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powerpc/code-patching: Use jump_label for testing freed initmem

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Once init is done, initmem is freed forever so no need to
test system_state at every call to patch_instruction().

Use jump_label.

This reduces by 2% the time needed to activate ftrace 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/0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2022-03-22 16:40:20 +01:00
committed by Michael Ellerman
parent cb3ac45214
commit b033767848
3 changed files with 8 additions and 1 deletions
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5
arch/powerpc/lib/code-patching.c
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@@ -8,6 +8,7 @@
#include <linux/init.h>
#include <linux/cpuhotplug.h>
#include <linux/uaccess.h>
#include <linux/jump_label.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
@@ -188,10 +189,12 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
#endif /* CONFIG_STRICT_KERNEL_RWX */
__ro_after_init DEFINE_STATIC_KEY_FALSE(init_mem_is_free);
int patch_instruction(u32 *addr, ppc_inst_t instr)
{
/* Make sure we aren't patching a freed init section */
if (system_state >= SYSTEM_FREEING_INITMEM && init_section_contains(addr, 4))
if (static_branch_likely(&init_mem_is_free) && init_section_contains(addr, 4))
return 0;
return do_patch_instruction(addr, instr);