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Diffstat (limited to 'arch/arm/kernel/ftrace.c')
-rw-r--r--arch/arm/kernel/ftrace.c100
1 files changed, 28 insertions, 72 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index c0062ad..df0bf0c 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -16,10 +16,13 @@
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
+#include <asm/opcodes.h>
#include <asm/ftrace.h>
+#include "insn.h"
+
#ifdef CONFIG_THUMB2_KERNEL
-#define NOP 0xeb04f85d /* pop.w {lr} */
+#define NOP 0xf85deb04 /* pop.w {lr} */
#else
#define NOP 0xe8bd4000 /* pop {lr} */
#endif
@@ -60,76 +63,31 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
}
#endif
-#ifdef CONFIG_THUMB2_KERNEL
-static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,
- bool link)
-{
- unsigned long s, j1, j2, i1, i2, imm10, imm11;
- unsigned long first, second;
- long offset;
-
- offset = (long)addr - (long)(pc + 4);
- if (offset < -16777216 || offset > 16777214) {
- WARN_ON_ONCE(1);
- return 0;
- }
-
- s = (offset >> 24) & 0x1;
- i1 = (offset >> 23) & 0x1;
- i2 = (offset >> 22) & 0x1;
- imm10 = (offset >> 12) & 0x3ff;
- imm11 = (offset >> 1) & 0x7ff;
-
- j1 = (!i1) ^ s;
- j2 = (!i2) ^ s;
-
- first = 0xf000 | (s << 10) | imm10;
- second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;
- if (link)
- second |= 1 << 14;
-
- return (second << 16) | first;
-}
-#else
-static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,
- bool link)
-{
- unsigned long opcode = 0xea000000;
- long offset;
-
- if (link)
- opcode |= 1 << 24;
-
- offset = (long)addr - (long)(pc + 8);
- if (unlikely(offset < -33554432 || offset > 33554428)) {
- /* Can't generate branches that far (from ARM ARM). Ftrace
- * doesn't generate branches outside of kernel text.
- */
- WARN_ON_ONCE(1);
- return 0;
- }
-
- offset = (offset >> 2) & 0x00ffffff;
-
- return opcode | offset;
-}
-#endif
-
static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
{
- return ftrace_gen_branch(pc, addr, true);
+ return arm_gen_branch_link(pc, addr);
}
static int ftrace_modify_code(unsigned long pc, unsigned long old,
- unsigned long new)
+ unsigned long new, bool validate)
{
unsigned long replaced;
- if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))
- return -EFAULT;
+ 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 (replaced != old)
- return -EINVAL;
+ if (validate) {
+ if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ if (replaced != old)
+ return -EINVAL;
+ }
if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE))
return -EPERM;
@@ -141,23 +99,21 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
int ftrace_update_ftrace_func(ftrace_func_t func)
{
- unsigned long pc, old;
+ unsigned long pc;
unsigned long new;
int ret;
pc = (unsigned long)&ftrace_call;
- memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, (unsigned long)func);
- ret = ftrace_modify_code(pc, old, new);
+ ret = ftrace_modify_code(pc, 0, new, false);
#ifdef CONFIG_OLD_MCOUNT
if (!ret) {
pc = (unsigned long)&ftrace_call_old;
- memcpy(&old, &ftrace_call_old, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, (unsigned long)func);
- ret = ftrace_modify_code(pc, old, new);
+ ret = ftrace_modify_code(pc, 0, new, false);
}
#endif
@@ -172,7 +128,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
old = ftrace_nop_replace(rec);
new = ftrace_call_replace(ip, adjust_address(rec, addr));
- return ftrace_modify_code(rec->ip, old, new);
+ return ftrace_modify_code(rec->ip, old, new, true);
}
int ftrace_make_nop(struct module *mod,
@@ -185,7 +141,7 @@ int ftrace_make_nop(struct module *mod,
old = ftrace_call_replace(ip, adjust_address(rec, addr));
new = ftrace_nop_replace(rec);
- ret = ftrace_modify_code(ip, old, new);
+ ret = ftrace_modify_code(ip, old, new, true);
#ifdef CONFIG_OLD_MCOUNT
if (ret == -EINVAL && addr == MCOUNT_ADDR) {
@@ -193,7 +149,7 @@ int ftrace_make_nop(struct module *mod,
old = ftrace_call_replace(ip, adjust_address(rec, addr));
new = ftrace_nop_replace(rec);
- ret = ftrace_modify_code(ip, old, new);
+ ret = ftrace_modify_code(ip, old, new, true);
}
#endif
@@ -249,12 +205,12 @@ static int __ftrace_modify_caller(unsigned long *callsite,
{
unsigned long caller_fn = (unsigned long) func;
unsigned long pc = (unsigned long) callsite;
- unsigned long branch = ftrace_gen_branch(pc, caller_fn, false);
+ unsigned long branch = arm_gen_branch(pc, caller_fn);
unsigned long nop = 0xe1a00000; /* mov r0, r0 */
unsigned long old = enable ? nop : branch;
unsigned long new = enable ? branch : nop;
- return ftrace_modify_code(pc, old, new);
+ return ftrace_modify_code(pc, old, new, true);
}
static int ftrace_modify_graph_caller(bool enable)