From: Anil S Keshavamurthy Date: Thu, 23 Jun 2005 07:09:28 +0000 (-0700) Subject: [PATCH] Kprobes/IA64: arch specific handling X-Git-Tag: v2.6.13-rc1~68^2~444 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fd7b231ff98578308d8f5fb76a25a369ce1074ae;p=linux-2.6 [PATCH] Kprobes/IA64: arch specific handling This is an IA64 arch specific handling of Kprobes Signed-off-by: Anil S Keshavamurthy Signed-off-by: Rusty Lynch Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/ia64/Kconfig.debug b/arch/ia64/Kconfig.debug index de9d507ba0..fda67ac993 100644 --- a/arch/ia64/Kconfig.debug +++ b/arch/ia64/Kconfig.debug @@ -2,6 +2,17 @@ menu "Kernel hacking" source "lib/Kconfig.debug" +config KPROBES + bool "Kprobes" + depends on DEBUG_KERNEL + help + Kprobes allows you to trap at almost any kernel address and + execute a callback function. register_kprobe() establishes + a probepoint and specifies the callback. Kprobes is useful + for kernel debugging, non-intrusive instrumentation and testing. + If in doubt, say "N". + + choice prompt "Physical memory granularity" default IA64_GRANULE_64MB diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile index 4c73d8ba2e..5290fa4c33 100644 --- a/arch/ia64/kernel/Makefile +++ b/arch/ia64/kernel/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o domain.o obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o obj-$(CONFIG_IA64_CYCLONE) += cyclone.o obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o +obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR) += uncached.o mca_recovery-y += mca_drv.o mca_drv_asm.o diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c new file mode 100644 index 0000000000..81a53f99a5 --- /dev/null +++ b/arch/ia64/kernel/kprobes.c @@ -0,0 +1,332 @@ +/* + * 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 and Anil S Keshavamurthy + * adapted from i386 + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +/* kprobe_status settings */ +#define KPROBE_HIT_ACTIVE 0x00000001 +#define KPROBE_HIT_SS 0x00000002 + +static struct kprobe *current_kprobe; +static unsigned long kprobe_status; + +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 */ +}; + +int arch_prepare_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long) p->addr; + unsigned long bundle_addr = addr & ~0xFULL; + unsigned long slot = addr & 0xf; + bundle_t bundle; + unsigned long template; + + /* + * TODO: Verify that a probe is not being inserted + * in sensitive regions of code + * TODO: Verify that the memory holding the probe is rwx + * TODO: verify this is a kernel address + */ + memcpy(&bundle, (unsigned long *)bundle_addr, sizeof(bundle_t)); + template = bundle.quad0.template; + if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) { + printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", addr); + return -EINVAL; + } + return 0; +} + +void arch_copy_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + unsigned long bundle_addr = addr & ~0xFULL; + + memcpy(&p->ainsn.insn.bundle, (unsigned long *)bundle_addr, + sizeof(bundle_t)); + memcpy(&p->opcode.bundle, &p->ainsn.insn.bundle, sizeof(bundle_t)); +} + +void arch_arm_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + unsigned long arm_addr = addr & ~0xFULL; + unsigned long slot = addr & 0xf; + unsigned long template; + bundle_t bundle; + + memcpy(&bundle, &p->ainsn.insn.bundle, sizeof(bundle_t)); + + template = bundle.quad0.template; + if (slot == 1 && bundle_encoding[template][1] == L) + slot = 2; + 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; + } + + /* Flush icache for the instruction at the emulated address */ + flush_icache_range((unsigned long)&p->ainsn.insn.bundle, + (unsigned long)&p->ainsn.insn.bundle + + sizeof(bundle_t)); + /* + * Patch the original instruction with the probe instruction + * and flush the instruction cache + */ + memcpy((char *) arm_addr, (char *) &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, and if we see that + * the slot has incremented back to zero, then we need to point to the next + * slot location. + */ +static void resume_execution(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long bundle = (unsigned long)p->addr & ~0xFULL; + + /* + * TODO: Handle cases where kprobe was inserted on a branch instruction + */ + + if (!ia64_psr(regs)->ri) + regs->cr_iip = bundle + 0x10; + else + regs->cr_iip = bundle; + + ia64_psr(regs)->ss = 0; +} + +static void prepare_ss(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long bundle_addr = (unsigned long) &p->ainsn.insn.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 pt_regs *regs) +{ + struct kprobe *p; + int ret = 0; + 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; + } + arch_disarm_kprobe(p); + ret = 1; + } else { + /* + * jprobe instrumented function just completed + */ + p = current_kprobe; + if (p->break_handler && p->break_handler(p, regs)) { + goto ss_probe; + } + } + } + + lock_kprobes(); + p = get_kprobe(addr); + if (!p) { + unlock_kprobes(); + goto no_kprobe; + } + + kprobe_status = KPROBE_HIT_ACTIVE; + 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. + */ + 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 (current_kprobe->post_handler) + current_kprobe->post_handler(current_kprobe, regs, 0); + + resume_execution(current_kprobe, regs); + + unlock_kprobes(); + 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->regs)) + 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) +{ + printk(KERN_WARNING "Jprobes is not supported\n"); + return 0; +} + +void jprobe_return(void) +{ +} + +int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + return 0; +} diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h new file mode 100644 index 0000000000..2a6f2a1488 --- /dev/null +++ b/include/asm-ia64/kprobes.h @@ -0,0 +1,72 @@ +#ifndef _ASM_KPROBES_H +#define _ASM_KPROBES_H +/* + * Kernel Probes (KProbes) + * include/asm-ia64/kprobes.h + * + * 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 and Anil S Keshavamurthy + * adapted from i386 + */ +#include +#include +#include + +#define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6) + +typedef struct _bundle { + struct { + unsigned long long template : 5; + unsigned long long slot0 : 41; + unsigned long long slot1_p0 : 64-46; + } quad0; + struct { + unsigned long long slot1_p1 : 41 - (64-46); + unsigned long long slot2 : 41; + } quad1; +} __attribute__((__aligned__(16))) bundle_t; + +#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry + +typedef struct kprobe_opcode { + bundle_t bundle; +} kprobe_opcode_t; + +struct fnptr { + unsigned long ip; + unsigned long gp; +}; + +/* Architecture specific copy of original instruction*/ +struct arch_specific_insn { + /* copy of the original instruction */ + kprobe_opcode_t insn; +}; + +#ifdef CONFIG_KPROBES +extern int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data); +#else /* !CONFIG_KPROBES */ +static inline int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + return 0; +} +#endif +#endif /* _ASM_KPROBES_H */