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ARM: smp: Pass task to secondary_start_kernel

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This avoids needing to compute the task pointer in this function, which
will no longer be possible once we move thread_info off the stack.

Signed-off-by: Keith Packard <keithpac@amazon.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
This commit is contained in:
Keith Packard 2021-09-18 10:44:35 +02:00 committed by Ard Biesheuvel
parent dfbdcda280
commit 19f29aebd9
4 changed files with 12 additions and 5 deletions
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3
arch/arm/include/asm/smp.h
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@ -48,7 +48,7 @@ extern void set_smp_ipi_range(int ipi_base, int nr_ipi);
* Called from platform specific assembly code, this is the
* secondary CPU entry point.
*/
asmlinkage void secondary_start_kernel(void);
asmlinkage void secondary_start_kernel(struct task_struct *task);
/*
@ -61,6 +61,7 @@ struct secondary_data {
};
unsigned long swapper_pg_dir;
void *stack;
struct task_struct *task;
};
extern struct secondary_data secondary_data;
extern void secondary_startup(void);

1
arch/arm/kernel/head-nommu.S
View File

@ -115,6 +115,7 @@ ENTRY(secondary_startup)
ret r12
1: bl __after_proc_init
ldr sp, [r7, #12] @ set up the stack pointer
ldr r0, [r7, #16] @ set up task pointer
mov fp, #0
b secondary_start_kernel
ENDPROC(secondary_startup)

5
arch/arm/kernel/head.S
View File

@ -424,8 +424,9 @@ ENDPROC(secondary_startup)
ENDPROC(secondary_startup_arm)
ENTRY(__secondary_switched)
ldr_l r7, secondary_data + 12 @ get secondary_data.stack
mov sp, r7
adr_l r7, secondary_data + 12 @ get secondary_data.stack
ldr sp, [r7]
ldr r0, [r7, #4] @ get secondary_data.task
mov fp, #0
b secondary_start_kernel
ENDPROC(__secondary_switched)

8
arch/arm/kernel/smp.c
View File

@ -153,6 +153,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
secondary_data.pgdir = virt_to_phys(idmap_pgd);
secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
#endif
secondary_data.task = idle;
sync_cache_w(&secondary_data);
/*
@ -375,9 +376,12 @@ void arch_cpu_idle_dead(void)
*/
__asm__("mov sp, %0\n"
" mov fp, #0\n"
" mov r0, %1\n"
" b secondary_start_kernel"
:
: "r" (task_stack_page(current) + THREAD_SIZE - 8));
: "r" (task_stack_page(current) + THREAD_SIZE - 8),
"r" (current)
: "r0");
}
#endif /* CONFIG_HOTPLUG_CPU */
@ -400,7 +404,7 @@ static void smp_store_cpu_info(unsigned int cpuid)
* This is the secondary CPU boot entry. We're using this CPUs
* idle thread stack, but a set of temporary page tables.
*/
asmlinkage void secondary_start_kernel(void)
asmlinkage void secondary_start_kernel(struct task_struct *task)
{
struct mm_struct *mm = &init_mm;
unsigned int cpu;