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| author | Mark Rutland <mark.rutland@arm.com> | 2023-09-06 09:02:58 -0700 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-09-25 17:15:28 +0100 |
| commit | 2b2d0a7a96ab36ed6d963e29b6211b184ef81596 (patch) | |
| tree | bdb4e00131b94e20f8cc5ea3e5ae4fc1e8a389ac /arch/arm64/include/asm/smp.h | |
| parent | d0c14a7d36f035aeae1bdd6f4afc6488400ed5cf (diff) | |
| download | linux-stable-2b2d0a7a96ab36ed6d963e29b6211b184ef81596.tar.gz linux-stable-2b2d0a7a96ab36ed6d963e29b6211b184ef81596.tar.bz2 linux-stable-2b2d0a7a96ab36ed6d963e29b6211b184ef81596.zip | |
arm64: smp: Remove dedicated wakeup IPI
To enable NMI backtrace and KGDB's NMI cpu roundup, we need to free up
at least one dedicated IPI.
On arm64 the IPI_WAKEUP IPI is only used for the ACPI parking protocol,
which itself is only used on some very early ARMv8 systems which
couldn't implement PSCI.
Remove the IPI_WAKEUP IPI, and rely on the IPI_RESCHEDULE IPI to wake
CPUs from the parked state. This will cause a tiny amonut of redundant
work to check the thread flags, but this is miniscule in relation to the
cost of taking and handling the IPI in the first place. We can safely
handle redundant IPI_RESCHEDULE IPIs, so there should be no functional
impact as a result of this change.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230906090246.v13.3.I7209db47ef8ec151d3de61f59005bbc59fe8f113@changeid
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/smp.h')
| -rw-r--r-- | arch/arm64/include/asm/smp.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 9b31e6d0da17..efb13112b408 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -89,9 +89,9 @@ extern void arch_send_call_function_single_ipi(int cpu); extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL -extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask); +extern void arch_send_wakeup_ipi(unsigned int cpu); #else -static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask) +static inline void arch_send_wakeup_ipi(unsigned int cpu) { BUILD_BUG(); } |