diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 128e63d3a6329bf993d3d0a41905657720c2ac9a..b8e9de1e78322b9e6c6803e8b3c4f0c4e8bcde09 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -18,6 +18,7 @@ config XTENSA select HAVE_DMA_ATTRS select HAVE_FUNCTION_TRACER select HAVE_FUTEX_CMPXCHG if !MMU + select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_OPROFILE select HAVE_PERF_EVENTS diff --git a/arch/xtensa/include/asm/hw_breakpoint.h b/arch/xtensa/include/asm/hw_breakpoint.h new file mode 100644 index 0000000000000000000000000000000000000000..dbe3053b284a4286970decf9f3d966f53e7c3a28 --- /dev/null +++ b/arch/xtensa/include/asm/hw_breakpoint.h @@ -0,0 +1,58 @@ +/* + * Xtensa hardware breakpoints/watchpoints handling functions + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2016 Cadence Design Systems Inc. + */ + +#ifndef __ASM_XTENSA_HW_BREAKPOINT_H +#define __ASM_XTENSA_HW_BREAKPOINT_H + +#ifdef CONFIG_HAVE_HW_BREAKPOINT + +#include +#include +#include + +/* Breakpoint */ +#define XTENSA_BREAKPOINT_EXECUTE 0 + +/* Watchpoints */ +#define XTENSA_BREAKPOINT_LOAD 1 +#define XTENSA_BREAKPOINT_STORE 2 + +struct arch_hw_breakpoint { + unsigned long address; + u16 len; + u16 type; +}; + +struct perf_event; +struct pt_regs; +struct task_struct; + +int hw_breakpoint_slots(int type); +int arch_check_bp_in_kernelspace(struct perf_event *bp); +int arch_validate_hwbkpt_settings(struct perf_event *bp); +int hw_breakpoint_exceptions_notify(struct notifier_block *unused, + unsigned long val, void *data); + +int arch_install_hw_breakpoint(struct perf_event *bp); +void arch_uninstall_hw_breakpoint(struct perf_event *bp); +void hw_breakpoint_pmu_read(struct perf_event *bp); +int check_hw_breakpoint(struct pt_regs *regs); +void clear_ptrace_hw_breakpoint(struct task_struct *tsk); + +#else + +struct task_struct; + +static inline void clear_ptrace_hw_breakpoint(struct task_struct *tsk) +{ +} + +#endif /* CONFIG_HAVE_HW_BREAKPOINT */ +#endif /* __ASM_XTENSA_HW_BREAKPOINT_H */ diff --git a/arch/xtensa/include/asm/irqflags.h b/arch/xtensa/include/asm/irqflags.h index 8e090c709046f9663d4c80d16e5011846d8cf3a6..407606e576f8911728ab0232e8419e63d39b343d 100644 --- a/arch/xtensa/include/asm/irqflags.h +++ b/arch/xtensa/include/asm/irqflags.h @@ -13,6 +13,7 @@ #define _XTENSA_IRQFLAGS_H #include +#include static inline unsigned long arch_local_save_flags(void) { diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 744ecf0dc3a4f51c441732493f29ab977ae572ea..d2e40d39c6158102de48debffe76a0c5fe4f4cbc 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -130,11 +130,10 @@ struct thread_struct { unsigned long bad_vaddr; /* last user fault */ unsigned long bad_uaddr; /* last kernel fault accessing user space */ unsigned long error_code; - - unsigned long ibreak[XCHAL_NUM_IBREAK]; - unsigned long dbreaka[XCHAL_NUM_DBREAK]; - unsigned long dbreakc[XCHAL_NUM_DBREAK]; - +#ifdef CONFIG_HAVE_HW_BREAKPOINT + struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK]; + struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK]; +#endif /* Make structure 16 bytes aligned. */ int align[0] __attribute__ ((aligned(16))); }; diff --git a/arch/xtensa/include/asm/regs.h b/arch/xtensa/include/asm/regs.h index 4ba9f516b0e27b934e174592b8ad0653c7af62ac..881a1134a4b40f1838822518be9d463eec33df67 100644 --- a/arch/xtensa/include/asm/regs.h +++ b/arch/xtensa/include/asm/regs.h @@ -28,6 +28,7 @@ /* Special registers. */ #define SREG_MR 32 +#define SREG_IBREAKENABLE 96 #define SREG_IBREAKA 128 #define SREG_DBREAKA 144 #define SREG_DBREAKC 160 @@ -103,6 +104,8 @@ /* DEBUGCAUSE register fields. */ +#define DEBUGCAUSE_DBNUM_MASK 0xf00 +#define DEBUGCAUSE_DBNUM_SHIFT 8 /* First bit of DBNUM field */ #define DEBUGCAUSE_DEBUGINT_BIT 5 /* External debug interrupt */ #define DEBUGCAUSE_BREAKN_BIT 4 /* BREAK.N instruction */ #define DEBUGCAUSE_BREAK_BIT 3 /* BREAK instruction */ diff --git a/arch/xtensa/include/asm/thread_info.h b/arch/xtensa/include/asm/thread_info.h index 9ad12c6171842513d0df4a6dd31de0666a31cbfc..7be2400f745a088d553bbbdf6c2cc232fc1d18a0 100644 --- a/arch/xtensa/include/asm/thread_info.h +++ b/arch/xtensa/include/asm/thread_info.h @@ -111,6 +111,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_MEMDIE 5 /* is terminating due to OOM killer */ #define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */ #define TIF_NOTIFY_RESUME 7 /* callback before returning to user */ +#define TIF_DB_DISABLED 8 /* debug trap disabled for syscall */ #define _TIF_SYSCALL_TRACE (1< +#include +#include +#include +#include + +/* Breakpoint currently in use for each IBREAKA. */ +static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[XCHAL_NUM_IBREAK]); + +/* Watchpoint currently in use for each DBREAKA. */ +static DEFINE_PER_CPU(struct perf_event *, wp_on_reg[XCHAL_NUM_DBREAK]); + +int hw_breakpoint_slots(int type) +{ + switch (type) { + case TYPE_INST: + return XCHAL_NUM_IBREAK; + case TYPE_DATA: + return XCHAL_NUM_DBREAK; + default: + pr_warn("unknown slot type: %d\n", type); + return 0; + } +} + +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 = bp->attr.bp_len; + + return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); +} + +/* + * Construct an arch_hw_breakpoint from a perf_event. + */ +static int arch_build_bp_info(struct perf_event *bp) +{ + struct arch_hw_breakpoint *info = counter_arch_bp(bp); + + /* Type */ + switch (bp->attr.bp_type) { + case HW_BREAKPOINT_X: + info->type = XTENSA_BREAKPOINT_EXECUTE; + break; + case HW_BREAKPOINT_R: + info->type = XTENSA_BREAKPOINT_LOAD; + break; + case HW_BREAKPOINT_W: + info->type = XTENSA_BREAKPOINT_STORE; + break; + case HW_BREAKPOINT_RW: + info->type = XTENSA_BREAKPOINT_LOAD | XTENSA_BREAKPOINT_STORE; + break; + default: + return -EINVAL; + } + + /* Len */ + info->len = bp->attr.bp_len; + if (info->len < 1 || info->len > 64 || !is_power_of_2(info->len)) + return -EINVAL; + + /* Address */ + info->address = bp->attr.bp_addr; + if (info->address & (info->len - 1)) + return -EINVAL; + + return 0; +} + +int arch_validate_hwbkpt_settings(struct perf_event *bp) +{ + int ret; + + /* Build the arch_hw_breakpoint. */ + ret = arch_build_bp_info(bp); + return ret; +} + +int hw_breakpoint_exceptions_notify(struct notifier_block *unused, + unsigned long val, void *data) +{ + return NOTIFY_DONE; +} + +static void xtensa_wsr(unsigned long v, u8 sr) +{ + /* We don't have indexed wsr and creating instruction dynamically + * doesn't seem worth it given how small XCHAL_NUM_IBREAK and + * XCHAL_NUM_DBREAK are. Thus the switch. In case build breaks here + * the switch below needs to be extended. + */ + BUILD_BUG_ON(XCHAL_NUM_IBREAK > 2); + BUILD_BUG_ON(XCHAL_NUM_DBREAK > 2); + + switch (sr) { +#if XCHAL_NUM_IBREAK > 0 + case SREG_IBREAKA + 0: + WSR(v, SREG_IBREAKA + 0); + break; +#endif +#if XCHAL_NUM_IBREAK > 1 + case SREG_IBREAKA + 1: + WSR(v, SREG_IBREAKA + 1); + break; +#endif + +#if XCHAL_NUM_DBREAK > 0 + case SREG_DBREAKA + 0: + WSR(v, SREG_DBREAKA + 0); + break; + case SREG_DBREAKC + 0: + WSR(v, SREG_DBREAKC + 0); + break; +#endif +#if XCHAL_NUM_DBREAK > 1 + case SREG_DBREAKA + 1: + WSR(v, SREG_DBREAKA + 1); + break; + + case SREG_DBREAKC + 1: + WSR(v, SREG_DBREAKC + 1); + break; +#endif + } +} + +static int alloc_slot(struct perf_event **slot, size_t n, + struct perf_event *bp) +{ + size_t i; + + for (i = 0; i < n; ++i) { + if (!slot[i]) { + slot[i] = bp; + return i; + } + } + return -EBUSY; +} + +static void set_ibreak_regs(int reg, struct perf_event *bp) +{ + struct arch_hw_breakpoint *info = counter_arch_bp(bp); + unsigned long ibreakenable; + + xtensa_wsr(info->address, SREG_IBREAKA + reg); + RSR(ibreakenable, SREG_IBREAKENABLE); + WSR(ibreakenable | (1 << reg), SREG_IBREAKENABLE); +} + +static void set_dbreak_regs(int reg, struct perf_event *bp) +{ + struct arch_hw_breakpoint *info = counter_arch_bp(bp); + unsigned long dbreakc = DBREAKC_MASK_MASK & -info->len; + + if (info->type & XTENSA_BREAKPOINT_LOAD) + dbreakc |= DBREAKC_LOAD_MASK; + if (info->type & XTENSA_BREAKPOINT_STORE) + dbreakc |= DBREAKC_STOR_MASK; + + xtensa_wsr(info->address, SREG_DBREAKA + reg); + xtensa_wsr(dbreakc, SREG_DBREAKC + reg); +} + +int arch_install_hw_breakpoint(struct perf_event *bp) +{ + int i; + + if (counter_arch_bp(bp)->type == XTENSA_BREAKPOINT_EXECUTE) { + /* Breakpoint */ + i = alloc_slot(this_cpu_ptr(bp_on_reg), XCHAL_NUM_IBREAK, bp); + if (i < 0) + return i; + set_ibreak_regs(i, bp); + + } else { + /* Watchpoint */ + i = alloc_slot(this_cpu_ptr(wp_on_reg), XCHAL_NUM_DBREAK, bp); + if (i < 0) + return i; + set_dbreak_regs(i, bp); + } + return 0; +} + +static int free_slot(struct perf_event **slot, size_t n, + struct perf_event *bp) +{ + size_t i; + + for (i = 0; i < n; ++i) { + if (slot[i] == bp) { + slot[i] = NULL; + return i; + } + } + return -EBUSY; +} + +void arch_uninstall_hw_breakpoint(struct perf_event *bp) +{ + struct arch_hw_breakpoint *info = counter_arch_bp(bp); + int i; + + if (info->type == XTENSA_BREAKPOINT_EXECUTE) { + unsigned long ibreakenable; + + /* Breakpoint */ + i = free_slot(this_cpu_ptr(bp_on_reg), XCHAL_NUM_IBREAK, bp); + if (i >= 0) { + RSR(ibreakenable, SREG_IBREAKENABLE); + WSR(ibreakenable & ~(1 << i), SREG_IBREAKENABLE); + } + } else { + /* Watchpoint */ + i = free_slot(this_cpu_ptr(wp_on_reg), XCHAL_NUM_DBREAK, bp); + if (i >= 0) + xtensa_wsr(0, SREG_DBREAKC + i); + } +} + +void hw_breakpoint_pmu_read(struct perf_event *bp) +{ +} + +void flush_ptrace_hw_breakpoint(struct task_struct *tsk) +{ + int i; + struct thread_struct *t = &tsk->thread; + + for (i = 0; i < XCHAL_NUM_IBREAK; ++i) { + if (t->ptrace_bp[i]) { + unregister_hw_breakpoint(t->ptrace_bp[i]); + t->ptrace_bp[i] = NULL; + } + } + for (i = 0; i < XCHAL_NUM_DBREAK; ++i) { + if (t->ptrace_wp[i]) { + unregister_hw_breakpoint(t->ptrace_wp[i]); + t->ptrace_wp[i] = NULL; + } + } +} + +/* + * Set ptrace breakpoint pointers to zero for this task. + * This is required in order to prevent child processes from unregistering + * breakpoints held by their parent. + */ +void clear_ptrace_hw_breakpoint(struct task_struct *tsk) +{ + memset(tsk->thread.ptrace_bp, 0, sizeof(tsk->thread.ptrace_bp)); + memset(tsk->thread.ptrace_wp, 0, sizeof(tsk->thread.ptrace_wp)); +} + +void restore_dbreak(void) +{ + int i; + + for (i = 0; i < XCHAL_NUM_DBREAK; ++i) { + struct perf_event *bp = this_cpu_ptr(wp_on_reg)[i]; + + if (bp) + set_dbreak_regs(i, bp); + } + clear_thread_flag(TIF_DB_DISABLED); +} + +int check_hw_breakpoint(struct pt_regs *regs) +{ + if (regs->debugcause & BIT(DEBUGCAUSE_IBREAK_BIT)) { + int i; + struct perf_event **bp = this_cpu_ptr(bp_on_reg); + + for (i = 0; i < XCHAL_NUM_IBREAK; ++i) { + if (bp[i] && !bp[i]->attr.disabled && + regs->pc == bp[i]->attr.bp_addr) + perf_bp_event(bp[i], regs); + } + return 0; + } else if (regs->debugcause & BIT(DEBUGCAUSE_DBREAK_BIT)) { + struct perf_event **bp = this_cpu_ptr(wp_on_reg); + int dbnum = (regs->debugcause & DEBUGCAUSE_DBNUM_MASK) >> + DEBUGCAUSE_DBNUM_SHIFT; + + if (dbnum < XCHAL_NUM_DBREAK && bp[dbnum]) { + if (user_mode(regs)) { + perf_bp_event(bp[dbnum], regs); + } else { + set_thread_flag(TIF_DB_DISABLED); + xtensa_wsr(0, SREG_DBREAKC + dbnum); + } + } else { + WARN_ONCE(1, + "Wrong/unconfigured DBNUM reported in DEBUGCAUSE: %d\n", + dbnum); + } + return 0; + } + return -ENOENT; +} diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 1c85323f01d7de73c2781b4b8b295ac98ceb6cb9..5bbfed81c97be65eef96a68935a6c5fc672c2087 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -43,6 +44,7 @@ #include #include #include +#include extern void ret_from_fork(void); extern void ret_from_kernel_thread(void); @@ -131,6 +133,7 @@ void flush_thread(void) coprocessor_flush_all(ti); coprocessor_release_all(ti); #endif + flush_ptrace_hw_breakpoint(current); } /* @@ -273,6 +276,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, ti->cpenable = 0; #endif + clear_ptrace_hw_breakpoint(p); + return 0; } diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c index 4d54b481123b64e286f45f6fc03121a0d5024474..a651f3a628eec0b4708d34d4f736192c344bd5b6 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -13,21 +13,23 @@ * Marc Gauthier */ +#include +#include #include -#include #include -#include +#include #include -#include +#include #include #include +#include -#include +#include +#include #include -#include +#include #include -#include -#include +#include void user_enable_single_step(struct task_struct *child) @@ -267,6 +269,146 @@ int ptrace_pokeusr(struct task_struct *child, long regno, long val) return 0; } +#ifdef CONFIG_HAVE_HW_BREAKPOINT +static void ptrace_hbptriggered(struct perf_event *bp, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + int i; + siginfo_t info; + struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp); + + if (bp->attr.bp_type & HW_BREAKPOINT_X) { + for (i = 0; i < XCHAL_NUM_IBREAK; ++i) + if (current->thread.ptrace_bp[i] == bp) + break; + i <<= 1; + } else { + for (i = 0; i < XCHAL_NUM_DBREAK; ++i) + if (current->thread.ptrace_wp[i] == bp) + break; + i = (i << 1) | 1; + } + + info.si_signo = SIGTRAP; + info.si_errno = i; + info.si_code = TRAP_HWBKPT; + info.si_addr = (void __user *)bkpt->address; + + force_sig_info(SIGTRAP, &info, current); +} + +static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type) +{ + struct perf_event_attr attr; + + ptrace_breakpoint_init(&attr); + + /* Initialise fields to sane defaults. */ + attr.bp_addr = 0; + attr.bp_len = 1; + attr.bp_type = type; + attr.disabled = 1; + + return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, + tsk); +} + +/* + * Address bit 0 choose instruction (0) or data (1) break register, bits + * 31..1 are the register number. + * Both PTRACE_GETHBPREGS and PTRACE_SETHBPREGS transfer two 32-bit words: + * address (0) and control (1). + * Instruction breakpoint contorl word is 0 to clear breakpoint, 1 to set. + * Data breakpoint control word bit 31 is 'trigger on store', bit 30 is + * 'trigger on load, bits 29..0 are length. Length 0 is used to clear a + * breakpoint. To set a breakpoint length must be a power of 2 in the range + * 1..64 and the address must be length-aligned. + */ + +static long ptrace_gethbpregs(struct task_struct *child, long addr, + long __user *datap) +{ + struct perf_event *bp; + u32 user_data[2] = {0}; + bool dbreak = addr & 1; + unsigned idx = addr >> 1; + + if ((!dbreak && idx >= XCHAL_NUM_IBREAK) || + (dbreak && idx >= XCHAL_NUM_DBREAK)) + return -EINVAL; + + if (dbreak) + bp = child->thread.ptrace_wp[idx]; + else + bp = child->thread.ptrace_bp[idx]; + + if (bp) { + user_data[0] = bp->attr.bp_addr; + user_data[1] = bp->attr.disabled ? 0 : bp->attr.bp_len; + if (dbreak) { + if (bp->attr.bp_type & HW_BREAKPOINT_R) + user_data[1] |= DBREAKC_LOAD_MASK; + if (bp->attr.bp_type & HW_BREAKPOINT_W) + user_data[1] |= DBREAKC_STOR_MASK; + } + } + + if (copy_to_user(datap, user_data, sizeof(user_data))) + return -EFAULT; + + return 0; +} + +static long ptrace_sethbpregs(struct task_struct *child, long addr, + long __user *datap) +{ + struct perf_event *bp; + struct perf_event_attr attr; + u32 user_data[2]; + bool dbreak = addr & 1; + unsigned idx = addr >> 1; + int bp_type = 0; + + if ((!dbreak && idx >= XCHAL_NUM_IBREAK) || + (dbreak && idx >= XCHAL_NUM_DBREAK)) + return -EINVAL; + + if (copy_from_user(user_data, datap, sizeof(user_data))) + return -EFAULT; + + if (dbreak) { + bp = child->thread.ptrace_wp[idx]; + if (user_data[1] & DBREAKC_LOAD_MASK) + bp_type |= HW_BREAKPOINT_R; + if (user_data[1] & DBREAKC_STOR_MASK) + bp_type |= HW_BREAKPOINT_W; + } else { + bp = child->thread.ptrace_bp[idx]; + bp_type = HW_BREAKPOINT_X; + } + + if (!bp) { + bp = ptrace_hbp_create(child, + bp_type ? bp_type : HW_BREAKPOINT_RW); + if (IS_ERR(bp)) + return PTR_ERR(bp); + if (dbreak) + child->thread.ptrace_wp[idx] = bp; + else + child->thread.ptrace_bp[idx] = bp; + } + + attr = bp->attr; + attr.bp_addr = user_data[0]; + attr.bp_len = user_data[1] & ~(DBREAKC_LOAD_MASK | DBREAKC_STOR_MASK); + attr.bp_type = bp_type; + attr.disabled = !attr.bp_len; + + return modify_user_hw_breakpoint(bp, &attr); +} +#endif + long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) { @@ -307,7 +449,15 @@ long arch_ptrace(struct task_struct *child, long request, case PTRACE_SETXTREGS: ret = ptrace_setxregs(child, datap); break; +#ifdef CONFIG_HAVE_HW_BREAKPOINT + case PTRACE_GETHBPREGS: + ret = ptrace_gethbpregs(child, addr, datap); + break; + case PTRACE_SETHBPREGS: + ret = ptrace_sethbpregs(child, addr, datap); + break; +#endif default: ret = ptrace_request(child, request, addr, data); break; diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index e4764f216a7ad19928e60ed8b3364b279d9f4f49..d02fc304b31c10ea9019172b8fd15d8aaea41bdc 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -39,6 +39,7 @@ #include #include #include +#include /* * Machine specific interrupt handlers @@ -338,9 +339,22 @@ do_unaligned_user (struct pt_regs *regs) } #endif +/* Handle debug events. + * When CONFIG_HAVE_HW_BREAKPOINT is on this handler is called with + * preemption disabled to avoid rescheduling and keep mapping of hardware + * breakpoint structures to debug registers intact, so that + * DEBUGCAUSE.DBNUM could be used in case of data breakpoint hit. + */ void do_debug(struct pt_regs *regs) { +#ifdef CONFIG_HAVE_HW_BREAKPOINT + int ret = check_hw_breakpoint(regs); + + preempt_enable(); + if (ret == 0) + return; +#endif __die_if_kernel("Breakpoint in kernel", regs, SIGKILL); /* If in user mode, send SIGTRAP signal to current process */