diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/x86/kernel/hw_breakpoint.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/x86/kernel/hw_breakpoint.c | 524 |
1 files changed, 0 insertions, 524 deletions
diff --git a/ANDROID_3.4.5/arch/x86/kernel/hw_breakpoint.c b/ANDROID_3.4.5/arch/x86/kernel/hw_breakpoint.c deleted file mode 100644 index 02f07634..00000000 --- a/ANDROID_3.4.5/arch/x86/kernel/hw_breakpoint.c +++ /dev/null @@ -1,524 +0,0 @@ -/* - * 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) 2007 Alan Stern - * Copyright (C) 2009 IBM Corporation - * Copyright (C) 2009 Frederic Weisbecker <fweisbec@gmail.com> - * - * Authors: Alan Stern <stern@rowland.harvard.edu> - * K.Prasad <prasad@linux.vnet.ibm.com> - * Frederic Weisbecker <fweisbec@gmail.com> - */ - -/* - * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, - * using the CPU's debug registers. - */ - -#include <linux/perf_event.h> -#include <linux/hw_breakpoint.h> -#include <linux/irqflags.h> -#include <linux/notifier.h> -#include <linux/kallsyms.h> -#include <linux/kprobes.h> -#include <linux/percpu.h> -#include <linux/kdebug.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/sched.h> -#include <linux/init.h> -#include <linux/smp.h> - -#include <asm/hw_breakpoint.h> -#include <asm/processor.h> -#include <asm/debugreg.h> - -/* Per cpu debug control register value */ -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]); - -/* - * Stores the breakpoints currently in use on each breakpoint address - * register for each cpus - */ -static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]); - - -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)); - - 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. - */ -int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type) -{ - int bp_info = dr7 >> (DR_CONTROL_SHIFT + bpnum * DR_CONTROL_SIZE); - - *len = (bp_info & 0xc) | 0x40; - *type = (bp_info & 0x3) | 0x80; - - return (dr7 >> (bpnum * DR_ENABLE_SIZE)) & 0x3; -} - -/* - * Install a perf counter breakpoint. - * - * We seek a free debug address register and use it for this - * breakpoint. Eventually we enable it in the debug control register. - * - * Atomic: we hold the counter->ctx->lock and we only handle variables - * and registers local to this cpu. - */ -int arch_install_hw_breakpoint(struct perf_event *bp) -{ - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - unsigned long *dr7; - int i; - - for (i = 0; i < HBP_NUM; i++) { - struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]); - - if (!*slot) { - *slot = bp; - break; - } - } - - if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) - return -EBUSY; - - set_debugreg(info->address, i); - __this_cpu_write(cpu_debugreg[i], info->address); - - dr7 = &__get_cpu_var(cpu_dr7); - *dr7 |= encode_dr7(i, info->len, info->type); - - set_debugreg(*dr7, 7); - - return 0; -} - -/* - * Uninstall the breakpoint contained in the given counter. - * - * First we search the debug address register it uses and then we disable - * it. - * - * Atomic: we hold the counter->ctx->lock and we only handle variables - * and registers local to this cpu. - */ -void arch_uninstall_hw_breakpoint(struct perf_event *bp) -{ - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - unsigned long *dr7; - int i; - - for (i = 0; i < HBP_NUM; i++) { - struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]); - - if (*slot == bp) { - *slot = NULL; - break; - } - } - - if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) - return; - - dr7 = &__get_cpu_var(cpu_dr7); - *dr7 &= ~__encode_dr7(i, info->len, info->type); - - set_debugreg(*dr7, 7); -} - -static int get_hbp_len(u8 hbp_len) -{ - unsigned int len_in_bytes = 0; - - switch (hbp_len) { - case X86_BREAKPOINT_LEN_1: - len_in_bytes = 1; - break; - case X86_BREAKPOINT_LEN_2: - len_in_bytes = 2; - break; - case X86_BREAKPOINT_LEN_4: - len_in_bytes = 4; - break; -#ifdef CONFIG_X86_64 - case X86_BREAKPOINT_LEN_8: - len_in_bytes = 8; - break; -#endif - } - return len_in_bytes; -} - -/* - * Check for virtual address in kernel space. - */ -int arch_check_bp_in_kernelspace(struct perf_event *bp) -{ - unsigned int len; - unsigned long va; - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - - va = info->address; - len = get_hbp_len(info->len); - - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); -} - -int arch_bp_generic_fields(int x86_len, int x86_type, - int *gen_len, int *gen_type) -{ - /* Type */ - switch (x86_type) { - case X86_BREAKPOINT_EXECUTE: - if (x86_len != X86_BREAKPOINT_LEN_X) - return -EINVAL; - - *gen_type = HW_BREAKPOINT_X; - *gen_len = sizeof(long); - return 0; - case X86_BREAKPOINT_WRITE: - *gen_type = HW_BREAKPOINT_W; - break; - case X86_BREAKPOINT_RW: - *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; - break; - default: - return -EINVAL; - } - - /* Len */ - switch (x86_len) { - case X86_BREAKPOINT_LEN_1: - *gen_len = HW_BREAKPOINT_LEN_1; - break; - case X86_BREAKPOINT_LEN_2: - *gen_len = HW_BREAKPOINT_LEN_2; - break; - case X86_BREAKPOINT_LEN_4: - *gen_len = HW_BREAKPOINT_LEN_4; - break; -#ifdef CONFIG_X86_64 - case X86_BREAKPOINT_LEN_8: - *gen_len = HW_BREAKPOINT_LEN_8; - break; -#endif - default: - return -EINVAL; - } - - return 0; -} - - -static int arch_build_bp_info(struct perf_event *bp) -{ - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - - info->address = bp->attr.bp_addr; - - /* Type */ - switch (bp->attr.bp_type) { - case HW_BREAKPOINT_W: - info->type = X86_BREAKPOINT_WRITE; - break; - case HW_BREAKPOINT_W | HW_BREAKPOINT_R: - info->type = X86_BREAKPOINT_RW; - break; - case HW_BREAKPOINT_X: - info->type = X86_BREAKPOINT_EXECUTE; - /* - * x86 inst breakpoints need to have a specific undefined len. - * But we still need to check userspace is not trying to setup - * an unsupported length, to get a range breakpoint for example. - */ - if (bp->attr.bp_len == sizeof(long)) { - info->len = X86_BREAKPOINT_LEN_X; - return 0; - } - default: - return -EINVAL; - } - - /* Len */ - switch (bp->attr.bp_len) { - case HW_BREAKPOINT_LEN_1: - info->len = X86_BREAKPOINT_LEN_1; - break; - case HW_BREAKPOINT_LEN_2: - info->len = X86_BREAKPOINT_LEN_2; - break; - case HW_BREAKPOINT_LEN_4: - info->len = X86_BREAKPOINT_LEN_4; - break; -#ifdef CONFIG_X86_64 - case HW_BREAKPOINT_LEN_8: - info->len = X86_BREAKPOINT_LEN_8; - break; -#endif - default: - return -EINVAL; - } - - return 0; -} -/* - * Validate the arch-specific HW Breakpoint register settings - */ -int arch_validate_hwbkpt_settings(struct perf_event *bp) -{ - struct arch_hw_breakpoint *info = counter_arch_bp(bp); - unsigned int align; - int ret; - - - ret = arch_build_bp_info(bp); - if (ret) - return ret; - - ret = -EINVAL; - - switch (info->len) { - case X86_BREAKPOINT_LEN_1: - align = 0; - break; - case X86_BREAKPOINT_LEN_2: - align = 1; - break; - case X86_BREAKPOINT_LEN_4: - align = 3; - break; -#ifdef CONFIG_X86_64 - case X86_BREAKPOINT_LEN_8: - align = 7; - break; -#endif - default: - return ret; - } - - /* - * Check that the low-order bits of the address are appropriate - * for the alignment implied by len. - */ - if (info->address & align) - return -EINVAL; - - return 0; -} - -/* - * 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) -{ - int i; - struct thread_struct *t = &tsk->thread; - - for (i = 0; i < HBP_NUM; i++) { - unregister_hw_breakpoint(t->ptrace_bps[i]); - t->ptrace_bps[i] = NULL; - } -} - -void hw_breakpoint_restore(void) -{ - set_debugreg(__this_cpu_read(cpu_debugreg[0]), 0); - set_debugreg(__this_cpu_read(cpu_debugreg[1]), 1); - set_debugreg(__this_cpu_read(cpu_debugreg[2]), 2); - set_debugreg(__this_cpu_read(cpu_debugreg[3]), 3); - set_debugreg(current->thread.debugreg6, 6); - set_debugreg(__this_cpu_read(cpu_dr7), 7); -} -EXPORT_SYMBOL_GPL(hw_breakpoint_restore); - -/* - * Handle debug exception notifications. - * - * Return value is either NOTIFY_STOP or NOTIFY_DONE as explained below. - * - * NOTIFY_DONE returned if one of the following conditions is true. - * i) When the causative address is from user-space and the exception - * is a valid one, i.e. not triggered as a result of lazy debug register - * switching - * ii) When there are more bits than trap<n> set in DR6 register (such - * as BD, BS or BT) indicating that more than one debug condition is - * met and requires some more action in do_debug(). - * - * NOTIFY_STOP returned for all other cases - * - */ -static int __kprobes hw_breakpoint_handler(struct die_args *args) -{ - int i, cpu, rc = NOTIFY_STOP; - struct perf_event *bp; - unsigned long dr7, dr6; - unsigned long *dr6_p; - - /* The DR6 value is pointed by args->err */ - dr6_p = (unsigned long *)ERR_PTR(args->err); - dr6 = *dr6_p; - - /* If it's a single step, TRAP bits are random */ - if (dr6 & DR_STEP) - return NOTIFY_DONE; - - /* Do an early return if no trap bits are set in DR6 */ - if ((dr6 & DR_TRAP_BITS) == 0) - return NOTIFY_DONE; - - get_debugreg(dr7, 7); - /* Disable breakpoints during exception handling */ - set_debugreg(0UL, 7); - /* - * Assert that local interrupts are disabled - * Reset the DRn bits in the virtualized register value. - * The ptrace trigger routine will add in whatever is needed. - */ - current->thread.debugreg6 &= ~DR_TRAP_BITS; - cpu = get_cpu(); - - /* Handle all the breakpoints that were triggered */ - for (i = 0; i < HBP_NUM; ++i) { - if (likely(!(dr6 & (DR_TRAP0 << i)))) - continue; - - /* - * The counter may be concurrently released but that can only - * occur from a call_rcu() path. We can then safely fetch - * the breakpoint, use its callback, touch its counter - * while we are in an rcu_read_lock() path. - */ - rcu_read_lock(); - - bp = per_cpu(bp_per_reg[i], cpu); - /* - * Reset the 'i'th TRAP bit in dr6 to denote completion of - * exception handling - */ - (*dr6_p) &= ~(DR_TRAP0 << i); - /* - * bp can be NULL due to lazy debug register switching - * or due to concurrent perf counter removing. - */ - if (!bp) { - rcu_read_unlock(); - break; - } - - perf_bp_event(bp, args->regs); - - /* - * Set up resume flag to avoid breakpoint recursion when - * returning back to origin. - */ - if (bp->hw.info.type == X86_BREAKPOINT_EXECUTE) - args->regs->flags |= X86_EFLAGS_RF; - - rcu_read_unlock(); - } - /* - * 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); - put_cpu(); - - return rc; -} - -/* - * Handle debug exception notifications. - */ -int __kprobes hw_breakpoint_exceptions_notify( - struct notifier_block *unused, unsigned long val, void *data) -{ - if (val != DIE_DEBUG) - return NOTIFY_DONE; - - return hw_breakpoint_handler(data); -} - -void hw_breakpoint_pmu_read(struct perf_event *bp) -{ - /* TODO */ -} |