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x86/mce: Address objtools noinstr complaints 

Mark the relevant functions noinstr, use the plain non-instrumented MSR
accessors. The only odd part is the instrumentation_begin()/end() pair around the
indirect machine_check_vector() call as objtool can't figure that out. The
possible invoked functions are annotated correctly.

Also use notrace variant of nmi_enter/exit(). If MCEs happen then hardware
latency tracing is the least of the worries.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135315.476734898@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-04-21 21:22:36 +02:00
parent 75347bb253
commit 865d3a9afe
4 changed files with 22 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
arch/x86/kernel/cpu/mce/core.c
View File

@ -130,7 +130,7 @@ static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
BLOCKING_NOTIFIER_HEAD(x86_mce_decoder_chain);
/* Do initial initialization of a struct mce */
void mce_setup(struct mce *m)
noinstr void mce_setup(struct mce *m)
{
memset(m, 0, sizeof(struct mce));
m->cpu = m->extcpu = smp_processor_id();
@ -140,12 +140,12 @@ void mce_setup(struct mce *m)
m->cpuid = cpuid_eax(1);
m->socketid = cpu_data(m->extcpu).phys_proc_id;
m->apicid = cpu_data(m->extcpu).initial_apicid;
rdmsrl(MSR_IA32_MCG_CAP, m->mcgcap);
m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP);
if (this_cpu_has(X86_FEATURE_INTEL_PPIN))
rdmsrl(MSR_PPIN, m->ppin);
m->ppin = __rdmsr(MSR_PPIN);
else if (this_cpu_has(X86_FEATURE_AMD_PPIN))
rdmsrl(MSR_AMD_PPIN, m->ppin);
m->ppin = __rdmsr(MSR_AMD_PPIN);
m->microcode = boot_cpu_data.microcode;
}
@ -1895,10 +1895,12 @@ bool filter_mce(struct mce *m)
}
/* Handle unconfigured int18 (should never happen) */
static void unexpected_machine_check(struct pt_regs *regs)
static noinstr void unexpected_machine_check(struct pt_regs *regs)
{
instrumentation_begin();
pr_err("CPU#%d: Unexpected int18 (Machine Check)\n",
smp_processor_id());
instrumentation_end();
}
/* Call the installed machine check handler for this CPU setup. */
@ -1915,14 +1917,22 @@ static __always_inline void exc_machine_check_kernel(struct pt_regs *regs)
return;
nmi_enter();
/*
* The call targets are marked noinstr, but objtool can't figure
* that out because it's an indirect call. Annotate it.
*/
instrumentation_begin();
machine_check_vector(regs);
instrumentation_end();
nmi_exit();
}
static __always_inline void exc_machine_check_user(struct pt_regs *regs)
{
idtentry_enter(regs);
instrumentation_begin();
machine_check_vector(regs);
instrumentation_end();
idtentry_exit(regs);
}

4
arch/x86/kernel/cpu/mce/p5.c
View File

@ -21,10 +21,11 @@
int mce_p5_enabled __read_mostly;
/* Machine check handler for Pentium class Intel CPUs: */
static void pentium_machine_check(struct pt_regs *regs)
static noinstr void pentium_machine_check(struct pt_regs *regs)
{
u32 loaddr, hi, lotype;
instrumentation_begin();
rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
@ -37,6 +38,7 @@ static void pentium_machine_check(struct pt_regs *regs)
}
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
instrumentation_end();
}
/* Set up machine check reporting for processors with Intel style MCE: */

4
arch/x86/kernel/cpu/mce/winchip.c
View File

@ -17,10 +17,12 @@
#include "internal.h"
/* Machine check handler for WinChip C6: */
static void winchip_machine_check(struct pt_regs *regs)
static noinstr void winchip_machine_check(struct pt_regs *regs)
{
instrumentation_begin();
pr_emerg("CPU0: Machine Check Exception.\n");
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
instrumentation_end();
}
/* Set up machine check reporting on the Winchip C6 series */

2
kernel/time/timekeeping.c
View File

@ -953,7 +953,7 @@ EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
* but without the sequence counter protect. This internal function
* is called just when timekeeping lock is already held.
*/
time64_t __ktime_get_real_seconds(void)
noinstr time64_t __ktime_get_real_seconds(void)
{
struct timekeeper *tk = &tk_core.timekeeper;