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>hifive-unleashed-5.1
Rabin Vincent
Russell King
parent
d82227cf8f
commit
b21d55e98a
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@ -8,6 +8,7 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
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ifdef CONFIG_FUNCTION_TRACER
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CFLAGS_REMOVE_ftrace.o = -pg
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CFLAGS_REMOVE_insn.o = -pg
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CFLAGS_REMOVE_patch.o = -pg
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endif
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CFLAGS_REMOVE_return_address.o = -pg
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@ -38,7 +39,7 @@ obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
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obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o
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obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
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obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
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obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o
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obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o patch.o
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ifdef CONFIG_THUMB2_KERNEL
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obj-$(CONFIG_KPROBES) += kprobes-thumb.o
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else
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@ -29,6 +29,7 @@
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#include <asm/cacheflush.h>
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#include "kprobes.h"
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#include "patch.h"
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#define MIN_STACK_SIZE(addr) \
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min((unsigned long)MAX_STACK_SIZE, \
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@ -103,58 +104,34 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
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return 0;
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}
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#ifdef CONFIG_THUMB2_KERNEL
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/*
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* For a 32-bit Thumb breakpoint spanning two memory words we need to take
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* special precautions to insert the breakpoint atomically, especially on SMP
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* systems. This is achieved by calling this arming function using stop_machine.
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*/
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static int __kprobes set_t32_breakpoint(void *addr)
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{
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((u16 *)addr)[0] = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION >> 16;
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((u16 *)addr)[1] = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION & 0xffff;
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flush_insns(addr, 2*sizeof(u16));
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return 0;
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}
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void __kprobes arch_arm_kprobe(struct kprobe *p)
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{
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uintptr_t addr = (uintptr_t)p->addr & ~1; /* Remove any Thumb flag */
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unsigned int brkp;
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void *addr;
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if (!is_wide_instruction(p->opcode)) {
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*(u16 *)addr = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION;
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flush_insns(addr, sizeof(u16));
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} else if (addr & 2) {
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/* A 32-bit instruction spanning two words needs special care */
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stop_machine(set_t32_breakpoint, (void *)addr, &cpu_online_map);
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if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
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/* Remove any Thumb flag */
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addr = (void *)((uintptr_t)p->addr & ~1);
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if (is_wide_instruction(p->opcode))
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brkp = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION;
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else
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brkp = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION;
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} else {
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/* Word aligned 32-bit instruction can be written atomically */
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u32 bkp = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION;
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#ifndef __ARMEB__ /* Swap halfwords for little-endian */
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bkp = (bkp >> 16) | (bkp << 16);
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#endif
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*(u32 *)addr = bkp;
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flush_insns(addr, sizeof(u32));
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kprobe_opcode_t insn = p->opcode;
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addr = p->addr;
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brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION;
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if (insn >= 0xe0000000)
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brkp |= 0xe0000000; /* Unconditional instruction */
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else
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brkp |= insn & 0xf0000000; /* Copy condition from insn */
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}
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patch_text(addr, brkp);
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}
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#else /* !CONFIG_THUMB2_KERNEL */
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void __kprobes arch_arm_kprobe(struct kprobe *p)
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{
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kprobe_opcode_t insn = p->opcode;
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kprobe_opcode_t brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION;
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if (insn >= 0xe0000000)
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brkp |= 0xe0000000; /* Unconditional instruction */
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else
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brkp |= insn & 0xf0000000; /* Copy condition from insn */
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*p->addr = brkp;
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flush_insns(p->addr, sizeof(p->addr[0]));
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}
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#endif /* !CONFIG_THUMB2_KERNEL */
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/*
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* The actual disarming is done here on each CPU and synchronized using
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* stop_machine. This synchronization is necessary on SMP to avoid removing
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@ -166,25 +143,10 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
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int __kprobes __arch_disarm_kprobe(void *p)
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{
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struct kprobe *kp = p;
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#ifdef CONFIG_THUMB2_KERNEL
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u16 *addr = (u16 *)((uintptr_t)kp->addr & ~1);
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kprobe_opcode_t insn = kp->opcode;
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unsigned int len;
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void *addr = (void *)((uintptr_t)kp->addr & ~1);
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if (is_wide_instruction(insn)) {
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((u16 *)addr)[0] = insn>>16;
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((u16 *)addr)[1] = insn;
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len = 2*sizeof(u16);
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} else {
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((u16 *)addr)[0] = insn;
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len = sizeof(u16);
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}
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flush_insns(addr, len);
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__patch_text(addr, kp->opcode);
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#else /* !CONFIG_THUMB2_KERNEL */
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*kp->addr = kp->opcode;
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flush_insns(kp->addr, sizeof(kp->addr[0]));
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#endif
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return 0;
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}
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@ -0,0 +1,75 @@
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/stop_machine.h>
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#include <asm/cacheflush.h>
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#include <asm/smp_plat.h>
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#include <asm/opcodes.h>
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#include "patch.h"
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struct patch {
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void *addr;
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unsigned int insn;
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};
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void __kprobes __patch_text(void *addr, unsigned int insn)
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{
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bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
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int size;
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if (thumb2 && __opcode_is_thumb16(insn)) {
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*(u16 *)addr = __opcode_to_mem_thumb16(insn);
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size = sizeof(u16);
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} else if (thumb2 && ((uintptr_t)addr & 2)) {
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u16 first = __opcode_thumb32_first(insn);
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u16 second = __opcode_thumb32_second(insn);
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u16 *addrh = addr;
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addrh[0] = __opcode_to_mem_thumb16(first);
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addrh[1] = __opcode_to_mem_thumb16(second);
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size = sizeof(u32);
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} else {
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if (thumb2)
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insn = __opcode_to_mem_thumb32(insn);
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else
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insn = __opcode_to_mem_arm(insn);
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*(u32 *)addr = insn;
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size = sizeof(u32);
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}
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flush_icache_range((uintptr_t)(addr),
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(uintptr_t)(addr) + size);
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}
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static int __kprobes patch_text_stop_machine(void *data)
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{
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struct patch *patch = data;
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__patch_text(patch->addr, patch->insn);
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return 0;
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}
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void __kprobes patch_text(void *addr, unsigned int insn)
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{
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struct patch patch = {
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.addr = addr,
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.insn = insn,
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};
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if (cache_ops_need_broadcast()) {
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stop_machine(patch_text_stop_machine, &patch, cpu_online_mask);
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} else {
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bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL)
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&& __opcode_is_thumb32(insn)
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&& ((uintptr_t)addr & 2);
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if (straddles_word)
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stop_machine(patch_text_stop_machine, &patch, NULL);
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else
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__patch_text(addr, insn);
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}
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}
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@ -0,0 +1,7 @@
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#ifndef _ARM_KERNEL_PATCH_H
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#define _ARM_KERNEL_PATCH_H
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void patch_text(void *addr, unsigned int insn);
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void __patch_text(void *addr, unsigned int insn);
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#endif
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