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 51c3c62b58b3 ("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

diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
index 1c6316ec4b74f9bdc9722bfd03d9e1cbf39be6cf..3f881548fb61c12fcd04a9d8a5cf518aeb6d706b 100644 (file)
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -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 :
  *

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index a6a5047f8ba2324abfc28d6f4aea49475a006a36..73ce4b90bb1b808949251684fc96a84dd803ca40 100644 (file)
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -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)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 84d171953ba44eb4fbcfb42772da104404554ff3..8b121df7b08f8677d72c08fa0d63b1d7509fef96 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -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();
 }