Commit 6f3a81b6 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/code-patching: Remove protection against patching init addresses after init 



Once init section is freed, attempting to patch init code
ends up in the weed.

Commit 51c3c62b ("powerpc: Avoid code patching freed init sections")
protected patch_instruction() against that, but it is the responsibility
of the caller to ensure that the patched memory is valid.

All callers have now been verified and fixed so the check
can be removed.

This improves ftrace activation by about 2% on 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/504310828f473d424e2ed229eff57bf075f52796.1669969781.git.christophe.leroy@csgroup.eu
parent b988e779

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

+0 −2
Original line number Diff line number Diff line
@@ -22,8 +22,6 @@ 
#define BRANCH_SET_LINK	0x1

#define BRANCH_ABSOLUTE	0x2



DECLARE_STATIC_KEY_FALSE(init_mem_is_free);



/*

 * Powerpc branch instruction is :

 *

arch/powerpc/lib/code-patching.c

+1 −12
Original line number Diff line number Diff line
@@ -349,7 +349,7 @@ static int __do_patch_instruction(u32 *addr, ppc_inst_t instr) 
	return err;

}



static int do_patch_instruction(u32 *addr, ppc_inst_t instr)

int patch_instruction(u32 *addr, ppc_inst_t instr)

{

	int err;

	unsigned long flags;
@@ -372,17 +372,6 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) 


	return err;

}



__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 (static_branch_likely(&init_mem_is_free) && init_section_contains(addr, 4))

		return 0;



	return do_patch_instruction(addr, instr);

}

NOKPROBE_SYMBOL(patch_instruction);



int patch_branch(u32 *addr, unsigned long target, int flags)

arch/powerpc/mm/mem.c

+0 −1
Original line number Diff line number Diff line
@@ -344,7 +344,6 @@ 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);

	ftrace_free_init_tramp();

}