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.le...@csgroup.eu>
---
arch/powerpc/lib/code-patching.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index ab434c3853c9..8bd74bbe8b8d 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);
}
static unsigned long get_patch_pfn(void *addr)
@@ -176,7 +179,7 @@ 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);
--
2.35.1
