This patch implements CONFIG_DEBUG_RODATA on PPC32.
As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings
in order to allow page protection setup at the level of each page.
As BAT/LTLB mappings are deactivated, their might be performance
impact. For this reason, we keep it OFF by default.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 32509de6ce4c..06d2ac53f471 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -46,6 +46,7 @@ static int
ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
{
unsigned int replaced;
+ int err;
/*
* Note:
@@ -67,10 +68,11 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
}
/* replace the text with the new text */
- if (patch_instruction((unsigned int *)ip, new))
- return -EPERM;
+ set_kernel_text_rw(ip);
+ err = patch_instruction((unsigned int *)ip, new);
+ set_kernel_text_ro(ip);