From: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
This patch adds an inline function in_module() to check which space the
instruction pointer in, kernel space or module space.
Note: This will not work when the kernel space and module space are the
same. If they are the same, we need to modify scripts/recordmcount.pl,
ftrace_make_nop/call() and the other related parts to ensure the
enabling/disabling of the calling site to _mcount is right for both
kernel and module.
Signed-off-by: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
---
arch/mips/kernel/ftrace.c | 22 +++++++++++++++++++---
1 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index 628e90b..5a84a1f 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -17,6 +17,22 @@
#include <asm/cacheflush.h>
#include <asm/uasm.h>
+/*
+ * If the Instruction Pointer is in module space (0xc0000000), return true;
+ * otherwise, it is in kernel space (0x80000000), return false.
+ *
+ * FIXME: This will not work when the kernel space and module space are the
+ * same. If they are the same, we need to modify scripts/recordmcount.pl,
+ * ftrace_make_nop/call() and the other related parts to ensure the
+ * enabling/disabling of the calling site to _mcount is right for both kernel
+ * and module.
+ */
+
+static inline int in_module(unsigned long ip)
+{
+ return ip & 0x40000000;
+}
+
#ifdef CONFIG_DYNAMIC_FTRACE
#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */
@@ -78,7 +94,7 @@ int ftrace_make_nop(struct module *mod,
* We have compiled module with -mlong-calls, but compiled the kernel
* without it, we need to cope with them respectively.
*/
- if (ip & 0x40000000) {
+ if (in_module(ip)) {
#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
/*
* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
@@ -117,7 +133,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
unsigned long ip = rec->ip;
/* ip, module: 0xc0000000, kernel: 0x80000000 */
- new = (ip & 0x40000000) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller;
+ new = in_module(ip) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller;
return ftrace_modify_code(ip, new);
}
@@ -188,7 +204,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr,
* instruction "lui v1, hi_16bit_of_mcount"(offset is 20), but for
* kernel, move to the instruction "move ra, at"(offset is 12)
*/
- ip = self_addr - ((self_addr & 0x40000000) ? 20 : 12);
+ ip = self_addr - (in_module(self_addr) ? 20 : 12);
/*
* search the text until finding the non-store instruction or "s{d,w}
--
1.7.0.4
