> --- /dev/null
> +++ b/arch/x86/kernel/acpi/madt.S
> @@ -0,0 +1,28 @@
> +#include <linux/linkage.h>
> +#include <asm/nospec-branch.h>
> +#include <asm/page_types.h>
> +#include <asm/processor-flags.h>
> +
> + .text
> + .align PAGE_SIZE
> +SYM_FUNC_START(asm_acpi_mp_play_dead)
> + /* Load address of reset vector into RCX to jump when kernel is ready */
> + movq acpi_mp_reset_vector_paddr(%rip), %rcx
> +
> + /* zero out flags, and disable interrupts */
> + pushq $0
> + popfq
> +
> + /* Turn off global entries. Following CR3 write will flush them. */
> + movq %cr4, %rdx
> + andq $~(X86_CR4_PGE), %rdx
> + movq %rdx, %cr4
> +
> + /* Switch to identity mapping */
> + movq acpi_mp_pgd(%rip), %rax
> + movq %rax, %cr3
> +
> + /* Jump to reset vector */
> + ANNOTATE_RETPOLINE_SAFE
> + jmp *%rcx
> +SYM_FUNC_END(asm_acpi_mp_play_dead)
> diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
> index 4e92d1d4a5fa..2cc8590ec7a5 100644
> --- a/arch/x86/kernel/acpi/madt_wakeup.c
> +++ b/arch/x86/kernel/acpi/madt_wakeup.c
> @@ -1,12 +1,162 @@
> #include <linux/acpi.h>
> #include <linux/cpu.h>
> +#include <linux/delay.h>
> +#include <linux/memblock.h>
> +#include <linux/pgtable.h>
> +#include <linux/sched/hotplug.h>
> #include <asm/apic.h>
> +#include <asm/init.h>
>
> /* Physical address of the Multiprocessor Wakeup Structure mailbox */
> static u64 acpi_mp_wake_mailbox_paddr;
> /* Virtual address of the Multiprocessor Wakeup Structure mailbox */
> static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox;
>
> +unsigned long acpi_mp_pgd;
> +u64 acpi_mp_reset_vector_paddr;
Nit:
They are both physical address. It's a little bit odd for one to use 'unsigned
long' and the other to use 'u64'.
> +
> +void asm_acpi_mp_play_dead(void);
> +
> +static void __init *alloc_pgt_page(void *context)
> +{
> + return memblock_alloc(PAGE_SIZE, PAGE_SIZE);
> +}
If I am reading correclty, @context is never used. It's not used inside this
function, and all the callers call this with @context = NULL.
[...]
> +
> +static void acpi_mp_play_dead(void)
> +{
> + idle_task_exit();
> + cpuhp_ap_report_dead();
> + asm_acpi_mp_play_dead();
> +}
> +
Looks you can use play_dead_common() here, if you take IRQ disable part out from
the assembly, because play_dead_common() does:
void play_dead_common(void)
{
idle_task_exit();
cpuhp_ap_report_dead();
local_irq_disable();
}
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