mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-18 00:24:58 +08:00
arm64: restore get_current() optimisation
Commit c02433dd6d
("arm64: split thread_info from task stack")
inverted the relationship between get_current() and
current_thread_info(), with sp_el0 now holding the current task_struct
rather than the current thead_info. The new implementation of
get_current() prevents the compiler from being able to optimize repeated
calls to either, resulting in a noticeable penalty in some
microbenchmarks.
This patch restores the previous optimisation by implementing
get_current() in the same way as our old current_thread_info(), using a
non-volatile asm statement.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
parent
6ef4fb387d
commit
9d84fb27fa
@ -9,9 +9,17 @@
|
||||
|
||||
struct task_struct;
|
||||
|
||||
/*
|
||||
* We don't use read_sysreg() as we want the compiler to cache the value where
|
||||
* possible.
|
||||
*/
|
||||
static __always_inline struct task_struct *get_current(void)
|
||||
{
|
||||
return (struct task_struct *)read_sysreg(sp_el0);
|
||||
unsigned long sp_el0;
|
||||
|
||||
asm ("mrs %0, sp_el0" : "=r" (sp_el0));
|
||||
|
||||
return (struct task_struct *)sp_el0;
|
||||
}
|
||||
|
||||
#define current get_current()
|
||||
|
Loading…
Reference in New Issue
Block a user