From 054419ed8405da7aa93f88f698d696980efd3e37 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 18 Jan 2013 15:12:18 +0530 Subject: ARC: Non-MMU Exception Handling Signed-off-by: Vineet Gupta --- arch/arc/kernel/traps.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 arch/arc/kernel/traps.c (limited to 'arch/arc/kernel/traps.c') diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c new file mode 100644 index 000000000000..fd2457cec226 --- /dev/null +++ b/arch/arc/kernel/traps.c @@ -0,0 +1,125 @@ +/* + * Traps/Non-MMU Exception handling for ARC + * + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Rahul Trivedi: Codito Technologies 2004 + */ + +#include +#include +#include +#include +#include + +void __init trap_init(void) +{ + return; +} + +void die(const char *str, struct pt_regs *regs, unsigned long address, + unsigned long cause_reg) +{ + show_kernel_fault_diag(str, regs, address, cause_reg); + + /* DEAD END */ + __asm__("flag 1"); +} + +/* + * Helper called for bulk of exceptions NOT needing specific handling + * -for user faults enqueues requested signal + * -for kernel, chk if due to copy_(to|from)_user, otherwise die() + */ +static noinline int handle_exception(unsigned long cause, char *str, + struct pt_regs *regs, siginfo_t *info) +{ + if (user_mode(regs)) { + struct task_struct *tsk = current; + + tsk->thread.fault_address = (__force unsigned int)info->si_addr; + tsk->thread.cause_code = cause; + + force_sig_info(info->si_signo, info, tsk); + + } else { + /* If not due to copy_(to|from)_user, we are doomed */ + if (fixup_exception(regs)) + return 0; + + die(str, regs, (unsigned long)info->si_addr, cause); + } + + return 1; +} + +#define DO_ERROR_INFO(signr, str, name, sicode) \ +int name(unsigned long cause, unsigned long address, struct pt_regs *regs) \ +{ \ + siginfo_t info = { \ + .si_signo = signr, \ + .si_errno = 0, \ + .si_code = sicode, \ + .si_addr = (void __user *)address, \ + }; \ + return handle_exception(cause, str, regs, &info);\ +} + +/* + * Entry points for exceptions NOT needing specific handling + */ +DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC) +DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC) +DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC) +DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", do_memory_error, BUS_ADRERR) +DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT) + +DO_ERROR_INFO(SIGSEGV, "Misaligned Access", do_misaligned_access, SEGV_ACCERR) + +/* + * Entry point for miscll errors such as Nested Exceptions + * -Duplicate TLB entry is handled seperately though + */ +void do_machine_check_fault(unsigned long cause, unsigned long address, + struct pt_regs *regs) +{ + die("Machine Check Exception", regs, address, cause); +} + +/* + * Entry point for traps induced by ARCompact TRAP_S insn + * This is same family as TRAP0/SWI insn (use the same vector). + * The only difference being SWI insn take no operand, while TRAP_S does + * which reflects in ECR Reg as 8 bit param. + * Thus TRAP_S can be used for specific purpose + * -1 used for software breakpointing (gdb) + * -2 used by kprobes + */ +void do_non_swi_trap(unsigned long cause, unsigned long address, + struct pt_regs *regs) +{ + unsigned int param = cause & 0xff; + + switch (param) { + case 1: + trap_is_brkpt(cause, address, regs); + break; + + default: + break; + } +} + +/* + * Entry point for Instruction Error Exception + */ +void do_insterror_or_kprobe(unsigned long cause, + unsigned long address, + struct pt_regs *regs) +{ + insterror_is_error(cause, address, regs); +} -- cgit v1.2.3 From 4d86dfbbda09b3c67bcaeb370f22a2cc7f39205b Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Tue, 22 Jan 2013 17:03:59 +0530 Subject: ARC: kprobes support Origin port done by Rajeshwar Ranga Signed-off-by: Vineet Gupta Cc: Rajeshwar Ranga --- arch/arc/Kconfig | 2 + arch/arc/include/asm/kprobes.h | 62 +++++ arch/arc/include/asm/ptrace.h | 5 + arch/arc/kernel/Makefile | 1 + arch/arc/kernel/disasm.c | 5 +- arch/arc/kernel/kprobes.c | 525 +++++++++++++++++++++++++++++++++++++++++ arch/arc/kernel/traps.c | 13 + 7 files changed, 610 insertions(+), 3 deletions(-) create mode 100644 arch/arc/include/asm/kprobes.h create mode 100644 arch/arc/kernel/kprobes.c (limited to 'arch/arc/kernel/traps.c') diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 84b23fae661c..cde8d3fcec94 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -24,6 +24,8 @@ config ARC select GENERIC_SMP_IDLE_THREAD select HAVE_ARCH_TRACEHOOK select HAVE_GENERIC_HARDIRQS + select HAVE_KPROBES + select HAVE_KRETPROBES select HAVE_MEMBLOCK select HAVE_MOD_ARCH_SPECIFIC if ARC_DW2_UNWIND select HAVE_OPROFILE diff --git a/arch/arc/include/asm/kprobes.h b/arch/arc/include/asm/kprobes.h new file mode 100644 index 000000000000..4d9c211fce70 --- /dev/null +++ b/arch/arc/include/asm/kprobes.h @@ -0,0 +1,62 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ARC_KPROBES_H +#define _ARC_KPROBES_H + +#ifdef CONFIG_KPROBES + +typedef u16 kprobe_opcode_t; + +#define UNIMP_S_INSTRUCTION 0x79e0 +#define TRAP_S_2_INSTRUCTION 0x785e + +#define MAX_INSN_SIZE 8 +#define MAX_STACK_SIZE 64 + +struct arch_specific_insn { + int is_short; + kprobe_opcode_t *t1_addr, *t2_addr; + kprobe_opcode_t t1_opcode, t2_opcode; +}; + +#define flush_insn_slot(p) do { } while (0) + +#define kretprobe_blacklist_size 0 + +struct kprobe; + +void arch_remove_kprobe(struct kprobe *p); + +int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data); + +struct prev_kprobe { + struct kprobe *kp; + unsigned long status; +}; + +struct kprobe_ctlblk { + unsigned int kprobe_status; + struct pt_regs jprobe_saved_regs; + char jprobes_stack[MAX_STACK_SIZE]; + struct prev_kprobe prev_kprobe; +}; + +int kprobe_fault_handler(struct pt_regs *regs, unsigned long cause); +void kretprobe_trampoline(void); +void trap_is_kprobe(unsigned long cause, unsigned long address, + struct pt_regs *regs); +#else +static void trap_is_kprobe(unsigned long cause, unsigned long address, + struct pt_regs *regs) +{ +} +#endif + +#endif diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h index a98957a95fb3..063ed0040ef7 100644 --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -111,6 +111,11 @@ struct callee_regs { (struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \ }) +static inline long regs_return_value(struct pt_regs *regs) +{ + return regs->r0; +} + #endif /* !__ASSEMBLY__ */ #define orig_r8_IS_SCALL 0x0001 diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile index 6ae4dd4ecea0..d331bd7047a1 100644 --- a/arch/arc/kernel/Makefile +++ b/arch/arc/kernel/Makefile @@ -15,6 +15,7 @@ obj-y += devtree.o obj-$(CONFIG_MODULES) += arcksyms.o module.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_ARC_DW2_UNWIND) += unwind.o +obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o CFLAGS_fpu.o += -mdpfp diff --git a/arch/arc/kernel/disasm.c b/arch/arc/kernel/disasm.c index 254d11a4f495..51bad8ff373b 100644 --- a/arch/arc/kernel/disasm.c +++ b/arch/arc/kernel/disasm.c @@ -497,9 +497,8 @@ void __kprobes set_reg(int reg, long val, struct pt_regs *regs, * @pc +2/4/6 (ARCompact ISA allows free intermixing of 16/32 bit insns). * * If @pc is a branch - * -@tgt_if_br is set to branch target. - * -If branch has delay slot, @next_pc updated with actual next PC. - * + * -@tgt_if_br is set to branch target. + * -If branch has delay slot, @next_pc updated with actual next PC. */ int __kprobes disasm_next_pc(unsigned long pc, struct pt_regs *regs, struct callee_regs *cregs, diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c new file mode 100644 index 000000000000..47e42f29f927 --- /dev/null +++ b/arch/arc/kernel/kprobes.c @@ -0,0 +1,525 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define MIN_STACK_SIZE(addr) min((unsigned long)MAX_STACK_SIZE, \ + (unsigned long)current_thread_info() + THREAD_SIZE - (addr)) + +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + /* Attempt to probe at unaligned address */ + if ((unsigned long)p->addr & 0x01) + return -EINVAL; + + /* Address should not be in exception handling code */ + + p->ainsn.is_short = is_short_instr((unsigned long)p->addr); + p->opcode = *p->addr; + + return 0; +} + +void __kprobes arch_arm_kprobe(struct kprobe *p) +{ + *p->addr = UNIMP_S_INSTRUCTION; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); +} + +void __kprobes arch_disarm_kprobe(struct kprobe *p) +{ + *p->addr = p->opcode; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); +} + +void __kprobes arch_remove_kprobe(struct kprobe *p) +{ + arch_disarm_kprobe(p); + + /* Can we remove the kprobe in the middle of kprobe handling? */ + if (p->ainsn.t1_addr) { + *(p->ainsn.t1_addr) = p->ainsn.t1_opcode; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t1_addr = NULL; + } + + if (p->ainsn.t2_addr) { + *(p->ainsn.t2_addr) = p->ainsn.t2_opcode; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t2_addr = NULL; + } +} + +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; +} + +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; +} + +static inline void __kprobes set_current_kprobe(struct kprobe *p) +{ + __get_cpu_var(current_kprobe) = p; +} + +static void __kprobes resume_execution(struct kprobe *p, unsigned long addr, + struct pt_regs *regs) +{ + /* Remove the trap instructions inserted for single step and + * restore the original instructions + */ + if (p->ainsn.t1_addr) { + *(p->ainsn.t1_addr) = p->ainsn.t1_opcode; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t1_addr = NULL; + } + + if (p->ainsn.t2_addr) { + *(p->ainsn.t2_addr) = p->ainsn.t2_opcode; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t2_addr = NULL; + } + + return; +} + +static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long next_pc; + unsigned long tgt_if_br = 0; + int is_branch; + unsigned long bta; + + /* Copy the opcode back to the kprobe location and execute the + * instruction. Because of this we will not be able to get into the + * same kprobe until this kprobe is done + */ + *(p->addr) = p->opcode; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); + + /* Now we insert the trap at the next location after this instruction to + * single step. If it is a branch we insert the trap at possible branch + * targets + */ + + bta = regs->bta; + + if (regs->status32 & 0x40) { + /* We are in a delay slot with the branch taken */ + + next_pc = bta & ~0x01; + + if (!p->ainsn.is_short) { + if (bta & 0x01) + regs->blink += 2; + else { + /* Branch not taken */ + next_pc += 2; + + /* next pc is taken from bta after executing the + * delay slot instruction + */ + regs->bta += 2; + } + } + + is_branch = 0; + } else + is_branch = + disasm_next_pc((unsigned long)p->addr, regs, + (struct callee_regs *) current->thread.callee_reg, + &next_pc, &tgt_if_br); + + p->ainsn.t1_addr = (kprobe_opcode_t *) next_pc; + p->ainsn.t1_opcode = *(p->ainsn.t1_addr); + *(p->ainsn.t1_addr) = TRAP_S_2_INSTRUCTION; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + if (is_branch) { + p->ainsn.t2_addr = (kprobe_opcode_t *) tgt_if_br; + p->ainsn.t2_opcode = *(p->ainsn.t2_addr); + *(p->ainsn.t2_addr) = TRAP_S_2_INSTRUCTION; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + } +} + +int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs) +{ + struct kprobe *p; + struct kprobe_ctlblk *kcb; + + preempt_disable(); + + kcb = get_kprobe_ctlblk(); + p = get_kprobe((unsigned long *)addr); + + if (p) { + /* + * We have reentered the kprobe_handler, since another kprobe + * was hit while within the handler, we save the original + * kprobes and single step on the instruction of the new probe + * without calling any user handlers to avoid recursive + * kprobes. + */ + if (kprobe_running()) { + save_previous_kprobe(kcb); + set_current_kprobe(p); + kprobes_inc_nmissed_count(p); + setup_singlestep(p, regs); + kcb->kprobe_status = KPROBE_REENTER; + return 1; + } + + set_current_kprobe(p); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + + /* If we have no pre-handler or it returned 0, we continue with + * normal processing. If we have a pre-handler and it returned + * non-zero - which is expected from setjmp_pre_handler for + * jprobe, we return without single stepping and leave that to + * the break-handler which is invoked by a kprobe from + * jprobe_return + */ + if (!p->pre_handler || !p->pre_handler(p, regs)) { + setup_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + } + + return 1; + } else if (kprobe_running()) { + p = __get_cpu_var(current_kprobe); + if (p->break_handler && p->break_handler(p, regs)) { + setup_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + return 1; + } + } + + /* no_kprobe: */ + preempt_enable_no_resched(); + return 0; +} + +static int __kprobes arc_post_kprobe_handler(unsigned long addr, + struct pt_regs *regs) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (!cur) + return 0; + + resume_execution(cur, addr, regs); + + /* Rearm the kprobe */ + arch_arm_kprobe(cur); + + /* + * When we return from trap instruction we go to the next instruction + * We restored the actual instruction in resume_exectuiont and we to + * return to the same address and execute it + */ + regs->ret = addr; + + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + cur->post_handler(cur, regs, 0); + } + + if (kcb->kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(kcb); + goto out; + } + + reset_current_kprobe(); + +out: + preempt_enable_no_resched(); + return 1; +} + +/* + * Fault can be for the instruction being single stepped or for the + * pre/post handlers in the module. + * This is applicable for applications like user probes, where we have the + * probe in user space and the handlers in the kernel + */ + +int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned long trapnr) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + switch (kcb->kprobe_status) { + case KPROBE_HIT_SS: + case KPROBE_REENTER: + /* + * We are here because the instruction being single stepped + * caused the fault. We reset the current kprobe and allow the + * exception handler as if it is regular exception. In our + * case it doesn't matter because the system will be halted + */ + resume_execution(cur, (unsigned long)cur->addr, regs); + + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); + + preempt_enable_no_resched(); + break; + + case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SSDONE: + /* + * We are here because the instructions in the pre/post handler + * caused the fault. + */ + + /* We increment the nmissed count for accounting, + * we can also use npre/npostfault count for accouting + * these specific fault cases. + */ + kprobes_inc_nmissed_count(cur); + + /* + * We come here because instructions in the pre/post + * handler caused the page_fault, this could happen + * if handler tries to access user space by + * copy_from_user(), get_user() etc. Let the + * user-specified handler try to fix it first. + */ + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; + + /* + * In case the user-specified fault handler returned zero, + * try to fix up. + */ + if (fixup_exception(regs)) + return 1; + + /* + * fixup_exception() could not handle it, + * Let do_page_fault() fix it. + */ + break; + + default: + break; + } + return 0; +} + +int __kprobes kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + unsigned long addr = args->err; + int ret = NOTIFY_DONE; + + switch (val) { + case DIE_IERR: + if (arc_kprobe_handler(addr, args->regs)) + return NOTIFY_STOP; + break; + + case DIE_TRAP: + if (arc_post_kprobe_handler(addr, args->regs)) + return NOTIFY_STOP; + 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(); + unsigned long sp_addr = regs->sp; + + kcb->jprobe_saved_regs = *regs; + memcpy(kcb->jprobes_stack, (void *)sp_addr, MIN_STACK_SIZE(sp_addr)); + regs->ret = (unsigned long)(jp->entry); + + return 1; +} + +void __kprobes jprobe_return(void) +{ + __asm__ __volatile__("unimp_s"); + return; +} + +int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + unsigned long sp_addr; + + *regs = kcb->jprobe_saved_regs; + sp_addr = regs->sp; + memcpy((void *)sp_addr, kcb->jprobes_stack, MIN_STACK_SIZE(sp_addr)); + preempt_enable_no_resched(); + + return 1; +} + +static void __used kretprobe_trampoline_holder(void) +{ + __asm__ __volatile__(".global kretprobe_trampoline\n" + "kretprobe_trampoline:\n" "nop\n"); +} + +void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + + ri->ret_addr = (kprobe_opcode_t *) regs->blink; + + /* Replace the return addr with trampoline addr */ + regs->blink = (unsigned long)&kretprobe_trampoline; +} + +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 *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 an 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, 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, &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); + regs->ret = orig_ret_address; + + reset_current_kprobe(); + kretprobe_hash_unlock(current, &flags); + preempt_enable_no_resched(); + + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } + + /* By returning a non zero value, we are telling the kprobe handler + * that we don't want the post_handler to run + */ + return 1; +} + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) &kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init_kprobes(void) +{ + /* Registering the trampoline code for the kret probe */ + return register_kprobe(&trampoline_p); +} + +int __kprobes arch_trampoline_kprobe(struct kprobe *p) +{ + if (p->addr == (kprobe_opcode_t *) &kretprobe_trampoline) + return 1; + + return 0; +} + +void trap_is_kprobe(unsigned long cause, unsigned long address, + struct pt_regs *regs) +{ + notify_die(DIE_TRAP, "kprobe_trap", regs, address, cause, SIGTRAP); +} diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c index fd2457cec226..c6396b48fcd2 100644 --- a/arch/arc/kernel/traps.c +++ b/arch/arc/kernel/traps.c @@ -15,6 +15,7 @@ #include #include #include +#include void __init trap_init(void) { @@ -90,6 +91,7 @@ void do_machine_check_fault(unsigned long cause, unsigned long address, die("Machine Check Exception", regs, address, cause); } + /* * Entry point for traps induced by ARCompact TRAP_S insn * This is same family as TRAP0/SWI insn (use the same vector). @@ -109,6 +111,10 @@ void do_non_swi_trap(unsigned long cause, unsigned long address, trap_is_brkpt(cause, address, regs); break; + case 2: + trap_is_kprobe(param, address, regs); + break; + default: break; } @@ -116,10 +122,17 @@ void do_non_swi_trap(unsigned long cause, unsigned long address, /* * Entry point for Instruction Error Exception + * -For a corner case, ARC kprobes implementation resorts to using + * this exception, hence the check */ void do_insterror_or_kprobe(unsigned long cause, unsigned long address, struct pt_regs *regs) { + /* Check if this exception is caused by kprobes */ + if (notify_die(DIE_IERR, "kprobe_ierr", regs, address, + cause, SIGILL) == NOTIFY_STOP) + return; + insterror_is_error(cause, address, regs); } -- cgit v1.2.3 From 2e651ea1596b0ee25af4fcdc4cd13cbb33ffc254 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Wed, 23 Jan 2013 16:30:36 +0530 Subject: ARC: Unaligned access emulation ARC700 doesn't natively support unaligned access, but can be emulated -Unaligned Access Exception -Disassembly at the Fault address to find the exact insn (long/short) Also per Arnd's comment, we runtime control it using 2 sysctl knobs: * SYSCTL_ARCH_UNALIGN_ALLOW: Runtime enable/disble * SYSCTL_ARCH_UNALIGN_NO_WARN: Warn on each emulation attempt Originally contributed by Tim Yao Signed-off-by: Vineet Gupta Cc: Tim Yao Acked-by: Arnd Bergmann --- arch/arc/Kconfig | 11 ++ arch/arc/include/asm/Kbuild | 1 - arch/arc/include/asm/ptrace.h | 3 + arch/arc/include/asm/unaligned.h | 29 +++++ arch/arc/kernel/Makefile | 1 + arch/arc/kernel/disasm.c | 2 +- arch/arc/kernel/entry.S | 13 +++ arch/arc/kernel/traps.c | 26 +++++ arch/arc/kernel/unaligned.c | 245 +++++++++++++++++++++++++++++++++++++++ 9 files changed, 329 insertions(+), 2 deletions(-) create mode 100644 arch/arc/include/asm/unaligned.h create mode 100644 arch/arc/kernel/unaligned.c (limited to 'arch/arc/kernel/traps.c') diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index cde8d3fcec94..f8042835e746 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -336,6 +336,17 @@ config ARC_CURR_IN_REG This reserved Register R25 to point to Current Task in kernel mode. This saves memory access for each such access + +config ARC_MISALIGN_ACCESS + bool "Emulate unaligned memory access (userspace only)" + default N + select SYSCTL_ARCH_UNALIGN_NO_WARN + select SYSCTL_ARCH_UNALIGN_ALLOW + help + This enables misaligned 16 & 32 bit memory access from user space. + Use ONLY-IF-ABS-NECESSARY as it will be very slow and also can hide + potential bugs in code + config ARC_STACK_NONEXEC bool "Make stack non-executable" default n diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index 78e982dad537..b24089c974a9 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -52,7 +52,6 @@ generic-y += topology.h generic-y += trace_clock.h generic-y += types.h generic-y += ucontext.h -generic-y += unaligned.h generic-y += user.h generic-y += vga.h generic-y += xor.h diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h index 063ed0040ef7..df5b95213776 100644 --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -97,6 +97,9 @@ struct callee_regs { sp; \ }) +/* return 1 if PC in delay slot */ +#define delay_mode(regs) ((regs->status32 & STATUS_DE_MASK) == STATUS_DE_MASK) + #define in_syscall(regs) (regs->event & orig_r8_IS_SCALL) #define in_brkpt_trap(regs) (regs->event & orig_r8_IS_BRKPT) diff --git a/arch/arc/include/asm/unaligned.h b/arch/arc/include/asm/unaligned.h new file mode 100644 index 000000000000..5dbe63f17b66 --- /dev/null +++ b/arch/arc/include/asm/unaligned.h @@ -0,0 +1,29 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_ARC_UNALIGNED_H +#define _ASM_ARC_UNALIGNED_H + +/* ARC700 can't handle unaligned Data accesses. */ + +#include +#include + +#ifdef CONFIG_ARC_MISALIGN_ACCESS +int misaligned_fixup(unsigned long address, struct pt_regs *regs, + unsigned long cause, struct callee_regs *cregs); +#else +static inline int +misaligned_fixup(unsigned long address, struct pt_regs *regs, + unsigned long cause, struct callee_regs *cregs) +{ + return 0; +} +#endif + +#endif /* _ASM_ARC_UNALIGNED_H */ diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile index d331bd7047a1..507a33d4a255 100644 --- a/arch/arc/kernel/Makefile +++ b/arch/arc/kernel/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_MODULES) += arcksyms.o module.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_ARC_DW2_UNWIND) += unwind.o obj-$(CONFIG_KPROBES) += kprobes.o +obj-$(CONFIG_ARC_MISALIGN_ACCESS) += unaligned.o obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o CFLAGS_fpu.o += -mdpfp diff --git a/arch/arc/kernel/disasm.c b/arch/arc/kernel/disasm.c index 51bad8ff373b..2f390289a792 100644 --- a/arch/arc/kernel/disasm.c +++ b/arch/arc/kernel/disasm.c @@ -15,7 +15,7 @@ #include #include -#if defined(CONFIG_KGDB) || defined(CONFIG_MISALIGN_ACCESS) || \ +#if defined(CONFIG_KGDB) || defined(CONFIG_ARC_MISALIGN_ACCESS) || \ defined(CONFIG_KPROBES) /* disasm_instr: Analyses instruction at addr, stores diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 021cfa46a1dc..f8efade15368 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -7,6 +7,9 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * + * vineetg: May 2011 + * -Userspace unaligned access emulation + * * vineetg: Feb 2011 (ptrace low level code fixes) * -traced syscall return code (r0) was not saved into pt_regs for restoring * into user reg-file when traded task rets to user space. @@ -387,7 +390,17 @@ ARC_ENTRY EV_TLBProtV mov r1, r4 ; faulting address mov r2, sp ; pt_regs +#ifdef CONFIG_ARC_MISALIGN_ACCESS + SAVE_CALLEE_SAVED_USER + mov r3, sp ; callee_regs +#endif + bl do_misaligned_access + +#ifdef CONFIG_ARC_MISALIGN_ACCESS + DISCARD_CALLEE_SAVED_USER +#endif + b ret_from_exception ARC_EXIT EV_TLBProtV diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c index c6396b48fcd2..ec802c52a1ca 100644 --- a/arch/arc/kernel/traps.c +++ b/arch/arc/kernel/traps.c @@ -7,6 +7,9 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * + * vineetg: May 2011 + * -user-space unaligned access emulation + * * Rahul Trivedi: Codito Technologies 2004 */ @@ -16,6 +19,7 @@ #include #include #include +#include void __init trap_init(void) { @@ -79,7 +83,29 @@ DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC) DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", do_memory_error, BUS_ADRERR) DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT) +#ifdef CONFIG_ARC_MISALIGN_ACCESS +/* + * Entry Point for Misaligned Data access Exception, for emulating in software + */ +int do_misaligned_access(unsigned long cause, unsigned long address, + struct pt_regs *regs, struct callee_regs *cregs) +{ + if (misaligned_fixup(address, regs, cause, cregs) != 0) { + siginfo_t info; + + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRALN; + info.si_addr = (void __user *)address; + return handle_exception(cause, "Misaligned Access", regs, + &info); + } + return 0; +} + +#else DO_ERROR_INFO(SIGSEGV, "Misaligned Access", do_misaligned_access, SEGV_ACCERR) +#endif /* * Entry point for miscll errors such as Nested Exceptions diff --git a/arch/arc/kernel/unaligned.c b/arch/arc/kernel/unaligned.c new file mode 100644 index 000000000000..4cd81633febd --- /dev/null +++ b/arch/arc/kernel/unaligned.c @@ -0,0 +1,245 @@ +/* + * Copyright (C) 2011-2012 Synopsys (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * vineetg : May 2011 + * -Adapted (from .26 to .35) + * -original contribution by Tim.yao@amlogic.com + * + */ + +#include +#include +#include +#include + +#define __get8_unaligned_check(val, addr, err) \ + __asm__( \ + "1: ldb.ab %1, [%2, 1]\n" \ + "2:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + "3: mov %0, 1\n" \ + " b 2b\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b, 3b\n" \ + " .previous\n" \ + : "=r" (err), "=&r" (val), "=r" (addr) \ + : "0" (err), "2" (addr)) + +#define get16_unaligned_check(val, addr) \ + do { \ + unsigned int err = 0, v, a = addr; \ + __get8_unaligned_check(v, a, err); \ + val = v ; \ + __get8_unaligned_check(v, a, err); \ + val |= v << 8; \ + if (err) \ + goto fault; \ + } while (0) + +#define get32_unaligned_check(val, addr) \ + do { \ + unsigned int err = 0, v, a = addr; \ + __get8_unaligned_check(v, a, err); \ + val = v << 0; \ + __get8_unaligned_check(v, a, err); \ + val |= v << 8; \ + __get8_unaligned_check(v, a, err); \ + val |= v << 16; \ + __get8_unaligned_check(v, a, err); \ + val |= v << 24; \ + if (err) \ + goto fault; \ + } while (0) + +#define put16_unaligned_check(val, addr) \ + do { \ + unsigned int err = 0, v = val, a = addr;\ + \ + __asm__( \ + "1: stb.ab %1, [%2, 1]\n" \ + " lsr %1, %1, 8\n" \ + "2: stb %1, [%2]\n" \ + "3:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + "4: mov %0, 1\n" \ + " b 3b\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b, 4b\n" \ + " .long 2b, 4b\n" \ + " .previous\n" \ + : "=r" (err), "=&r" (v), "=&r" (a) \ + : "0" (err), "1" (v), "2" (a)); \ + \ + if (err) \ + goto fault; \ + } while (0) + +#define put32_unaligned_check(val, addr) \ + do { \ + unsigned int err = 0, v = val, a = addr;\ + __asm__( \ + \ + "1: stb.ab %1, [%2, 1]\n" \ + " lsr %1, %1, 8\n" \ + "2: stb.ab %1, [%2, 1]\n" \ + " lsr %1, %1, 8\n" \ + "3: stb.ab %1, [%2, 1]\n" \ + " lsr %1, %1, 8\n" \ + "4: stb %1, [%2]\n" \ + "5:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + "6: mov %0, 1\n" \ + " b 5b\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b, 6b\n" \ + " .long 2b, 6b\n" \ + " .long 3b, 6b\n" \ + " .long 4b, 6b\n" \ + " .previous\n" \ + : "=r" (err), "=&r" (v), "=&r" (a) \ + : "0" (err), "1" (v), "2" (a)); \ + \ + if (err) \ + goto fault; \ + } while (0) + +/* sysctl hooks */ +int unaligned_enabled __read_mostly = 1; /* Enabled by default */ +int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */ + +static void fixup_load(struct disasm_state *state, struct pt_regs *regs, + struct callee_regs *cregs) +{ + int val; + + /* register write back */ + if ((state->aa == 1) || (state->aa == 2)) { + set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs); + + if (state->aa == 2) + state->src2 = 0; + } + + if (state->zz == 0) { + get32_unaligned_check(val, state->src1 + state->src2); + } else { + get16_unaligned_check(val, state->src1 + state->src2); + + if (state->x) + val = (val << 16) >> 16; + } + + if (state->pref == 0) + set_reg(state->dest, val, regs, cregs); + + return; + +fault: state->fault = 1; +} + +static void fixup_store(struct disasm_state *state, struct pt_regs *regs, + struct callee_regs *cregs) +{ + /* register write back */ + if ((state->aa == 1) || (state->aa == 2)) { + set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs); + + if (state->aa == 3) + state->src3 = 0; + } else if (state->aa == 3) { + if (state->zz == 2) { + set_reg(state->wb_reg, state->src2 + (state->src3 << 1), + regs, cregs); + } else if (!state->zz) { + set_reg(state->wb_reg, state->src2 + (state->src3 << 2), + regs, cregs); + } else { + goto fault; + } + } + + /* write fix-up */ + if (!state->zz) + put32_unaligned_check(state->src1, state->src2 + state->src3); + else + put16_unaligned_check(state->src1, state->src2 + state->src3); + + return; + +fault: state->fault = 1; +} + +/* + * Handle an unaligned access + * Returns 0 if successfully handled, 1 if some error happened + */ +int misaligned_fixup(unsigned long address, struct pt_regs *regs, + unsigned long cause, struct callee_regs *cregs) +{ + struct disasm_state state; + char buf[TASK_COMM_LEN]; + + /* handle user mode only and only if enabled by sysadmin */ + if (!user_mode(regs) || !unaligned_enabled) + return 1; + + if (no_unaligned_warning) { + pr_warn_once("%s(%d) made unaligned access which was emulated" + " by kernel assist\n. This can degrade application" + " performance significantly\n. To enable further" + " logging of such instances, please \n" + " echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n", + get_task_comm(buf, current), task_pid_nr(current)); + } else { + /* Add rate limiting if it gets down to it */ + pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n", + get_task_comm(buf, current), task_pid_nr(current), + address, regs->ret); + + } + + disasm_instr(regs->ret, &state, 1, regs, cregs); + + if (state.fault) + goto fault; + + /* ldb/stb should not have unaligned exception */ + if ((state.zz == 1) || (state.di)) + goto fault; + + if (!state.write) + fixup_load(&state, regs, cregs); + else + fixup_store(&state, regs, cregs); + + if (state.fault) + goto fault; + + if (delay_mode(regs)) { + regs->ret = regs->bta; + regs->status32 &= ~STATUS_DE_MASK; + } else { + regs->ret += state.instr_len; + } + + return 0; + +fault: + pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n", + state.words[0], address); + + return 1; +} -- cgit v1.2.3 From f46121bd26d7957866739313f1e098a682e8d3e4 Mon Sep 17 00:00:00 2001 From: Mischa Jonker Date: Fri, 18 Jan 2013 15:12:24 +0530 Subject: ARC: kgdb support Signed-off-by: Mischa Jonker Signed-off-by: Vineet Gupta Cc: Jason Wessel Acked-by: Jason Wessel --- arch/arc/Kconfig | 3 +- arch/arc/include/asm/kgdb.h | 61 +++++++++++++ arch/arc/kernel/Makefile | 1 + arch/arc/kernel/kgdb.c | 205 ++++++++++++++++++++++++++++++++++++++++++++ arch/arc/kernel/traps.c | 6 ++ 5 files changed, 275 insertions(+), 1 deletion(-) create mode 100644 arch/arc/include/asm/kgdb.h create mode 100644 arch/arc/kernel/kgdb.c (limited to 'arch/arc/kernel/traps.c') diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index f8042835e746..69a939af72c6 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -22,6 +22,7 @@ config ARC select GENERIC_PENDING_IRQ if SMP select GENERIC_SIGALTSTACK select GENERIC_SMP_IDLE_THREAD + select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_GENERIC_HARDIRQS select HAVE_KPROBES @@ -378,7 +379,7 @@ config ARC_DW2_UNWIND config ARC_DBG_TLB_PARANOIA bool "Paranoia Checks in Low Level TLB Handlers" - depends on ARC_DBG && !SMP + depends on ARC_DBG default n config ARC_DBG_TLB_MISS_COUNT diff --git a/arch/arc/include/asm/kgdb.h b/arch/arc/include/asm/kgdb.h new file mode 100644 index 000000000000..f3c4934f0ca9 --- /dev/null +++ b/arch/arc/include/asm/kgdb.h @@ -0,0 +1,61 @@ +/* + * kgdb support for ARC + * + * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ARC_KGDB_H__ +#define __ARC_KGDB_H__ + +#ifdef CONFIG_KGDB + +#include + +/* to ensure compatibility with Linux 2.6.35, we don't implement the get/set + * register API yet */ +#undef DBG_MAX_REG_NUM + +#define GDB_MAX_REGS 39 + +#define BREAK_INSTR_SIZE 2 +#define CACHE_FLUSH_IS_SAFE 1 +#define NUMREGBYTES (GDB_MAX_REGS * 4) +#define BUFMAX 2048 + +static inline void arch_kgdb_breakpoint(void) +{ + __asm__ __volatile__ ("trap_s 0x4\n"); +} + +extern void kgdb_trap(struct pt_regs *regs, int param); + +enum arc700_linux_regnums { + _R0 = 0, + _R1, _R2, _R3, _R4, _R5, _R6, _R7, _R8, _R9, _R10, _R11, _R12, _R13, + _R14, _R15, _R16, _R17, _R18, _R19, _R20, _R21, _R22, _R23, _R24, + _R25, _R26, + _BTA = 27, + _LP_START = 28, + _LP_END = 29, + _LP_COUNT = 30, + _STATUS32 = 31, + _BLINK = 32, + _FP = 33, + __SP = 34, + _EFA = 35, + _RET = 36, + _ORIG_R8 = 37, + _STOP_PC = 38 +}; + +#else +static inline void kgdb_trap(struct pt_regs *regs, int param) +{ +} +#endif + +#endif /* __ARC_KGDB_H__ */ diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile index 507a33d4a255..6da2b12cf7e3 100644 --- a/arch/arc/kernel/Makefile +++ b/arch/arc/kernel/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_ARC_DW2_UNWIND) += unwind.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_ARC_MISALIGN_ACCESS) += unaligned.o +obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o CFLAGS_fpu.o += -mdpfp diff --git a/arch/arc/kernel/kgdb.c b/arch/arc/kernel/kgdb.c new file mode 100644 index 000000000000..2888ba5be47e --- /dev/null +++ b/arch/arc/kernel/kgdb.c @@ -0,0 +1,205 @@ +/* + * kgdb support for ARC + * + * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include + +static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, + struct callee_regs *cregs) +{ + int regno; + + for (regno = 0; regno <= 26; regno++) + gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs); + + for (regno = 27; regno < GDB_MAX_REGS; regno++) + gdb_regs[regno] = 0; + + gdb_regs[_FP] = kernel_regs->fp; + gdb_regs[__SP] = kernel_regs->sp; + gdb_regs[_BLINK] = kernel_regs->blink; + gdb_regs[_RET] = kernel_regs->ret; + gdb_regs[_STATUS32] = kernel_regs->status32; + gdb_regs[_LP_COUNT] = kernel_regs->lp_count; + gdb_regs[_LP_END] = kernel_regs->lp_end; + gdb_regs[_LP_START] = kernel_regs->lp_start; + gdb_regs[_BTA] = kernel_regs->bta; + gdb_regs[_STOP_PC] = kernel_regs->ret; +} + +static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs, + struct callee_regs *cregs) +{ + int regno; + + for (regno = 0; regno <= 26; regno++) + set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs); + + kernel_regs->fp = gdb_regs[_FP]; + kernel_regs->sp = gdb_regs[__SP]; + kernel_regs->blink = gdb_regs[_BLINK]; + kernel_regs->ret = gdb_regs[_RET]; + kernel_regs->status32 = gdb_regs[_STATUS32]; + kernel_regs->lp_count = gdb_regs[_LP_COUNT]; + kernel_regs->lp_end = gdb_regs[_LP_END]; + kernel_regs->lp_start = gdb_regs[_LP_START]; + kernel_regs->bta = gdb_regs[_BTA]; +} + + +void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) +{ + to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) + current->thread.callee_reg); +} + +void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs) +{ + from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *) + current->thread.callee_reg); +} + +void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, + struct task_struct *task) +{ + if (task) + to_gdb_regs(gdb_regs, task_pt_regs(task), + (struct callee_regs *) task->thread.callee_reg); +} + +struct single_step_data_t { + uint16_t opcode[2]; + unsigned long address[2]; + int is_branch; + int armed; +} single_step_data; + +static void undo_single_step(struct pt_regs *regs) +{ + if (single_step_data.armed) { + int i; + + for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) { + memcpy((void *) single_step_data.address[i], + &single_step_data.opcode[i], + BREAK_INSTR_SIZE); + + flush_icache_range(single_step_data.address[i], + single_step_data.address[i] + + BREAK_INSTR_SIZE); + } + single_step_data.armed = 0; + } +} + +static void place_trap(unsigned long address, void *save) +{ + memcpy(save, (void *) address, BREAK_INSTR_SIZE); + memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr, + BREAK_INSTR_SIZE); + flush_icache_range(address, address + BREAK_INSTR_SIZE); +} + +static void do_single_step(struct pt_regs *regs) +{ + single_step_data.is_branch = disasm_next_pc((unsigned long) + regs->ret, regs, (struct callee_regs *) + current->thread.callee_reg, + &single_step_data.address[0], + &single_step_data.address[1]); + + place_trap(single_step_data.address[0], &single_step_data.opcode[0]); + + if (single_step_data.is_branch) { + place_trap(single_step_data.address[1], + &single_step_data.opcode[1]); + } + + single_step_data.armed++; +} + +int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, + char *remcomInBuffer, char *remcomOutBuffer, + struct pt_regs *regs) +{ + unsigned long addr; + char *ptr; + + undo_single_step(regs); + + switch (remcomInBuffer[0]) { + case 's': + case 'c': + ptr = &remcomInBuffer[1]; + if (kgdb_hex2long(&ptr, &addr)) + regs->ret = addr; + + case 'D': + case 'k': + atomic_set(&kgdb_cpu_doing_single_step, -1); + + if (remcomInBuffer[0] == 's') { + do_single_step(regs); + atomic_set(&kgdb_cpu_doing_single_step, + smp_processor_id()); + } + + return 0; + } + return -1; +} + +unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +int kgdb_arch_init(void) +{ + single_step_data.armed = 0; + return 0; +} + +void kgdb_trap(struct pt_regs *regs, int param) +{ + /* trap_s 3 is used for breakpoints that overwrite existing + * instructions, while trap_s 4 is used for compiled breakpoints. + * + * with trap_s 3 breakpoints the original instruction needs to be + * restored and continuation needs to start at the location of the + * breakpoint. + * + * with trap_s 4 (compiled) breakpoints, continuation needs to + * start after the breakpoint. + */ + if (param == 3) + instruction_pointer(regs) -= BREAK_INSTR_SIZE; + + kgdb_handle_exception(1, SIGTRAP, 0, regs); +} + +void kgdb_arch_exit(void) +{ +} + +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) +{ + instruction_pointer(regs) = ip; +} + +struct kgdb_arch arch_kgdb_ops = { + /* breakpoint instruction: TRAP_S 0x3 */ +#ifdef CONFIG_CPU_BIG_ENDIAN + .gdb_bpt_instr = {0x78, 0x7e}, +#else + .gdb_bpt_instr = {0x7e, 0x78}, +#endif +}; diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c index ec802c52a1ca..7496995371e8 100644 --- a/arch/arc/kernel/traps.c +++ b/arch/arc/kernel/traps.c @@ -20,6 +20,7 @@ #include #include #include +#include void __init trap_init(void) { @@ -141,6 +142,11 @@ void do_non_swi_trap(unsigned long cause, unsigned long address, trap_is_kprobe(param, address, regs); break; + case 3: + case 4: + kgdb_trap(regs, param); + break; + default: break; } -- cgit v1.2.3