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x86/kprobes: Convert to text-patching.h 

Convert kprobes to the new text-poke naming.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132458.103959370@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2019-10-09 13:57:17 +02:00 committed by Ingo Molnar
parent 38ebd8d119
commit ab09e95ca0
4 changed files with 37 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
arch/x86/include/asm/kprobes.h
View File

@ -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 optprobe_template_entry[];
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 */

2
arch/x86/include/asm/text-patching.h
View File

@ -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;

18
arch/x86/kernel/kprobes/core.c
View File

@ -119,14 +119,14 @@ __synthesize_relative_insn(void *dest, void *from, void *to, u8 op)
/* 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;
}
@ -356,7 +356,7 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn)
return 0;
/* 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 */
@ -400,14 +400,14 @@ static int prepare_boost(kprobe_opcode_t *buf, struct kprobe *p,
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;
@ -501,7 +501,7 @@ 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)
@ -609,7 +609,7 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
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;
@ -695,7 +695,7 @@ int kprobe_int3_handler(struct pt_regs *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

44
arch/x86/kernel/kprobes/opt.c
View File

@ -38,7 +38,7 @@ unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr)
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 @@ found:
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_template_func);
#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_kprobe *op, struct pt_regs *regs)
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(u8 *dest, u8 *src, u8 *real)
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 paddr)
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 paddr)
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 optimized_kprobe *op,
* 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 optimized_kprobe *op,
/* 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 @@ err:
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_head *oplist)
/* 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));
}