[PATCH v1 2/6] powerpc/code-patching: Remove #ifdef CONFIG_STRICT_KERNEL_RWX

Christophe Leroy christophe.leroy at csgroup.eu
Wed Sep 28 00:33:04 AEST 2022


No need to have one implementation of patch_instruction() for
CONFIG_STRICT_KERNEL_RWX and one for !CONFIG_STRICT_KERNEL_RWX.

In patch_instruction(), call raw_patch_instruction() when
!CONFIG_STRICT_KERNEL_RWX.

In poking_init(), bail out immediately, it will be equivalent
to the weak default implementation.

Everything else is declared static and will be discarded by
GCC when !CONFIG_STRICT_KERNEL_RWX.

Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
---
 arch/powerpc/lib/code-patching.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 0f3acb0534b6..647a0bb35848 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -41,7 +41,6 @@ int raw_patch_instruction(u32 *addr, ppc_inst_t instr)
 	return __patch_instruction(addr, instr, addr);
 }
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
 static DEFINE_PER_CPU(struct vm_struct *, text_poke_area);
 
 static int map_patch_area(void *addr, unsigned long text_poke_addr);
@@ -88,6 +87,9 @@ static __ro_after_init DEFINE_STATIC_KEY_FALSE(poking_init_done);
  */
 void __init poking_init(void)
 {
+	if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+		return;
+
 	BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
 		"powerpc/text_poke:online", text_area_cpu_up,
 		text_area_cpu_down));
@@ -182,7 +184,8 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 	 * when text_poke_area is not ready, but we still need
 	 * to allow patching. We just do the plain old patching
 	 */
-	if (!static_branch_likely(&poking_init_done))
+	if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) ||
+	    !static_branch_likely(&poking_init_done))
 		return raw_patch_instruction(addr, instr);
 
 	local_irq_save(flags);
@@ -191,14 +194,6 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 
 	return err;
 }
-#else /* !CONFIG_STRICT_KERNEL_RWX */
-
-static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
-{
-	return raw_patch_instruction(addr, instr);
-}
-
-#endif /* CONFIG_STRICT_KERNEL_RWX */
 
 __ro_after_init DEFINE_STATIC_KEY_FALSE(init_mem_is_free);
 
-- 
2.37.1



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