ARM: 7332/1: extract out code patch function from kprobes
Extract out the code patching code from kprobes so that it can be used
from the jump label code. Additionally, the separated code:
- Uses the IS_ENABLED() macros instead of the #ifdefs for THUMB2
support
- Unifies the two separate functions in kprobes, providing one function
that uses stop_machine() internally, and one that can be called from
stop_machine() directly
- Patches the text on all CPUs only on processors requiring software
broadcasting of cache operations
Acked-by: Jon Medhurst <tixy@yxit.co.uk>
Tested-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 129c116..ab1869d 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -29,6 +29,7 @@
#include <asm/cacheflush.h>
#include "kprobes.h"
+#include "patch.h"
#define MIN_STACK_SIZE(addr) \
min((unsigned long)MAX_STACK_SIZE, \
@@ -103,58 +104,34 @@
return 0;
}
-#ifdef CONFIG_THUMB2_KERNEL
-
-/*
- * For a 32-bit Thumb breakpoint spanning two memory words we need to take
- * special precautions to insert the breakpoint atomically, especially on SMP
- * systems. This is achieved by calling this arming function using stop_machine.
- */
-static int __kprobes set_t32_breakpoint(void *addr)
-{
- ((u16 *)addr)[0] = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION >> 16;
- ((u16 *)addr)[1] = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION & 0xffff;
- flush_insns(addr, 2*sizeof(u16));
- return 0;
-}
-
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- uintptr_t addr = (uintptr_t)p->addr & ~1; /* Remove any Thumb flag */
+ unsigned int brkp;
+ void *addr;
- if (!is_wide_instruction(p->opcode)) {
- *(u16 *)addr = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION;
- flush_insns(addr, sizeof(u16));
- } else if (addr & 2) {
- /* A 32-bit instruction spanning two words needs special care */
- stop_machine(set_t32_breakpoint, (void *)addr, &cpu_online_map);
+ if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
+ /* Remove any Thumb flag */
+ addr = (void *)((uintptr_t)p->addr & ~1);
+
+ if (is_wide_instruction(p->opcode))
+ brkp = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION;
+ else
+ brkp = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION;
} else {
- /* Word aligned 32-bit instruction can be written atomically */
- u32 bkp = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION;
-#ifndef __ARMEB__ /* Swap halfwords for little-endian */
- bkp = (bkp >> 16) | (bkp << 16);
-#endif
- *(u32 *)addr = bkp;
- flush_insns(addr, sizeof(u32));
+ kprobe_opcode_t insn = p->opcode;
+
+ addr = p->addr;
+ brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION;
+
+ if (insn >= 0xe0000000)
+ brkp |= 0xe0000000; /* Unconditional instruction */
+ else
+ brkp |= insn & 0xf0000000; /* Copy condition from insn */
}
+
+ patch_text(addr, brkp);
}
-#else /* !CONFIG_THUMB2_KERNEL */
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- kprobe_opcode_t insn = p->opcode;
- kprobe_opcode_t brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION;
- if (insn >= 0xe0000000)
- brkp |= 0xe0000000; /* Unconditional instruction */
- else
- brkp |= insn & 0xf0000000; /* Copy condition from insn */
- *p->addr = brkp;
- flush_insns(p->addr, sizeof(p->addr[0]));
-}
-
-#endif /* !CONFIG_THUMB2_KERNEL */
-
/*
* The actual disarming is done here on each CPU and synchronized using
* stop_machine. This synchronization is necessary on SMP to avoid removing
@@ -166,25 +143,10 @@
int __kprobes __arch_disarm_kprobe(void *p)
{
struct kprobe *kp = p;
-#ifdef CONFIG_THUMB2_KERNEL
- u16 *addr = (u16 *)((uintptr_t)kp->addr & ~1);
- kprobe_opcode_t insn = kp->opcode;
- unsigned int len;
+ void *addr = (void *)((uintptr_t)kp->addr & ~1);
- if (is_wide_instruction(insn)) {
- ((u16 *)addr)[0] = insn>>16;
- ((u16 *)addr)[1] = insn;
- len = 2*sizeof(u16);
- } else {
- ((u16 *)addr)[0] = insn;
- len = sizeof(u16);
- }
- flush_insns(addr, len);
+ __patch_text(addr, kp->opcode);
-#else /* !CONFIG_THUMB2_KERNEL */
- *kp->addr = kp->opcode;
- flush_insns(kp->addr, sizeof(kp->addr[0]));
-#endif
return 0;
}