diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-03-22 18:40:21 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-05-11 16:06:39 +0300 |
| commit | 1751289268ef959db68b0b6f798d904d6403309a (patch) | |
| tree | 83454af245f0f90cdd7e9b7279956eb503fb3c92 | |
| parent | b033767848c4115e486b1a51946de3bee2ac0fa6 (diff) | |
| download | linux-1751289268ef959db68b0b6f798d904d6403309a.tar.xz | |
powerpc/code-patching: Use jump_label to check if poking_init() is done
It's only during early startup that poking_init() is not done yet,
for instance when calling ftrace_init().
Once poking_init() has been called there must be a poking area, no
need to check it everytime patch_instruction() is called.
ftrace activation time is reduced by 7% with the change on an 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8d6088aca7b63247377b6d9e4897d08d935fbe93.1647962456.git.christophe.leroy@csgroup.eu
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 1ecd166091c9..be670e1abafa 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -79,6 +79,8 @@ static int text_area_cpu_down(unsigned int cpu) return 0; } +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poking_init_done); + /* * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and * we judge it as being preferable to a kernel that will crash later when @@ -89,6 +91,7 @@ void __init poking_init(void) BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke:online", text_area_cpu_up, text_area_cpu_down)); + static_branch_enable(&poking_init_done); } /* @@ -171,7 +174,7 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) * when text_poke_area is not ready, but we still need * to allow patching. We just do the plain old patching */ - if (!this_cpu_read(text_poke_area)) + if (!static_branch_likely(&poking_init_done)) return raw_patch_instruction(addr, instr); local_irq_save(flags); |