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| author |   Zhen Lei <thunder.leizhen@huawei.com> | 2022-08-25 07:31:54 +0100 |
|---|---|---|
| committer |   Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-08-31 14:50:08 +0100 |
| commit | 370d51c84216d1a41f125f0b04614e677ffe54e3 (patch) | |
| tree | fa1945f22dc9c5c248c0cb732752eee5f0a90af2 /arch/arm/kernel/traps.c | |
| parent | ARM: 9228/1: vfp: kill vfp_flush/release_thread() (diff) | |
| download | linux-dev-370d51c84216d1a41f125f0b04614e677ffe54e3.tar.xz linux-dev-370d51c84216d1a41f125f0b04614e677ffe54e3.zip | |
ARM: 9232/1: Replace this_cpu_* with raw_cpu_* in handle_bad_stack()
The hardware automatically disable the IRQ interrupt before jumping to the
interrupt or exception vector. Therefore, the preempt_disable() operation
in this_cpu_read() after macro expansion is unnecessary. In fact, function
this_cpu_read() may trigger scheduling, see pseudocode below.
Pseudocode of this_cpu_read(xx):
preempt_disable_notrace();
raw_cpu_read(xx);
if (unlikely(__preempt_count_dec_and_test()))
__preempt_schedule_notrace();
Therefore, use raw_cpu_* instead of this_cpu_* to eliminate potential
hazards. At the very least, it reduces a few lines of assembly code.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/traps.c')
| -rw-r--r-- | arch/arm/kernel/traps.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 82fde11d6b8d..a24d26eaa2cb 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -920,9 +920,9 @@ asmlinkage void handle_bad_stack(struct pt_regs *regs) { unsigned long tsk_stk = (unsigned long)current->stack; #ifdef CONFIG_IRQSTACKS - unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr); + unsigned long irq_stk = (unsigned long)raw_cpu_read(irq_stack_ptr); #endif - unsigned long ovf_stk = (unsigned long)this_cpu_read(overflow_stack_ptr); + unsigned long ovf_stk = (unsigned long)raw_cpu_read(overflow_stack_ptr); console_verbose(); pr_emerg("Insufficient stack space to handle exception!"); |