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Date: Mon, 21 Oct 2019 23:57:19 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, rostedt@...dmis.org,
mhiramat@...nel.org, bristot@...hat.com, jbaron@...mai.com,
torvalds@...ux-foundation.org, tglx@...utronix.de,
mingo@...nel.org, namit@...are.com, hpa@...or.com, luto@...nel.org,
ard.biesheuvel@...aro.org, jpoimboe@...hat.com, jeyu@...nel.org
Subject: Re: [PATCH v4 11/16] x86/kprobes: Convert to text-patching.h
Hi Peter,
On Fri, 18 Oct 2019 09:35:36 +0200
Peter Zijlstra <peterz@...radead.org> wrote:
> Convert kprobes to the new text-poke naming.
>
Looks good to me :)
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
Thanks,
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> ---
> arch/x86/include/asm/kprobes.h | 14 +++--------
> arch/x86/include/asm/text-patching.h | 2 +
> arch/x86/kernel/kprobes/core.c | 18 +++++++-------
> arch/x86/kernel/kprobes/opt.c | 44 ++++++++++++++++-------------------
> 4 files changed, 37 insertions(+), 41 deletions(-)
>
> --- a/arch/x86/include/asm/kprobes.h
> +++ b/arch/x86/include/asm/kprobes.h
> @@ -11,12 +11,11 @@
>
> #include <asm-generic/kprobes.h>
>
> -#define BREAKPOINT_INSTRUCTION 0xcc
> -
> #ifdef CONFIG_KPROBES
> #include <linux/types.h>
> #include <linux/ptrace.h>
> #include <linux/percpu.h>
> +#include <asm/text-patching.h>
> #include <asm/insn.h>
>
> #define __ARCH_WANT_KPROBES_INSN_SLOT
> @@ -25,10 +24,7 @@ struct pt_regs;
> struct kprobe;
>
> typedef u8 kprobe_opcode_t;
> -#define RELATIVEJUMP_OPCODE 0xe9
> -#define RELATIVEJUMP_SIZE 5
> -#define RELATIVECALL_OPCODE 0xe8
> -#define RELATIVE_ADDR_SIZE 4
> +
> #define MAX_STACK_SIZE 64
> #define CUR_STACK_SIZE(ADDR) \
> (current_top_of_stack() - (unsigned long)(ADDR))
> @@ -43,11 +39,11 @@ extern __visible kprobe_opcode_t optprob
> extern __visible kprobe_opcode_t optprobe_template_val[];
> extern __visible kprobe_opcode_t optprobe_template_call[];
> extern __visible kprobe_opcode_t optprobe_template_end[];
> -#define MAX_OPTIMIZED_LENGTH (MAX_INSN_SIZE + RELATIVE_ADDR_SIZE)
> +#define MAX_OPTIMIZED_LENGTH (MAX_INSN_SIZE + DISP32_SIZE)
> #define MAX_OPTINSN_SIZE \
> (((unsigned long)optprobe_template_end - \
> (unsigned long)optprobe_template_entry) + \
> - MAX_OPTIMIZED_LENGTH + RELATIVEJUMP_SIZE)
> + MAX_OPTIMIZED_LENGTH + JMP32_INSN_SIZE)
>
> extern const int kretprobe_blacklist_size;
>
> @@ -73,7 +69,7 @@ struct arch_specific_insn {
>
> struct arch_optimized_insn {
> /* copy of the original instructions */
> - kprobe_opcode_t copied_insn[RELATIVE_ADDR_SIZE];
> + kprobe_opcode_t copied_insn[DISP32_SIZE];
> /* detour code buffer */
> kprobe_opcode_t *insn;
> /* the size of instructions copied to detour code buffer */
> --- a/arch/x86/include/asm/text-patching.h
> +++ b/arch/x86/include/asm/text-patching.h
> @@ -61,6 +61,8 @@ extern void text_poke_finish(void);
> #define JMP8_INSN_SIZE 2
> #define JMP8_INSN_OPCODE 0xEB
>
> +#define DISP32_SIZE 4
> +
> static inline int text_opcode_size(u8 opcode)
> {
> int size = 0;
> --- a/arch/x86/kernel/kprobes/core.c
> +++ b/arch/x86/kernel/kprobes/core.c
> @@ -119,14 +119,14 @@ __synthesize_relative_insn(void *dest, v
> /* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
> void synthesize_reljump(void *dest, void *from, void *to)
> {
> - __synthesize_relative_insn(dest, from, to, RELATIVEJUMP_OPCODE);
> + __synthesize_relative_insn(dest, from, to, JMP32_INSN_OPCODE);
> }
> NOKPROBE_SYMBOL(synthesize_reljump);
>
> /* Insert a call instruction at address 'from', which calls address 'to'.*/
> void synthesize_relcall(void *dest, void *from, void *to)
> {
> - __synthesize_relative_insn(dest, from, to, RELATIVECALL_OPCODE);
> + __synthesize_relative_insn(dest, from, to, CALL_INSN_OPCODE);
> }
> NOKPROBE_SYMBOL(synthesize_relcall);
>
> @@ -301,7 +301,7 @@ static int can_probe(unsigned long paddr
> * Another debugging subsystem might insert this breakpoint.
> * In that case, we can't recover it.
> */
> - if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
> + if (insn.opcode.bytes[0] == INT3_INSN_OPCODE)
> return 0;
> addr += insn.length;
> }
> @@ -352,7 +352,7 @@ int __copy_instruction(u8 *dest, u8 *src
> insn_get_length(insn);
>
> /* Another subsystem puts a breakpoint, failed to recover */
> - if (insn->opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
> + if (insn->opcode.bytes[0] == INT3_INSN_OPCODE)
> return 0;
>
> /* We should not singlestep on the exception masking instructions */
> @@ -396,14 +396,14 @@ static int prepare_boost(kprobe_opcode_t
> int len = insn->length;
>
> if (can_boost(insn, p->addr) &&
> - MAX_INSN_SIZE - len >= RELATIVEJUMP_SIZE) {
> + MAX_INSN_SIZE - len >= JMP32_INSN_SIZE) {
> /*
> * These instructions can be executed directly if it
> * jumps back to correct address.
> */
> synthesize_reljump(buf + len, p->ainsn.insn + len,
> p->addr + insn->length);
> - len += RELATIVEJUMP_SIZE;
> + len += JMP32_INSN_SIZE;
> p->ainsn.boostable = true;
> } else {
> p->ainsn.boostable = false;
> @@ -497,7 +497,7 @@ int arch_prepare_kprobe(struct kprobe *p
>
> void arch_arm_kprobe(struct kprobe *p)
> {
> - text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
> + text_poke(p->addr, ((unsigned char []){INT3_INSN_OPCODE}), 1);
> }
>
> void arch_disarm_kprobe(struct kprobe *p)
> @@ -605,7 +605,7 @@ static void setup_singlestep(struct kpro
> regs->flags |= X86_EFLAGS_TF;
> regs->flags &= ~X86_EFLAGS_IF;
> /* single step inline if the instruction is an int3 */
> - if (p->opcode == BREAKPOINT_INSTRUCTION)
> + if (p->opcode == INT3_INSN_OPCODE)
> regs->ip = (unsigned long)p->addr;
> else
> regs->ip = (unsigned long)p->ainsn.insn;
> @@ -691,7 +691,7 @@ int kprobe_int3_handler(struct pt_regs *
> reset_current_kprobe();
> return 1;
> }
> - } else if (*addr != BREAKPOINT_INSTRUCTION) {
> + } else if (*addr != INT3_INSN_OPCODE) {
> /*
> * The breakpoint instruction was removed right
> * after we hit it. Another cpu has removed
> --- a/arch/x86/kernel/kprobes/opt.c
> +++ b/arch/x86/kernel/kprobes/opt.c
> @@ -38,7 +38,7 @@ unsigned long __recover_optprobed_insn(k
> long offs;
> int i;
>
> - for (i = 0; i < RELATIVEJUMP_SIZE; i++) {
> + for (i = 0; i < JMP32_INSN_SIZE; i++) {
> kp = get_kprobe((void *)addr - i);
> /* This function only handles jump-optimized kprobe */
> if (kp && kprobe_optimized(kp)) {
> @@ -62,10 +62,10 @@ unsigned long __recover_optprobed_insn(k
>
> if (addr == (unsigned long)kp->addr) {
> buf[0] = kp->opcode;
> - memcpy(buf + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE);
> + memcpy(buf + 1, op->optinsn.copied_insn, DISP32_SIZE);
> } else {
> offs = addr - (unsigned long)kp->addr - 1;
> - memcpy(buf, op->optinsn.copied_insn + offs, RELATIVE_ADDR_SIZE - offs);
> + memcpy(buf, op->optinsn.copied_insn + offs, DISP32_SIZE - offs);
> }
>
> return (unsigned long)buf;
> @@ -141,8 +141,6 @@ STACK_FRAME_NON_STANDARD(optprobe_templa
> #define TMPL_END_IDX \
> ((long)optprobe_template_end - (long)optprobe_template_entry)
>
> -#define INT3_SIZE sizeof(kprobe_opcode_t)
> -
> /* Optimized kprobe call back function: called from optinsn */
> static void
> optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
> @@ -162,7 +160,7 @@ optimized_callback(struct optimized_kpro
> regs->cs |= get_kernel_rpl();
> regs->gs = 0;
> #endif
> - regs->ip = (unsigned long)op->kp.addr + INT3_SIZE;
> + regs->ip = (unsigned long)op->kp.addr + INT3_INSN_SIZE;
> regs->orig_ax = ~0UL;
>
> __this_cpu_write(current_kprobe, &op->kp);
> @@ -179,7 +177,7 @@ static int copy_optimized_instructions(u
> struct insn insn;
> int len = 0, ret;
>
> - while (len < RELATIVEJUMP_SIZE) {
> + while (len < JMP32_INSN_SIZE) {
> ret = __copy_instruction(dest + len, src + len, real + len, &insn);
> if (!ret || !can_boost(&insn, src + len))
> return -EINVAL;
> @@ -271,7 +269,7 @@ static int can_optimize(unsigned long pa
> return 0;
>
> /* Check there is enough space for a relative jump. */
> - if (size - offset < RELATIVEJUMP_SIZE)
> + if (size - offset < JMP32_INSN_SIZE)
> return 0;
>
> /* Decode instructions */
> @@ -290,15 +288,15 @@ static int can_optimize(unsigned long pa
> kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE);
> insn_get_length(&insn);
> /* Another subsystem puts a breakpoint */
> - if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
> + if (insn.opcode.bytes[0] == INT3_INSN_OPCODE)
> return 0;
> /* Recover address */
> insn.kaddr = (void *)addr;
> insn.next_byte = (void *)(addr + insn.length);
> /* Check any instructions don't jump into target */
> if (insn_is_indirect_jump(&insn) ||
> - insn_jump_into_range(&insn, paddr + INT3_SIZE,
> - RELATIVE_ADDR_SIZE))
> + insn_jump_into_range(&insn, paddr + INT3_INSN_SIZE,
> + DISP32_SIZE))
> return 0;
> addr += insn.length;
> }
> @@ -374,7 +372,7 @@ int arch_prepare_optimized_kprobe(struct
> * Verify if the address gap is in 2GB range, because this uses
> * a relative jump.
> */
> - rel = (long)slot - (long)op->kp.addr + RELATIVEJUMP_SIZE;
> + rel = (long)slot - (long)op->kp.addr + JMP32_INSN_SIZE;
> if (abs(rel) > 0x7fffffff) {
> ret = -ERANGE;
> goto err;
> @@ -401,7 +399,7 @@ int arch_prepare_optimized_kprobe(struct
> /* Set returning jmp instruction at the tail of out-of-line buffer */
> synthesize_reljump(buf + len, slot + len,
> (u8 *)op->kp.addr + op->optinsn.size);
> - len += RELATIVEJUMP_SIZE;
> + len += JMP32_INSN_SIZE;
>
> /* We have to use text_poke() for instruction buffer because it is RO */
> text_poke(slot, buf, len);
> @@ -422,22 +420,22 @@ int arch_prepare_optimized_kprobe(struct
> void arch_optimize_kprobes(struct list_head *oplist)
> {
> struct optimized_kprobe *op, *tmp;
> - u8 insn_buff[RELATIVEJUMP_SIZE];
> + u8 insn_buff[JMP32_INSN_SIZE];
>
> list_for_each_entry_safe(op, tmp, oplist, list) {
> s32 rel = (s32)((long)op->optinsn.insn -
> - ((long)op->kp.addr + RELATIVEJUMP_SIZE));
> + ((long)op->kp.addr + JMP32_INSN_SIZE));
>
> WARN_ON(kprobe_disabled(&op->kp));
>
> /* Backup instructions which will be replaced by jump address */
> - memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_SIZE,
> - RELATIVE_ADDR_SIZE);
> + memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_INSN_SIZE,
> + DISP32_SIZE);
>
> - insn_buff[0] = RELATIVEJUMP_OPCODE;
> + insn_buff[0] = JMP32_INSN_OPCODE;
> *(s32 *)(&insn_buff[1]) = rel;
>
> - text_poke_bp(op->kp.addr, insn_buff, RELATIVEJUMP_SIZE, NULL);
> + text_poke_bp(op->kp.addr, insn_buff, JMP32_INSN_SIZE, NULL);
>
> list_del_init(&op->list);
> }
> @@ -446,13 +444,13 @@ void arch_optimize_kprobes(struct list_h
> /* Replace a relative jump with a breakpoint (int3). */
> void arch_unoptimize_kprobe(struct optimized_kprobe *op)
> {
> - u8 insn_buff[RELATIVEJUMP_SIZE];
> + u8 insn_buff[JMP32_INSN_SIZE];
>
> /* Set int3 to first byte for kprobes */
> - insn_buff[0] = BREAKPOINT_INSTRUCTION;
> - memcpy(insn_buff + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE);
> + insn_buff[0] = INT3_INSN_OPCODE;
> + memcpy(insn_buff + 1, op->optinsn.copied_insn, DISP32_SIZE);
>
> - text_poke_bp(op->kp.addr, insn_buff, RELATIVEJUMP_SIZE,
> + text_poke_bp(op->kp.addr, insn_buff, JMP32_INSN_SIZE,
> text_gen_insn(JMP32_INSN_OPCODE, op->kp.addr, op->optinsn.insn));
> }
>
>
>
--
Masami Hiramatsu <mhiramat@...nel.org>
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