diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2020-05-08 14:34:01 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-05-19 00:10:34 +1000 |
| commit | d2cbbd45d433b96e41711a293e59cff259143694 (patch) | |
| tree | f8885d31c2c29c8e845c6ff8f9f23a1497c112a1 /arch/powerpc | |
| parent | d7b14c5c042865070a1411078ab49ea17bad0b41 (diff) | |
powerpc/pseries: Limit machine check stack to 4GB
This allows rtas_args to be put on the machine check stack, which
avoids a lot of complications with re-entrancy deadlocks.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-10-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/setup_64.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 438a9befce41..defe05b6b7a9 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -709,7 +709,7 @@ void __init exc_lvl_early_init(void) */ void __init emergency_stack_init(void) { - u64 limit; + u64 limit, mce_limit; unsigned int i; /* @@ -726,7 +726,16 @@ void __init emergency_stack_init(void) * initialized in kernel/irq.c. These are initialized here in order * to have emergency stacks available as early as possible. */ - limit = min(ppc64_bolted_size(), ppc64_rma_size); + limit = mce_limit = min(ppc64_bolted_size(), ppc64_rma_size); + + /* + * Machine check on pseries calls rtas, but can't use the static + * rtas_args due to a machine check hitting while the lock is held. + * rtas args have to be under 4GB, so the machine check stack is + * limited to 4GB so args can be put on stack. + */ + if (firmware_has_feature(FW_FEATURE_LPAR) && mce_limit > SZ_4G) + mce_limit = SZ_4G; for_each_possible_cpu(i) { paca_ptrs[i]->emergency_sp = alloc_stack(limit, i) + THREAD_SIZE; @@ -736,7 +745,7 @@ void __init emergency_stack_init(void) paca_ptrs[i]->nmi_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE; /* emergency stack for machine check exception handling. */ - paca_ptrs[i]->mc_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE; + paca_ptrs[i]->mc_emergency_sp = alloc_stack(mce_limit, i) + THREAD_SIZE; #endif } } |