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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-03-22 16:40:20 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-05-11 23:06:39 +1000 |
| commit | b033767848c4115e486b1a51946de3bee2ac0fa6 (patch) | |
| tree | 92673a5723ab58269ac2e7d458fa8f4e45643796 | |
| parent | cb3ac45214c03852430979a43180371a44b74596 (diff) | |
| download | lwn-b033767848c4115e486b1a51946de3bee2ac0fa6.tar.gz lwn-b033767848c4115e486b1a51946de3bee2ac0fa6.zip | |
powerpc/code-patching: Use jump_label for testing freed initmem
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
| -rw-r--r-- | arch/powerpc/include/asm/code-patching.h | 2 | ||||
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 5 | ||||
| -rw-r--r-- | arch/powerpc/mm/mem.c | 2 |
3 files changed, 8 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index 409483b2d0ce..bccc3a538b9f 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -22,6 +22,8 @@ #define BRANCH_SET_LINK 0x1 #define BRANCH_ABSOLUTE 0x2 +DECLARE_STATIC_KEY_FALSE(init_mem_is_free); + bool is_offset_in_branch_range(long offset); bool is_offset_in_cond_branch_range(long offset); int create_branch(ppc_inst_t *instr, const u32 *addr, diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index f970f189875b..1ecd166091c9 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -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); diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 4d221d033804..177fae5ea0d1 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -22,6 +22,7 @@ #include <asm/kasan.h> #include <asm/svm.h> #include <asm/mmzone.h> +#include <asm/code-patching.h> #include <mm/mmu_decl.h> @@ -311,6 +312,7 @@ void free_initmem(void) { ppc_md.progress = ppc_printk_progress; mark_initmem_nx(); + static_branch_enable(&init_mem_is_free); free_initmem_default(POISON_FREE_INITMEM); } |