From: Borislav Petkov bp@suse.de
[ Upstream commit 0a5b288e85bbef5227bb6397e31fcf1d7ba9142a ]
Mark all the MCE severity computation logic noinstr and allow instrumentation when it "calls out".
Fixes
vmlinux.o: warning: objtool: do_machine_check()+0xc5d: call to mce_severity() leaves .noinstr.text section
Signed-off-by: Borislav Petkov bp@suse.de Link: https://lore.kernel.org/r/20211208111343.8130-7-bp@alien8.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/mce/severity.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c index bb019a594a2c9..171a1495111b1 100644 --- a/arch/x86/kernel/cpu/mce/severity.c +++ b/arch/x86/kernel/cpu/mce/severity.c @@ -263,24 +263,36 @@ static bool is_copy_from_user(struct pt_regs *regs) * distinguish an exception taken in user from from one * taken in the kernel. */ -static int error_context(struct mce *m, struct pt_regs *regs) +static noinstr int error_context(struct mce *m, struct pt_regs *regs) { + int fixup_type; + bool copy_user; + if ((m->cs & 3) == 3) return IN_USER; + if (!mc_recoverable(m->mcgstatus)) return IN_KERNEL;
- switch (ex_get_fixup_type(m->ip)) { + /* Allow instrumentation around external facilities usage. */ + instrumentation_begin(); + fixup_type = ex_get_fixup_type(m->ip); + copy_user = is_copy_from_user(regs); + instrumentation_end(); + + switch (fixup_type) { case EX_TYPE_UACCESS: case EX_TYPE_COPY: - if (!regs || !is_copy_from_user(regs)) + if (!regs || !copy_user) return IN_KERNEL; m->kflags |= MCE_IN_KERNEL_COPYIN; fallthrough; + case EX_TYPE_FAULT_MCE_SAFE: case EX_TYPE_DEFAULT_MCE_SAFE: m->kflags |= MCE_IN_KERNEL_RECOV; return IN_KERNEL_RECOV; + default: return IN_KERNEL; } @@ -317,8 +329,8 @@ static int mce_severity_amd_smca(struct mce *m, enum context err_ctx) * See AMD Error Scope Hierarchy table in a newer BKDG. For example * 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features" */ -static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant, - char **msg, bool is_excp) +static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant, + char **msg, bool is_excp) { enum context ctx = error_context(m, regs);
@@ -370,8 +382,8 @@ static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant, return MCE_KEEP_SEVERITY; }
-static int mce_severity_intel(struct mce *m, struct pt_regs *regs, - int tolerant, char **msg, bool is_excp) +static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs, + int tolerant, char **msg, bool is_excp) { enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP); enum context ctx = error_context(m, regs); @@ -407,8 +419,8 @@ static int mce_severity_intel(struct mce *m, struct pt_regs *regs, } }
-int mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg, - bool is_excp) +int noinstr mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg, + bool is_excp) { if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)