--- /dev/null
+/* 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 *cur_kprobe;
+static unsigned long cur_kprobe_orig_pc;
+static unsigned long cur_kprobe_next_pc;
+static int cur_kprobe_ss_flags;
+static unsigned long kprobe_status;
+static kprobe_opcode_t cur_kprobe_ss_buf[MAX_INSN_SIZE + 2];
+static unsigned long cur_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)
+{
+#ifndef CONFIG_MN10300_CACHE_SNOOP
+ mn10300_dcache_flush();
+ mn10300_icache_inv();
+#endif
+}
+
+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;
+#ifndef CONFIG_MN10300_CACHE_SNOOP
+ mn10300_dcache_flush();
+ mn10300_icache_inv();
+#endif
+}
+
+static inline
+void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long nextpc;
+
+ cur_kprobe_orig_pc = regs->pc;
+ memcpy(cur_kprobe_ss_buf, &p->ainsn.insn[0], MAX_INSN_SIZE);
+ regs->pc = (unsigned long) cur_kprobe_ss_buf;
+
+ nextpc = find_nextpc(regs, &cur_kprobe_ss_flags);
+ if (cur_kprobe_ss_flags & SINGLESTEP_PCREL)
+ cur_kprobe_next_pc = cur_kprobe_orig_pc + (nextpc - regs->pc);
+ else
+ cur_kprobe_next_pc = nextpc;
+
+ /* branching instructions need special handling */
+ if (cur_kprobe_ss_flags & SINGLESTEP_BRANCH)
+ nextpc = singlestep_branch_setup(regs);
+
+ cur_kprobe_bp_addr = nextpc;
+
+ *(u8 *) nextpc = BREAKPOINT_INSTRUCTION;
+ mn10300_dcache_flush_range2((unsigned) cur_kprobe_ss_buf,
+ sizeof(cur_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 = cur_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;
+ cur_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 (cur_kprobe_ss_flags & SINGLESTEP_BRANCH) {
+ regs->pc = cur_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 = cur_kprobe_next_pc;
+ cur_kprobe_bp_addr = 0;
+}
+
+static inline int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ if (!kprobe_running())
+ return 0;
+
+ if (cur_kprobe->post_handler)
+ cur_kprobe->post_handler(cur_kprobe, regs, 0);
+
+ resume_execution(cur_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 (cur_kprobe->fault_handler &&
+ cur_kprobe->fault_handler(cur_kprobe, regs, trapnr))
+ return 1;
+
+ if (kprobe_status & KPROBE_HIT_SS) {
+ resume_execution(cur_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 (cur_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;
+}
Code Review / kvmfornfv.git / blobdiff