diff options
| -rw-r--r-- | arch/tile/Kconfig | 2 | ||||
| -rw-r--r-- | arch/tile/include/asm/Kbuild | 1 | ||||
| -rw-r--r-- | arch/tile/include/asm/kdebug.h | 28 | ||||
| -rw-r--r-- | arch/tile/include/asm/kprobes.h | 79 | ||||
| -rw-r--r-- | arch/tile/include/asm/ptrace.h | 1 | ||||
| -rw-r--r-- | arch/tile/include/uapi/arch/opcode_tilegx.h | 1 | ||||
| -rw-r--r-- | arch/tile/include/uapi/arch/opcode_tilepro.h | 1 | ||||
| -rw-r--r-- | arch/tile/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/tile/kernel/kprobes.c | 528 | ||||
| -rw-r--r-- | arch/tile/kernel/smp.c | 14 | ||||
| -rw-r--r-- | arch/tile/kernel/traps.c | 45 | ||||
| -rw-r--r-- | arch/tile/kernel/vmlinux.lds.S | 1 | ||||
| -rw-r--r-- | arch/tile/mm/fault.c | 12 | ||||
| -rw-r--r-- | samples/kprobes/kprobe_example.c | 9 |
14 files changed, 718 insertions, 5 deletions
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig index d2277c4..616e234 100644 --- a/arch/tile/Kconfig +++ b/arch/tile/Kconfig @@ -125,6 +125,8 @@ config TILEGX select HAVE_FUNCTION_GRAPH_TRACER select HAVE_DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_KPROBES + select HAVE_KRETPROBES config TILEPRO def_bool !TILEGX diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild index b17b9b8..4c0b3c2 100644 --- a/arch/tile/include/asm/Kbuild +++ b/arch/tile/include/asm/Kbuild @@ -15,7 +15,6 @@ generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h generic-y += irq_regs.h -generic-y += kdebug.h generic-y += local.h generic-y += msgbuf.h generic-y += mutex.h diff --git a/arch/tile/include/asm/kdebug.h b/arch/tile/include/asm/kdebug.h new file mode 100644 index 0000000..5bbbfa9 --- /dev/null +++ b/arch/tile/include/asm/kdebug.h @@ -0,0 +1,28 @@ +/* + * Copyright 2012 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#ifndef _ASM_TILE_KDEBUG_H +#define _ASM_TILE_KDEBUG_H + +#include <linux/notifier.h> + +enum die_val { + DIE_OOPS = 1, + DIE_BREAK, + DIE_SSTEPBP, + DIE_PAGE_FAULT, + DIE_COMPILED_BPT +}; + +#endif /* _ASM_TILE_KDEBUG_H */ diff --git a/arch/tile/include/asm/kprobes.h b/arch/tile/include/asm/kprobes.h new file mode 100644 index 0000000..d8f9a83 --- /dev/null +++ b/arch/tile/include/asm/kprobes.h @@ -0,0 +1,79 @@ +/* + * arch/tile/include/asm/kprobes.h + * + * Copyright 2012 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#ifndef _ASM_TILE_KPROBES_H +#define _ASM_TILE_KPROBES_H + +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/percpu.h> + +#include <arch/opcode.h> + +#define __ARCH_WANT_KPROBES_INSN_SLOT +#define MAX_INSN_SIZE 2 + +#define kretprobe_blacklist_size 0 + +typedef tile_bundle_bits kprobe_opcode_t; + +#define flush_insn_slot(p) \ + flush_icache_range((unsigned long)p->addr, \ + (unsigned long)p->addr + \ + (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) + +struct kprobe; + +/* Architecture specific copy of original instruction. */ +struct arch_specific_insn { + kprobe_opcode_t *insn; +}; + +struct prev_kprobe { + struct kprobe *kp; + unsigned long status; + unsigned long saved_pc; +}; + +#define MAX_JPROBES_STACK_SIZE 128 +#define MAX_JPROBES_STACK_ADDR \ + (((unsigned long)current_thread_info()) + THREAD_SIZE - 32 \ + - sizeof(struct pt_regs)) + +#define MIN_JPROBES_STACK_SIZE(ADDR) \ + ((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \ + ? MAX_JPROBES_STACK_ADDR - (ADDR) \ + : MAX_JPROBES_STACK_SIZE) + +/* per-cpu kprobe control block. */ +struct kprobe_ctlblk { + unsigned long kprobe_status; + unsigned long kprobe_saved_pc; + unsigned long jprobe_saved_sp; + struct prev_kprobe prev_kprobe; + struct pt_regs jprobe_saved_regs; + char jprobes_stack[MAX_JPROBES_STACK_SIZE]; +}; + +extern tile_bundle_bits breakpoint2_insn; +extern tile_bundle_bits breakpoint_insn; + +void arch_remove_kprobe(struct kprobe *); + +extern int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data); + +#endif /* _ASM_TILE_KPROBES_H */ diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h index 73b681b..0d25c21 100644 --- a/arch/tile/include/asm/ptrace.h +++ b/arch/tile/include/asm/ptrace.h @@ -33,6 +33,7 @@ typedef unsigned long pt_reg_t; #ifndef __ASSEMBLY__ +#define regs_return_value(regs) ((regs)->regs[0]) #define instruction_pointer(regs) ((regs)->pc) #define profile_pc(regs) instruction_pointer(regs) #define user_stack_pointer(regs) ((regs)->sp) diff --git a/arch/tile/include/uapi/arch/opcode_tilegx.h b/arch/tile/include/uapi/arch/opcode_tilegx.h index c14d02c..d76ff2d 100644 --- a/arch/tile/include/uapi/arch/opcode_tilegx.h +++ b/arch/tile/include/uapi/arch/opcode_tilegx.h @@ -61,6 +61,7 @@ typedef tilegx_bundle_bits tile_bundle_bits; #define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEGX_BUNDLE_ALIGNMENT_IN_BYTES #define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \ TILEGX_LOG2_BUNDLE_ALIGNMENT_IN_BYTES +#define TILE_BPT_BUNDLE TILEGX_BPT_BUNDLE /* 64-bit pattern for a { bpt ; nop } bundle. */ #define TILEGX_BPT_BUNDLE 0x286a44ae51485000ULL diff --git a/arch/tile/include/uapi/arch/opcode_tilepro.h b/arch/tile/include/uapi/arch/opcode_tilepro.h index 71b763b..4451cff 100644 --- a/arch/tile/include/uapi/arch/opcode_tilepro.h +++ b/arch/tile/include/uapi/arch/opcode_tilepro.h @@ -71,6 +71,7 @@ typedef tilepro_bundle_bits tile_bundle_bits; #define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEPRO_BUNDLE_ALIGNMENT_IN_BYTES #define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \ TILEPRO_LOG2_BUNDLE_ALIGNMENT_IN_BYTES +#define TILE_BPT_BUNDLE TILEPRO_BPT_BUNDLE /* 64-bit pattern for a { bpt ; nop } bundle. */ #define TILEPRO_BPT_BUNDLE 0x400b3cae70166000ULL diff --git a/arch/tile/kernel/Makefile b/arch/tile/kernel/Makefile index 2e6eaa1..b7c8b5e 100644 --- a/arch/tile/kernel/Makefile +++ b/arch/tile/kernel/Makefile @@ -28,5 +28,6 @@ endif obj-$(CONFIG_TILE_USB) += usb.o obj-$(CONFIG_TILE_HVGLUE_TRACE) += hvglue_trace.o obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount_64.o +obj-$(CONFIG_KPROBES) += kprobes.o obj-y += vdso/ diff --git a/arch/tile/kernel/kprobes.c b/arch/tile/kernel/kprobes.c new file mode 100644 index 0000000..27cdcac --- /dev/null +++ b/arch/tile/kernel/kprobes.c @@ -0,0 +1,528 @@ +/* + * arch/tile/kernel/kprobes.c + * Kprobes on TILE-Gx + * + * Some portions copied from the MIPS version. + * + * Copyright (C) IBM Corporation, 2002, 2004 + * Copyright 2006 Sony Corp. + * Copyright 2010 Cavium Networks + * + * Copyright 2012 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#include <linux/kprobes.h> +#include <linux/kdebug.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <asm/cacheflush.h> + +#include <arch/opcode.h> + +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); + +tile_bundle_bits breakpoint_insn = TILEGX_BPT_BUNDLE; +tile_bundle_bits breakpoint2_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP; + +/* + * Check whether instruction is branch or jump, or if executing it + * has different results depending on where it is executed (e.g. lnk). + */ +static int __kprobes insn_has_control(kprobe_opcode_t insn) +{ + if (get_Mode(insn) != 0) { /* Y-format bundle */ + if (get_Opcode_Y1(insn) != RRR_1_OPCODE_Y1 || + get_RRROpcodeExtension_Y1(insn) != UNARY_RRR_1_OPCODE_Y1) + return 0; + + switch (get_UnaryOpcodeExtension_Y1(insn)) { + case JALRP_UNARY_OPCODE_Y1: + case JALR_UNARY_OPCODE_Y1: + case JRP_UNARY_OPCODE_Y1: + case JR_UNARY_OPCODE_Y1: + case LNK_UNARY_OPCODE_Y1: + return 1; + default: + return 0; + } + } + + switch (get_Opcode_X1(insn)) { + case BRANCH_OPCODE_X1: /* branch instructions */ + case JUMP_OPCODE_X1: /* jump instructions: j and jal */ + return 1; + + case RRR_0_OPCODE_X1: /* other jump instructions */ + if (get_RRROpcodeExtension_X1(insn) != UNARY_RRR_0_OPCODE_X1) + return 0; + switch (get_UnaryOpcodeExtension_X1(insn)) { + case JALRP_UNARY_OPCODE_X1: + case JALR_UNARY_OPCODE_X1: + case JRP_UNARY_OPCODE_X1: + case JR_UNARY_OPCODE_X1: + case LNK_UNARY_OPCODE_X1: + return 1; + default: + return 0; + } + default: + return 0; + } +} + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + + if (addr & (sizeof(kprobe_opcode_t) - 1)) + return -EINVAL; + + if (insn_has_control(*p->addr)) { + pr_notice("Kprobes for control instructions are not " + "supported\n"); + return -EINVAL; + } + + /* insn: must be on special executable page on tile. */ + p->ainsn.insn = get_insn_slot(); + if (!p->ainsn.insn) + return -ENOMEM; + + /* + * In the kprobe->ainsn.insn[] array we store the original + * instruction at index zero and a break trap instruction at + * index one. + */ + memcpy(&p->ainsn.insn[0], p->addr, sizeof(kprobe_opcode_t)); + p->ainsn.insn[1] = breakpoint2_insn; + p->opcode = *p->addr; + + return 0; +} + +void __kprobes arch_arm_kprobe(struct kprobe *p) +{ + unsigned long addr_wr; + + /* Operate on writable kernel text mapping. */ + addr_wr = (unsigned long)p->addr - MEM_SV_START + PAGE_OFFSET; + + if (probe_kernel_write((void *)addr_wr, &breakpoint_insn, + sizeof(breakpoint_insn))) + pr_err("%s: failed to enable kprobe\n", __func__); + + smp_wmb(); + flush_insn_slot(p); +} + +void __kprobes arch_disarm_kprobe(struct kprobe *kp) +{ + unsigned long addr_wr; + + /* Operate on writable kernel text mapping. */ + addr_wr = (unsigned long)kp->addr - MEM_SV_START + PAGE_OFFSET; + + if (probe_kernel_write((void *)addr_wr, &kp->opcode, + sizeof(kp->opcode))) + pr_err("%s: failed to enable kprobe\n", __func__); + + smp_wmb(); + flush_insn_slot(kp); +} + +void __kprobes arch_remove_kprobe(struct kprobe *p) +{ + if (p->ainsn.insn) { + free_insn_slot(p->ainsn.insn, 0); + p->ainsn.insn = NULL; + } +} + +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; + kcb->prev_kprobe.saved_pc = kcb->kprobe_saved_pc; +} + +static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); + kcb->kprobe_status = kcb->prev_kprobe.status; + kcb->kprobe_saved_pc = kcb->prev_kprobe.saved_pc; +} + +static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ + __this_cpu_write(current_kprobe, p); + kcb->kprobe_saved_pc = regs->pc; +} + +static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) +{ + /* Single step inline if the instruction is a break. */ + if (p->opcode == breakpoint_insn || + p->opcode == breakpoint2_insn) + regs->pc = (unsigned long)p->addr; + else + regs->pc = (unsigned long)&p->ainsn.insn[0]; +} + +static int __kprobes kprobe_handler(struct pt_regs *regs) +{ + struct kprobe *p; + int ret = 0; + kprobe_opcode_t *addr; + struct kprobe_ctlblk *kcb; + + addr = (kprobe_opcode_t *)regs->pc; + + /* + * We don't want to be preempted for the entire + * duration of kprobe processing. + */ + preempt_disable(); + kcb = get_kprobe_ctlblk(); + + /* Check we're not actually recursing. */ + if (kprobe_running()) { + p = get_kprobe(addr); + if (p) { + if (kcb->kprobe_status == KPROBE_HIT_SS && + p->ainsn.insn[0] == breakpoint_insn) { + goto no_kprobe; + } + /* + * 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_insn) { + /* + * The breakpoint instruction was removed by + * another cpu right after we hit, no further + * handling of this interrupt is appropriate. + */ + ret = 1; + goto no_kprobe; + } + p = __this_cpu_read(current_kprobe); + if (p->break_handler && p->break_handler(p, regs)) + goto ss_probe; + } + goto no_kprobe; + } + + p = get_kprobe(addr); + if (!p) { + if (*addr != breakpoint_insn) { + /* + * The breakpoint instruction was removed right + * after we hit it. Another cpu has removed + * either a probepoint or a debugger breakpoint + * at this address. In either case, no further + * handling of this interrupt is appropriate. + */ + ret = 1; + } + /* Not one of ours: let kernel handle it. */ + goto no_kprobe; + } + + set_current_kprobe(p, regs, kcb); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + + if (p->pre_handler && p->pre_handler(p, regs)) { + /* Handler has already set things up, so skip ss setup. */ + return 1; + } + +ss_probe: + prepare_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + return 1; + +no_kprobe: + preempt_enable_no_resched(); + return ret; +} + +/* + * Called after single-stepping. p->addr is the address of the + * instruction that has been replaced by the breakpoint. To avoid the + * SMP problems that can occur when we temporarily put back the + * original opcode to single-step, we single-stepped a copy of the + * instruction. The address of this copy is p->ainsn.insn. + * + * This function prepares to return from the post-single-step + * breakpoint trap. + */ +static void __kprobes resume_execution(struct kprobe *p, + struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ + unsigned long orig_pc = kcb->kprobe_saved_pc; + regs->pc = orig_pc + 8; +} + +static inline int post_kprobe_handler(struct pt_regs *regs) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (!cur) + return 0; + + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + cur->post_handler(cur, regs, 0); + } + + resume_execution(cur, regs, kcb); + + /* Restore back the original saved kprobes variables and continue. */ + if (kcb->kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(kcb); + goto out; + } + reset_current_kprobe(); +out: + preempt_enable_no_resched(); + + return 1; +} + +static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; + + if (kcb->kprobe_status & KPROBE_HIT_SS) { + /* + * We are here because the instruction being single + * stepped caused a page fault. We reset the current + * kprobe and the ip points back to the probe address + * and allow the page fault handler to continue as a + * normal page fault. + */ + resume_execution(cur, regs, kcb); + reset_current_kprobe(); + preempt_enable_no_resched(); + } + return 0; +} + +/* + * Wrapper routine for handling exceptions. + */ +int __kprobes kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = (struct die_args *)data; + int ret = NOTIFY_DONE; + + switch (val) { + case DIE_BREAK: + if (kprobe_handler(args->regs)) + ret = NOTIFY_STOP; + break; + case DIE_SSTEPBP: + if (post_kprobe_handler(args->regs)) + ret = NOTIFY_STOP; + break; + case DIE_PAGE_FAULT: + /* kprobe_running() needs smp_processor_id(). */ + preempt_disable(); + + if (kprobe_running() + && kprobe_fault_handler(args->regs, args->trapnr)) + ret = NOTIFY_STOP; + preempt_enable(); + break; + default: + break; + } + return ret; +} + +int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct jprobe *jp = container_of(p, struct jprobe, kp); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + kcb->jprobe_saved_regs = *regs; + kcb->jprobe_saved_sp = regs->sp; + + memcpy(kcb->jprobes_stack, (void *)kcb->jprobe_saved_sp, + MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); + + regs->pc = (unsigned long)(jp->entry); + + return 1; +} + +/* Defined in the inline asm below. */ +void jprobe_return_end(void); + +void __kprobes jprobe_return(void) +{ + asm volatile( + "bpt\n\t" + ".globl jprobe_return_end\n" + "jprobe_return_end:\n"); +} + +int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (regs->pc >= (unsigned long)jprobe_return && + regs->pc <= (unsigned long)jprobe_return_end) { + *regs = kcb->jprobe_saved_regs; + memcpy((void *)kcb->jprobe_saved_sp, kcb->jprobes_stack, + MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); + preempt_enable_no_resched(); + + return 1; + } + return 0; +} + +/* + * Function return probe trampoline: + * - init_kprobes() establishes a probepoint here + * - When the probed function returns, this probe causes the + * handlers to fire + */ +static void __used kretprobe_trampoline_holder(void) +{ + asm volatile( + "nop\n\t" + ".global kretprobe_trampoline\n" + "kretprobe_trampoline:\n\t" + "nop\n\t" + : : : "memory"); +} + +void kretprobe_trampoline(void); + +void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + ri->ret_addr = (kprobe_opcode_t *) regs->lr; + + /* Replace the return addr with trampoline addr */ + regs->lr = (unsigned long)kretprobe_trampoline; +} + +/* + * Called when the probe at kretprobe trampoline is hit. + */ +static int __kprobes trampoline_probe_handler(struct kprobe *p, + struct pt_regs *regs) +{ + struct kretprobe_instance *ri = NULL; + struct hlist_head *head, empty_rp; + struct hlist_node *tmp; + unsigned long flags, orig_ret_address = 0; + unsigned long trampoline_address = (unsigned long)kretprobe_trampoline; + + INIT_HLIST_HEAD(&empty_rp); + kretprobe_hash_lock(current, &head, &flags); + + /* + * It is possible to have multiple instances associated with a given + * task either because multiple functions in the call path have + * a return probe installed on them, and/or more than 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, 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, &empty_rp); + + 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; + } + } + + kretprobe_assert(ri, orig_ret_address, trampoline_address); + instruction_pointer(regs) = orig_ret_address; + + reset_current_kprobe(); + kretprobe_hash_unlock(current, &flags); + preempt_enable_no_resched(); + + hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } + /* + * By returning a non-zero value, we are telling + * kprobe_handler() that we don't want the post_handler + * to run (and have re-enabled preemption) + */ + return 1; +} + +int __kprobes arch_trampoline_kprobe(struct kprobe *p) +{ + if (p->addr == (kprobe_opcode_t *)kretprobe_trampoline) + return 1; + + return 0; +} + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *)kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init_kprobes(void) +{ + register_kprobe(&trampoline_p); + return 0; +} diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c index 6cc520d..0ae1c59 100644 --- a/arch/tile/kernel/smp.c +++ b/arch/tile/kernel/smp.c @@ -20,6 +20,7 @@ #include <linux/irq.h> #include <linux/module.h> #include <asm/cacheflush.h> +#include <asm/homecache.h> HV_Topology smp_topology __write_once; EXPORT_SYMBOL(smp_topology); @@ -167,9 +168,16 @@ static void ipi_flush_icache_range(void *info) void flush_icache_range(unsigned long start, unsigned long end) { struct ipi_flush flush = { start, end }; - preempt_disable(); - on_each_cpu(ipi_flush_icache_range, &flush, 1); - preempt_enable(); + + /* If invoked with irqs disabled, we can not issue IPIs. */ + if (irqs_disabled()) + flush_remote(0, HV_FLUSH_EVICT_L1I, NULL, 0, 0, 0, + NULL, NULL, 0); + else { + preempt_disable(); + on_each_cpu(ipi_flush_icache_range, &flush, 1); + preempt_enable(); + } } diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c index a1bbc5de..cfff6f9 100644 --- a/arch/tile/kernel/traps.c +++ b/arch/tile/kernel/traps.c @@ -15,6 +15,7 @@ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/kprobes.h> +#include <linux/kdebug.h> #include <linux/module.h> #include <linux/reboot.h> #include <linux/uaccess.h> @@ -214,6 +215,43 @@ static const char *const int_name[] = { #endif }; +static int do_bpt(struct pt_regs *regs) +{ + unsigned long bundle, bcode, bpt; + + bundle = *(unsigned long *)instruction_pointer(regs); + + /* + * bpt shoule be { bpt; nop }, which is 0x286a44ae51485000ULL. + * we encode the unused least significant bits for other purpose. + */ + bpt = bundle & ~((1ULL << 12) - 1); + if (bpt != TILE_BPT_BUNDLE) + return 0; + + bcode = bundle & ((1ULL << 12) - 1); + /* + * notify the kprobe handlers, if instruction is likely to + * pertain to them. + */ + switch (bcode) { + /* breakpoint_insn */ + case 0: + notify_die(DIE_BREAK, "debug", regs, bundle, + INT_ILL, SIGTRAP); + break; + /* breakpoint2_insn */ + case DIE_SSTEPBP: + notify_die(DIE_SSTEPBP, "single_step", regs, bundle, + INT_ILL, SIGTRAP); + break; + default: + return 0; + } + + return 1; +} + void __kprobes do_trap(struct pt_regs *regs, int fault_num, unsigned long reason) { @@ -221,6 +259,11 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num, int signo, code; unsigned long address = 0; bundle_bits instr; + int is_kernel = !user_mode(regs); + + /* Handle breakpoints, etc. */ + if (is_kernel && fault_num == INT_ILL && do_bpt(regs)) + return; /* Re-enable interrupts, if they were previously enabled. */ if (!(regs->flags & PT_FLAGS_DISABLE_IRQ)) @@ -230,7 +273,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num, * If it hits in kernel mode and we can't fix it up, just exit the * current process and hope for the best. */ - if (!user_mode(regs)) { + if (is_kernel) { const char *name; char buf[100]; if (fixup_exception(regs)) /* ILL_TRANS or UNALIGN_DATA */ diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S index 673d00a..aab9955 100644 --- a/arch/tile/kernel/vmlinux.lds.S +++ b/arch/tile/kernel/vmlinux.lds.S @@ -43,6 +43,7 @@ SECTIONS HEAD_TEXT SCHED_TEXT LOCK_TEXT + KPROBES_TEXT IRQENTRY_TEXT __fix_text_end = .; /* tile-cpack won't rearrange before this */ TEXT_TEXT diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c index 502664a..64eec3f 100644 --- a/arch/tile/mm/fault.c +++ b/arch/tile/mm/fault.c @@ -34,6 +34,7 @@ #include <linux/hugetlb.h> #include <linux/syscalls.h> #include <linux/uaccess.h> +#include <linux/kdebug.h> #include <asm/pgalloc.h> #include <asm/sections.h> @@ -721,6 +722,17 @@ void do_page_fault(struct pt_regs *regs, int fault_num, { int is_page_fault; +#ifdef CONFIG_KPROBES + /* + * This is to notify the fault handler of the kprobes. The + * exception code is redundant as it is also carried in REGS, + * but we pass it anyhow. + */ + if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1, + regs->faultnum, SIGSEGV) == NOTIFY_STOP) + return; +#endif + #ifdef __tilegx__ /* * We don't need early do_page_fault_ics() support, since unlike diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c index ebf5e0c..366db1a 100644 --- a/samples/kprobes/kprobe_example.c +++ b/samples/kprobes/kprobe_example.c @@ -37,6 +37,11 @@ static int handler_pre(struct kprobe *p, struct pt_regs *regs) " status = 0x%lx\n", p->addr, regs->cp0_epc, regs->cp0_status); #endif +#ifdef CONFIG_TILEGX + printk(KERN_INFO "pre_handler: p->addr = 0x%p, pc = 0x%lx," + " ex1 = 0x%lx\n", + p->addr, regs->pc, regs->ex1); +#endif /* A dump_stack() here will give a stack backtrace */ return 0; @@ -58,6 +63,10 @@ static void handler_post(struct kprobe *p, struct pt_regs *regs, printk(KERN_INFO "post_handler: p->addr = 0x%p, status = 0x%lx\n", p->addr, regs->cp0_status); #endif +#ifdef CONFIG_TILEGX + printk(KERN_INFO "post_handler: p->addr = 0x%p, ex1 = 0x%lx\n", + p->addr, regs->ex1); +#endif } /* |
