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

From: Christophe Leroy
Date: Tue Sep 27 2022 - 10:36:38 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>
---
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