@progbits \n" -" .type cfi_bpf_subprog_hash,@object \n" -" .globl cfi_bpf_subprog_hash \n" -" .p2align 2, 0x0 \n" -"cfi_bpf_subprog_hash: \n" -" .long __kcfi_typeid___bpf_callback_fn \n" -" .size cfi_bpf_subprog_hash, 4 \n" -" .popsection \n" -); +DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); u32 cfi_get_func_hash(void *func) { diff --git a/include/linux/cfi_types.h b/include/linux/cfi_types.h index 6b8713675765..209c8a16ac4e 100644 --- a/include/linux/cfi_types.h +++ b/include/linux/cfi_types.h @@ -41,5 +41,28 @@ SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) #endif +#else /* __ASSEMBLY__ */ + +#ifdef CONFIG_CFI_CLANG +#define DEFINE_CFI_TYPE(name, func) \ + /* \ + * Force a reference to the function so the compiler generates \ + * __kcfi_typeid_. \ + */ \ + __ADDRESSABLE(func); \ + /* u32 name = __kcfi_typeid_ */ \ + extern u32 name; \ + asm ( \ + " .pushsection .data..ro_after_init,\"aw\",@progbits \n" \ + " .type " #name ",@object \n" \ + " .globl " #name " \n" \ + " .p2align 2, 0x0 \n" \ + #name ": \n" \ + " .4byte __kcfi_typeid_" #func " \n" \ + " .size " #name ", 4 \n" \ + " .popsection \n" \ + ); +#endif + #endif /* __ASSEMBLY__ */ #endif /* _LINUX_CFI_TYPES_H */