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authorDouglas Anderson <dianders@chromium.org>2023-08-04 07:00:42 -0700
committerAndrew Morton <akpm@linux-foundation.org>2023-08-18 10:19:00 -0700
commit8d539b84f1e3478436f978ceaf55a0b6cab497b5 (patch)
tree305d70872637b1eb8f771dba5b4b408a469ea3b4 /arch/sparc/kernel
parent3c9d017cc283df0dabf6b16a6cb4574426cbd53b (diff)
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/kernel')
-rw-r--r--arch/sparc/kernel/process_64.c6
1 files changed, 3 insertions, 3 deletions
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;