diff options
| -rw-r--r-- | arch/ia64/kernel/kprobes.c | 133 | ||||
| -rw-r--r-- | include/asm-ia64/kprobes.h | 7 |
2 files changed, 113 insertions, 27 deletions
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 8d9a446a0d17..233434f4f88f 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -78,6 +78,20 @@ static enum instruction_type bundle_encoding[32][3] = { { u, u, u }, /* 1F */ }; +/* Insert a long branch code */ +static void __kprobes set_brl_inst(void *from, void *to) +{ + s64 rel = ((s64) to - (s64) from) >> 4; + bundle_t *brl; + brl = (bundle_t *) ((u64) from & ~0xf); + brl->quad0.template = 0x05; /* [MLX](stop) */ + brl->quad0.slot0 = NOP_M_INST; /* nop.m 0x0 */ + brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2; + brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46); + /* brl.cond.sptk.many.clr rel<<4 (qp=0) */ + brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff); +} + /* * In this function we check to see if the instruction * is IP relative instruction and update the kprobe @@ -496,6 +510,77 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip; } +/* Check the instruction in the slot is break */ +static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot) +{ + unsigned int major_opcode; + unsigned int template = bundle->quad0.template; + unsigned long kprobe_inst; + + /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */ + if (slot == 1 && bundle_encoding[template][1] == L) + slot++; + + /* Get Kprobe probe instruction at given slot*/ + get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode); + + /* For break instruction, + * Bits 37:40 Major opcode to be zero + * Bits 27:32 X6 to be zero + * Bits 32:35 X3 to be zero + */ + if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) { + /* Not a break instruction */ + return 0; + } + + /* Is a break instruction */ + return 1; +} + +/* + * In this function, we check whether the target bundle modifies IP or + * it triggers an exception. If so, it cannot be boostable. + */ +static int __kprobes can_boost(bundle_t *bundle, uint slot, + unsigned long bundle_addr) +{ + unsigned int template = bundle->quad0.template; + + do { + if (search_exception_tables(bundle_addr + slot) || + __is_ia64_break_inst(bundle, slot)) + return 0; /* exception may occur in this bundle*/ + } while ((++slot) < 3); + template &= 0x1e; + if (template >= 0x10 /* including B unit */ || + template == 0x04 /* including X unit */ || + template == 0x06) /* undefined */ + return 0; + + return 1; +} + +/* Prepare long jump bundle and disables other boosters if need */ +static void __kprobes prepare_booster(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr & ~0xFULL; + unsigned int slot = (unsigned long)p->addr & 0xf; + struct kprobe *other_kp; + + if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) { + set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1); + p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE; + } + + /* disables boosters in previous slots */ + for (; addr < (unsigned long)p->addr; addr++) { + other_kp = get_kprobe((void *)addr); + if (other_kp) + other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE; + } +} + int __kprobes arch_prepare_kprobe(struct kprobe *p) { unsigned long addr = (unsigned long) p->addr; @@ -530,6 +615,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp); + prepare_booster(p); + return 0; } @@ -543,7 +630,9 @@ void __kprobes arch_arm_kprobe(struct kprobe *p) src = &p->opcode.bundle; flush_icache_range((unsigned long)p->ainsn.insn, - (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); + (unsigned long)p->ainsn.insn + + sizeof(kprobe_opcode_t) * MAX_INSN_SIZE); + switch (p->ainsn.slot) { case 0: dest->quad0.slot0 = src->quad0.slot0; @@ -584,13 +673,13 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p) void __kprobes arch_remove_kprobe(struct kprobe *p) { mutex_lock(&kprobe_mutex); - free_insn_slot(p->ainsn.insn, 0); + free_insn_slot(p->ainsn.insn, p->ainsn.inst_flag & INST_FLAG_BOOSTABLE); mutex_unlock(&kprobe_mutex); } /* * We are resuming execution after a single step fault, so the pt_regs * structure reflects the register state after we executed the instruction - * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust + * located in the kprobe (p->ainsn.insn->bundle). We still need to adjust * the ip to point back to the original stack address. To set the IP address * to original stack address, handle the case where we need to fixup the * relative IP address and/or fixup branch register. @@ -607,7 +696,7 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) if (slot == 1 && bundle_encoding[template][1] == L) slot = 2; - if (p->ainsn.inst_flag) { + if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) { if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) { /* Fix relative IP address */ @@ -686,33 +775,12 @@ static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs) static int __kprobes is_ia64_break_inst(struct pt_regs *regs) { unsigned int slot = ia64_psr(regs)->ri; - unsigned int template, major_opcode; - unsigned long kprobe_inst; unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip; bundle_t bundle; memcpy(&bundle, kprobe_addr, sizeof(bundle_t)); - template = bundle.quad0.template; - - /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */ - if (slot == 1 && bundle_encoding[template][1] == L) - slot++; - /* Get Kprobe probe instruction at given slot*/ - get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode); - - /* For break instruction, - * Bits 37:40 Major opcode to be zero - * Bits 27:32 X6 to be zero - * Bits 32:35 X3 to be zero - */ - if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) { - /* Not a break instruction */ - return 0; - } - - /* Is a break instruction */ - return 1; + return __is_ia64_break_inst(&bundle, slot); } static int __kprobes pre_kprobes_handler(struct die_args *args) @@ -802,6 +870,19 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) return 1; ss_probe: +#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM) + if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) { + /* Boost up -- we can execute copied instructions directly */ + ia64_psr(regs)->ri = p->ainsn.slot; + regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL; + /* turn single stepping off */ + ia64_psr(regs)->ss = 0; + + reset_current_kprobe(); + preempt_enable_no_resched(); + return 1; + } +#endif prepare_ss(p, regs); kcb->kprobe_status = KPROBE_HIT_SS; return 1; diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h index d03bf9ff68e3..ef71b57fc2f4 100644 --- a/include/asm-ia64/kprobes.h +++ b/include/asm-ia64/kprobes.h @@ -30,8 +30,12 @@ #include <asm/break.h> #define __ARCH_WANT_KPROBES_INSN_SLOT -#define MAX_INSN_SIZE 1 +#define MAX_INSN_SIZE 2 /* last half is for kprobe-booster */ #define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6) +#define NOP_M_INST (long)(1<<27) +#define BRL_INST(i1, i2) ((long)((0xcL << 37) | /* brl */ \ + (0x1L << 12) | /* many */ \ + (((i1) & 1) << 36) | ((i2) << 13))) /* imm */ typedef union cmp_inst { struct { @@ -112,6 +116,7 @@ struct arch_specific_insn { #define INST_FLAG_FIX_RELATIVE_IP_ADDR 1 #define INST_FLAG_FIX_BRANCH_REG 2 #define INST_FLAG_BREAK_INST 4 + #define INST_FLAG_BOOSTABLE 8 unsigned long inst_flag; unsigned short target_br_reg; unsigned short slot; |