[PATCH v2 1/5] powerpc/code-patching: Remove #ifdef CONFIG_STRICT_KERNEL_RWX

From: Christophe Leroy
Date: Fri Dec 02 2022 - 03:34:38 EST


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@xxxxxxxxxx>
---
v2 of the series is only a rebase over today's powerpc/next
---
arch/powerpc/lib/code-patching.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 0c5fdfd4765d..98a7bbfc8f67 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -46,8 +46,6 @@ int raw_patch_instruction(u32 *addr, ppc_inst_t instr)
return __patch_instruction(addr, instr, addr);
}

-#ifdef CONFIG_STRICT_KERNEL_RWX
-
struct patch_context {
union {
struct vm_struct *area;
@@ -208,6 +206,9 @@ void __init poking_init(void)
{
int ret;

+ if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+ return;
+
if (mm_patch_enabled())
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
"powerpc/text_poke_mm:online",
@@ -358,7 +359,8 @@ 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);
@@ -370,14 +372,6 @@ 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);

--
2.38.1