[PATCH -v5 13/17] arm/ftrace: Use __patch_text_real()

Peter Zijlstra
2019-11-11T14:47:36Z

Instead of flipping text protection, use the patch_text infrastructure
that uses a fixmap alias where required.

This removes the last user of set_all_modules_text_*().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ard.biesheuvel@linaro.org
Cc: rabin@rab.in
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: james.morse@arm.com
---
arch/arm/kernel/ftrace.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -22,6 +22,7 @@
#include <asm/ftrace.h>
#include <asm/insn.h>
#include <asm/set_memory.h>
+#include <asm/patch.h>

#ifdef CONFIG_THUMB2_KERNEL
#define NOP 0xf85deb04 /* pop.w {lr} */
@@ -31,13 +32,15 @@

#ifdef CONFIG_DYNAMIC_FTRACE

+static int patch_text_remap = 0;
+
static int __ftrace_modify_code(void *data)
{
int *command = data;

- set_kernel_text_rw();
+ patch_text_remap++;
ftrace_modify_all_code(*command);
- set_kernel_text_ro();
+ patch_text_remap--;

return 0;
}
@@ -59,13 +62,13 @@ static unsigned long adjust_address(stru

int ftrace_arch_code_modify_prepare(void)
{
- set_all_modules_text_rw();
+ patch_text_remap++;
return 0;
}

int ftrace_arch_code_modify_post_process(void)
{
- set_all_modules_text_ro();
+ patch_text_remap--;
/* Make sure any TLB misses during machine stop are cleared. */
flush_tlb_all();
return 0;
@@ -97,10 +100,7 @@ static int ftrace_modify_code(unsigned l
return -EINVAL;
}

- if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE))
- return -EPERM;
-
- flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
+ __patch_text_real((void *)pc, new, patch_text_remap);

return 0;
}