path: root/arch/arm64/kernel
diff options
authorHoeun Ryu <hoeun.ryu@gmail.com>2017-08-17 11:24:27 +0900
committerCatalin Marinas <catalin.marinas@arm.com>2017-08-21 18:01:04 +0100
commita88ce63b642cf8cd82cbc278429ccd9de4455a07 (patch)
treedca6db72c66d83af27733dcbca50f5d89f55e1a8 /arch/arm64/kernel
parentarm64: dma-mapping: Mark atomic_pool as __ro_after_init (diff)
arm64: kexec: have own crash_smp_send_stop() for crash dump for nonpanic cores
Commit 0ee5941 : (x86/panic: replace smp_send_stop() with kdump friendly version in panic path) introduced crash_smp_send_stop() which is a weak function and can be overridden by architecture codes to fix the side effect caused by commit f06e515 : (kernel/panic.c: add "crash_kexec_post_ notifiers" option). ARM64 architecture uses the weak version function and the problem is that the weak function simply calls smp_send_stop() which makes other CPUs offline and takes away the chance to save crash information for nonpanic CPUs in machine_crash_shutdown() when crash_kexec_post_notifiers kernel option is enabled. Calling smp_send_crash_stop() in machine_crash_shutdown() is useless because all nonpanic CPUs are already offline by smp_send_stop() in this case and smp_send_crash_stop() only works against online CPUs. The result is that secondary CPUs registers are not saved by crash_save_cpu() and the vmcore file misreports these CPUs as being offline. crash_smp_send_stop() is implemented to fix this problem by replacing the existing smp_send_crash_stop() and adding a check for multiple calling to the function. The function (strong symbol version) saves crash information for nonpanic CPUs and machine_crash_shutdown() tries to save crash information for nonpanic CPUs only when crash_kexec_post_notifiers kernel option is disabled. * crash_kexec_post_notifiers : false panic() __crash_kexec() machine_crash_shutdown() crash_smp_send_stop() <= save crash dump for nonpanic cores * crash_kexec_post_notifiers : true panic() crash_smp_send_stop() <= save crash dump for nonpanic cores __crash_kexec() machine_crash_shutdown() crash_smp_send_stop() <= just return. Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com> Reviewed-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
2 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 481f54a866c5..11121f608eb5 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -252,7 +252,7 @@ void machine_crash_shutdown(struct pt_regs *regs)
/* shutdown non-crashing cpus */
- smp_send_crash_stop();
+ crash_smp_send_stop();
/* for crashing cpu */
crash_save_cpu(regs, smp_processor_id());
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index f13ddb2404f9..ffe089942ac4 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -977,11 +977,21 @@ void smp_send_stop(void)
-void smp_send_crash_stop(void)
+void crash_smp_send_stop(void)
+ static int cpus_stopped;
cpumask_t mask;
unsigned long timeout;
+ /*
+ * This function can be called twice in panic path, but obviously
+ * we execute this only once.
+ */
+ if (cpus_stopped)
+ return;
+ cpus_stopped = 1;
if (num_online_cpus() == 1)