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ARM: 7331/1: extract out insn generation code from ftrace

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Extract out the instruction generation code so that it can be used
for jump labels too.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Rabin Vincent
2012-02-18 17:50:06 +01:00
committed by Russell King
parent 4394e2824c
commit d82227cf8f
4 changed files with 87 additions and 59 deletions
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61
arch/arm/kernel/ftrace.c
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@@ -19,6 +19,8 @@
#include <asm/opcodes.h>
#include <asm/ftrace.h>
#include "insn.h"
#ifdef CONFIG_THUMB2_KERNEL
#define NOP 0xf85deb04 /* pop.w {lr} */
#else
@@ -61,64 +63,9 @@ 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 __opcode_thumb32_compose(first, second);
}
#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,
@@ -258,7 +205,7 @@ 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;