diff options
author | Ingo Molnar <mingo@kernel.org> | 2014-05-05 10:59:47 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2014-05-05 10:59:47 +0200 |
commit | 8e02ae573e6ae86930d08662790827a938203e70 (patch) | |
tree | ef87732e10e1c4162c45774274da07b32bee32ef /arch/x86 | |
parent | 3617660e4e1618a888a2e3a4067224534302cb33 (diff) | |
parent | 13f59c5e45be59665c11ddde19799b6295543b7d (diff) | |
download | op-kernel-dev-8e02ae573e6ae86930d08662790827a938203e70.zip op-kernel-dev-8e02ae573e6ae86930d08662790827a938203e70.tar.gz |
Merge branch 'uprobes/core' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/uprobes
Pull uprobes updates from Oleg Nesterov:
"This hopefully completes the previous 'fix the handling of relative
jmp/call's' series, all changes except the last 3 unrelated fixes try
to address TODO's mentioned in the changelogs."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/include/asm/uprobes.h | 13 | ||||
-rw-r--r-- | arch/x86/kernel/process_64.c | 7 | ||||
-rw-r--r-- | arch/x86/kernel/uprobes.c | 333 |
3 files changed, 174 insertions, 179 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 93bee7b..a040d49 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -41,18 +41,21 @@ struct arch_uprobe { u8 ixol[MAX_UINSN_BYTES]; }; - u16 fixups; const struct uprobe_xol_ops *ops; union { -#ifdef CONFIG_X86_64 - unsigned long rip_rela_target_address; -#endif struct { s32 offs; u8 ilen; u8 opc1; - } branch; + } branch; + struct { +#ifdef CONFIG_X86_64 + long riprel_target; +#endif + u8 fixups; + u8 ilen; + } def; }; }; diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 9c0280f..9b53940 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -413,12 +413,11 @@ void set_personality_ia32(bool x32) set_thread_flag(TIF_ADDR32); /* Mark the associated mm as containing 32-bit tasks. */ - if (current->mm) - current->mm->context.ia32_compat = 1; - if (x32) { clear_thread_flag(TIF_IA32); set_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_X32; current->personality &= ~READ_IMPLIES_EXEC; /* is_compat_task() uses the presence of the x32 syscall bit flag to determine compat status */ @@ -426,6 +425,8 @@ void set_personality_ia32(bool x32) } else { set_thread_flag(TIF_IA32); clear_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_IA32; current->personality |= force_personality32; /* Prepare the first "return" to user space */ current_thread_info()->status |= TS_COMPAT; diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index ace2291..2ebadb2 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -32,20 +32,17 @@ /* Post-execution fixups. */ -/* No fixup needed */ -#define UPROBE_FIX_NONE 0x0 - /* Adjust IP back to vicinity of actual insn */ -#define UPROBE_FIX_IP 0x1 +#define UPROBE_FIX_IP 0x01 /* Adjust the return address of a call insn */ -#define UPROBE_FIX_CALL 0x2 +#define UPROBE_FIX_CALL 0x02 /* Instruction will modify TF, don't change it */ -#define UPROBE_FIX_SETF 0x4 +#define UPROBE_FIX_SETF 0x04 -#define UPROBE_FIX_RIP_AX 0x8000 -#define UPROBE_FIX_RIP_CX 0x4000 +#define UPROBE_FIX_RIP_AX 0x08 +#define UPROBE_FIX_RIP_CX 0x10 #define UPROBE_TRAP_NR UINT_MAX @@ -67,6 +64,7 @@ * to keep gcc from statically optimizing it out, as variable_test_bit makes * some versions of gcc to think only *(unsigned long*) is used. */ +#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) static volatile u32 good_insns_32[256 / 32] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ /* ---------------------------------------------- */ @@ -89,33 +87,12 @@ static volatile u32 good_insns_32[256 / 32] = { /* ---------------------------------------------- */ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ }; +#else +#define good_insns_32 NULL +#endif -/* Using this for both 64-bit and 32-bit apps */ -static volatile u32 good_2byte_insns[256 / 32] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ---------------------------------------------- */ - W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */ - W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* 10 */ - W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 20 */ - W(0x30, 0, 1, 1, 1, 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, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */ - W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 60 */ - W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */ - W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */ - W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */ - W(0xa0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1) | /* a0 */ - W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* b0 */ - W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */ - W(0xd0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */ - W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* e0 */ - W(0xf0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* f0 */ - /* ---------------------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ -}; - -#ifdef CONFIG_X86_64 /* Good-instruction tables for 64-bit apps */ +#if defined(CONFIG_X86_64) static volatile u32 good_insns_64[256 / 32] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ /* ---------------------------------------------- */ @@ -138,7 +115,33 @@ static volatile u32 good_insns_64[256 / 32] = { /* ---------------------------------------------- */ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ }; +#else +#define good_insns_64 NULL #endif + +/* Using this for both 64-bit and 32-bit apps */ +static volatile u32 good_2byte_insns[256 / 32] = { + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ + /* ---------------------------------------------- */ + W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */ + W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* 10 */ + W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 20 */ + W(0x30, 0, 1, 1, 1, 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, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */ + W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 60 */ + W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */ + W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */ + W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */ + W(0xa0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1) | /* a0 */ + W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* b0 */ + W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */ + W(0xd0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */ + W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* e0 */ + W(0xf0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* f0 */ + /* ---------------------------------------------- */ + /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ +}; #undef W /* @@ -209,16 +212,25 @@ static bool is_prefix_bad(struct insn *insn) return false; } -static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn) +static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool x86_64) { - insn_init(insn, auprobe->insn, false); + u32 volatile *good_insns; + + insn_init(insn, auprobe->insn, x86_64); + /* has the side-effect of processing the entire instruction */ + insn_get_length(insn); + if (WARN_ON_ONCE(!insn_complete(insn))) + return -ENOEXEC; - /* Skip good instruction prefixes; reject "bad" ones. */ - insn_get_opcode(insn); if (is_prefix_bad(insn)) return -ENOTSUPP; - if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_32)) + if (x86_64) + good_insns = good_insns_64; + else + good_insns = good_insns_32; + + if (test_bit(OPCODE1(insn), (unsigned long *)good_insns)) return 0; if (insn->opcode.nbytes == 2) { @@ -230,14 +242,18 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn) } #ifdef CONFIG_X86_64 +static inline bool is_64bit_mm(struct mm_struct *mm) +{ + return !config_enabled(CONFIG_IA32_EMULATION) || + !(mm->context.ia32_compat == TIF_IA32); +} /* * If arch_uprobe->insn doesn't use rip-relative addressing, return * immediately. Otherwise, rewrite the instruction so that it accesses * its memory operand indirectly through a scratch register. Set - * arch_uprobe->fixups and arch_uprobe->rip_rela_target_address - * accordingly. (The contents of the scratch register will be saved - * before we single-step the modified instruction, and restored - * afterward.) + * def->fixups and def->riprel_target accordingly. (The contents of the + * scratch register will be saved before we single-step the modified + * instruction, and restored afterward). * * We do this because a rip-relative instruction can access only a * relatively small area (+/- 2 GB from the instruction), and the XOL @@ -252,8 +268,7 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn) * - There's never a SIB byte. * - The displacement is always 4 bytes. */ -static void -handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn) +static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) { u8 *cursor; u8 reg; @@ -277,8 +292,6 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn) * is the immediate operand. */ cursor = auprobe->insn + insn_offset_modrm(insn); - insn_get_length(insn); - /* * Convert from rip-relative addressing to indirect addressing * via a scratch register. Change the r/m field from 0x5 (%rip) @@ -293,18 +306,18 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn) * is NOT the register operand, so we use %rcx (register * #1) for the scratch register. */ - auprobe->fixups = UPROBE_FIX_RIP_CX; + auprobe->def.fixups |= UPROBE_FIX_RIP_CX; /* Change modrm from 00 000 101 to 00 000 001. */ *cursor = 0x1; } else { /* Use %rax (register #0) for the scratch register. */ - auprobe->fixups = UPROBE_FIX_RIP_AX; + auprobe->def.fixups |= UPROBE_FIX_RIP_AX; /* Change modrm from 00 xxx 101 to 00 xxx 000 */ *cursor = (reg << 3); } /* Target address = address of next instruction + (signed) offset */ - auprobe->rip_rela_target_address = (long)insn->length + insn->displacement.value; + auprobe->def.riprel_target = (long)insn->length + insn->displacement.value; /* Displacement field is gone; slide immediate field (if any) over. */ if (insn->immediate.nbytes) { @@ -313,37 +326,35 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn) } } +static inline unsigned long * +scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + return (auprobe->def.fixups & UPROBE_FIX_RIP_AX) ? ®s->ax : ®s->cx; +} + /* * If we're emulating a rip-relative instruction, save the contents * of the scratch register and store the target address in that register. */ -static void -pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs, - struct arch_uprobe_task *autask) -{ - if (auprobe->fixups & UPROBE_FIX_RIP_AX) { - autask->saved_scratch_register = regs->ax; - regs->ax = current->utask->vaddr; - regs->ax += auprobe->rip_rela_target_address; - } else if (auprobe->fixups & UPROBE_FIX_RIP_CX) { - autask->saved_scratch_register = regs->cx; - regs->cx = current->utask->vaddr; - regs->cx += auprobe->rip_rela_target_address; +static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + if (auprobe->def.fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) { + struct uprobe_task *utask = current->utask; + unsigned long *sr = scratch_reg(auprobe, regs); + + utask->autask.saved_scratch_register = *sr; + *sr = utask->vaddr + auprobe->def.riprel_target; } } -static void -handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction) +static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, + long *correction) { - if (auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) { - struct arch_uprobe_task *autask; - - autask = ¤t->utask->autask; - if (auprobe->fixups & UPROBE_FIX_RIP_AX) - regs->ax = autask->saved_scratch_register; - else - regs->cx = autask->saved_scratch_register; + if (auprobe->def.fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) { + struct uprobe_task *utask = current->utask; + unsigned long *sr = scratch_reg(auprobe, regs); + *sr = utask->autask.saved_scratch_register; /* * The original instruction includes a displacement, and so * is 4 bytes longer than what we've just single-stepped. @@ -354,58 +365,31 @@ handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long * *correction += 4; } } - -static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn) -{ - insn_init(insn, auprobe->insn, true); - - /* Skip good instruction prefixes; reject "bad" ones. */ - insn_get_opcode(insn); - if (is_prefix_bad(insn)) - return -ENOTSUPP; - - if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_64)) - return 0; - - if (insn->opcode.nbytes == 2) { - if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns)) - return 0; - } - return -ENOTSUPP; -} - -static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) +#else /* 32-bit: */ +static inline bool is_64bit_mm(struct mm_struct *mm) { - if (mm->context.ia32_compat) - return validate_insn_32bits(auprobe, insn); - return validate_insn_64bits(auprobe, insn); + return false; } -#else /* 32-bit: */ /* * No RIP-relative addressing on 32-bit */ -static void handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn) +static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) { } -static void pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs, - struct arch_uprobe_task *autask) +static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { } -static void handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, +static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction) { } - -static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) -{ - return validate_insn_32bits(auprobe, insn); -} #endif /* CONFIG_X86_64 */ struct uprobe_xol_ops { bool (*emulate)(struct arch_uprobe *, struct pt_regs *); int (*pre_xol)(struct arch_uprobe *, struct pt_regs *); int (*post_xol)(struct arch_uprobe *, struct pt_regs *); + void (*abort)(struct arch_uprobe *, struct pt_regs *); }; static inline int sizeof_long(void) @@ -415,25 +399,18 @@ static inline int sizeof_long(void) static int default_pre_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs) { - pre_xol_rip_insn(auprobe, regs, ¤t->utask->autask); + riprel_pre_xol(auprobe, regs); return 0; } -/* - * Adjust the return address pushed by a call insn executed out of line. - */ -static int adjust_ret_addr(unsigned long sp, long correction) +static int push_ret_address(struct pt_regs *regs, unsigned long ip) { - int rasize = sizeof_long(); - long ra; + unsigned long new_sp = regs->sp - sizeof_long(); - if (copy_from_user(&ra, (void __user *)sp, rasize)) - return -EFAULT; - - ra += correction; - if (copy_to_user((void __user *)sp, &ra, rasize)) + if (copy_to_user((void __user *)new_sp, &ip, sizeof_long())) return -EFAULT; + regs->sp = new_sp; return 0; } @@ -442,23 +419,30 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs struct uprobe_task *utask = current->utask; long correction = (long)(utask->vaddr - utask->xol_vaddr); - handle_riprel_post_xol(auprobe, regs, &correction); - if (auprobe->fixups & UPROBE_FIX_IP) + riprel_post_xol(auprobe, regs, &correction); + if (auprobe->def.fixups & UPROBE_FIX_IP) { regs->ip += correction; - - if (auprobe->fixups & UPROBE_FIX_CALL) { - if (adjust_ret_addr(regs->sp, correction)) { - regs->sp += sizeof_long(); + } else if (auprobe->def.fixups & UPROBE_FIX_CALL) { + regs->sp += sizeof_long(); + if (push_ret_address(regs, utask->vaddr + auprobe->def.ilen)) return -ERESTART; - } } + /* popf; tell the caller to not touch TF */ + if (auprobe->def.fixups & UPROBE_FIX_SETF) + utask->autask.saved_tf = true; return 0; } +static void default_abort_op(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + riprel_post_xol(auprobe, regs, NULL); +} + static struct uprobe_xol_ops default_xol_ops = { .pre_xol = default_pre_xol_op, .post_xol = default_post_xol_op, + .abort = default_abort_op, }; static bool branch_is_call(struct arch_uprobe *auprobe) @@ -520,7 +504,6 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) unsigned long offs = (long)auprobe->branch.offs; if (branch_is_call(auprobe)) { - unsigned long new_sp = regs->sp - sizeof_long(); /* * If it fails we execute this (mangled, see the comment in * branch_clear_offset) insn out-of-line. In the likely case @@ -530,9 +513,8 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) * * But there is corner case, see the comment in ->post_xol(). */ - if (copy_to_user((void __user *)new_sp, &new_ip, sizeof_long())) + if (push_ret_address(regs, new_ip)) return false; - regs->sp = new_sp; } else if (!check_jmp_cond(auprobe, regs)) { offs = 0; } @@ -583,11 +565,7 @@ static struct uprobe_xol_ops branch_xol_ops = { static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) { u8 opc1 = OPCODE1(insn); - - /* has the side-effect of processing the entire instruction */ - insn_get_length(insn); - if (WARN_ON_ONCE(!insn_complete(insn))) - return -ENOEXEC; + int i; switch (opc1) { case 0xeb: /* jmp 8 */ @@ -612,6 +590,16 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) return -ENOSYS; } + /* + * 16-bit overrides such as CALLW (66 e8 nn nn) are not supported. + * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix. + * No one uses these insns, reject any branch insns with such prefix. + */ + for (i = 0; i < insn->prefixes.nbytes; i++) { + if (insn->prefixes.bytes[i] == 0x66) + return -ENOTSUPP; + } + auprobe->branch.opc1 = opc1; auprobe->branch.ilen = insn->length; auprobe->branch.offs = insn->immediate.value; @@ -630,10 +618,10 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr) { struct insn insn; - bool fix_ip = true, fix_call = false; + u8 fix_ip_or_call = UPROBE_FIX_IP; int ret; - ret = validate_insn_bits(auprobe, mm, &insn); + ret = uprobe_init_insn(auprobe, &insn, is_64bit_mm(mm)); if (ret) return ret; @@ -642,44 +630,40 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, return ret; /* - * Figure out which fixups arch_uprobe_post_xol() will need to perform, - * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups - * is either zero or it reflects rip-related fixups. + * Figure out which fixups default_post_xol_op() will need to perform, + * and annotate def->fixups accordingly. To start with, ->fixups is + * either zero or it reflects rip-related fixups. */ switch (OPCODE1(&insn)) { case 0x9d: /* popf */ - auprobe->fixups |= UPROBE_FIX_SETF; + auprobe->def.fixups |= UPROBE_FIX_SETF; break; case 0xc3: /* ret or lret -- ip is correct */ case 0xcb: case 0xc2: case 0xca: - fix_ip = false; + case 0xea: /* jmp absolute -- ip is correct */ + fix_ip_or_call = 0; break; case 0x9a: /* call absolute - Fix return addr, not ip */ - fix_call = true; - fix_ip = false; - break; - case 0xea: /* jmp absolute -- ip is correct */ - fix_ip = false; + fix_ip_or_call = UPROBE_FIX_CALL; break; case 0xff: - insn_get_modrm(&insn); switch (MODRM_REG(&insn)) { case 2: case 3: /* call or lcall, indirect */ - fix_call = true; + fix_ip_or_call = UPROBE_FIX_CALL; + break; case 4: case 5: /* jmp or ljmp, indirect */ - fix_ip = false; + fix_ip_or_call = 0; + break; } /* fall through */ default: - handle_riprel_insn(auprobe, &insn); + riprel_analyze(auprobe, &insn); } - if (fix_ip) - auprobe->fixups |= UPROBE_FIX_IP; - if (fix_call) - auprobe->fixups |= UPROBE_FIX_CALL; + auprobe->def.ilen = insn.length; + auprobe->def.fixups |= fix_ip_or_call; auprobe->ops = &default_xol_ops; return 0; @@ -694,6 +678,12 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; + if (auprobe->ops->pre_xol) { + int err = auprobe->ops->pre_xol(auprobe, regs); + if (err) + return err; + } + regs->ip = utask->xol_vaddr; utask->autask.saved_trap_nr = current->thread.trap_nr; current->thread.trap_nr = UPROBE_TRAP_NR; @@ -703,8 +693,6 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) if (test_tsk_thread_flag(current, TIF_BLOCKSTEP)) set_task_blockstep(current, false); - if (auprobe->ops->pre_xol) - return auprobe->ops->pre_xol(auprobe, regs); return 0; } @@ -753,35 +741,38 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t) int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; + bool send_sigtrap = utask->autask.saved_tf; + int err = 0; WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); + current->thread.trap_nr = utask->autask.saved_trap_nr; if (auprobe->ops->post_xol) { - int err = auprobe->ops->post_xol(auprobe, regs); + err = auprobe->ops->post_xol(auprobe, regs); if (err) { - arch_uprobe_abort_xol(auprobe, regs); /* - * Restart the probed insn. ->post_xol() must ensure - * this is really possible if it returns -ERESTART. + * Restore ->ip for restart or post mortem analysis. + * ->post_xol() must not return -ERESTART unless this + * is really possible. */ + regs->ip = utask->vaddr; if (err == -ERESTART) - return 0; - return err; + err = 0; + send_sigtrap = false; } } - - current->thread.trap_nr = utask->autask.saved_trap_nr; /* * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP * so we can get an extra SIGTRAP if we do not clear TF. We need * to examine the opcode to make it right. */ - if (utask->autask.saved_tf) + if (send_sigtrap) send_sig(SIGTRAP, current, 0); - else if (!(auprobe->fixups & UPROBE_FIX_SETF)) + + if (!utask->autask.saved_tf) regs->flags &= ~X86_EFLAGS_TF; - return 0; + return err; } /* callback routine for handling exceptions. */ @@ -815,18 +806,18 @@ int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, /* * This function gets called when XOL instruction either gets trapped or - * the thread has a fatal signal, or if arch_uprobe_post_xol() failed. - * Reset the instruction pointer to its probed address for the potential - * restart or for post mortem analysis. + * the thread has a fatal signal. Reset the instruction pointer to its + * probed address for the potential restart or for post mortem analysis. */ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; - current->thread.trap_nr = utask->autask.saved_trap_nr; - handle_riprel_post_xol(auprobe, regs, NULL); - instruction_pointer_set(regs, utask->vaddr); + if (auprobe->ops->abort) + auprobe->ops->abort(auprobe, regs); + current->thread.trap_nr = utask->autask.saved_trap_nr; + regs->ip = utask->vaddr; /* clear TF if it was set by us in arch_uprobe_pre_xol() */ if (!utask->autask.saved_tf) regs->flags &= ~X86_EFLAGS_TF; |