diff options
Diffstat (limited to 'arch/mn10300/kernel/kprobes.c')
| -rw-r--r-- | arch/mn10300/kernel/kprobes.c | 653 |
1 files changed, 653 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/kprobes.c b/arch/mn10300/kernel/kprobes.c new file mode 100644 index 000000000000..dacafab00eb2 --- /dev/null +++ b/arch/mn10300/kernel/kprobes.c @@ -0,0 +1,653 @@ +/* MN10300 Kernel probes implementation + * + * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. + * Written by Mark Salter (msalter@redhat.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public Licence as published by + * the Free Software Foundation; either version 2 of the Licence, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public Licence for more details. + * + * You should have received a copy of the GNU General Public Licence + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ +#include <linux/kprobes.h> +#include <linux/ptrace.h> +#include <linux/spinlock.h> +#include <linux/preempt.h> +#include <linux/kdebug.h> +#include <asm/cacheflush.h> + +struct kretprobe_blackpoint kretprobe_blacklist[] = { { NULL, NULL } }; +const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist); + +/* kprobe_status settings */ +#define KPROBE_HIT_ACTIVE 0x00000001 +#define KPROBE_HIT_SS 0x00000002 + +static struct kprobe *current_kprobe; +static unsigned long current_kprobe_orig_pc; +static unsigned long current_kprobe_next_pc; +static int current_kprobe_ss_flags; +static unsigned long kprobe_status; +static kprobe_opcode_t current_kprobe_ss_buf[MAX_INSN_SIZE + 2]; +static unsigned long current_kprobe_bp_addr; + +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; + + +/* singlestep flag bits */ +#define SINGLESTEP_BRANCH 1 +#define SINGLESTEP_PCREL 2 + +#define READ_BYTE(p, valp) \ + do { *(u8 *)(valp) = *(u8 *)(p); } while (0) + +#define READ_WORD16(p, valp) \ + do { \ + READ_BYTE((p), (valp)); \ + READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \ + } while (0) + +#define READ_WORD32(p, valp) \ + do { \ + READ_BYTE((p), (valp)); \ + READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \ + READ_BYTE((u8 *)(p) + 2, (u8 *)(valp) + 2); \ + READ_BYTE((u8 *)(p) + 3, (u8 *)(valp) + 3); \ + } while (0) + + +static const u8 mn10300_insn_sizes[256] = +{ + /* 1 2 3 4 5 6 7 8 9 a b c d e f */ + 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */ + 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */ + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */ + 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */ + 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */ + 0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */ +}; + +#define LT (1 << 0) +#define GT (1 << 1) +#define GE (1 << 2) +#define LE (1 << 3) +#define CS (1 << 4) +#define HI (1 << 5) +#define CC (1 << 6) +#define LS (1 << 7) +#define EQ (1 << 8) +#define NE (1 << 9) +#define RA (1 << 10) +#define VC (1 << 11) +#define VS (1 << 12) +#define NC (1 << 13) +#define NS (1 << 14) + +static const u16 cond_table[] = { + /* V C N Z */ + /* 0 0 0 0 */ (NE | NC | CC | VC | GE | GT | HI), + /* 0 0 0 1 */ (EQ | NC | CC | VC | GE | LE | LS), + /* 0 0 1 0 */ (NE | NS | CC | VC | LT | LE | HI), + /* 0 0 1 1 */ (EQ | NS | CC | VC | LT | LE | LS), + /* 0 1 0 0 */ (NE | NC | CS | VC | GE | GT | LS), + /* 0 1 0 1 */ (EQ | NC | CS | VC | GE | LE | LS), + /* 0 1 1 0 */ (NE | NS | CS | VC | LT | LE | LS), + /* 0 1 1 1 */ (EQ | NS | CS | VC | LT | LE | LS), + /* 1 0 0 0 */ (NE | NC | CC | VS | LT | LE | HI), + /* 1 0 0 1 */ (EQ | NC | CC | VS | LT | LE | LS), + /* 1 0 1 0 */ (NE | NS | CC | VS | GE | GT | HI), + /* 1 0 1 1 */ (EQ | NS | CC | VS | GE | LE | LS), + /* 1 1 0 0 */ (NE | NC | CS | VS | LT | LE | LS), + /* 1 1 0 1 */ (EQ | NC | CS | VS | LT | LE | LS), + /* 1 1 1 0 */ (NE | NS | CS | VS | GE | GT | LS), + /* 1 1 1 1 */ (EQ | NS | CS | VS | GE | LE | LS), +}; + +/* + * Calculate what the PC will be after executing next instruction + */ +static unsigned find_nextpc(struct pt_regs *regs, int *flags) +{ + unsigned size; + s8 x8; + s16 x16; + s32 x32; + u8 opc, *pc, *sp, *next; + + next = 0; + *flags = SINGLESTEP_PCREL; + + pc = (u8 *) regs->pc; + sp = (u8 *) (regs + 1); + opc = *pc; + + size = mn10300_insn_sizes[opc]; + if (size > 0) { + next = pc + size; + } else { + switch (opc) { + /* Bxx (d8,PC) */ + case 0xc0 ... 0xca: + x8 = 2; + if (cond_table[regs->epsw & 0xf] & (1 << (opc & 0xf))) + x8 = (s8)pc[1]; + next = pc + x8; + *flags |= SINGLESTEP_BRANCH; + break; + + /* JMP (d16,PC) or CALL (d16,PC) */ + case 0xcc: + case 0xcd: + READ_WORD16(pc + 1, &x16); + next = pc + x16; + *flags |= SINGLESTEP_BRANCH; + break; + + /* JMP (d32,PC) or CALL (d32,PC) */ + case 0xdc: + case 0xdd: + READ_WORD32(pc + 1, &x32); + next = pc + x32; + *flags |= SINGLESTEP_BRANCH; + break; + + /* RETF */ + case 0xde: + next = (u8 *)regs->mdr; + *flags &= ~SINGLESTEP_PCREL; + *flags |= SINGLESTEP_BRANCH; + break; + + /* RET */ + case 0xdf: + sp += pc[2]; + READ_WORD32(sp, &x32); + next = (u8 *)x32; + *flags &= ~SINGLESTEP_PCREL; + *flags |= SINGLESTEP_BRANCH; + break; + + case 0xf0: + next = pc + 2; + opc = pc[1]; + if (opc >= 0xf0 && opc <= 0xf7) { + /* JMP (An) / CALLS (An) */ + switch (opc & 3) { + case 0: + next = (u8 *)regs->a0; + break; + case 1: + next = (u8 *)regs->a1; + break; + case 2: + next = (u8 *)regs->a2; + break; + case 3: + next = (u8 *)regs->a3; + break; + } + *flags &= ~SINGLESTEP_PCREL; + *flags |= SINGLESTEP_BRANCH; + } else if (opc == 0xfc) { + /* RETS */ + READ_WORD32(sp, &x32); + next = (u8 *)x32; + *flags &= ~SINGLESTEP_PCREL; + *flags |= SINGLESTEP_BRANCH; + } else if (opc == 0xfd) { + /* RTI */ + READ_WORD32(sp + 4, &x32); + next = (u8 *)x32; + *flags &= ~SINGLESTEP_PCREL; + *flags |= SINGLESTEP_BRANCH; + } + break; + + /* potential 3-byte conditional branches */ + case 0xf8: + next = pc + 3; + opc = pc[1]; + if (opc >= 0xe8 && opc <= 0xeb && + (cond_table[regs->epsw & 0xf] & + (1 << ((opc & 0xf) + 3))) + ) { + READ_BYTE(pc+2, &x8); + next = pc + x8; + *flags |= SINGLESTEP_BRANCH; + } + break; + + case 0xfa: + if (pc[1] == 0xff) { + /* CALLS (d16,PC) */ + READ_WORD16(pc + 2, &x16); + next = pc + x16; + } else + next = pc + 4; + *flags |= SINGLESTEP_BRANCH; + break; + + case 0xfc: + x32 = 6; + if (pc[1] == 0xff) { + /* CALLS (d32,PC) */ + READ_WORD32(pc + 2, &x32); + } + next = pc + x32; + *flags |= SINGLESTEP_BRANCH; + break; + /* LXX (d8,PC) */ + /* SETLB - loads the next four bytes into the LIR reg */ + case 0xd0 ... 0xda: + case 0xdb: + panic("Can't singlestep Lxx/SETLB\n"); + break; + } + } + return (unsigned)next; + +} + +/* + * set up out of place singlestep of some branching instructions + */ +static unsigned __kprobes singlestep_branch_setup(struct pt_regs *regs) +{ + u8 opc, *pc, *sp, *next; + + next = NULL; + pc = (u8 *) regs->pc; + sp = (u8 *) (regs + 1); + + switch (pc[0]) { + case 0xc0 ... 0xca: /* Bxx (d8,PC) */ + case 0xcc: /* JMP (d16,PC) */ + case 0xdc: /* JMP (d32,PC) */ + case 0xf8: /* Bxx (d8,PC) 3-byte version */ + /* don't really need to do anything except cause trap */ + next = pc; + break; + + case 0xcd: /* CALL (d16,PC) */ + pc[1] = 5; + pc[2] = 0; + next = pc + 5; + break; + + case 0xdd: /* CALL (d32,PC) */ + pc[1] = 7; + pc[2] = 0; + pc[3] = 0; + pc[4] = 0; + next = pc + 7; + break; + + case 0xde: /* RETF */ + next = pc + 3; + regs->mdr = (unsigned) next; + break; + + case 0xdf: /* RET */ + sp += pc[2]; + next = pc + 3; + *(unsigned *)sp = (unsigned) next; + break; + + case 0xf0: + next = pc + 2; + opc = pc[1]; + if (opc >= 0xf0 && opc <= 0xf3) { + /* CALLS (An) */ + /* use CALLS (d16,PC) to avoid mucking with An */ + pc[0] = 0xfa; + pc[1] = 0xff; + pc[2] = 4; + pc[3] = 0; + next = pc + 4; + } else if (opc >= 0xf4 && opc <= 0xf7) { + /* JMP (An) */ + next = pc; + } else if (opc == 0xfc) { + /* RETS */ + next = pc + 2; + *(unsigned *) sp = (unsigned) next; + } else if (opc == 0xfd) { + /* RTI */ + next = pc + 2; + *(unsigned *)(sp + 4) = (unsigned) next; + } + break; + + case 0xfa: /* CALLS (d16,PC) */ + pc[2] = 4; + pc[3] = 0; + next = pc + 4; + break; + + case 0xfc: /* CALLS (d32,PC) */ + pc[2] = 6; + pc[3] = 0; + pc[4] = 0; + pc[5] = 0; + next = pc + 6; + break; + + case 0xd0 ... 0xda: /* LXX (d8,PC) */ + case 0xdb: /* SETLB */ + panic("Can't singlestep Lxx/SETLB\n"); + } + + return (unsigned) next; +} + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + return 0; +} + +void __kprobes arch_copy_kprobe(struct kprobe *p) +{ + memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE); +} + +void __kprobes arch_arm_kprobe(struct kprobe *p) +{ + *p->addr = BREAKPOINT_INSTRUCTION; + flush_icache_range((unsigned long) p->addr, + (unsigned long) p->addr + sizeof(kprobe_opcode_t)); +} + +void __kprobes arch_disarm_kprobe(struct kprobe *p) +{ + mn10300_dcache_flush(); + mn10300_icache_inv(); +} + +void arch_remove_kprobe(struct kprobe *p) +{ +} + +static inline +void __kprobes disarm_kprobe(struct kprobe *p, struct pt_regs *regs) +{ + *p->addr = p->opcode; + regs->pc = (unsigned long) p->addr; + mn10300_dcache_flush(); + mn10300_icache_inv(); +} + +static inline +void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long nextpc; + + current_kprobe_orig_pc = regs->pc; + memcpy(current_kprobe_ss_buf, &p->ainsn.insn[0], MAX_INSN_SIZE); + regs->pc = (unsigned long) current_kprobe_ss_buf; + + nextpc = find_nextpc(regs, ¤t_kprobe_ss_flags); + if (current_kprobe_ss_flags & SINGLESTEP_PCREL) + current_kprobe_next_pc = + current_kprobe_orig_pc + (nextpc - regs->pc); + else + current_kprobe_next_pc = nextpc; + + /* branching instructions need special handling */ + if (current_kprobe_ss_flags & SINGLESTEP_BRANCH) + nextpc = singlestep_branch_setup(regs); + + current_kprobe_bp_addr = nextpc; + + *(u8 *) nextpc = BREAKPOINT_INSTRUCTION; + mn10300_dcache_flush_range2((unsigned) current_kprobe_ss_buf, + sizeof(current_kprobe_ss_buf)); + mn10300_icache_inv(); +} + +static inline int __kprobes kprobe_handler(struct pt_regs *regs) +{ + struct kprobe *p; + int ret = 0; + unsigned int *addr = (unsigned int *) regs->pc; + + /* We're in an interrupt, but this is clear and BUG()-safe. */ + preempt_disable(); + + /* Check we're not actually recursing */ + if (kprobe_running()) { + /* We *are* holding lock here, so this is safe. + Disarm the probe we just hit, and ignore it. */ + p = get_kprobe(addr); + if (p) { + disarm_kprobe(p, regs); + ret = 1; + } else { + p = current_kprobe; + if (p->break_handler && p->break_handler(p, regs)) + goto ss_probe; + } + /* If it's not ours, can't be delete race, (we hold lock). */ + goto no_kprobe; + } + + p = get_kprobe(addr); + if (!p) { + if (*addr != BREAKPOINT_INSTRUCTION) { + /* The breakpoint instruction was removed right after + * we hit it. Another cpu has removed either a + * probepoint or a debugger breakpoint at this address. + * In either case, no further handling of this + * interrupt is appropriate. + */ + ret = 1; + } + /* Not one of ours: let kernel handle it */ + goto no_kprobe; + } + + kprobe_status = KPROBE_HIT_ACTIVE; + current_kprobe = p; + if (p->pre_handler(p, regs)) { + /* handler has already set things up, so skip ss setup */ + return 1; + } + +ss_probe: + prepare_singlestep(p, regs); + kprobe_status = KPROBE_HIT_SS; + return 1; + +no_kprobe: + preempt_enable_no_resched(); + return ret; +} + +/* + * Called after single-stepping. p->addr is the address of the + * instruction whose first byte 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. + */ +static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) +{ + /* we may need to fixup regs/stack after singlestepping a call insn */ + if (current_kprobe_ss_flags & SINGLESTEP_BRANCH) { + regs->pc = current_kprobe_orig_pc; + switch (p->ainsn.insn[0]) { + case 0xcd: /* CALL (d16,PC) */ + *(unsigned *) regs->sp = regs->mdr = regs->pc + 5; + break; + case 0xdd: /* CALL (d32,PC) */ + /* fixup mdr and return address on stack */ + *(unsigned *) regs->sp = regs->mdr = regs->pc + 7; + break; + case 0xf0: + if (p->ainsn.insn[1] >= 0xf0 && + p->ainsn.insn[1] <= 0xf3) { + /* CALLS (An) */ + /* fixup MDR and return address on stack */ + regs->mdr = regs->pc + 2; + *(unsigned *) regs->sp = regs->mdr; + } + break; + + case 0xfa: /* CALLS (d16,PC) */ + /* fixup MDR and return address on stack */ + *(unsigned *) regs->sp = regs->mdr = regs->pc + 4; + break; + + case 0xfc: /* CALLS (d32,PC) */ + /* fixup MDR and return address on stack */ + *(unsigned *) regs->sp = regs->mdr = regs->pc + 6; + break; + } + } + + regs->pc = current_kprobe_next_pc; + current_kprobe_bp_addr = 0; +} + +static inline int __kprobes post_kprobe_handler(struct pt_regs *regs) +{ + if (!kprobe_running()) + return 0; + + if (current_kprobe->post_handler) + current_kprobe->post_handler(current_kprobe, regs, 0); + + resume_execution(current_kprobe, regs); + reset_current_kprobe(); + preempt_enable_no_resched(); + return 1; +} + +/* Interrupts disabled, kprobe_lock held. */ +static inline +int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) +{ + if (current_kprobe->fault_handler && + current_kprobe->fault_handler(current_kprobe, regs, trapnr)) + return 1; + + if (kprobe_status & KPROBE_HIT_SS) { + resume_execution(current_kprobe, regs); + reset_current_kprobe(); + preempt_enable_no_resched(); + } + return 0; +} + +/* + * Wrapper routine to for handling exceptions. + */ +int __kprobes kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + + switch (val) { + case DIE_BREAKPOINT: + if (current_kprobe_bp_addr != args->regs->pc) { + if (kprobe_handler(args->regs)) + return NOTIFY_STOP; + } else { + if (post_kprobe_handler(args->regs)) + return NOTIFY_STOP; + } + break; + case DIE_GPF: + if (kprobe_running() && + kprobe_fault_handler(args->regs, args->trapnr)) + return NOTIFY_STOP; + break; + default: + break; + } + return NOTIFY_DONE; +} + +/* Jprobes support. */ +static struct pt_regs jprobe_saved_regs; +static struct pt_regs *jprobe_saved_regs_location; +static kprobe_opcode_t jprobe_saved_stack[MAX_STACK_SIZE]; + +int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct jprobe *jp = container_of(p, struct jprobe, kp); + + jprobe_saved_regs_location = regs; + memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs)); + + /* Save a whole stack frame, this gets arguments + * pushed onto the stack after using up all the + * arg registers. + */ + memcpy(&jprobe_saved_stack, regs + 1, sizeof(jprobe_saved_stack)); + + /* setup return addr to the jprobe handler routine */ + regs->pc = (unsigned long) jp->entry; + return 1; +} + +void __kprobes jprobe_return(void) +{ + void *orig_sp = jprobe_saved_regs_location + 1; + + preempt_enable_no_resched(); + asm volatile(" mov %0,sp\n" + ".globl jprobe_return_bp_addr\n" + "jprobe_return_bp_addr:\n\t" + " .byte 0xff\n" + : : "d" (orig_sp)); +} + +extern void jprobe_return_bp_addr(void); + +int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + u8 *addr = (u8 *) regs->pc; + + if (addr == (u8 *) jprobe_return_bp_addr) { + if (jprobe_saved_regs_location != regs) { + printk(KERN_ERR"JPROBE:" + " Current regs (%p) does not match saved regs" + " (%p).\n", + regs, jprobe_saved_regs_location); + BUG(); + } + + /* Restore old register state. + */ + memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs)); + + memcpy(regs + 1, &jprobe_saved_stack, + sizeof(jprobe_saved_stack)); + return 1; + } + return 0; +} + +int __init arch_init_kprobes(void) +{ + return 0; +} |