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author | Hoeun Ryu <hoeun.ryu@gmail.com> | 2017-08-17 11:24:27 +0900 |
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committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-08-21 18:01:04 +0100 |
commit | a88ce63b642cf8cd82cbc278429ccd9de4455a07 (patch) | |
tree | dca6db72c66d83af27733dcbca50f5d89f55e1a8 /arch/arm64/kernel/machine_kexec.c | |
parent | 8165f70648da0a4a51e5871693781b2cc29b29d6 (diff) | |
download | lwn-a88ce63b642cf8cd82cbc278429ccd9de4455a07.tar.gz lwn-a88ce63b642cf8cd82cbc278429ccd9de4455a07.zip |
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/machine_kexec.c')
-rw-r--r-- | arch/arm64/kernel/machine_kexec.c | 2 |
1 files changed, 1 insertions, 1 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) local_irq_disable(); /* shutdown non-crashing cpus */ - smp_send_crash_stop(); + crash_smp_send_stop(); /* for crashing cpu */ crash_save_cpu(regs, smp_processor_id()); |