Re: [PATCH v2 4/9] x86/cfi: Standardize on common "CFI:" prefix for CFI reports

Nathan Chancellor
2025-09-05T02:17:25Z

On Wed, Sep 03, 2025 at 08:46:43PM -0700, Kees Cook wrote:
> Use a regular "CFI:" prefix for CFI reports during alternatives setup,
> including reporting when nothing has happened (i.e. CONFIG_FINEIBT=n).
>
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Obviously minor but I had pointed out on v1 that there appears to be
some inconsistency within the diff around capitalization, "ignoring" vs.
"Ignoring".

> ---
> arch/x86/kernel/alternative.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 7bde68247b5f..d8f4ac95b4df 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -1266,26 +1266,26 @@ static __init int cfi_parse_cmdline(char *str)
> } else if (!strcmp(str, "norand")) {
> cfi_rand = false;
> } else if (!strcmp(str, "warn")) {
> - pr_alert("CFI mismatch non-fatal!\n");
> + pr_alert("CFI: mismatch non-fatal!\n");
> cfi_warn = true;
> } else if (!strcmp(str, "paranoid")) {
> if (cfi_mode == CFI_FINEIBT) {
> cfi_paranoid = true;
> } else {
> - pr_err("Ignoring paranoid; depends on fineibt.\n");
> + pr_err("CFI: ignoring paranoid; depends on fineibt.\n");
> }
> } else if (!strcmp(str, "bhi")) {
> #ifdef CONFIG_FINEIBT_BHI
> if (cfi_mode == CFI_FINEIBT) {
> cfi_bhi = true;
> } else {
> - pr_err("Ignoring bhi; depends on fineibt.\n");
> + pr_err("CFI: ignoring bhi; depends on fineibt.\n");
> }
> #else
> - pr_err("Ignoring bhi; depends on FINEIBT_BHI=y.\n");
> + pr_err("CFI: ignoring bhi; depends on FINEIBT_BHI=y.\n");
> #endif
> } else {
> - pr_err("Ignoring unknown cfi option (%s).", str);
> + pr_err("CFI: Ignoring unknown option (%s).", str);
> }
>
> str = next;
> @@ -1757,7 +1757,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> switch (cfi_mode) {
> case CFI_OFF:
> if (builtin)
> - pr_info("Disabling CFI\n");
> + pr_info("CFI: disabled\n");
> return;
>
> case CFI_KCFI:
> @@ -1766,7 +1766,8 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> goto err;
>
> if (builtin)
> - pr_info("Using kCFI\n");
> + pr_info("CFI: Using %sretpoline kCFI\n",
> + cfi_rand ? "rehashed " : "");
> return;
>
> case CFI_FINEIBT:
> @@ -2005,6 +2006,8 @@ bool decode_fineibt_insn(struct pt_regs *regs, unsigned long *target, u32 *type)
> static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
> s32 *start_cfi, s32 *end_cfi, bool builtin)
> {
> + if (IS_ENABLED(CONFIG_CFI) && builtin)
> + pr_info("CFI: Using standard kCFI\n");
> }
>
> #ifdef CONFIG_X86_KERNEL_IBT
> --
> 2.34.1
>