X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=arch%2Fx86%2Fkernel%2Fhw_breakpoint.c;h=dca2802c666f240019c54a75c5ff5240d5778bb9;hb=6556a6743549defc32e5f90ee2cb1ecd833a44c3;hp=e622620790bdafa59fd6309edf6f5cb48cd10847;hpb=24f1e32c60c45c89a997c73395b69c8af6f0a84e;p=safe%2Fjmp%2Flinux-2.6 diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index e622620..dca2802 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -16,6 +16,10 @@ * Copyright (C) 2007 Alan Stern * Copyright (C) 2009 IBM Corporation * Copyright (C) 2009 Frederic Weisbecker + * + * Authors: Alan Stern + * K.Prasad + * Frederic Weisbecker */ /* @@ -42,7 +46,8 @@ #include /* Per cpu debug control register value */ -DEFINE_PER_CPU(unsigned long, dr7); +DEFINE_PER_CPU(unsigned long, cpu_dr7); +EXPORT_PER_CPU_SYMBOL(cpu_dr7); /* Per cpu debug address registers values */ static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]); @@ -54,22 +59,28 @@ static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]); static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]); -/* - * Encode the length, type, Exact, and Enable bits for a particular breakpoint - * as stored in debug register 7. - */ -unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type) +static inline unsigned long +__encode_dr7(int drnum, unsigned int len, unsigned int type) { unsigned long bp_info; bp_info = (len | type) & 0xf; bp_info <<= (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE); - bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)) | - DR_GLOBAL_SLOWDOWN; + bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)); + return bp_info; } /* + * Encode the length, type, Exact, and Enable bits for a particular breakpoint + * as stored in debug register 7. + */ +unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type) +{ + return __encode_dr7(drnum, len, type) | DR_GLOBAL_SLOWDOWN; +} + +/* * Decode the length and type bits for a particular breakpoint as * stored in debug register 7. Return the "enabled" status. */ @@ -113,7 +124,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp) set_debugreg(info->address, i); __get_cpu_var(cpu_debugreg[i]) = info->address; - dr7 = &__get_cpu_var(dr7); + dr7 = &__get_cpu_var(cpu_dr7); *dr7 |= encode_dr7(i, info->len, info->type); set_debugreg(*dr7, 7); @@ -148,8 +159,8 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp) if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) return; - dr7 = &__get_cpu_var(dr7); - *dr7 &= ~encode_dr7(i, info->len, info->type); + dr7 = &__get_cpu_var(cpu_dr7); + *dr7 &= ~__encode_dr7(i, info->len, info->type); set_debugreg(*dr7, 7); } @@ -201,25 +212,6 @@ static int arch_check_va_in_kernelspace(unsigned long va, u8 hbp_len) return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); } -/* - * Store a breakpoint's encoded address, length, and type. - */ -static int arch_store_info(struct perf_event *bp) -{ - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - /* - * For kernel-addresses, either the address or symbol name can be - * specified. - */ - if (info->name) - info->address = (unsigned long) - kallsyms_lookup_name(info->name); - if (info->address) - return 0; - - return -EINVAL; -} - int arch_bp_generic_fields(int x86_len, int x86_type, int *gen_len, int *gen_type) { @@ -351,11 +343,13 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp, return ret; } - if (bp->callback) - ret = arch_store_info(bp); - - if (ret < 0) - return ret; + /* + * For kernel-addresses, either the address or symbol name can be + * specified. + */ + if (info->name) + info->address = (unsigned long) + kallsyms_lookup_name(info->name); /* * Check that the low-order bits of the address are appropriate * for the alignment implied by len. @@ -376,6 +370,42 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp, } /* + * Dump the debug register contents to the user. + * We can't dump our per cpu values because it + * may contain cpu wide breakpoint, something that + * doesn't belong to the current task. + * + * TODO: include non-ptrace user breakpoints (perf) + */ +void aout_dump_debugregs(struct user *dump) +{ + int i; + int dr7 = 0; + struct perf_event *bp; + struct arch_hw_breakpoint *info; + struct thread_struct *thread = ¤t->thread; + + for (i = 0; i < HBP_NUM; i++) { + bp = thread->ptrace_bps[i]; + + if (bp && !bp->attr.disabled) { + dump->u_debugreg[i] = bp->attr.bp_addr; + info = counter_arch_bp(bp); + dr7 |= encode_dr7(i, info->len, info->type); + } else { + dump->u_debugreg[i] = 0; + } + } + + dump->u_debugreg[4] = 0; + dump->u_debugreg[5] = 0; + dump->u_debugreg[6] = current->thread.debugreg6; + + dump->u_debugreg[7] = dr7; +} +EXPORT_SYMBOL_GPL(aout_dump_debugregs); + +/* * Release the user breakpoints used by ptrace */ void flush_ptrace_hw_breakpoint(struct task_struct *tsk) @@ -389,7 +419,6 @@ void flush_ptrace_hw_breakpoint(struct task_struct *tsk) } } -#ifdef CONFIG_KVM void hw_breakpoint_restore(void) { set_debugreg(__get_cpu_var(cpu_debugreg[0]), 0); @@ -397,10 +426,9 @@ void hw_breakpoint_restore(void) set_debugreg(__get_cpu_var(cpu_debugreg[2]), 2); set_debugreg(__get_cpu_var(cpu_debugreg[3]), 3); set_debugreg(current->thread.debugreg6, 6); - set_debugreg(__get_cpu_var(dr7), 7); + set_debugreg(__get_cpu_var(cpu_dr7), 7); } EXPORT_SYMBOL_GPL(hw_breakpoint_restore); -#endif /* * Handle debug exception notifications. @@ -458,8 +486,6 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args) rcu_read_lock(); bp = per_cpu(bp_per_reg[i], cpu); - if (bp) - rc = NOTIFY_DONE; /* * Reset the 'i'th TRAP bit in dr6 to denote completion of * exception handling @@ -474,11 +500,17 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args) break; } - (bp->callback)(bp, args->regs); + perf_bp_event(bp, args->regs); rcu_read_unlock(); } - if (dr6 & (~DR_TRAP_BITS)) + /* + * Further processing in do_debug() is needed for a) user-space + * breakpoints (to generate signals) and b) when the system has + * taken exception due to multiple causes + */ + if ((current->thread.debugreg6 & DR_TRAP_BITS) || + (dr6 & (~DR_TRAP_BITS))) rc = NOTIFY_DONE; set_debugreg(dr7, 7);