#include <linux/kprobes.h>
#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
#include <linux/preempt.h>
+#include <linux/module.h>
#include <linux/kdebug.h>
+
#include <asm/cacheflush.h>
#include <asm/desc.h>
+#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/alternative.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+/*
+ * "®s->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
+ * don't save the ss and esp registers if the CPU is already in kernel
+ * mode when it traps. So for kprobes, regs->sp and regs->ss are not
+ * the [nonexistent] saved stack pointer and ss register, but rather
+ * the top 8 bytes of the pre-int3 stack. So ®s->sp happens to
+ * point to the top of the pre-int3 stack.
+ */
+#define stack_addr(regs) ((unsigned long *)®s->sp)
+
+#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 boost.
+ */
+static const u32 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 */
+};
+static const u32 onebyte_has_modrm[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ----------------------------------------------- */
+ W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
+ W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
+ W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
+ W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
+ W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
+ W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
+ W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
+ W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
+ W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
+ W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
+ W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
+ W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
+ W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
+ W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
+ W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
+ W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */
+ /* ----------------------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+};
+static const u32 twobyte_has_modrm[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ----------------------------------------------- */
+ W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
+ W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
+ W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
+ W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
+ W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
+ W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
+ W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
+ W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
+ W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
+ W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
+ W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
+ W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
+ W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
+ W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
+ W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
+ W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */
+ /* ----------------------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+};
+#undef W
+
struct kretprobe_blackpoint kretprobe_blacklist[] = {
{"__switch_to", }, /* This function switches only current task, but
- doesn't switch kernel stack.*/
+ doesn't switch kernel stack.*/
{NULL, NULL} /* Terminator */
};
const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
-/* insert a jmp code */
+/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
static __always_inline void set_jmp_op(void *from, void *to)
{
struct __arch_jmp_op {
char op;
- long raddr;
- } __attribute__((packed)) *jop;
+ s32 raddr;
+ } __attribute__((packed)) * jop;
jop = (struct __arch_jmp_op *)from;
- jop->raddr = (long)(to) - ((long)(from) + 5);
+ jop->raddr = (s32)((long)(to) - ((long)(from) + 5));
jop->op = RELATIVEJUMP_INSTRUCTION;
}
/*
- * returns non-zero if opcodes can be boosted.
+ * returns non-zero if opcode is boostable.
*/
static __always_inline int can_boost(kprobe_opcode_t *opcodes)
{
-#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;
if (opcode == 0x0f) {
if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
return 0;
- return test_bit(*opcodes, twobyte_is_boostable);
+ return test_bit(*opcodes,
+ (unsigned long *)twobyte_is_boostable);
}
switch (opcode & 0xf0) {
case 0xf0:
if ((opcode & 0x0c) == 0 && opcode != 0xf1)
goto retry; /* lock/rep(ne) prefix */
- /* clear and set flags can be boost */
+ /* clear and set flags are boostable */
return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
default:
+ /* segment override prefixes are boostable */
if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
goto retry; /* prefixes */
- /* can't boost CS override and call */
+ /* CS override prefix and call are not boostable */
return (opcode != 0x2e && opcode != 0x9a);
}
}
/*
* returns non-zero if opcode modifies the interrupt flag.
*/
-static int __kprobes is_IF_modifier(kprobe_opcode_t opcode)
+static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
{
- switch (opcode) {
+ switch (*insn) {
case 0xfa: /* cli */
case 0xfb: /* sti */
case 0xcf: /* iret/iretd */
return 0;
}
+static void __kprobes arch_copy_kprobe(struct kprobe *p)
+{
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ if (can_boost(p->addr))
+ p->ainsn.boostable = 0;
+ else
+ p->ainsn.boostable = -1;
+
+ p->opcode = *p->addr;
+}
+
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
- /* insn: must be on special executable page on i386. */
+ /* insn: must be on special executable page on x86. */
p->ainsn.insn = get_insn_slot();
if (!p->ainsn.insn)
return -ENOMEM;
-
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
- p->opcode = *p->addr;
- if (can_boost(p->addr)) {
- p->ainsn.boostable = 0;
- } else {
- p->ainsn.boostable = -1;
- }
+ arch_copy_kprobe(p);
return 0;
}
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags;
- kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags;
+ kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
+ kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
}
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;
- kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags;
- kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags;
+ kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
+ kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
}
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags
+ kcb->kprobe_saved_flags = kcb->kprobe_old_flags
= (regs->flags & (TF_MASK | IF_MASK));
- if (is_IF_modifier(p->opcode))
- kcb->kprobe_saved_eflags &= ~IF_MASK;
+ if (is_IF_modifier(p->ainsn.insn))
+ kcb->kprobe_saved_flags &= ~IF_MASK;
}
static __always_inline void clear_btf(void)
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
- unsigned long *sara = (unsigned long *)®s->sp;
+ unsigned long *sara = stack_addr(regs);
ri->ret_addr = (kprobe_opcode_t *) *sara;
if (kcb->kprobe_status == KPROBE_HIT_SS &&
*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
regs->flags &= ~TF_MASK;
- regs->flags |= kcb->kprobe_saved_eflags;
+ regs->flags |= kcb->kprobe_saved_flags;
goto no_kprobe;
}
/* We have reentered the kprobe_handler(), since
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
- regs->ip -= sizeof(kprobe_opcode_t);
+ regs->ip = (unsigned long)addr;
ret = 1;
goto no_kprobe;
}
* Back up over the (now missing) int3 and run
* the original instruction.
*/
- regs->ip -= sizeof(kprobe_opcode_t);
+ regs->ip = (unsigned long)addr;
ret = 1;
}
/* Not one of ours: let kernel handle it */
ss_probe:
#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
- if (p->ainsn.boostable == 1 && !p->post_handler){
+ if (p->ainsn.boostable == 1 && !p->post_handler) {
/* Boost up -- we can execute copied instructions directly */
reset_current_kprobe();
regs->ip = (unsigned long)p->ainsn.insn;
}
/*
- * For function-return probes, init_kprobes() establishes a probepoint
- * here. When a retprobed function returns, this probe is hit and
- * trampoline_probe_handler() runs, calling the kretprobe's handler.
+ * When a retprobed function returns, this code saves registers and
+ * calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
void __kprobes kretprobe_trampoline_holder(void)
{
asm volatile ( ".global kretprobe_trampoline\n"
"kretprobe_trampoline: \n"
" pushf\n"
- /* skip cs, ip, orig_ax */
+ /*
+ * Skip cs, ip, orig_ax.
+ * trampoline_handler() will plug in these values
+ */
" subl $12, %esp\n"
" pushl %fs\n"
" pushl %ds\n"
" pushl %ebx\n"
" movl %esp, %eax\n"
" call trampoline_handler\n"
- /* move flags to cs */
+ /* Move flags to cs */
" movl 52(%esp), %edx\n"
" movl %edx, 48(%esp)\n"
- /* save true return address on flags */
+ /* Replace saved flags with true return address. */
" movl %eax, 52(%esp)\n"
" popl %ebx\n"
" popl %ecx\n"
" popl %edi\n"
" popl %ebp\n"
" popl %eax\n"
- /* skip ip, orig_ax, es, ds, fs */
+ /* Skip ip, orig_ax, es, ds, fs */
" addl $20, %esp\n"
" popf\n"
" ret\n");
-}
+ }
/*
* Called from kretprobe_trampoline
*/
-void *__kprobes trampoline_handler(struct pt_regs *regs)
+void * __kprobes trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
/* fixup registers */
regs->cs = __KERNEL_CS | get_kernel_rpl();
regs->ip = trampoline_address;
- regs->orig_ax = 0xffffffff;
+ regs->orig_ax = ~0UL;
/*
* It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
+ * task either because multiple functions in the call path have
+ * return probes installed on them, and/or more then one
* return probe was registered for a target function.
*
* We can handle this because:
- * - instances are always inserted at the head of the list
+ * - instances are always pushed into the head of the list
* - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
+ * function, the (chronologically) first instance's ret_addr
+ * will be the real return address, and all the rest will
+ * point to kretprobe_trampoline.
*/
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
- if (ri->rp && ri->rp->handler){
+ if (ri->rp && ri->rp->handler) {
__get_cpu_var(current_kprobe) = &ri->rp->kp;
get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
ri->rp->handler(ri, regs);
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
spin_unlock_irqrestore(&kretprobe_lock, flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
- return (void*)orig_ret_address;
+ return (void *)orig_ret_address;
}
/*
* that is atop the stack is the address following the copied instruction.
* We need to make it the address following the original instruction.
*
- * This function also checks instruction size for preparing direct execution.
+ * If this is the first time we've single-stepped the instruction at
+ * this probepoint, and the instruction is boostable, boost it: add a
+ * jump instruction after the copied instruction, that jumps to the next
+ * instruction after the probepoint.
*/
static void __kprobes resume_execution(struct kprobe *p,
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
- unsigned long *tos = (unsigned long *)®s->sp;
- unsigned long copy_eip = (unsigned long)p->ainsn.insn;
- unsigned long orig_eip = (unsigned long)p->addr;
+ unsigned long *tos = stack_addr(regs);
+ unsigned long copy_ip = (unsigned long)p->ainsn.insn;
+ unsigned long orig_ip = (unsigned long)p->addr;
+ kprobe_opcode_t *insn = p->ainsn.insn;
regs->flags &= ~TF_MASK;
- switch (p->ainsn.insn[0]) {
- case 0x9c: /* pushfl */
+ switch (*insn) {
+ case 0x9c: /* pushfl */
*tos &= ~(TF_MASK | IF_MASK);
- *tos |= kcb->kprobe_old_eflags;
+ *tos |= kcb->kprobe_old_flags;
break;
- case 0xc2: /* iret/ret/lret */
+ case 0xc2: /* iret/ret/lret */
case 0xc3:
case 0xca:
case 0xcb:
case 0xcf:
- case 0xea: /* jmp absolute -- ip is correct */
+ case 0xea: /* jmp absolute -- ip is correct */
/* ip is already adjusted, no more changes required */
p->ainsn.boostable = 1;
goto no_change;
- case 0xe8: /* call relative - Fix return addr */
- *tos = orig_eip + (*tos - copy_eip);
+ case 0xe8: /* call relative - Fix return addr */
+ *tos = orig_ip + (*tos - copy_ip);
break;
- case 0x9a: /* call absolute -- same as call absolute, indirect */
- *tos = orig_eip + (*tos - copy_eip);
+ case 0x9a: /* call absolute -- same as call absolute, indirect */
+ *tos = orig_ip + (*tos - copy_ip);
goto no_change;
case 0xff:
- if ((p->ainsn.insn[1] & 0x30) == 0x10) {
+ if ((insn[1] & 0x30) == 0x10) {
/*
* call absolute, indirect
* Fix return addr; ip is correct.
* But this is not boostable
*/
- *tos = orig_eip + (*tos - copy_eip);
+ *tos = orig_ip + (*tos - copy_ip);
goto no_change;
- } else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
- /* ip is correct. And this is boostable */
+ } else if (((insn[1] & 0x31) == 0x20) ||
+ ((insn[1] & 0x31) == 0x21)) {
+ /*
+ * jmp near and far, absolute indirect
+ * ip is correct. And this is boostable
+ */
p->ainsn.boostable = 1;
goto no_change;
}
}
if (p->ainsn.boostable == 0) {
- if ((regs->ip > copy_eip) &&
- (regs->ip - copy_eip) + 5 < MAX_INSN_SIZE) {
+ if ((regs->ip > copy_ip) &&
+ (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
/*
* These instructions can be executed directly if it
* jumps back to correct address.
*/
set_jmp_op((void *)regs->ip,
- (void *)orig_eip + (regs->ip - copy_eip));
+ (void *)orig_ip + (regs->ip - copy_ip));
p->ainsn.boostable = 1;
} else {
p->ainsn.boostable = -1;
}
}
- regs->ip = orig_eip + (regs->ip - copy_eip);
+ regs->ip += orig_ip - copy_ip;
no_change:
restore_btf();
}
resume_execution(cur, regs, kcb);
- regs->flags |= kcb->kprobe_saved_eflags;
+ regs->flags |= kcb->kprobe_saved_flags;
trace_hardirqs_fixup_flags(regs->flags);
- /*Restore back the original saved kprobes variables and continue. */
+ /* Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
* normal page fault.
*/
regs->ip = (unsigned long)cur->addr;
- regs->flags |= kcb->kprobe_old_eflags;
+ regs->flags |= kcb->kprobe_old_flags;
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
case KPROBE_HIT_SSDONE:
/*
* We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
+ * we can also use npre/npostfault count for accounting
* these specific fault cases.
*/
kprobes_inc_nmissed_count(cur);
return 1;
/*
- * fixup_exception() could not handle it,
+ * fixup routine could not handle it,
* Let do_page_fault() fix it.
*/
break;
}
/*
- * Wrapper routine to for handling exceptions.
+ * Wrapper routine for handling exceptions.
*/
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_esp = ®s->sp;
- addr = (unsigned long)(kcb->jprobe_saved_esp);
+ kcb->jprobe_saved_sp = stack_addr(regs);
+ addr = (unsigned long)(kcb->jprobe_saved_sp);
/*
- * TBD: As Linus pointed out, gcc assumes that the callee
+ * As Linus pointed out, gcc assumes that the callee
* owns the argument space and could overwrite it, e.g.
* tailcall optimization. So, to be absolutely safe
* we also save and restore enough stack bytes to cover
" .globl jprobe_return_end \n"
" jprobe_return_end: \n"
" nop \n"::"b"
- (kcb->jprobe_saved_esp):"memory");
+ (kcb->jprobe_saved_sp):"memory");
}
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
u8 *addr = (u8 *) (regs->ip - 1);
- unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp);
struct jprobe *jp = container_of(p, struct jprobe, kp);
if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
- if (®s->sp != kcb->jprobe_saved_esp) {
+ if (stack_addr(regs) != kcb->jprobe_saved_sp) {
struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
printk("current sp %p does not match saved sp %p\n",
- ®s->sp, kcb->jprobe_saved_esp);
+ stack_addr(regs), kcb->jprobe_saved_sp);
printk("Saved registers for jprobe %p\n", jp);
show_registers(saved_regs);
printk("Current registers\n");
BUG();
}
*regs = kcb->jprobe_saved_regs;
- memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
+ memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
+ kcb->jprobes_stack,
+ MIN_STACK_SIZE(kcb->jprobe_saved_sp));
preempt_enable_no_resched();
return 1;
}
return 0;
}
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+int __init arch_init_kprobes(void)
{
return 0;
}
-int __init arch_init_kprobes(void)
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
return 0;
}
#include <linux/module.h>
#include <linux/kdebug.h>
+#include <asm/cacheflush.h>
+#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/alternative.h>
void jprobe_return_end(void);
-static void __kprobes arch_copy_kprobe(struct kprobe *p);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+#define stack_addr(regs) ((unsigned long *)regs->sp)
+
+#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 boost.
+ */
+static const u32 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 */
+};
+static const u32 onebyte_has_modrm[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ----------------------------------------------- */
+ W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
+ W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
+ W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
+ W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
+ W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
+ W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
+ W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
+ W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
+ W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
+ W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
+ W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
+ W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
+ W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
+ W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
+ W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
+ W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */
+ /* ----------------------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+};
+static const u32 twobyte_has_modrm[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ----------------------------------------------- */
+ W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
+ W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
+ W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
+ W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
+ W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
+ W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
+ W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
+ W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
+ W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
+ W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
+ W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
+ W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
+ W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
+ W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
+ W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
+ W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */
+ /* ----------------------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+};
+#undef W
+
struct kretprobe_blackpoint kretprobe_blacklist[] = {
{"__switch_to", }, /* This function switches only current task, but
doesn't switch kernel stack.*/
}
/*
- * returns non-zero if opcode is boostable
+ * returns non-zero if opcode is boostable.
* RIP relative instructions are adjusted at copying time
*/
static __always_inline int can_boost(kprobe_opcode_t *opcodes)
{
-#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 % 64))
- /*
- * Undefined/reserved opcodes, conditional jump, Opcode Extension
- * Groups, and some special opcodes can not boost.
- */
- static const unsigned long twobyte_is_boostable[256 / 64] = {
- /* 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;
if (opcode == 0x0f) {
if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
return 0;
- return test_bit(*opcodes, twobyte_is_boostable);
+ return test_bit(*opcodes,
+ (unsigned long *)twobyte_is_boostable);
}
switch (opcode & 0xf0) {
return 1;
}
- if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf)
- return 1;
- return 0;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- /* insn: must be on special executable page on x86_64. */
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn) {
- return -ENOMEM;
- }
- arch_copy_kprobe(p);
+ /*
+ * on 64 bit x86, 0x40-0x4f are prefixes so we need to look
+ * at the next byte instead.. but of course not recurse infinitely
+ */
+ if (*insn >= 0x40 && *insn <= 0x4f)
+ return is_IF_modifier(++insn);
return 0;
}
/*
- * Determine if the instruction uses the %rip-relative addressing mode.
+ * Adjust the displacement if the instruction uses the %rip-relative
+ * addressing mode.
* If it does, Return the address of the 32-bit displacement word.
* If not, return null.
*/
-static s32 __kprobes *is_riprel(u8 *insn)
+static void __kprobes fix_riprel(struct kprobe *p)
{
-#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 % 64))
- static const u64 onebyte_has_modrm[256 / 64] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ------------------------------- */
- W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */
- W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */
- W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */
- W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */
- W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */
- W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */
- W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */
- W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */
- W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */
- W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */
- W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */
- W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */
- W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */
- W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */
- W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */
- W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */
- /* ------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- };
- static const u64 twobyte_has_modrm[256 / 64] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ------------------------------- */
- W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */
- W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */
- W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */
- W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */
- W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */
- W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */
- W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */
- W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */
- W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */
- W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */
- W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */
- W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */
- W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */
- W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */
- W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */
- W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */
- /* ------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- };
-#undef W
+ u8 *insn = p->ainsn.insn;
+ s64 disp;
int need_modrm;
/* Skip legacy instruction prefixes. */
if (*insn == 0x0f) { /* Two-byte opcode. */
++insn;
- need_modrm = test_bit(*insn, twobyte_has_modrm);
- } else { /* One-byte opcode. */
- need_modrm = test_bit(*insn, onebyte_has_modrm);
- }
+ need_modrm = test_bit(*insn,
+ (unsigned long *)twobyte_has_modrm);
+ } else /* One-byte opcode. */
+ need_modrm = test_bit(*insn,
+ (unsigned long *)onebyte_has_modrm);
if (need_modrm) {
u8 modrm = *++insn;
if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
/* Displacement follows ModRM byte. */
- return (s32 *) ++insn;
+ ++insn;
+ /*
+ * The copied instruction uses the %rip-relative
+ * addressing mode. Adjust the displacement for the
+ * difference between the original location of this
+ * instruction and the location of the copy that will
+ * actually be run. The tricky bit here is making sure
+ * that the sign extension happens correctly in this
+ * calculation, since we need a signed 32-bit result to
+ * be sign-extended to 64 bits when it's added to the
+ * %rip value and yield the same 64-bit result that the
+ * sign-extension of the original signed 32-bit
+ * displacement would have given.
+ */
+ disp = (u8 *) p->addr + *((s32 *) insn) -
+ (u8 *) p->ainsn.insn;
+ BUG_ON((s64) (s32) disp != disp); /* Sanity check. */
+ *(s32 *)insn = (s32) disp;
}
}
-
- /* No %rip-relative addressing mode here. */
- return NULL;
}
static void __kprobes arch_copy_kprobe(struct kprobe *p)
{
- s32 *ripdisp;
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
- ripdisp = is_riprel(p->ainsn.insn);
- if (ripdisp) {
- /*
- * The copied instruction uses the %rip-relative
- * addressing mode. Adjust the displacement for the
- * difference between the original location of this
- * instruction and the location of the copy that will
- * actually be run. The tricky bit here is making sure
- * that the sign extension happens correctly in this
- * calculation, since we need a signed 32-bit result to
- * be sign-extended to 64 bits when it's added to the
- * %rip value and yield the same 64-bit result that the
- * sign-extension of the original signed 32-bit
- * displacement would have given.
- */
- s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn;
- BUG_ON((s64) (s32) disp != disp); /* Sanity check. */
- *ripdisp = disp;
- }
- if (can_boost(p->addr)) {
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ fix_riprel(p);
+ if (can_boost(p->addr))
p->ainsn.boostable = 0;
- } else {
+ else
p->ainsn.boostable = -1;
- }
+
p->opcode = *p->addr;
}
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ /* insn: must be on special executable page on x86. */
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+ arch_copy_kprobe(p);
+ return 0;
+}
+
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.old_rflags = kcb->kprobe_old_rflags;
- kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags;
+ kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
+ kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
}
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;
- kcb->kprobe_old_rflags = kcb->prev_kprobe.old_rflags;
- kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags;
+ kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
+ kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
}
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_rflags = kcb->kprobe_old_rflags
+ kcb->kprobe_saved_flags = kcb->kprobe_old_flags
= (regs->flags & (TF_MASK | IF_MASK));
if (is_IF_modifier(p->ainsn.insn))
- kcb->kprobe_saved_rflags &= ~IF_MASK;
+ kcb->kprobe_saved_flags &= ~IF_MASK;
}
static __always_inline void clear_btf(void)
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
- unsigned long *sara = (unsigned long *)regs->sp;
+ unsigned long *sara = stack_addr(regs);
ri->ret_addr = (kprobe_opcode_t *) *sara;
+
/* Replace the return addr with trampoline addr */
*sara = (unsigned long) &kretprobe_trampoline;
}
-int __kprobes kprobe_handler(struct pt_regs *regs)
+/*
+ * Interrupts are disabled on entry as trap3 is an interrupt gate and they
+ * remain disabled thorough out this function.
+ */
+static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
- kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
+ kprobe_opcode_t *addr;
struct kprobe_ctlblk *kcb;
+ addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
+
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
if (kcb->kprobe_status == KPROBE_HIT_SS &&
*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
regs->flags &= ~TF_MASK;
- regs->flags |= kcb->kprobe_saved_rflags;
+ regs->flags |= kcb->kprobe_saved_flags;
goto no_kprobe;
} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
/* TODO: Provide re-entrancy from
arch_disarm_kprobe(p);
regs->ip = (unsigned long)p->addr;
reset_current_kprobe();
- ret = 1;
- } else {
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the
- * handler. We here save the original kprobe
- * variables and just single step on instruction
- * of the new probe without calling any user
- * handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
return 1;
}
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
} else {
if (*addr != BREAKPOINT_INSTRUCTION) {
/* The breakpoint instruction was removed by
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
- /* fixup rt_regs */
+ /* fixup registers */
regs->cs = __KERNEL_CS;
regs->ip = trampoline_address;
- regs->orig_ax = 0xffffffffffffffff;
+ regs->orig_ax = ~0UL;
/*
* It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
+ * task either because multiple functions in the call path have
+ * return probes installed on them, and/or more then one
* return probe was registered for a target function.
*
* We can handle this because:
- * - instances are always inserted at the head of the list
+ * - instances are always pushed into the head of the list
* - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
+ * function, the (chronologically) first instance's ret_addr
+ * will be the real return address, and all the rest will
+ * point to kretprobe_trampoline.
*/
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task != current)
static void __kprobes resume_execution(struct kprobe *p,
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
- unsigned long *tos = (unsigned long *)regs->sp;
- unsigned long copy_rip = (unsigned long)p->ainsn.insn;
- unsigned long orig_rip = (unsigned long)p->addr;
+ unsigned long *tos = stack_addr(regs);
+ unsigned long copy_ip = (unsigned long)p->ainsn.insn;
+ unsigned long orig_ip = (unsigned long)p->addr;
kprobe_opcode_t *insn = p->ainsn.insn;
/*skip the REX prefix*/
switch (*insn) {
case 0x9c: /* pushfl */
*tos &= ~(TF_MASK | IF_MASK);
- *tos |= kcb->kprobe_old_rflags;
+ *tos |= kcb->kprobe_old_flags;
break;
case 0xc2: /* iret/ret/lret */
case 0xc3:
p->ainsn.boostable = 1;
goto no_change;
case 0xe8: /* call relative - Fix return addr */
- *tos = orig_rip + (*tos - copy_rip);
+ *tos = orig_ip + (*tos - copy_ip);
break;
case 0xff:
if ((insn[1] & 0x30) == 0x10) {
- /* call absolute, indirect */
- /* Fix return addr; ip is correct. */
- /* not boostable */
- *tos = orig_rip + (*tos - copy_rip);
+ /*
+ * call absolute, indirect
+ * Fix return addr; ip is correct.
+ * But this is not boostable
+ */
+ *tos = orig_ip + (*tos - copy_ip);
goto no_change;
- } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
- /* ip is correct. And this is boostable */
+ } else if (((insn[1] & 0x31) == 0x20) ||
+ ((insn[1] & 0x31) == 0x21)) {
+ /*
+ * jmp near and far, absolute indirect
+ * ip is correct. And this is boostable
+ */
p->ainsn.boostable = 1;
goto no_change;
}
}
if (p->ainsn.boostable == 0) {
- if ((regs->ip > copy_rip) &&
- (regs->ip - copy_rip) + 5 < MAX_INSN_SIZE) {
+ if ((regs->ip > copy_ip) &&
+ (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
/*
* These instructions can be executed directly if it
* jumps back to correct address.
*/
set_jmp_op((void *)regs->ip,
- (void *)orig_rip + (regs->ip - copy_rip));
+ (void *)orig_ip + (regs->ip - copy_ip));
p->ainsn.boostable = 1;
} else {
p->ainsn.boostable = -1;
}
}
- regs->ip = orig_rip + (regs->ip - copy_rip);
+ regs->ip += orig_ip - copy_ip;
no_change:
restore_btf();
return;
}
-int __kprobes post_kprobe_handler(struct pt_regs *regs)
+/*
+ * Interrupts are disabled on entry as trap1 is an interrupt gate and they
+ * remain disabled thoroughout this function.
+ */
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
}
resume_execution(cur, regs, kcb);
- regs->flags |= kcb->kprobe_saved_rflags;
+ regs->flags |= kcb->kprobe_saved_flags;
trace_hardirqs_fixup_flags(regs->flags);
- /* Restore the original saved kprobes variables and continue. */
+ /* Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
* normal page fault.
*/
regs->ip = (unsigned long)cur->addr;
- regs->flags |= kcb->kprobe_old_rflags;
+ regs->flags |= kcb->kprobe_old_flags;
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
case KPROBE_HIT_SSDONE:
/*
* We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
+ * we can also use npre/npostfault count for accounting
* these specific fault cases.
*/
kprobes_inc_nmissed_count(cur);
}
/*
- * fixup() could not handle it,
+ * fixup routine could not handle it,
* Let do_page_fault() fix it.
*/
break;
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) {
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_rsp = (long *) regs->sp;
- addr = (unsigned long)(kcb->jprobe_saved_rsp);
+ kcb->jprobe_saved_sp = stack_addr(regs);
+ addr = (unsigned long)(kcb->jprobe_saved_sp);
+
/*
* As Linus pointed out, gcc assumes that the callee
* owns the argument space and could overwrite it, e.g.
" .globl jprobe_return_end \n"
" jprobe_return_end: \n"
" nop \n"::"b"
- (kcb->jprobe_saved_rsp):"memory");
+ (kcb->jprobe_saved_sp):"memory");
}
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
u8 *addr = (u8 *) (regs->ip - 1);
- unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_rsp);
struct jprobe *jp = container_of(p, struct jprobe, kp);
if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
- if ((unsigned long *)regs->sp != kcb->jprobe_saved_rsp) {
+ if (stack_addr(regs) != kcb->jprobe_saved_sp) {
struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
printk("current sp %p does not match saved sp %p\n",
- (long *)regs->sp, kcb->jprobe_saved_rsp);
+ stack_addr(regs), kcb->jprobe_saved_sp);
printk("Saved registers for jprobe %p\n", jp);
show_registers(saved_regs);
printk("Current registers\n");
BUG();
}
*regs = kcb->jprobe_saved_regs;
- memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
+ memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
+ kcb->jprobes_stack,
+ MIN_STACK_SIZE(kcb->jprobe_saved_sp));
preempt_enable_no_resched();
return 1;
}
projects / linux-2.6 / commitdiff