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powerpc/fadump: save CPU reg data in vmcore when PHYP terminates LPAR

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An LPAR can be terminated by the POWER Hypervisor (PHYP) for various
reasons. If FADump was configured when PHYP terminates the LPAR,
platform-assisted dump is initiated to save the kernel dump. But CPU
register data would not be processed/saved in the vmcore in such case
because CPU mask is set in crash_fadump() at the time of kernel crash
and it remains unset in this case with LPAR being terminated by PHYP
abruptly.

To get around the problem, initialize cpu_mask to cpu_possible_mask
so as to ensure all possible CPUs' register data is processed for the
vmcore generated on PHYP terminated LPAR. Also, rename the crash info
member variable from online_mask to cpu_mask as it doesn't necessarily
have to be online CPU mask always.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220404182137.59231-1-hbathini@linux.ibm.com
This commit is contained in:
Hari Bathini 2022-04-04 23:51:37 +05:30 committed by Michael Ellerman
parent b74196af37
commit 6584cec0a2
3 changed files with 8 additions and 3 deletions
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2
arch/powerpc/include/asm/fadump-internal.h
View File

@ -50,7 +50,7 @@ struct fadump_crash_info_header {
u64 elfcorehdr_addr;
u32 crashing_cpu;
struct pt_regs regs;
struct cpumask online_mask;
struct cpumask cpu_mask;
};
struct fadump_memory_range {

7
arch/powerpc/kernel/fadump.c
View File

@ -728,7 +728,7 @@ void crash_fadump(struct pt_regs *regs, const char *str)
else
ppc_save_regs(&fdh->regs);
fdh->online_mask = *cpu_online_mask;
fdh->cpu_mask = *cpu_online_mask;
/*
* If we came in via system reset, wait a while for the secondary
@ -1164,6 +1164,11 @@ static unsigned long init_fadump_header(unsigned long addr)
fdh->elfcorehdr_addr = addr;
/* We will set the crashing cpu id in crash_fadump() during crash. */
fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
/*
* When LPAR is terminated by PYHP, ensure all possible CPUs'
* register data is processed while exporting the vmcore.
*/
fdh->cpu_mask = *cpu_possible_mask;
return addr;
}

2
arch/powerpc/platforms/pseries/rtas-fadump.c
View File

@ -351,7 +351,7 @@ static int __init rtas_fadump_build_cpu_notes(struct fw_dump *fadump_conf)
/* Lower 4 bytes of reg_value contains logical cpu id */
cpu = (be64_to_cpu(reg_entry->reg_value) &
RTAS_FADUMP_CPU_ID_MASK);
if (fdh && !cpumask_test_cpu(cpu, &fdh->online_mask)) {
if (fdh && !cpumask_test_cpu(cpu, &fdh->cpu_mask)) {
RTAS_FADUMP_SKIP_TO_NEXT_CPU(reg_entry);
continue;
}