> From: Mark Rutland <mark.rutland@xxxxxxx>
>
> 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 <mark.rutland@xxxxxxx>
> Co-Developed-by: Maxwell Bland <mbland@xxxxxxxxxxxx>
> Signed-off-by: Maxwell Bland <mbland@xxxxxxxxxxxx>
> Co-Developed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> ---
> 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 <linux/cfi_types.h>
> #include <linux/cfi.h>
> #include <asm/insn.h>
>
> @@ -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 c71b575bf229..a9f415e873dd 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 <linux/cfi_types.h>
> #include <linux/module.h>
> #include <linux/sched.h>
> #include <linux/perf_event.h>
> @@ -934,41 +935,11 @@ 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_<func>. \
> + */ \
> + __ADDRESSABLE(func); \
> + /* u32 name = __kcfi_typeid_<func> */ \
> + 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 */
> --
> 2.49.0.rc0.332.g42c0ae87b1-goog
we oppo team have tested this patch on Mediatek DX-5(arm64)
with a kernel based on android-16(kernel-6.12). It has been running
fine for a week on both machines.
