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| author | Jean-Philippe Brucker <jean-philippe@linaro.org> | 2024-05-29 14:34:42 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2024-06-28 18:38:31 +0100 |
| commit | 643e12da4a4983a34658e33f2b1581caee9cac8c (patch) | |
| tree | 41063efa666f729411297302cd2ede8d0244d8e1 /arch/arm64/kernel/psci.c | |
| parent | d633da5d3ab1a0eb26a2213d65da1e189e82f8ab (diff) | |
| download | lwn-643e12da4a4983a34658e33f2b1581caee9cac8c.tar.gz lwn-643e12da4a4983a34658e33f2b1581caee9cac8c.zip | |
arm64: psci: Ignore DENIED CPUs
When a CPU is marked as disabled, but online capable in the MADT, PSCI
applies some firmware policy to control when it can be brought online.
PSCI returns DENIED to a CPU_ON request if this is not currently
permitted. The OS can learn the current policy from the _STA enabled bit.
Handle the PSCI DENIED return code gracefully instead of printing an
error.
Note the alternatives to the PSCI cpu_boot() callback do not
return -EPERM so the change in smp.c has no affect.
See https://developer.arm.com/documentation/den0022/f/?lang=en page 58.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
[ morse: Rewrote commit message ]
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240529133446.28446-16-Jonathan.Cameron@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/psci.c')
| -rw-r--r-- | arch/arm64/kernel/psci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 29a8e444db83..fabd732d0a2d 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -40,7 +40,7 @@ static int cpu_psci_cpu_boot(unsigned int cpu) { phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry); int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry); - if (err) + if (err && err != -EPERM) pr_err("failed to boot CPU%d (%d)\n", cpu, err); return err; |