Commit b0337678 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu
parent cb3ac452

arch/powerpc/include/asm/code-patching.h

+2 −0
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/lib/code-patching.c

+4 −1
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/mm/mem.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

}