X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fsparc64%2Fkernel%2Fkprobes.c;h=ae221f0d4a6f2171ad9e43d83f08ca1cc8d3fa09;hb=refs%2Fheads%2Fvserver;hp=b9a9ce70e55c1f281ff4759b47abc6d03e10ae49;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c index b9a9ce70e..ae221f0d4 100644 --- a/arch/sparc64/kernel/kprobes.c +++ b/arch/sparc64/kernel/kprobes.c @@ -3,12 +3,13 @@ * Copyright (C) 2004 David S. Miller */ -#include #include #include +#include #include #include #include +#include /* We do not have hardware single-stepping on sparc64. * So we implement software single-stepping with breakpoint @@ -44,7 +45,11 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); int __kprobes arch_prepare_kprobe(struct kprobe *p) { p->ainsn.insn[0] = *p->addr; + flushi(&p->ainsn.insn[0]); + p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2; + flushi(&p->ainsn.insn[1]); + p->opcode = *p->addr; return 0; } @@ -61,7 +66,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p) flushi(p->addr); } -static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) { kcb->prev_kprobe.kp = kprobe_running(); kcb->prev_kprobe.status = kcb->kprobe_status; @@ -69,7 +74,7 @@ static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil; } -static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) +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; @@ -77,7 +82,7 @@ static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil; } -static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, +static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { __get_cpu_var(current_kprobe) = p; @@ -85,7 +90,7 @@ static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL); } -static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, +static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { regs->tstate |= TSTATE_PIL; @@ -184,16 +189,19 @@ no_kprobe: /* If INSN is a relative control transfer instruction, * return the corrected branch destination value. * - * The original INSN location was REAL_PC, it actually - * executed at PC and produced destination address NPC. + * regs->tpc and regs->tnpc still hold the values of the + * program counters at the time of trap due to the execution + * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1] + * */ -static unsigned long __kprobes relbranch_fixup(u32 insn, unsigned long real_pc, - unsigned long pc, - unsigned long npc) +static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p, + struct pt_regs *regs) { + unsigned long real_pc = (unsigned long) p->addr; + /* Branch not taken, no mods necessary. */ - if (npc == pc + 0x4UL) - return real_pc + 0x4UL; + if (regs->tnpc == regs->tpc + 0x4UL) + return real_pc + 0x8UL; /* The three cases are call, branch w/prediction, * and traditional branch. @@ -201,14 +209,21 @@ static unsigned long __kprobes relbranch_fixup(u32 insn, unsigned long real_pc, if ((insn & 0xc0000000) == 0x40000000 || (insn & 0xc1c00000) == 0x00400000 || (insn & 0xc1c00000) == 0x00800000) { + unsigned long ainsn_addr; + + ainsn_addr = (unsigned long) &p->ainsn.insn[0]; + /* The instruction did all the work for us * already, just apply the offset to the correct * instruction location. */ - return (real_pc + (npc - pc)); + return (real_pc + (regs->tnpc - ainsn_addr)); } - return real_pc + 0x4UL; + /* It is jmpl or some other absolute PC modification instruction, + * leave NPC as-is. + */ + return regs->tnpc; } /* If INSN is an instruction which writes it's PC location @@ -219,12 +234,12 @@ static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn, { unsigned long *slot = NULL; - /* Simplest cast is call, which always uses %o7 */ + /* Simplest case is 'call', which always uses %o7 */ if ((insn & 0xc0000000) == 0x40000000) { slot = ®s->u_regs[UREG_I7]; } - /* Jmpl encodes the register inside of the opcode */ + /* 'jmpl' encodes the register inside of the opcode */ if ((insn & 0xc1f80000) == 0x81c00000) { unsigned long rd = ((insn >> 25) & 0x1f); @@ -246,11 +261,11 @@ static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn, /* * Called after single-stepping. p->addr is the address of the - * instruction whose first byte has been replaced by the breakpoint + * instruction which has been replaced by the breakpoint * instruction. To avoid the SMP problems that can occur when we * temporarily put back the original opcode to single-step, we * single-stepped a copy of the instruction. The address of this - * copy is p->ainsn.insn. + * copy is &p->ainsn.insn[0]. * * This function prepares to return from the post-single-step * breakpoint trap. @@ -260,18 +275,18 @@ static void __kprobes resume_execution(struct kprobe *p, { u32 insn = p->ainsn.insn[0]; + regs->tnpc = relbranch_fixup(insn, p, regs); + + /* This assignment must occur after relbranch_fixup() */ regs->tpc = kcb->kprobe_orig_tnpc; - regs->tnpc = relbranch_fixup(insn, - (unsigned long) p->addr, - (unsigned long) &p->ainsn.insn[0], - regs->tnpc); + retpc_fixup(regs, insn, (unsigned long) p->addr); regs->tstate = ((regs->tstate & ~TSTATE_PIL) | kcb->kprobe_orig_tstate_pil); } -static inline int post_kprobe_handler(struct pt_regs *regs) +static int __kprobes post_kprobe_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -298,20 +313,72 @@ out: return 1; } -static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) +static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + const struct exception_table_entry *entry; + + switch(kcb->kprobe_status) { + case KPROBE_HIT_SS: + case KPROBE_REENTER: + /* + * We are here because the instruction being single + * stepped caused a page fault. We reset the current + * kprobe and the tpc points back to the probe address + * and allow the page fault handler to continue as a + * normal page fault. + */ + regs->tpc = (unsigned long)cur->addr; + regs->tnpc = kcb->kprobe_orig_tnpc; + regs->tstate = ((regs->tstate & ~TSTATE_PIL) | + kcb->kprobe_orig_tstate_pil); + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); + preempt_enable_no_resched(); + break; + case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SSDONE: + /* + * We increment the nmissed count for accounting, + * we can also use npre/npostfault count for accouting + * these specific fault cases. + */ + kprobes_inc_nmissed_count(cur); + + /* + * We come here because instructions in the pre/post + * handler caused the page_fault, this could happen + * if handler tries to access user space by + * copy_from_user(), get_user() etc. Let the + * user-specified handler try to fix it first. + */ + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; - if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) - return 1; + /* + * In case the user-specified fault handler returned + * zero, try to fix up. + */ - if (kcb->kprobe_status & KPROBE_HIT_SS) { - resume_execution(cur, regs, kcb); + entry = search_exception_tables(regs->tpc); + if (entry) { + regs->tpc = entry->fixup; + regs->tnpc = regs->tpc + 4; + return 1; + } - reset_current_kprobe(); - preempt_enable_no_resched(); + /* + * fixup_exception() could not handle it, + * Let do_page_fault() fix it. + */ + break; + default: + break; } + return 0; } @@ -324,6 +391,9 @@ 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)) + return ret; + switch (val) { case DIE_DEBUG: if (kprobe_handler(args->regs)) @@ -374,17 +444,8 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) struct jprobe *jp = container_of(p, struct jprobe, kp); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - kcb->jprobe_saved_regs_location = regs; memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs)); - /* Save a whole stack frame, this gets arguments - * pushed onto the stack after using up all the - * arg registers. - */ - memcpy(&(kcb->jprobe_saved_stack), - (char *) (regs->u_regs[UREG_FP] + STACK_BIAS), - sizeof(kcb->jprobe_saved_stack)); - regs->tpc = (unsigned long) jp->entry; regs->tnpc = ((unsigned long) jp->entry) + 0x4UL; regs->tstate |= TSTATE_PIL; @@ -394,10 +455,19 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) void __kprobes jprobe_return(void) { - __asm__ __volatile__( - ".globl jprobe_return_trap_instruction\n" + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + register unsigned long orig_fp asm("g1"); + + orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP]; + __asm__ __volatile__("\n" +"1: cmp %%sp, %0\n\t" + "blu,a,pt %%xcc, 1b\n\t" + " restore\n\t" + ".globl jprobe_return_trap_instruction\n" "jprobe_return_trap_instruction:\n\t" - "ta 0x70"); + "ta 0x70" + : /* no outputs */ + : "r" (orig_fp)); } extern void jprobe_return_trap_instruction(void); @@ -410,26 +480,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); if (addr == (u32 *) jprobe_return_trap_instruction) { - if (kcb->jprobe_saved_regs_location != regs) { - printk("JPROBE: Current regs (%p) does not match " - "saved regs (%p).\n", - regs, kcb->jprobe_saved_regs_location); - printk("JPROBE: Saved registers\n"); - __show_regs(kcb->jprobe_saved_regs_location); - printk("JPROBE: Current registers\n"); - __show_regs(regs); - BUG(); - } - /* Restore old register state. Do pt_regs - * first so that UREG_FP is the original one for - * the stack frame restore. - */ memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs)); - - memcpy((char *) (regs->u_regs[UREG_FP] + STACK_BIAS), - &(kcb->jprobe_saved_stack), - sizeof(kcb->jprobe_saved_stack)); - preempt_enable_no_resched(); return 1; }