diff options
Diffstat (limited to 'arch/x86/kernel/kprobes_64.c')
| -rw-r--r-- | arch/x86/kernel/kprobes_64.c | 409 |
1 files changed, 212 insertions, 197 deletions
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c index bc93b1dd9a0..2d7763749b1 100644 --- a/arch/x86/kernel/kprobes_64.c +++ b/arch/x86/kernel/kprobes_64.c @@ -40,16 +40,97 @@ #include <linux/module.h> #include <linux/kdebug.h> +#include <asm/cacheflush.h> +#include <asm/desc.h> #include <asm/pgtable.h> #include <asm/uaccess.h> #include <asm/alternative.h> void jprobe_return_end(void); -static void __kprobes arch_copy_kprobe(struct kprobe *p); DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); +#define stack_addr(regs) ((unsigned long *)regs->sp) + +#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ + (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ + (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \ + (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \ + (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \ + << (row % 32)) + /* + * Undefined/reserved opcodes, conditional jump, Opcode Extension + * Groups, and some special opcodes can not boost. + */ +static const u32 twobyte_is_boostable[256 / 32] = { + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ + /* ---------------------------------------------- */ + W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */ + W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */ + W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */ + W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */ + W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */ + W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */ + W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */ + W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */ + W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */ + W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */ + W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */ + W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */ + W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */ + W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */ + W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */ + W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0) /* f0 */ + /* ----------------------------------------------- */ + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ +}; +static const u32 onebyte_has_modrm[256 / 32] = { + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ + /* ----------------------------------------------- */ + W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */ + W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */ + W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */ + W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */ + W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */ + W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */ + W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */ + W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */ + W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */ + W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */ + W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */ + W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */ + W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */ + W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */ + W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */ + W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */ + /* ----------------------------------------------- */ + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ +}; +static const u32 twobyte_has_modrm[256 / 32] = { + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ + /* ----------------------------------------------- */ + W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */ + W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */ + W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */ + W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */ + W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */ + W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */ + W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */ + W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */ + W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */ + W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */ + W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */ + W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */ + W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */ + W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */ + W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */ + W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */ + /* ----------------------------------------------- */ + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ +}; +#undef W + struct kretprobe_blackpoint kretprobe_blacklist[] = { {"__switch_to", }, /* This function switches only current task, but doesn't switch kernel stack.*/ @@ -70,44 +151,11 @@ static __always_inline void set_jmp_op(void *from, void *to) } /* - * returns non-zero if opcode is boostable + * returns non-zero if opcode is boostable. * RIP relative instructions are adjusted at copying time */ static __always_inline int can_boost(kprobe_opcode_t *opcodes) { -#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ - (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ - (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \ - (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \ - (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \ - << (row % 64)) - /* - * Undefined/reserved opcodes, conditional jump, Opcode Extension - * Groups, and some special opcodes can not boost. - */ - static const unsigned long twobyte_is_boostable[256 / 64] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ---------------------------------------------- */ - W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0)|/* 00 */ - W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)|/* 10 */ - W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)|/* 20 */ - W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),/* 30 */ - W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1)|/* 40 */ - W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)|/* 50 */ - W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1)|/* 60 */ - W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1),/* 70 */ - W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)|/* 80 */ - W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1)|/* 90 */ - W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1)|/* a0 */ - W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1),/* b0 */ - W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1)|/* c0 */ - W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1)|/* d0 */ - W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1)|/* e0 */ - W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0) /* f0 */ - /* ----------------------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; -#undef W kprobe_opcode_t opcode; kprobe_opcode_t *orig_opcodes = opcodes; @@ -120,7 +168,8 @@ retry: if (opcode == 0x0f) { if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1) return 0; - return test_bit(*opcodes, twobyte_is_boostable); + return test_bit(*opcodes, + (unsigned long *)twobyte_is_boostable); } switch (opcode & 0xf0) { @@ -169,80 +218,25 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) return 1; } - if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf) - return 1; - return 0; -} - -int __kprobes arch_prepare_kprobe(struct kprobe *p) -{ - /* insn: must be on special executable page on x86_64. */ - p->ainsn.insn = get_insn_slot(); - if (!p->ainsn.insn) { - return -ENOMEM; - } - arch_copy_kprobe(p); + /* + * on 64 bit x86, 0x40-0x4f are prefixes so we need to look + * at the next byte instead.. but of course not recurse infinitely + */ + if (*insn >= 0x40 && *insn <= 0x4f) + return is_IF_modifier(++insn); return 0; } /* - * Determine if the instruction uses the %rip-relative addressing mode. + * Adjust the displacement if the instruction uses the %rip-relative + * addressing mode. * If it does, Return the address of the 32-bit displacement word. * If not, return null. */ -static s32 __kprobes *is_riprel(u8 *insn) +static void __kprobes fix_riprel(struct kprobe *p) { -#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \ - (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ - (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \ - (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \ - (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \ - << (row % 64)) - static const u64 onebyte_has_modrm[256 / 64] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ------------------------------- */ - W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */ - W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */ - W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */ - W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */ - W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */ - W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */ - W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */ - W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */ - W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */ - W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */ - W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */ - W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */ - W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */ - W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */ - W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */ - W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */ - /* ------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; - static const u64 twobyte_has_modrm[256 / 64] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ------------------------------- */ - W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */ - W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */ - W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */ - W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */ - W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */ - W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */ - W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */ - W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */ - W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */ - W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */ - W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */ - W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */ - W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */ - W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */ - W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */ - W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */ - /* ------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; -#undef W + u8 *insn = p->ainsn.insn; + s64 disp; int need_modrm; /* Skip legacy instruction prefixes. */ @@ -271,54 +265,60 @@ static s32 __kprobes *is_riprel(u8 *insn) if (*insn == 0x0f) { /* Two-byte opcode. */ ++insn; - need_modrm = test_bit(*insn, twobyte_has_modrm); - } else { /* One-byte opcode. */ - need_modrm = test_bit(*insn, onebyte_has_modrm); - } + need_modrm = test_bit(*insn, + (unsigned long *)twobyte_has_modrm); + } else /* One-byte opcode. */ + need_modrm = test_bit(*insn, + (unsigned long *)onebyte_has_modrm); if (need_modrm) { u8 modrm = *++insn; if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */ /* Displacement follows ModRM byte. */ - return (s32 *) ++insn; + ++insn; + /* + * The copied instruction uses the %rip-relative + * addressing mode. Adjust the displacement for the + * difference between the original location of this + * instruction and the location of the copy that will + * actually be run. The tricky bit here is making sure + * that the sign extension happens correctly in this + * calculation, since we need a signed 32-bit result to + * be sign-extended to 64 bits when it's added to the + * %rip value and yield the same 64-bit result that the + * sign-extension of the original signed 32-bit + * displacement would have given. + */ + disp = (u8 *) p->addr + *((s32 *) insn) - + (u8 *) p->ainsn.insn; + BUG_ON((s64) (s32) disp != disp); /* Sanity check. */ + *(s32 *)insn = (s32) disp; } } - - /* No %rip-relative addressing mode here. */ - return NULL; } static void __kprobes arch_copy_kprobe(struct kprobe *p) { - s32 *ripdisp; - memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE); - ripdisp = is_riprel(p->ainsn.insn); - if (ripdisp) { - /* - * The copied instruction uses the %rip-relative - * addressing mode. Adjust the displacement for the - * difference between the original location of this - * instruction and the location of the copy that will - * actually be run. The tricky bit here is making sure - * that the sign extension happens correctly in this - * calculation, since we need a signed 32-bit result to - * be sign-extended to 64 bits when it's added to the - * %rip value and yield the same 64-bit result that the - * sign-extension of the original signed 32-bit - * displacement would have given. - */ - s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn; - BUG_ON((s64) (s32) disp != disp); /* Sanity check. */ - *ripdisp = disp; - } - if (can_boost(p->addr)) { + memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + fix_riprel(p); + if (can_boost(p->addr)) p->ainsn.boostable = 0; - } else { + else p->ainsn.boostable = -1; - } + p->opcode = *p->addr; } +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + /* insn: must be on special executable page on x86. */ + p->ainsn.insn = get_insn_slot(); + if (!p->ainsn.insn) + return -ENOMEM; + arch_copy_kprobe(p); + return 0; +} + void __kprobes arch_arm_kprobe(struct kprobe *p) { text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1); @@ -340,26 +340,26 @@ static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) { kcb->prev_kprobe.kp = kprobe_running(); kcb->prev_kprobe.status = kcb->kprobe_status; - kcb->prev_kprobe.old_rflags = kcb->kprobe_old_rflags; - kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags; + kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags; + kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags; } static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) { __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; kcb->kprobe_status = kcb->prev_kprobe.status; - kcb->kprobe_old_rflags = kcb->prev_kprobe.old_rflags; - kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags; + kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags; + kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags; } static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { __get_cpu_var(current_kprobe) = p; - kcb->kprobe_saved_rflags = kcb->kprobe_old_rflags + kcb->kprobe_saved_flags = kcb->kprobe_old_flags = (regs->flags & (TF_MASK | IF_MASK)); if (is_IF_modifier(p->ainsn.insn)) - kcb->kprobe_saved_rflags &= ~IF_MASK; + kcb->kprobe_saved_flags &= ~IF_MASK; } static __always_inline void clear_btf(void) @@ -390,20 +390,27 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { - unsigned long *sara = (unsigned long *)regs->sp; + unsigned long *sara = stack_addr(regs); ri->ret_addr = (kprobe_opcode_t *) *sara; + /* Replace the return addr with trampoline addr */ *sara = (unsigned long) &kretprobe_trampoline; } -int __kprobes kprobe_handler(struct pt_regs *regs) +/* + * Interrupts are disabled on entry as trap3 is an interrupt gate and they + * remain disabled thorough out this function. + */ +static int __kprobes kprobe_handler(struct pt_regs *regs) { struct kprobe *p; int ret = 0; - kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t)); + kprobe_opcode_t *addr; struct kprobe_ctlblk *kcb; + addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t)); + /* * We don't want to be preempted for the entire * duration of kprobe processing @@ -418,7 +425,7 @@ int __kprobes kprobe_handler(struct pt_regs *regs) if (kcb->kprobe_status == KPROBE_HIT_SS && *p->ainsn.insn == BREAKPOINT_INSTRUCTION) { regs->flags &= ~TF_MASK; - regs->flags |= kcb->kprobe_saved_rflags; + regs->flags |= kcb->kprobe_saved_flags; goto no_kprobe; } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) { /* TODO: Provide re-entrancy from @@ -429,22 +436,20 @@ int __kprobes kprobe_handler(struct pt_regs *regs) arch_disarm_kprobe(p); regs->ip = (unsigned long)p->addr; reset_current_kprobe(); - ret = 1; - } else { - /* We have reentered the kprobe_handler(), since - * another probe was hit while within the - * handler. We here save the original kprobe - * variables and just single step on instruction - * of the new probe without calling any user - * handlers. - */ - save_previous_kprobe(kcb); - set_current_kprobe(p, regs, kcb); - kprobes_inc_nmissed_count(p); - prepare_singlestep(p, regs); - kcb->kprobe_status = KPROBE_REENTER; return 1; } + /* We have reentered the kprobe_handler(), since + * another probe was hit while within the handler. + * We here save the original kprobes variables and + * just single step on the instruction of the new probe + * without calling any user handlers. + */ + save_previous_kprobe(kcb); + set_current_kprobe(p, regs, kcb); + kprobes_inc_nmissed_count(p); + prepare_singlestep(p, regs); + kcb->kprobe_status = KPROBE_REENTER; + return 1; } else { if (*addr != BREAKPOINT_INSTRUCTION) { /* The breakpoint instruction was removed by @@ -578,23 +583,23 @@ fastcall void * __kprobes trampoline_handler(struct pt_regs *regs) INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); - /* fixup rt_regs */ + /* fixup registers */ regs->cs = __KERNEL_CS; regs->ip = trampoline_address; - regs->orig_ax = 0xffffffffffffffff; + regs->orig_ax = ~0UL; /* * It is possible to have multiple instances associated with a given - * task either because an multiple functions in the call path - * have a return probe installed on them, and/or more then one return + * task either because multiple functions in the call path have + * return probes installed on them, and/or more then one * return probe was registered for a target function. * * We can handle this because: - * - instances are always inserted at the head of the list + * - instances are always pushed into the head of the list * - when multiple return probes are registered for the same - * function, the first instance's ret_addr will point to the - * real return address, and all the rest will point to - * kretprobe_trampoline + * function, the (chronologically) first instance's ret_addr + * will be the real return address, and all the rest will + * point to kretprobe_trampoline. */ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { if (ri->task != current) @@ -661,9 +666,9 @@ fastcall void * __kprobes trampoline_handler(struct pt_regs *regs) static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { - unsigned long *tos = (unsigned long *)regs->sp; - unsigned long copy_rip = (unsigned long)p->ainsn.insn; - unsigned long orig_rip = (unsigned long)p->addr; + unsigned long *tos = stack_addr(regs); + unsigned long copy_ip = (unsigned long)p->ainsn.insn; + unsigned long orig_ip = (unsigned long)p->addr; kprobe_opcode_t *insn = p->ainsn.insn; /*skip the REX prefix*/ @@ -674,7 +679,7 @@ static void __kprobes resume_execution(struct kprobe *p, switch (*insn) { case 0x9c: /* pushfl */ *tos &= ~(TF_MASK | IF_MASK); - *tos |= kcb->kprobe_old_rflags; + *tos |= kcb->kprobe_old_flags; break; case 0xc2: /* iret/ret/lret */ case 0xc3: @@ -686,18 +691,23 @@ static void __kprobes resume_execution(struct kprobe *p, p->ainsn.boostable = 1; goto no_change; case 0xe8: /* call relative - Fix return addr */ - *tos = orig_rip + (*tos - copy_rip); + *tos = orig_ip + (*tos - copy_ip); break; case 0xff: if ((insn[1] & 0x30) == 0x10) { - /* call absolute, indirect */ - /* Fix return addr; ip is correct. */ - /* not boostable */ - *tos = orig_rip + (*tos - copy_rip); + /* + * call absolute, indirect + * Fix return addr; ip is correct. + * But this is not boostable + */ + *tos = orig_ip + (*tos - copy_ip); goto no_change; - } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */ - ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */ - /* ip is correct. And this is boostable */ + } else if (((insn[1] & 0x31) == 0x20) || + ((insn[1] & 0x31) == 0x21)) { + /* + * jmp near and far, absolute indirect + * ip is correct. And this is boostable + */ p->ainsn.boostable = 1; goto no_change; } @@ -706,21 +716,21 @@ static void __kprobes resume_execution(struct kprobe *p, } if (p->ainsn.boostable == 0) { - if ((regs->ip > copy_rip) && - (regs->ip - copy_rip) + 5 < MAX_INSN_SIZE) { + if ((regs->ip > copy_ip) && + (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) { /* * These instructions can be executed directly if it * jumps back to correct address. */ set_jmp_op((void *)regs->ip, - (void *)orig_rip + (regs->ip - copy_rip)); + (void *)orig_ip + (regs->ip - copy_ip)); p->ainsn.boostable = 1; } else { p->ainsn.boostable = -1; } } - regs->ip = orig_rip + (regs->ip - copy_rip); + regs->ip += orig_ip - copy_ip; no_change: restore_btf(); @@ -728,7 +738,11 @@ no_change: return; } -int __kprobes post_kprobe_handler(struct pt_regs *regs) +/* + * Interrupts are disabled on entry as trap1 is an interrupt gate and they + * remain disabled thoroughout this function. + */ +static int __kprobes post_kprobe_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -742,10 +756,10 @@ int __kprobes post_kprobe_handler(struct pt_regs *regs) } resume_execution(cur, regs, kcb); - regs->flags |= kcb->kprobe_saved_rflags; + regs->flags |= kcb->kprobe_saved_flags; trace_hardirqs_fixup_flags(regs->flags); - /* Restore the original saved kprobes variables and continue. */ + /* Restore back the original saved kprobes variables and continue. */ if (kcb->kprobe_status == KPROBE_REENTER) { restore_previous_kprobe(kcb); goto out; @@ -782,7 +796,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) * normal page fault. */ regs->ip = (unsigned long)cur->addr; - regs->flags |= kcb->kprobe_old_rflags; + regs->flags |= kcb->kprobe_old_flags; if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); else @@ -793,7 +807,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) case KPROBE_HIT_SSDONE: /* * We increment the nmissed count for accounting, - * we can also use npre/npostfault count for accouting + * we can also use npre/npostfault count for accounting * these specific fault cases. */ kprobes_inc_nmissed_count(cur); @@ -819,7 +833,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) } /* - * fixup() could not handle it, + * fixup routine could not handle it, * Let do_page_fault() fix it. */ break; @@ -838,7 +852,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, struct die_args *args = (struct die_args *)data; int ret = NOTIFY_DONE; - if (args->regs && user_mode(args->regs)) + if (args->regs && user_mode_vm(args->regs)) return ret; switch (val) { @@ -871,8 +885,9 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); kcb->jprobe_saved_regs = *regs; - kcb->jprobe_saved_rsp = (long *) regs->sp; - addr = (unsigned long)(kcb->jprobe_saved_rsp); + kcb->jprobe_saved_sp = stack_addr(regs); + addr = (unsigned long)(kcb->jprobe_saved_sp); + /* * As Linus pointed out, gcc assumes that the callee * owns the argument space and could overwrite it, e.g. @@ -897,21 +912,20 @@ void __kprobes jprobe_return(void) " .globl jprobe_return_end \n" " jprobe_return_end: \n" " nop \n"::"b" - (kcb->jprobe_saved_rsp):"memory"); + (kcb->jprobe_saved_sp):"memory"); } int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); u8 *addr = (u8 *) (regs->ip - 1); - unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_rsp); struct jprobe *jp = container_of(p, struct jprobe, kp); if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) { - if ((unsigned long *)regs->sp != kcb->jprobe_saved_rsp) { + if (stack_addr(regs) != kcb->jprobe_saved_sp) { struct pt_regs *saved_regs = &kcb->jprobe_saved_regs; printk("current sp %p does not match saved sp %p\n", - (long *)regs->sp, kcb->jprobe_saved_rsp); + stack_addr(regs), kcb->jprobe_saved_sp); printk("Saved registers for jprobe %p\n", jp); show_registers(saved_regs); printk("Current registers\n"); @@ -919,8 +933,9 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) BUG(); } *regs = kcb->jprobe_saved_regs; - memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack, - MIN_STACK_SIZE(stack_addr)); + memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp), + kcb->jprobes_stack, + MIN_STACK_SIZE(kcb->jprobe_saved_sp)); preempt_enable_no_resched(); return 1; } |