diff options
| author |   Nicholas Piggin <npiggin@gmail.com> | 2022-09-26 15:43:02 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-09-28 19:22:11 +1000 |
| commit | 9524f2278f2e6925f147d9140c83f658e7a7c84f (patch) | |
| tree | f8bec0f3448e04cd1eb48944e8e443588e9dd520 /arch/powerpc/include/asm | |
| parent | powerpc/64/interrupt: Fix return to masked context after hard-mask irq becomes pending (diff) | |
| download | linux-dev-9524f2278f2e6925f147d9140c83f658e7a7c84f.tar.xz linux-dev-9524f2278f2e6925f147d9140c83f658e7a7c84f.zip | |
powerpc/64s: Fix irq state management in runlatch functions
When irqs are soft-disabled, MSR[EE] is volatile and can change from
1 to 0 asynchronously (if a PACA_IRQ_MUST_HARD_MASK interrupt hits).
So it can not be used to check hard IRQ enabled status, except to
confirm it is disabled.
ppc64_runlatch_on/off functions use MSR this way to decide whether to
re-enable MSR[EE] after disabling it, which leads to MSR[EE] being
enabled when it shouldn't be (when a PACA_IRQ_MUST_HARD_MASK had
disabled it between reading the MSR and clearing EE).
This has been tolerated in the kernel previously, and it doesn't seem
to cause a problem, but it is unexpected and may trip warnings or cause
other problems as we tighten up this state management. Fix this by only
re-enabling if PACA_IRQ_HARD_DIS is clear.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926054305.2671436-5-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include/asm')
| -rw-r--r-- | arch/powerpc/include/asm/runlatch.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/powerpc/include/asm/runlatch.h b/arch/powerpc/include/asm/runlatch.h index cfb390edf7d0..ceb66d761fe1 100644 --- a/arch/powerpc/include/asm/runlatch.h +++ b/arch/powerpc/include/asm/runlatch.h @@ -19,10 +19,9 @@ extern void __ppc64_runlatch_off(void); do { \ if (cpu_has_feature(CPU_FTR_CTRL) && \ test_thread_local_flags(_TLF_RUNLATCH)) { \ - unsigned long msr = mfmsr(); \ __hard_irq_disable(); \ __ppc64_runlatch_off(); \ - if (msr & MSR_EE) \ + if (!(local_paca->irq_happened & PACA_IRQ_HARD_DIS)) \ __hard_irq_enable(); \ } \ } while (0) @@ -31,10 +30,9 @@ extern void __ppc64_runlatch_off(void); do { \ if (cpu_has_feature(CPU_FTR_CTRL) && \ !test_thread_local_flags(_TLF_RUNLATCH)) { \ - unsigned long msr = mfmsr(); \ __hard_irq_disable(); \ __ppc64_runlatch_on(); \ - if (msr & MSR_EE) \ + if (!(local_paca->irq_happened & PACA_IRQ_HARD_DIS)) \ __hard_irq_enable(); \ } \ } while (0) |