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| author | Douglas Anderson <dianders@chromium.org> | 2023-08-04 07:00:42 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-18 10:19:00 -0700 |
| commit | 8d539b84f1e3478436f978ceaf55a0b6cab497b5 (patch) | |
| tree | 305d70872637b1eb8f771dba5b4b408a469ea3b4 /arch/sparc | |
| parent | 3c9d017cc283df0dabf6b16a6cb4574426cbd53b (diff) | |
| download | lwn-8d539b84f1e3478436f978ceaf55a0b6cab497b5.tar.gz lwn-8d539b84f1e3478436f978ceaf55a0b6cab497b5.zip | |
nmi_backtrace: allow excluding an arbitrary CPU
The APIs that allow backtracing across CPUs have always had a way to
exclude the current CPU. This convenience means callers didn't need to
find a place to allocate a CPU mask just to handle the common case.
Let's extend the API to take a CPU ID to exclude instead of just a
boolean. This isn't any more complex for the API to handle and allows the
hardlockup detector to exclude a different CPU (the one it already did a
trace for) without needing to find space for a CPU mask.
Arguably, this new API also encourages safer behavior. Specifically if
the caller wants to avoid tracing the current CPU (maybe because they
already traced the current CPU) this makes it more obvious to the caller
that they need to make sure that the current CPU ID can't change.
[akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub]
Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/sparc')
| -rw-r--r-- | arch/sparc/include/asm/irq_64.h | 2 | ||||
| -rw-r--r-- | arch/sparc/kernel/process_64.c | 6 |
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/sparc/include/asm/irq_64.h b/arch/sparc/include/asm/irq_64.h index b436029f1ced..8c4c0c87f998 100644 --- a/arch/sparc/include/asm/irq_64.h +++ b/arch/sparc/include/asm/irq_64.h @@ -87,7 +87,7 @@ static inline unsigned long get_softint(void) } void arch_trigger_cpumask_backtrace(const struct cpumask *mask, - bool exclude_self); + int exclude_cpu); #define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace extern void *hardirq_stack[NR_CPUS]; diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index b51d8fb0ecdc..1ea3f37fa985 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -236,7 +236,7 @@ static void __global_reg_poll(struct global_reg_snapshot *gp) } } -void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) { struct thread_info *tp = current_thread_info(); struct pt_regs *regs = get_irq_regs(); @@ -252,7 +252,7 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot)); - if (cpumask_test_cpu(this_cpu, mask) && !exclude_self) + if (cpumask_test_cpu(this_cpu, mask) && this_cpu != exclude_cpu) __global_reg_self(tp, regs, this_cpu); smp_fetch_global_regs(); @@ -260,7 +260,7 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) for_each_cpu(cpu, mask) { struct global_reg_snapshot *gp; - if (exclude_self && cpu == this_cpu) + if (cpu == exclude_cpu) continue; gp = &global_cpu_snapshot[cpu].reg; |