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| author | Nicholas Piggin <npiggin@gmail.com> | 2018-04-01 15:50:36 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-04-03 21:50:08 +1000 |
| commit | 252988cbf037f3d446eea222afb46cc134d32c71 (patch) | |
| tree | 06ef89cd7dbc79de88ce5a27cc8ce05d751a7bda /arch/powerpc/kernel/process.c | |
| parent | e303c08787c4cbe1ca07912817dff205ed802985 (diff) | |
| download | talos-op-linux-252988cbf037f3d446eea222afb46cc134d32c71.tar.gz talos-op-linux-252988cbf037f3d446eea222afb46cc134d32c71.zip | |
powerpc: Don't write to DABR on >= Power8 if DAWR is disabled
flush_thread() calls __set_breakpoint() via set_debug_reg_defaults()
without checking ppc_breakpoint_available(). On Power8 or later CPUs
which have the DAWR feature disabled that will cause a write to the
DABR which is incorrect as those CPUs don't have a DABR.
Fix it two ways, by checking ppc_breakpoint_available() in
set_debug_reg_defaults(), and also by reworking __set_breakpoint() to
only write to DABR on Power7 or earlier.
Fixes: 9654153158d3 ("powerpc: Disable DAWR in the base POWER9 CPU features")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Rework the logic in __set_breakpoint()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/process.c')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 24a591b4dbe9..1237f13fed51 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -718,7 +718,8 @@ static void set_debug_reg_defaults(struct thread_struct *thread) { thread->hw_brk.address = 0; thread->hw_brk.type = 0; - set_breakpoint(&thread->hw_brk); + if (ppc_breakpoint_available()) + set_breakpoint(&thread->hw_brk); } #endif /* !CONFIG_HAVE_HW_BREAKPOINT */ #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ @@ -815,9 +816,14 @@ void __set_breakpoint(struct arch_hw_breakpoint *brk) memcpy(this_cpu_ptr(¤t_brk), brk, sizeof(*brk)); if (cpu_has_feature(CPU_FTR_DAWR)) + // Power8 or later set_dawr(brk); - else + else if (!cpu_has_feature(CPU_FTR_ARCH_207S)) + // Power7 or earlier set_dabr(brk); + else + // Shouldn't happen due to higher level checks + WARN_ON_ONCE(1); } void set_breakpoint(struct arch_hw_breakpoint *brk) |
