#include <asm/pgtable.h>
#include <asm/kdebug.h>
+#include <asm/sections.h>
extern void jprobe_inst_return(void);
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
-static struct kprobe *current_kprobe;
-static unsigned long kprobe_status;
+static struct kprobe *current_kprobe, *kprobe_prev;
+static unsigned long kprobe_status, kprobe_status_prev;
static struct pt_regs jprobe_saved_regs;
enum instruction_type {A, I, M, F, B, L, X, u};
return;
}
+/*
+ * In this function we check to see if the instruction
+ * on which we are inserting kprobe is supported.
+ * Returns 0 if supported
+ * Returns -EINVAL if unsupported
+ */
+static int unsupported_inst(uint template, uint slot, uint major_opcode,
+ unsigned long kprobe_inst, struct kprobe *p)
+{
+ unsigned long addr = (unsigned long)p->addr;
+
+ if (bundle_encoding[template][slot] == I) {
+ switch (major_opcode) {
+ case 0x0: //I_UNIT_MISC_OPCODE:
+ /*
+ * Check for Integer speculation instruction
+ * - Bit 33-35 to be equal to 0x1
+ */
+ if (((kprobe_inst >> 33) & 0x7) == 1) {
+ printk(KERN_WARNING
+ "Kprobes on speculation inst at <0x%lx> not supported\n",
+ addr);
+ return -EINVAL;
+ }
+
+ /*
+ * IP relative mov instruction
+ * - Bit 27-35 to be equal to 0x30
+ */
+ if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
+ printk(KERN_WARNING
+ "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
+ addr);
+ return -EINVAL;
+
+ }
+ }
+ }
+ return 0;
+}
+
+
+/*
+ * In this function we check to see if the instruction
+ * (qp) cmpx.crel.ctype p1,p2=r2,r3
+ * on which we are inserting kprobe is cmp instruction
+ * with ctype as unc.
+ */
+static uint is_cmp_ctype_unc_inst(uint template, uint slot, uint major_opcode,
+unsigned long kprobe_inst)
+{
+ cmp_inst_t cmp_inst;
+ uint ctype_unc = 0;
+
+ if (!((bundle_encoding[template][slot] == I) ||
+ (bundle_encoding[template][slot] == M)))
+ goto out;
+
+ if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
+ (major_opcode == 0xE)))
+ goto out;
+
+ cmp_inst.l = kprobe_inst;
+ if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
+ /* Integere compare - Register Register (A6 type)*/
+ if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
+ &&(cmp_inst.f.c == 1))
+ ctype_unc = 1;
+ } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
+ /* Integere compare - Immediate Register (A8 type)*/
+ if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
+ ctype_unc = 1;
+ }
+out:
+ return ctype_unc;
+}
+
/*
* In this function we override the bundle with
* the break instruction at the given slot.
/*
* Copy the original kprobe_inst qualifying predicate(qp)
- * to the break instruction
+ * to the break instruction iff !is_cmp_ctype_unc_inst
+ * because for cmp instruction with ctype equal to unc,
+ * which is a special instruction always needs to be
+ * executed regradless of qp
*/
- break_inst |= (0x3f & kprobe_inst);
+ if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
+ break_inst |= (0x3f & kprobe_inst);
switch (slot) {
case 0:
}
}
+/* Returns non-zero if the addr is in the Interrupt Vector Table */
+static inline int in_ivt_functions(unsigned long addr)
+{
+ return (addr >= (unsigned long)__start_ivt_text
+ && addr < (unsigned long)__end_ivt_text);
+}
+
static int valid_kprobe_addr(int template, int slot, unsigned long addr)
{
if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
- printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
- addr);
+ printk(KERN_WARNING "Attempting to insert unaligned kprobe "
+ "at 0x%lx\n", addr);
return -EINVAL;
}
+
+ if (in_ivt_functions(addr)) {
+ printk(KERN_WARNING "Kprobes can't be inserted inside "
+ "IVT functions at 0x%lx\n", addr);
+ return -EINVAL;
+ }
+
+ if (slot == 1 && bundle_encoding[template][1] != L) {
+ printk(KERN_WARNING "Inserting kprobes on slot #1 "
+ "is not supported\n");
+ return -EINVAL;
+ }
+
return 0;
}
+static inline void save_previous_kprobe(void)
+{
+ kprobe_prev = current_kprobe;
+ kprobe_status_prev = kprobe_status;
+}
+
+static inline void restore_previous_kprobe(void)
+{
+ current_kprobe = kprobe_prev;
+ kprobe_status = kprobe_status_prev;
+}
+
+static inline void set_current_kprobe(struct kprobe *p)
+{
+ current_kprobe = p;
+}
+
+static void kretprobe_trampoline(void)
+{
+}
+
+/*
+ * At this point the target function has been tricked into
+ * returning into our trampoline. Lookup the associated instance
+ * and then:
+ * - call the handler function
+ * - cleanup by marking the instance as unused
+ * - long jump back to the original return address
+ */
+int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head;
+ struct hlist_node *node, *tmp;
+ unsigned long orig_ret_address = 0;
+ unsigned long trampoline_address =
+ ((struct fnptr *)kretprobe_trampoline)->ip;
+
+ head = kretprobe_inst_table_head(current);
+
+ /*
+ * 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
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at 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
+ */
+ 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)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
+ regs->cr_iip = orig_ret_address;
+
+ unlock_kprobes();
+ preempt_enable_no_resched();
+
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we have handled unlocking
+ * and re-enabling preemption.
+ */
+ return 1;
+}
+
+void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri;
+
+ if ((ri = get_free_rp_inst(rp)) != NULL) {
+ ri->rp = rp;
+ ri->task = current;
+ ri->ret_addr = (kprobe_opcode_t *)regs->b0;
+
+ /* Replace the return addr with trampoline addr */
+ regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
+
+ add_rp_inst(ri);
+ } else {
+ rp->nmissed++;
+ }
+}
+
int arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long) p->addr;
/* Get kprobe_inst and major_opcode from the bundle */
get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+ if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
+ return -EINVAL;
+
prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
return 0;
ia64_psr(regs)->ss = 1;
}
-static int pre_kprobes_handler(struct pt_regs *regs)
+static int pre_kprobes_handler(struct die_args *args)
{
struct kprobe *p;
int ret = 0;
+ struct pt_regs *regs = args->regs;
kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
preempt_disable();
unlock_kprobes();
goto no_kprobe;
}
- arch_disarm_kprobe(p);
- ret = 1;
- } else {
+ /* We have reentered the pre_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();
+ set_current_kprobe(p);
+ p->nmissed++;
+ prepare_ss(p, regs);
+ kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else if (args->err == __IA64_BREAK_JPROBE) {
/*
* jprobe instrumented function just completed
*/
if (p->break_handler && p->break_handler(p, regs)) {
goto ss_probe;
}
+ } else {
+ /* Not our break */
+ goto no_kprobe;
}
}
}
kprobe_status = KPROBE_HIT_ACTIVE;
- current_kprobe = p;
+ set_current_kprobe(p);
if (p->pre_handler && p->pre_handler(p, regs))
/*
* Our pre-handler is specifically requesting that we just
- * do a return. This is handling the case where the
- * pre-handler is really our special jprobe pre-handler.
+ * do a return. This is used for both the jprobe pre-handler
+ * and the kretprobe trampoline
*/
return 1;
if (!kprobe_running())
return 0;
- if (current_kprobe->post_handler)
+ if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
+ kprobe_status = KPROBE_HIT_SSDONE;
current_kprobe->post_handler(current_kprobe, regs, 0);
+ }
resume_execution(current_kprobe, regs);
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe();
+ goto out;
+ }
+
unlock_kprobes();
+
+out:
preempt_enable_no_resched();
return 1;
}
struct die_args *args = (struct die_args *)data;
switch(val) {
case DIE_BREAK:
- if (pre_kprobes_handler(args->regs))
+ if (pre_kprobes_handler(args))
return NOTIFY_STOP;
break;
case DIE_SS:
*regs = jprobe_saved_regs;
return 1;
}
+
+static struct kprobe trampoline_p = {
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init(void)
+{
+ trampoline_p.addr =
+ (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
+ return register_kprobe(&trampoline_p);
+}
projects / powerpc.git / blobdiff