diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-26 17:32:38 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-26 23:28:12 +1000 |
| commit | 45b21cfeb22087795f0b49397fbe529efeb99baf (patch) | |
| tree | 86845b00eb677d66b5c8b88c5f1e59e519083ea6 /arch/powerpc | |
| parent | 83c4919058459c32138a1ebe35f72b7013a9ddbc (diff) | |
powerpc/powernv: Fix oops on P9 DD1 in cause_ipi()
Recently we merged the native xive support for Power9, and then separately some
reworks for doorbell IPI support. In isolation both series were OK, but the
merged result had a bug in one case.
On P9 DD1 we use pnv_p9_dd1_cause_ipi() which tries to use doorbells, and then
falls back to the interrupt controller. However the fallback is implemented by
calling icp_ops->cause_ipi. But now that xive support is merged we might be
using xive, in which case icp_ops is not initialised, it's a xics specific
structure. This leads to an oops such as:
Unable to handle kernel paging request for data at address 0x00000028
Oops: Kernel access of bad area, sig: 11 [#1]
NIP pnv_p9_dd1_cause_ipi+0x74/0xe0
LR smp_muxed_ipi_message_pass+0x54/0x70
To fix it, rather than using icp_ops which might be NULL, have both xics and
xive set smp_ops->cause_ipi, and then in the powernv code we save that as
ic_cause_ipi before overriding smp_ops->cause_ipi. For paranoia add a WARN_ON()
to check if somehow smp_ops->cause_ipi is NULL.
Fixes: b866cc2199d6 ("powerpc: Change the doorbell IPI calling convention")
Tested-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/platforms/powernv/smp.c | 12 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/xics/xics-common.c | 3 |
2 files changed, 11 insertions, 4 deletions
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index 951a2e230cfa..5189445db164 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -249,12 +249,15 @@ static int pnv_smp_prepare_cpu(int cpu) return 0; } +/* Cause IPI as setup by the interrupt controller (xics or xive) */ +static void (*ic_cause_ipi)(int cpu); + static void pnv_cause_ipi(int cpu) { if (doorbell_try_core_ipi(cpu)) return; - icp_ops->cause_ipi(cpu); + ic_cause_ipi(cpu); } static void pnv_p9_dd1_cause_ipi(int cpu) @@ -269,7 +272,7 @@ static void pnv_p9_dd1_cause_ipi(int cpu) if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) doorbell_global_ipi(cpu); else - icp_ops->cause_ipi(cpu); + ic_cause_ipi(cpu); put_cpu(); } @@ -282,6 +285,9 @@ static void __init pnv_smp_probe(void) xics_smp_probe(); if (cpu_has_feature(CPU_FTR_DBELL)) { + ic_cause_ipi = smp_ops->cause_ipi; + WARN_ON(!ic_cause_ipi); + if (cpu_has_feature(CPU_FTR_ARCH_300)) { if (cpu_has_feature(CPU_FTR_POWER9_DD1)) smp_ops->cause_ipi = pnv_p9_dd1_cause_ipi; @@ -290,8 +296,6 @@ static void __init pnv_smp_probe(void) } else { smp_ops->cause_ipi = pnv_cause_ipi; } - } else { - smp_ops->cause_ipi = icp_ops->cause_ipi; } } diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c index 2eb53c12ee6e..ffe138b8b9dc 100644 --- a/arch/powerpc/sysdev/xics/xics-common.c +++ b/arch/powerpc/sysdev/xics/xics-common.c @@ -145,6 +145,9 @@ void __init xics_smp_probe(void) { /* Register all the IPIs */ xics_request_ipi(); + + /* Setup cause_ipi callback based on which ICP is used */ + smp_ops->cause_ipi = icp_ops->cause_ipi; } #endif /* CONFIG_SMP */ |