diff options
Diffstat (limited to 'arch/ia64/kernel/kprobes.c')
| -rw-r--r-- | arch/ia64/kernel/kprobes.c | 721 |
1 files changed, 721 insertions, 0 deletions
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c new file mode 100644 index 0000000..3aa3167 --- /dev/null +++ b/arch/ia64/kernel/kprobes.c @@ -0,0 +1,721 @@ +/* + * Kernel Probes (KProbes) + * arch/ia64/kernel/kprobes.c + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, 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 License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2002, 2004 + * Copyright (C) Intel Corporation, 2005 + * + * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy + * <anil.s.keshavamurthy@intel.com> adapted from i386 + */ + +#include <linux/config.h> +#include <linux/kprobes.h> +#include <linux/ptrace.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/preempt.h> +#include <linux/moduleloader.h> + +#include <asm/pgtable.h> +#include <asm/kdebug.h> +#include <asm/sections.h> + +extern void jprobe_inst_return(void); + +/* kprobe_status settings */ +#define KPROBE_HIT_ACTIVE 0x00000001 +#define KPROBE_HIT_SS 0x00000002 + +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}; +static enum instruction_type bundle_encoding[32][3] = { + { M, I, I }, /* 00 */ + { M, I, I }, /* 01 */ + { M, I, I }, /* 02 */ + { M, I, I }, /* 03 */ + { M, L, X }, /* 04 */ + { M, L, X }, /* 05 */ + { u, u, u }, /* 06 */ + { u, u, u }, /* 07 */ + { M, M, I }, /* 08 */ + { M, M, I }, /* 09 */ + { M, M, I }, /* 0A */ + { M, M, I }, /* 0B */ + { M, F, I }, /* 0C */ + { M, F, I }, /* 0D */ + { M, M, F }, /* 0E */ + { M, M, F }, /* 0F */ + { M, I, B }, /* 10 */ + { M, I, B }, /* 11 */ + { M, B, B }, /* 12 */ + { M, B, B }, /* 13 */ + { u, u, u }, /* 14 */ + { u, u, u }, /* 15 */ + { B, B, B }, /* 16 */ + { B, B, B }, /* 17 */ + { M, M, B }, /* 18 */ + { M, M, B }, /* 19 */ + { u, u, u }, /* 1A */ + { u, u, u }, /* 1B */ + { M, F, B }, /* 1C */ + { M, F, B }, /* 1D */ + { u, u, u }, /* 1E */ + { u, u, u }, /* 1F */ +}; + +/* + * In this function we check to see if the instruction + * is IP relative instruction and update the kprobe + * inst flag accordingly + */ +static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode, + unsigned long kprobe_inst, struct kprobe *p) +{ + p->ainsn.inst_flag = 0; + p->ainsn.target_br_reg = 0; + + if (bundle_encoding[template][slot] == B) { + switch (major_opcode) { + case INDIRECT_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + case IP_RELATIVE_PREDICT_OPCODE: + case IP_RELATIVE_BRANCH_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; + break; + case IP_RELATIVE_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + } + } else if (bundle_encoding[template][slot] == X) { + switch (major_opcode) { + case LONG_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + } + } + 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. + */ +static void prepare_break_inst(uint template, uint slot, uint major_opcode, + unsigned long kprobe_inst, struct kprobe *p) +{ + unsigned long break_inst = BREAK_INST; + bundle_t *bundle = &p->ainsn.insn.bundle; + + /* + * Copy the original kprobe_inst qualifying predicate(qp) + * 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 + */ + if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) + break_inst |= (0x3f & kprobe_inst); + + switch (slot) { + case 0: + bundle->quad0.slot0 = break_inst; + break; + case 1: + bundle->quad0.slot1_p0 = break_inst; + bundle->quad1.slot1_p1 = break_inst >> (64-46); + break; + case 2: + bundle->quad1.slot2 = break_inst; + break; + } + + /* + * Update the instruction flag, so that we can + * emulate the instruction properly after we + * single step on original instruction + */ + update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p); +} + +static inline void get_kprobe_inst(bundle_t *bundle, uint slot, + unsigned long *kprobe_inst, uint *major_opcode) +{ + unsigned long kprobe_inst_p0, kprobe_inst_p1; + unsigned int template; + + template = bundle->quad0.template; + + switch (slot) { + case 0: + *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT); + *kprobe_inst = bundle->quad0.slot0; + break; + case 1: + *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT); + kprobe_inst_p0 = bundle->quad0.slot1_p0; + kprobe_inst_p1 = bundle->quad1.slot1_p1; + *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46)); + break; + case 2: + *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT); + *kprobe_inst = bundle->quad1.slot2; + break; + } +} + +/* 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); + 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; + unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL); + unsigned long kprobe_inst=0; + unsigned int slot = addr & 0xf, template, major_opcode = 0; + bundle_t *bundle = &p->ainsn.insn.bundle; + + memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t)); + memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t)); + + template = bundle->quad0.template; + + if(valid_kprobe_addr(template, slot, addr)) + return -EINVAL; + + /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */ + if (slot == 1 && bundle_encoding[template][1] == L) + slot++; + + /* 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; +} + +void arch_arm_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + unsigned long arm_addr = addr & ~0xFULL; + + memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t)); + flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t)); +} + +void arch_disarm_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + unsigned long arm_addr = addr & ~0xFULL; + + /* p->opcode contains the original unaltered bundle */ + memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t)); + flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t)); +} + +void arch_remove_kprobe(struct kprobe *p) +{ +} + +/* + * We are resuming execution after a single step fault, so the pt_regs + * structure reflects the register state after we executed the instruction + * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust + * the ip to point back to the original stack address. To set the IP address + * to original stack address, handle the case where we need to fixup the + * relative IP address and/or fixup branch register. + */ +static void resume_execution(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL; + unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL; + unsigned long template; + int slot = ((unsigned long)p->addr & 0xf); + + template = p->opcode.bundle.quad0.template; + + if (slot == 1 && bundle_encoding[template][1] == L) + slot = 2; + + if (p->ainsn.inst_flag) { + + if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) { + /* Fix relative IP address */ + regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr; + } + + if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) { + /* + * Fix target branch register, software convention is + * to use either b0 or b6 or b7, so just checking + * only those registers + */ + switch (p->ainsn.target_br_reg) { + case 0: + if ((regs->b0 == bundle_addr) || + (regs->b0 == bundle_addr + 0x10)) { + regs->b0 = (regs->b0 - bundle_addr) + + resume_addr; + } + break; + case 6: + if ((regs->b6 == bundle_addr) || + (regs->b6 == bundle_addr + 0x10)) { + regs->b6 = (regs->b6 - bundle_addr) + + resume_addr; + } + break; + case 7: + if ((regs->b7 == bundle_addr) || + (regs->b7 == bundle_addr + 0x10)) { + regs->b7 = (regs->b7 - bundle_addr) + + resume_addr; + } + break; + } /* end switch */ + } + goto turn_ss_off; + } + + if (slot == 2) { + if (regs->cr_iip == bundle_addr + 0x10) { + regs->cr_iip = resume_addr + 0x10; + } + } else { + if (regs->cr_iip == bundle_addr) { + regs->cr_iip = resume_addr; + } + } + +turn_ss_off: + /* Turn off Single Step bit */ + ia64_psr(regs)->ss = 0; +} + +static void prepare_ss(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long bundle_addr = (unsigned long) &p->opcode.bundle; + unsigned long slot = (unsigned long)p->addr & 0xf; + + /* Update instruction pointer (IIP) and slot number (IPSR.ri) */ + regs->cr_iip = bundle_addr & ~0xFULL; + + if (slot > 2) + slot = 0; + + ia64_psr(regs)->ri = slot; + + /* turn on single stepping */ + ia64_psr(regs)->ss = 1; +} + +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(); + + /* Handle recursion cases */ + if (kprobe_running()) { + p = get_kprobe(addr); + if (p) { + if (kprobe_status == KPROBE_HIT_SS) { + unlock_kprobes(); + goto no_kprobe; + } + /* 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 + */ + p = current_kprobe; + if (p->break_handler && p->break_handler(p, regs)) { + goto ss_probe; + } + } else { + /* Not our break */ + goto no_kprobe; + } + } + + lock_kprobes(); + p = get_kprobe(addr); + if (!p) { + unlock_kprobes(); + goto no_kprobe; + } + + kprobe_status = KPROBE_HIT_ACTIVE; + 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 used for both the jprobe pre-handler + * and the kretprobe trampoline + */ + return 1; + +ss_probe: + prepare_ss(p, regs); + kprobe_status = KPROBE_HIT_SS; + return 1; + +no_kprobe: + preempt_enable_no_resched(); + return ret; +} + +static int post_kprobes_handler(struct pt_regs *regs) +{ + if (!kprobe_running()) + return 0; + + 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; +} + +static int kprobes_fault_handler(struct pt_regs *regs, int trapnr) +{ + if (!kprobe_running()) + return 0; + + 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); + unlock_kprobes(); + preempt_enable_no_resched(); + } + + return 0; +} + +int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, + void *data) +{ + struct die_args *args = (struct die_args *)data; + switch(val) { + case DIE_BREAK: + if (pre_kprobes_handler(args)) + return NOTIFY_STOP; + break; + case DIE_SS: + if (post_kprobes_handler(args->regs)) + return NOTIFY_STOP; + break; + case DIE_PAGE_FAULT: + if (kprobes_fault_handler(args->regs, args->trapnr)) + return NOTIFY_STOP; + default: + break; + } + return NOTIFY_DONE; +} + +int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct jprobe *jp = container_of(p, struct jprobe, kp); + unsigned long addr = ((struct fnptr *)(jp->entry))->ip; + + /* save architectural state */ + jprobe_saved_regs = *regs; + + /* after rfi, execute the jprobe instrumented function */ + regs->cr_iip = addr & ~0xFULL; + ia64_psr(regs)->ri = addr & 0xf; + regs->r1 = ((struct fnptr *)(jp->entry))->gp; + + /* + * fix the return address to our jprobe_inst_return() function + * in the jprobes.S file + */ + regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip; + + return 1; +} + +int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + *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); +} |
