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

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

Commit 51c3c62b58 ("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: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/504310828f473d424e2ed229eff57bf075f52796.1669969781.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2022-12-02 09:31:43 +01:00 committed by Michael Ellerman
parent b988e7797d
commit 6f3a81b600
3 changed files with 1 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/include/asm/code-patching.h
View File

@ -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 :
*

13
arch/powerpc/lib/code-patching.c
View File

@ -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)

1
arch/powerpc/mm/mem.c
View File

@ -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();
}