* <prasanna@in.ibm.com> added function-return probes.
*/
-#include <linux/config.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/preempt.h>
/*
* returns non-zero if opcodes can be boosted.
*/
-static __always_inline int can_boost(kprobe_opcode_t opcode)
+static __always_inline int can_boost(kprobe_opcode_t *opcodes)
{
- switch (opcode & 0xf0 ) {
+#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
+ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
+ (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
+ (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
+ (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
+ << (row % 32))
+ /*
+ * Undefined/reserved opcodes, conditional jump, Opcode Extension
+ * Groups, and some special opcodes can not be boost.
+ */
+ static const unsigned long twobyte_is_boostable[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ------------------------------- */
+ W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
+ W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
+ W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
+ W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
+ W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
+ W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
+ W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
+ W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
+ W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
+ W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
+ W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
+ W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
+ W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
+ W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
+ W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
+ W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
+ /* ------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ };
+#undef W
+ kprobe_opcode_t opcode;
+ kprobe_opcode_t *orig_opcodes = opcodes;
+retry:
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ opcode = *(opcodes++);
+
+ /* 2nd-byte opcode */
+ if (opcode == 0x0f) {
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ return test_bit(*opcodes, twobyte_is_boostable);
+ }
+
+ switch (opcode & 0xf0) {
+ case 0x60:
+ if (0x63 < opcode && opcode < 0x67)
+ goto retry; /* prefixes */
+ /* can't boost Address-size override and bound */
+ return (opcode != 0x62 && opcode != 0x67);
case 0x70:
return 0; /* can't boost conditional jump */
- case 0x90:
- /* can't boost call and pushf */
- return opcode != 0x9a && opcode != 0x9c;
case 0xc0:
- /* can't boost undefined opcodes and soft-interruptions */
- return (0xc1 < opcode && opcode < 0xc6) ||
- (0xc7 < opcode && opcode < 0xcc) || opcode == 0xcf;
+ /* can't boost software-interruptions */
+ return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
case 0xd0:
/* can boost AA* and XLAT */
return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
case 0xe0:
- /* can boost in/out and (may be) jmps */
- return (0xe3 < opcode && opcode != 0xe8);
+ /* can boost in/out and absolute jmps */
+ return ((opcode & 0x04) || opcode == 0xea);
case 0xf0:
+ if ((opcode & 0x0c) == 0 && opcode != 0xf1)
+ goto retry; /* lock/rep(ne) prefix */
/* clear and set flags can be boost */
return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
default:
- /* currently, can't boost 2 bytes opcodes */
- return opcode != 0x0f;
+ if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
+ goto retry; /* prefixes */
+ /* can't boost CS override and call */
+ return (opcode != 0x2e && opcode != 0x9a);
}
}
-
/*
* returns non-zero if opcode modifies the interrupt flag.
*/
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr;
- if (can_boost(p->opcode)) {
+ if (can_boost(p->addr)) {
p->ainsn.boostable = 0;
} else {
p->ainsn.boostable = -1;
struct kprobe_ctlblk *kcb;
#ifdef CONFIG_PREEMPT
unsigned pre_preempt_count = preempt_count();
-#endif /* CONFIG_PREEMPT */
+#else
+ unsigned pre_preempt_count = 1;
+#endif
addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
kcb->kprobe_status = KPROBE_REENTER;
return 1;
} else {
- if (regs->eflags & VM_MASK) {
- /* We are in virtual-8086 mode. Return 0 */
- goto no_kprobe;
- }
if (*addr != BREAKPOINT_INSTRUCTION) {
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
p = get_kprobe(addr);
if (!p) {
- if (regs->eflags & VM_MASK) {
- /* We are in virtual-8086 mode. Return 0 */
- goto no_kprobe;
- }
-
if (*addr != BREAKPOINT_INSTRUCTION) {
/*
* The breakpoint instruction was removed right
/* handler has already set things up, so skip ss setup */
return 1;
- if (p->ainsn.boostable == 1 &&
-#ifdef CONFIG_PREEMPT
- !(pre_preempt_count) && /*
- * This enables booster when the direct
- * execution path aren't preempted.
- */
-#endif /* CONFIG_PREEMPT */
- !p->post_handler && !p->break_handler ) {
+ss_probe:
+ if (pre_preempt_count && p->ainsn.boostable == 1 && !p->post_handler){
/* Boost up -- we can execute copied instructions directly */
reset_current_kprobe();
regs->eip = (unsigned long)p->ainsn.insn;
preempt_enable_no_resched();
return 1;
}
-
-ss_probe:
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
*tos &= ~(TF_MASK | IF_MASK);
*tos |= kcb->kprobe_old_eflags;
break;
- case 0xc3: /* ret/lret */
- case 0xcb:
- case 0xc2:
+ case 0xc2: /* iret/ret/lret */
+ case 0xc3:
case 0xca:
+ case 0xcb:
+ case 0xcf:
case 0xea: /* jmp absolute -- eip is correct */
/* eip is already adjusted, no more changes required */
p->ainsn.boostable = 1;
case 0xe8: /* call relative - Fix return addr */
*tos = orig_eip + (*tos - copy_eip);
break;
+ case 0x9a: /* call absolute -- same as call absolute, indirect */
+ *tos = orig_eip + (*tos - copy_eip);
+ goto no_change;
case 0xff:
if ((p->ainsn.insn[1] & 0x30) == 0x10) {
- /* call absolute, indirect */
/*
+ * call absolute, indirect
* Fix return addr; eip is correct.
* But this is not boostable
*/
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
- if (args->regs && user_mode(args->regs))
+ if (args->regs && user_mode_vm(args->regs))
return ret;
switch (val) {
git.openpandora.org / pandora-kernel.git / blobdiff