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x86/smp: Add smp_ops.stop_this_cpu() callback

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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>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Tao Liu <ltao@redhat.com>
Link: https://lore.kernel.org/r/20240614095904.1345461-17-kirill.shutemov@linux.intel.com
This commit is contained in:
Kirill A. Shutemov 2024-06-14 12:59:01 +03:00 committed by Borislav Petkov (AMD)
parent db0936830a
commit 26ba7353ca
3 changed files with 14 additions and 0 deletions
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1
arch/x86/include/asm/smp.h
View File

@ -35,6 +35,7 @@ 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);

7
arch/x86/kernel/process.c
View File

@ -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

6
arch/x86/kernel/reboot.c
View File

@ -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 (;;)