diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/arm/kernel/kprobes.c | 86 | ||||
| -rw-r--r-- | arch/arm/kernel/patch.c | 75 | ||||
| -rw-r--r-- | arch/arm/kernel/patch.h | 7 |
4 files changed, 108 insertions, 63 deletions
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index dd3d5f1..8c63ee8 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -8,6 +8,7 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_insn.o = -pg +CFLAGS_REMOVE_patch.o = -pg endif CFLAGS_REMOVE_return_address.o = -pg @@ -38,7 +39,7 @@ obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o -obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o +obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o patch.o ifdef CONFIG_THUMB2_KERNEL obj-$(CONFIG_KPROBES) += kprobes-thumb.o else 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, \ @@ -103,57 +104,33 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) 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 */ - - 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); + unsigned int brkp; + void *addr; + + 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; -#else /* !CONFIG_THUMB2_KERNEL */ + addr = p->addr; + brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION; -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])); -} + if (insn >= 0xe0000000) + brkp |= 0xe0000000; /* Unconditional instruction */ + else + brkp |= insn & 0xf0000000; /* Copy condition from insn */ + } -#endif /* !CONFIG_THUMB2_KERNEL */ + patch_text(addr, brkp); +} /* * The actual disarming is done here on each CPU and synchronized using @@ -166,25 +143,10 @@ void __kprobes arch_arm_kprobe(struct kprobe *p) 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; } diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c new file mode 100644 index 0000000..07314af --- /dev/null +++ b/arch/arm/kernel/patch.c @@ -0,0 +1,75 @@ +#include <linux/kernel.h> +#include <linux/kprobes.h> +#include <linux/stop_machine.h> + +#include <asm/cacheflush.h> +#include <asm/smp_plat.h> +#include <asm/opcodes.h> + +#include "patch.h" + +struct patch { + void *addr; + unsigned int insn; +}; + +void __kprobes __patch_text(void *addr, unsigned int insn) +{ + bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); + int size; + + if (thumb2 && __opcode_is_thumb16(insn)) { + *(u16 *)addr = __opcode_to_mem_thumb16(insn); + size = sizeof(u16); + } else if (thumb2 && ((uintptr_t)addr & 2)) { + u16 first = __opcode_thumb32_first(insn); + u16 second = __opcode_thumb32_second(insn); + u16 *addrh = addr; + + addrh[0] = __opcode_to_mem_thumb16(first); + addrh[1] = __opcode_to_mem_thumb16(second); + + size = sizeof(u32); + } else { + if (thumb2) + insn = __opcode_to_mem_thumb32(insn); + else + insn = __opcode_to_mem_arm(insn); + + *(u32 *)addr = insn; + size = sizeof(u32); + } + + flush_icache_range((uintptr_t)(addr), + (uintptr_t)(addr) + size); +} + +static int __kprobes patch_text_stop_machine(void *data) +{ + struct patch *patch = data; + + __patch_text(patch->addr, patch->insn); + + return 0; +} + +void __kprobes patch_text(void *addr, unsigned int insn) +{ + struct patch patch = { + .addr = addr, + .insn = insn, + }; + + if (cache_ops_need_broadcast()) { + stop_machine(patch_text_stop_machine, &patch, cpu_online_mask); + } else { + bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL) + && __opcode_is_thumb32(insn) + && ((uintptr_t)addr & 2); + + if (straddles_word) + stop_machine(patch_text_stop_machine, &patch, NULL); + else + __patch_text(addr, insn); + } +} diff --git a/arch/arm/kernel/patch.h b/arch/arm/kernel/patch.h new file mode 100644 index 0000000..b4731f2 --- /dev/null +++ b/arch/arm/kernel/patch.h @@ -0,0 +1,7 @@ +#ifndef _ARM_KERNEL_PATCH_H +#define _ARM_KERNEL_PATCH_H + +void patch_text(void *addr, unsigned int insn); +void __patch_text(void *addr, unsigned int insn); + +#endif |
