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author | Brian Gerst <brgerst@gmail.com> | 2023-03-17 01:21:03 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2023-03-21 15:35:53 +0300 |
commit | 3adee777ad0d328e76ca9015cb7924134a992e81 (patch) | |
tree | bee9a622486c7759ff8c4325d982143376fd67cb /arch/x86/include/asm/processor.h | |
parent | cefad862f23874174136a48d91cb4a6ac3b1c5ce (diff) | |
download | linux-3adee777ad0d328e76ca9015cb7924134a992e81.tar.xz |
x86/smpboot: Remove initial_stack on 64-bit
In order to facilitate parallel startup, start to eliminate some of the
global variables passing information to CPUs in the startup path.
However, start by introducing one more: smpboot_control. For now this
merely holds the CPU# of the CPU which is coming up. Each CPU can then
find its own per-cpu data, and everything else it needs can be found
from there, allowing the other global variables to be removed.
First to be removed is initial_stack. Each CPU can load %rsp from its
current_task->thread.sp instead. That is already set up with the correct
idle thread for APs. Set up the .sp field in INIT_THREAD on x86 so that
the BSP also finds a suitable stack pointer in the static per-cpu data
when coming up on first boot.
On resume from S3, the CPU needs a temporary stack because its idle task
is already active. Instead of setting initial_stack, the sleep code can
simply set its own current->thread.sp to point to the temporary stack.
Nobody else cares about ->thread.sp for a thread which is currently on
a CPU, because the true value is actually in the %rsp register. Which
is restored with the rest of the CPU context in do_suspend_lowlevel().
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Usama Arif <usama.arif@bytedance.com>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20230316222109.1940300-7-usama.arif@bytedance.com
Diffstat (limited to 'arch/x86/include/asm/processor.h')
-rw-r--r-- | arch/x86/include/asm/processor.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 8d73004e4cac..a1e4fa58b357 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -647,7 +647,11 @@ static inline void spin_lock_prefetch(const void *x) #define KSTK_ESP(task) (task_pt_regs(task)->sp) #else -#define INIT_THREAD { } +extern unsigned long __end_init_task[]; + +#define INIT_THREAD { \ + .sp = (unsigned long)&__end_init_task - sizeof(struct pt_regs), \ +} extern unsigned long KSTK_ESP(struct task_struct *task); |