Commit c7edc9e3 authored by David A. Long's avatar David A. Long
Browse files

ARM: add uprobes support



Using Rabin Vincent's ARM uprobes patches as a base, enable uprobes
support on ARM.

Caveats:

 - Thumb is not supported
Signed-off-by: default avatarRabin Vincent <rabin@rab.in>
Signed-off-by: default avatarDavid A. Long <dave.long@linaro.org>
parent b4cd605c
......@@ -207,6 +207,9 @@ config ZONE_DMA
config NEED_DMA_MAP_STATE
def_bool y
config ARCH_SUPPORTS_UPROBES
def_bool y
config ARCH_HAS_DMA_SET_COHERENT_MASK
bool
......
......@@ -80,6 +80,12 @@ static inline long regs_return_value(struct pt_regs *regs)
#define instruction_pointer(regs) (regs)->ARM_pc
static inline void instruction_pointer_set(struct pt_regs *regs,
unsigned long val)
{
instruction_pointer(regs) = val;
}
#ifdef CONFIG_SMP
extern unsigned long profile_pc(struct pt_regs *regs);
#else
......
......@@ -153,6 +153,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define TIF_SIGPENDING 0
#define TIF_NEED_RESCHED 1
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_UPROBE 7
#define TIF_SYSCALL_TRACE 8
#define TIF_SYSCALL_AUDIT 9
#define TIF_SYSCALL_TRACEPOINT 10
......@@ -165,6 +166,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_UPROBE (1 << TIF_UPROBE)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
......@@ -178,7 +180,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
/*
* Change these and you break ASM code in entry-common.S
*/
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_RESUME)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE)
#endif /* __KERNEL__ */
#endif /* __ASM_ARM_THREAD_INFO_H */
/*
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASM_UPROBES_H
#define _ASM_UPROBES_H
#include <asm/probes.h>
#include <asm/opcodes.h>
typedef u32 uprobe_opcode_t;
#define MAX_UINSN_BYTES 4
#define UPROBE_XOL_SLOT_BYTES 64
#define UPROBE_SWBP_ARM_INSN 0xe7f001f9
#define UPROBE_SS_ARM_INSN 0xe7f001fa
#define UPROBE_SWBP_INSN __opcode_to_mem_arm(UPROBE_SWBP_ARM_INSN)
#define UPROBE_SWBP_INSN_SIZE 4
struct arch_uprobe_task {
u32 backup;
unsigned long saved_trap_no;
};
struct arch_uprobe {
u8 insn[MAX_UINSN_BYTES];
unsigned long ixol[2];
uprobe_opcode_t bpinsn;
bool simulate;
u32 pcreg;
void (*prehandler)(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs);
void (*posthandler)(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs);
struct arch_probes_insn asi;
};
#endif
......@@ -50,6 +50,7 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_UPROBES) += probes.o probes-arm.o uprobes.o uprobes-arm.o
obj-$(CONFIG_KPROBES) += probes.o kprobes.o kprobes-common.o patch.o
ifdef CONFIG_THUMB2_KERNEL
obj-$(CONFIG_KPROBES) += kprobes-thumb.o probes-thumb.o
......
......@@ -13,6 +13,7 @@
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/uprobes.h>
#include <asm/elf.h>
#include <asm/cacheflush.h>
......@@ -590,6 +591,9 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
return restart;
}
syscall = 0;
} else if (thread_flags & _TIF_UPROBE) {
clear_thread_flag(TIF_UPROBE);
uprobe_notify_resume(regs);
} else {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
......
/*
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/wait.h>
#include <linux/uprobes.h>
#include <linux/module.h>
#include "probes.h"
#include "probes-arm.h"
#include "uprobes.h"
static int uprobes_substitute_pc(unsigned long *pinsn, u32 oregs)
{
probes_opcode_t insn = __mem_to_opcode_arm(*pinsn);
probes_opcode_t temp;
probes_opcode_t mask;
int freereg;
u32 free = 0xffff;
u32 regs;
for (regs = oregs; regs; regs >>= 4, insn >>= 4) {
if ((regs & 0xf) == REG_TYPE_NONE)
continue;
free &= ~(1 << (insn & 0xf));
}
/* No PC, no problem */
if (free & (1 << 15))
return 15;
if (!free)
return -1;
/*
* fls instead of ffs ensures that for "ldrd r0, r1, [pc]" we would
* pick LR instead of R1.
*/
freereg = free = fls(free) - 1;
temp = __mem_to_opcode_arm(*pinsn);
insn = temp;
regs = oregs;
mask = 0xf;
for (; regs; regs >>= 4, mask <<= 4, free <<= 4, temp >>= 4) {
if ((regs & 0xf) == REG_TYPE_NONE)
continue;
if ((temp & 0xf) != 15)
continue;
insn &= ~mask;
insn |= free & mask;
}
*pinsn = __opcode_to_mem_arm(insn);
return freereg;
}
static void uprobe_set_pc(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs)
{
u32 pcreg = auprobe->pcreg;
autask->backup = regs->uregs[pcreg];
regs->uregs[pcreg] = regs->ARM_pc + 8;
}
static void uprobe_unset_pc(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs)
{
/* PC will be taken care of by common code */
regs->uregs[auprobe->pcreg] = autask->backup;
}
static void uprobe_aluwrite_pc(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs)
{
u32 pcreg = auprobe->pcreg;
alu_write_pc(regs->uregs[pcreg], regs);
regs->uregs[pcreg] = autask->backup;
}
static void uprobe_write_pc(struct arch_uprobe *auprobe,
struct arch_uprobe_task *autask,
struct pt_regs *regs)
{
u32 pcreg = auprobe->pcreg;
load_write_pc(regs->uregs[pcreg], regs);
regs->uregs[pcreg] = autask->backup;
}
enum probes_insn
decode_pc_ro(probes_opcode_t insn, struct arch_probes_insn *asi,
const struct decode_header *d)
{
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
asi);
struct decode_emulate *decode = (struct decode_emulate *) d;
u32 regs = decode->header.type_regs.bits >> DECODE_TYPE_BITS;
int reg;
reg = uprobes_substitute_pc(&auprobe->ixol[0], regs);
if (reg == 15)
return INSN_GOOD;
if (reg == -1)
return INSN_REJECTED;
auprobe->pcreg = reg;
auprobe->prehandler = uprobe_set_pc;
auprobe->posthandler = uprobe_unset_pc;
return INSN_GOOD;
}
enum probes_insn
decode_wb_pc(probes_opcode_t insn, struct arch_probes_insn *asi,
const struct decode_header *d, bool alu)
{
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
asi);
enum probes_insn ret = decode_pc_ro(insn, asi, d);
if (((insn >> 12) & 0xf) == 15)
auprobe->posthandler = alu ? uprobe_aluwrite_pc
: uprobe_write_pc;
return ret;
}
enum probes_insn
decode_rd12rn16rm0rs8_rwflags(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *d)
{
return decode_wb_pc(insn, asi, d, true);
}
enum probes_insn
decode_ldr(probes_opcode_t insn, struct arch_probes_insn *asi,
const struct decode_header *d)
{
return decode_wb_pc(insn, asi, d, false);
}
enum probes_insn
uprobe_decode_ldmstm(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *d)
{
struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe,
asi);
unsigned reglist = insn & 0xffff;
int rn = (insn >> 16) & 0xf;
int lbit = insn & (1 << 20);
unsigned used = reglist | (1 << rn);
if (rn == 15)
return INSN_REJECTED;
if (!(used & (1 << 15)))
return INSN_GOOD;
if (used & (1 << 14))
return INSN_REJECTED;
/* Use LR instead of PC */
insn ^= 0xc000;
auprobe->pcreg = 14;
auprobe->ixol[0] = __opcode_to_mem_arm(insn);
auprobe->prehandler = uprobe_set_pc;
if (lbit)
auprobe->posthandler = uprobe_write_pc;
else
auprobe->posthandler = uprobe_unset_pc;
return INSN_GOOD;
}
const union decode_action uprobes_probes_actions[] = {
[PROBES_EMULATE_NONE] = {.handler = probes_simulate_nop},
[PROBES_SIMULATE_NOP] = {.handler = probes_simulate_nop},
[PROBES_PRELOAD_IMM] = {.handler = probes_simulate_nop},
[PROBES_PRELOAD_REG] = {.handler = probes_simulate_nop},
[PROBES_BRANCH_IMM] = {.handler = simulate_blx1},
[PROBES_MRS] = {.handler = simulate_mrs},
[PROBES_BRANCH_REG] = {.handler = simulate_blx2bx},
[PROBES_CLZ] = {.handler = probes_simulate_nop},
[PROBES_SATURATING_ARITHMETIC] = {.handler = probes_simulate_nop},
[PROBES_MUL1] = {.handler = probes_simulate_nop},
[PROBES_MUL2] = {.handler = probes_simulate_nop},
[PROBES_SWP] = {.handler = probes_simulate_nop},
[PROBES_LDRSTRD] = {.decoder = decode_pc_ro},
[PROBES_LOAD_EXTRA] = {.decoder = decode_pc_ro},
[PROBES_LOAD] = {.decoder = decode_ldr},
[PROBES_STORE_EXTRA] = {.decoder = decode_pc_ro},
[PROBES_STORE] = {.decoder = decode_pc_ro},
[PROBES_MOV_IP_SP] = {.handler = simulate_mov_ipsp},
[PROBES_DATA_PROCESSING_REG] = {
.decoder = decode_rd12rn16rm0rs8_rwflags},
[PROBES_DATA_PROCESSING_IMM] = {
.decoder = decode_rd12rn16rm0rs8_rwflags},
[PROBES_MOV_HALFWORD] = {.handler = probes_simulate_nop},
[PROBES_SEV] = {.handler = probes_simulate_nop},
[PROBES_WFE] = {.handler = probes_simulate_nop},
[PROBES_SATURATE] = {.handler = probes_simulate_nop},
[PROBES_REV] = {.handler = probes_simulate_nop},
[PROBES_MMI] = {.handler = probes_simulate_nop},
[PROBES_PACK] = {.handler = probes_simulate_nop},
[PROBES_EXTEND] = {.handler = probes_simulate_nop},
[PROBES_EXTEND_ADD] = {.handler = probes_simulate_nop},
[PROBES_MUL_ADD_LONG] = {.handler = probes_simulate_nop},
[PROBES_MUL_ADD] = {.handler = probes_simulate_nop},
[PROBES_BITFIELD] = {.handler = probes_simulate_nop},
[PROBES_BRANCH] = {.handler = simulate_bbl},
[PROBES_LDMSTM] = {.decoder = uprobe_decode_ldmstm}
};
/*
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/uprobes.h>
#include <linux/notifier.h>
#include <asm/opcodes.h>
#include <asm/traps.h>
#include "probes.h"
#include "probes-arm.h"
#include "uprobes.h"
#define UPROBE_TRAP_NR UINT_MAX
bool is_swbp_insn(uprobe_opcode_t *insn)
{
return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
(UPROBE_SWBP_ARM_INSN & 0x0fffffff);
}
int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
unsigned long vaddr)
{
return uprobe_write_opcode(mm, vaddr,
__opcode_to_mem_arm(auprobe->bpinsn));
}
bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) {
regs->ARM_pc += 4;
return true;
}
return false;
}
bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
probes_opcode_t opcode;
if (!auprobe->simulate)
return false;
opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn);
auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs);
return true;
}
unsigned long
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
struct pt_regs *regs)
{
unsigned long orig_ret_vaddr;
orig_ret_vaddr = regs->ARM_lr;
/* Replace the return addr with trampoline addr */
regs->ARM_lr = trampoline_vaddr;
return orig_ret_vaddr;
}
int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
unsigned long addr)
{
unsigned int insn;
unsigned int bpinsn;
enum probes_insn ret;
/* Thumb not yet support */
if (addr & 0x3)
return -EINVAL;
insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn);
auprobe->ixol[0] = __opcode_to_mem_arm(insn);
auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN);
ret = arm_probes_decode_insn(insn, &auprobe->asi, false,
uprobes_probes_actions);
switch (ret) {
case INSN_REJECTED:
return -EINVAL;
case INSN_GOOD_NO_SLOT:
auprobe->simulate = true;
break;
case INSN_GOOD:
default:
break;
}
bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff;
if (insn >= 0xe0000000)
bpinsn |= 0xe0000000; /* Unconditional instruction */
else
bpinsn |= insn & 0xf0000000; /* Copy condition from insn */
auprobe->bpinsn = bpinsn;
return 0;
}
int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
if (auprobe->prehandler)
auprobe->prehandler(auprobe, &utask->autask, regs);
utask->autask.saved_trap_no = current->thread.trap_no;
current->thread.trap_no = UPROBE_TRAP_NR;
regs->ARM_pc = utask->xol_vaddr;
return 0;
}
int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
current->thread.trap_no = utask->autask.saved_trap_no;
regs->ARM_pc = utask->vaddr + 4;
if (auprobe->posthandler)
auprobe->posthandler(auprobe, &utask->autask, regs);
return 0;
}
bool arch_uprobe_xol_was_trapped(struct task_struct *t)
{
if (t->thread.trap_no != UPROBE_TRAP_NR)
return true;
return false;
}
void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
current->thread.trap_no = utask->autask.saved_trap_no;
instruction_pointer_set(regs, utask->vaddr);
}
int arch_uprobe_exception_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return NOTIFY_DONE;
}
static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
{
unsigned long flags;
local_irq_save(flags);
instr &= 0x0fffffff;
if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
uprobe_pre_sstep_notifier(regs);
else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
uprobe_post_sstep_notifier(regs);
local_irq_restore(flags);
return 0;
}
unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
{
return instruction_pointer(regs);
}
static struct undef_hook uprobes_arm_break_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
.cpsr_mask = MODE_MASK,
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
static struct undef_hook uprobes_arm_ss_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
.cpsr_mask = MODE_MASK,
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
static int arch_uprobes_init(void)
{
register_undef_hook(&uprobes_arm_break_hook);
register_undef_hook(&uprobes_arm_ss_hook);
return 0;
}
device_initcall(arch_uprobes_init);
/*
* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ARM_KERNEL_UPROBES_H
#define __ARM_KERNEL_UPROBES_H
enum probes_insn uprobe_decode_ldmstm(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *d);
enum probes_insn decode_ldr(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *d);
enum probes_insn
decode_rd12rn16rm0rs8_rwflags(probes_opcode_t insn,
struct arch_probes_insn *asi,
const struct decode_header *d);
enum probes_insn
decode_wb_pc(probes_opcode_t insn, struct arch_probes_insn *asi,
const struct decode_header *d, bool alu);
enum probes_insn
decode_pc_ro(probes_opcode_t insn, struct arch_probes_insn *asi,
const struct decode_header *d);
extern const union decode_action uprobes_probes_actions[];
#endif
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