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arm64: smp: remove stack from secondary_data 

When we boot a secondary CPU, we pass it a task and a stack to use. As
the stack is always the task's stack, which can be derived from the
task, let's have the secondary CPU derive this itself and avoid passing
redundant information.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210520115031.18509-5-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Mark Rutland 2021-05-20 12:50:29 +01:00 committed by Will Deacon
parent 98c7a1666e
commit 3305e7f74a
4 changed files with 4 additions and 8 deletions
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2
arch/arm64/include/asm/smp.h
View File

@ -73,12 +73,10 @@ asmlinkage void secondary_start_kernel(void);
/*
* Initial data for bringing up a secondary CPU.
* @stack - sp for the secondary CPU
* @status - Result passed back from the secondary CPU to
* indicate failure.
*/
struct secondary_data {
void *stack;
struct task_struct *task;
long status;
};

1
arch/arm64/kernel/asm-offsets.c
View File

@ -99,7 +99,6 @@ int main(void)
DEFINE(SOFTIRQ_SHIFT, SOFTIRQ_SHIFT);
DEFINE(IRQ_CPUSTAT_SOFTIRQ_PENDING, offsetof(irq_cpustat_t, __softirq_pending));
BLANK();
DEFINE(CPU_BOOT_STACK, offsetof(struct secondary_data, stack));
DEFINE(CPU_BOOT_TASK, offsetof(struct secondary_data, task));
BLANK();
DEFINE(FTR_OVR_VAL_OFFSET, offsetof(struct arm64_ftr_override, val));

7
arch/arm64/kernel/head.S
View File

@ -645,11 +645,12 @@ SYM_FUNC_START_LOCAL(__secondary_switched)
isb
adr_l x0, secondary_data
ldr x1, [x0, #CPU_BOOT_STACK] // get secondary_data.stack
cbz x1, __secondary_too_slow
mov sp, x1
ldr x2, [x0, #CPU_BOOT_TASK]
cbz x2, __secondary_too_slow
ldr x1, [x2, #TSK_STACK]
add sp, x1, #THREAD_SIZE
msr sp_el0, x2
scs_load x2, x3
setup_final_frame

2
arch/arm64/kernel/smp.c
View File

@ -120,7 +120,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
* page tables.
*/
secondary_data.task = idle;
secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
update_cpu_boot_status(CPU_MMU_OFF);
/* Now bring the CPU into our world */
@ -141,7 +140,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
pr_crit("CPU%u: failed to come online\n", cpu);
secondary_data.task = NULL;
secondary_data.stack = NULL;
status = READ_ONCE(secondary_data.status);
if (status == CPU_MMU_OFF)
status = READ_ONCE(__early_cpu_boot_status);