[PATCHv2 2/6] ARM: ftrace: use canonical Thumb-2 wide instruction format
From: Rabin Vincent <hidden>
Date: 2012-01-28 13:35:21
Subsystem:
arm port, function hooks (ftrace), the rest · Maintainers:
Russell King, Steven Rostedt, Masami Hiramatsu, Linus Torvalds
As commit 592201a9f15 (ARM: Thumb-2: Support Thumb-2 in undefined
instruction handler) says:
32-bit Thumb instructions are specified in the form:
((first_half << 16 ) | second_half)
which matches the layout used by the ARM ARM.
Convert the ftrace code to use the same format to avoid the usage of
different formats in kernel code.
Signed-off-by: Rabin Vincent <redacted>
---
arch/arm/kernel/ftrace.c | 13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index e9488ad..72a381a 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c@@ -16,10 +16,11 @@ #include <linux/uaccess.h> #include <asm/cacheflush.h> +#include <asm/opcodes.h> #include <asm/ftrace.h> #ifdef CONFIG_THUMB2_KERNEL -#define NOP 0xeb04f85d /* pop.w {lr} */ +#define NOP 0xf85deb04 /* pop.w {lr} */ #else #define NOP 0xe8bd4000 /* pop {lr} */ #endif
@@ -88,7 +89,7 @@ static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, if (link) second |= 1 << 14; - return (second << 16) | first; + return __opcode_thumb32_compose(first, second); } #else static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,
@@ -125,6 +126,14 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old, { unsigned long replaced; + if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) { + old = __opcode_to_mem_thumb32(old); + new = __opcode_to_mem_thumb32(new); + } else { + old = __opcode_to_mem_arm(old); + new = __opcode_to_mem_arm(new); + } + if (old) { if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE)) return -EFAULT;
--
1.7.8.3