Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCHv8 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback | Date | Tue, 27 Feb 2024 20:16:14 +0200 |
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If the helper is defined, it is called instead of halt() to stop the CPU at the end of stop_this_cpu() and on crash CPU shutdown.
ACPI MADT will use it to hand over the CPU to BIOS in order to be able to wake it up again after kexec.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Kai Huang <kai.huang@intel.com> --- arch/x86/include/asm/smp.h | 1 + arch/x86/kernel/process.c | 7 +++++++ arch/x86/kernel/reboot.c | 6 ++++++ 3 files changed, 14 insertions(+)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 4fab2ed454f3..390d53fd34f9 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -38,6 +38,7 @@ struct smp_ops { int (*cpu_disable)(void); void (*cpu_die)(unsigned int cpu); void (*play_dead)(void); + void (*stop_this_cpu)(void); void (*send_call_func_ipi)(const struct cpumask *mask); void (*send_call_func_single_ipi)(int cpu); diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index ab49ade31b0d..00c1b957476d 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -835,6 +835,13 @@ void __noreturn stop_this_cpu(void *dummy) */ cpumask_clear_cpu(cpu, &cpus_stop_mask); +#ifdef CONFIG_SMP + if (smp_ops.stop_this_cpu) { + smp_ops.stop_this_cpu(); + unreachable(); + } +#endif + for (;;) { /* * Use native_halt() so that memory contents don't change diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 0574d4ad6b41..0a75efe579c0 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -880,6 +880,12 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs) cpu_emergency_disable_virtualization(); atomic_dec(&waiting_for_crash_ipi); + + if (smp_ops.stop_this_cpu) { + smp_ops.stop_this_cpu(); + unreachable(); + } + /* Assume hlt works */ halt(); for (;;) -- 2.43.0
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