diff options
| -rw-r--r-- | arch/xtensa/Kconfig | 1 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/hw_breakpoint.h | 58 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/irqflags.h | 1 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/processor.h | 9 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/regs.h | 3 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/thread_info.h | 1 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/traps.h | 8 | ||||
| -rw-r--r-- | arch/xtensa/include/uapi/asm/ptrace.h | 2 | ||||
| -rw-r--r-- | arch/xtensa/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/xtensa/kernel/asm-offsets.c | 6 | ||||
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 72 | ||||
| -rw-r--r-- | arch/xtensa/kernel/hw_breakpoint.c | 317 | ||||
| -rw-r--r-- | arch/xtensa/kernel/process.c | 5 | ||||
| -rw-r--r-- | arch/xtensa/kernel/ptrace.c | 164 | ||||
| -rw-r--r-- | arch/xtensa/kernel/traps.c | 14 |
15 files changed, 649 insertions, 13 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 128e63d3a632..b8e9de1e7832 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 000000000000..dbe3053b284a --- /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 <linux/kdebug.h> +#include <linux/types.h> +#include <uapi/linux/hw_breakpoint.h> + +/* 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 8e090c709046..407606e576f8 100644 --- a/arch/xtensa/include/asm/irqflags.h +++ b/arch/xtensa/include/asm/irqflags.h @@ -13,6 +13,7 @@ #define _XTENSA_IRQFLAGS_H #include <linux/types.h> +#include <asm/processor.h> 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 744ecf0dc3a4..d2e40d39c615 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 4ba9f516b0e2..881a1134a4b4 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 9ad12c617184..7be2400f745a 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<<TIF_SYSCALL_TRACE) #define _TIF_SIGPENDING (1<<TIF_SIGPENDING) diff --git a/arch/xtensa/include/asm/traps.h b/arch/xtensa/include/asm/traps.h index 3ad151aee6af..2e69aa4b843f 100644 --- a/arch/xtensa/include/asm/traps.h +++ b/arch/xtensa/include/asm/traps.h @@ -70,6 +70,14 @@ struct debug_table { void (*debug_exception)(void); /* Temporary register save area */ unsigned long debug_save[1]; +#ifdef CONFIG_HAVE_HW_BREAKPOINT + /* Save area for DBREAKC registers */ + unsigned long dbreakc_save[XCHAL_NUM_DBREAK]; + /* Saved ICOUNT register */ + unsigned long icount_save; + /* Saved ICOUNTLEVEL register */ + unsigned long icount_level_save; +#endif }; void debug_exception(void); diff --git a/arch/xtensa/include/uapi/asm/ptrace.h b/arch/xtensa/include/uapi/asm/ptrace.h index ee17aa842fdf..6ccbd9e38e35 100644 --- a/arch/xtensa/include/uapi/asm/ptrace.h +++ b/arch/xtensa/include/uapi/asm/ptrace.h @@ -72,6 +72,8 @@ #define PTRACE_SETREGS 13 #define PTRACE_GETXTREGS 18 #define PTRACE_SETXTREGS 19 +#define PTRACE_GETHBPREGS 20 +#define PTRACE_SETHBPREGS 21 #endif /* _UAPI_XTENSA_PTRACE_H */ diff --git a/arch/xtensa/kernel/Makefile b/arch/xtensa/kernel/Makefile index 17fa04dce3ba..c31f5d5afc7d 100644 --- a/arch/xtensa/kernel/Makefile +++ b/arch/xtensa/kernel/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_MODULES) += xtensa_ksyms.o module.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o obj-$(CONFIG_SMP) += smp.o mxhead.o obj-$(CONFIG_XTENSA_VARIANT_HAVE_PERF_EVENTS) += perf_event.o +obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o AFLAGS_head.o += -mtext-section-literals AFLAGS_mxhead.o += -mtext-section-literals diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c index 8fd46c6404ea..8e10e357ee32 100644 --- a/arch/xtensa/kernel/asm-offsets.c +++ b/arch/xtensa/kernel/asm-offsets.c @@ -122,6 +122,12 @@ int main(void) DEFINE(DT_DEBUG_EXCEPTION, offsetof(struct debug_table, debug_exception)); DEFINE(DT_DEBUG_SAVE, offsetof(struct debug_table, debug_save)); +#ifdef CONFIG_HAVE_HW_BREAKPOINT + DEFINE(DT_DBREAKC_SAVE, offsetof(struct debug_table, dbreakc_save)); + DEFINE(DT_ICOUNT_SAVE, offsetof(struct debug_table, icount_save)); + DEFINE(DT_ICOUNT_LEVEL_SAVE, + offsetof(struct debug_table, icount_level_save)); +#endif return 0; } diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index ab7904fd027f..fe8f7e7efb9d 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -543,6 +543,12 @@ common_exception_return: #endif 5: +#ifdef CONFIG_HAVE_HW_BREAKPOINT + _bbci.l a4, TIF_DB_DISABLED, 7f + movi a4, restore_dbreak + callx4 a4 +7: +#endif #ifdef CONFIG_DEBUG_TLB_SANITY l32i a4, a1, PT_DEPC bgeui a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f @@ -808,6 +814,18 @@ ENTRY(debug_exception) s32i a0, a2, PT_AREG2 mov a1, a2 + /* Debug exception is handled as an exception, so interrupts will + * likely be enabled in the common exception handler. Disable + * preemption if we have HW breakpoints to preserve DEBUGCAUSE.DBNUM + * meaning. + */ +#if defined(CONFIG_PREEMPT_COUNT) && defined(CONFIG_HAVE_HW_BREAKPOINT) + GET_THREAD_INFO(a2, a1) + l32i a3, a2, TI_PRE_COUNT + addi a3, a3, 1 + s32i a3, a2, TI_PRE_COUNT +#endif + rsr a2, ps bbsi.l a2, PS_UM_BIT, _user_exception j _kernel_exception @@ -816,8 +834,60 @@ ENTRY(debug_exception) l32i a2, a2, EXC_TABLE_KSTK # load kernel stack pointer j 3b - /* Debug exception while in exception mode. */ +#ifdef CONFIG_HAVE_HW_BREAKPOINT + /* Debug exception while in exception mode. This may happen when + * window overflow/underflow handler or fast exception handler hits + * data breakpoint, in which case save and disable all data + * breakpoints, single-step faulting instruction and restore data + * breakpoints. + */ +1: + bbci.l a0, PS_UM_BIT, 1b # jump if kernel mode + + rsr a0, debugcause + bbsi.l a0, DEBUGCAUSE_DBREAK_BIT, .Ldebug_save_dbreak + + .set _index, 0 + .rept XCHAL_NUM_DBREAK + l32i a0, a3, DT_DBREAKC_SAVE + _index * 4 + wsr a0, SREG_DBREAKC + _index + .set _index, _index + 1 + .endr + + l32i a0, a3, DT_ICOUNT_LEVEL_SAVE + wsr a0, icountlevel + + l32i a0, a3, DT_ICOUNT_SAVE + xsr a0, icount + + l32i a0, a3, DT_DEBUG_SAVE + xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL + rfi XCHAL_DEBUGLEVEL + +.Ldebug_save_dbreak: + .set _index, 0 + .rept XCHAL_NUM_DBREAK + movi a0, 0 + xsr a0, SREG_DBREAKC + _index + s32i a0, a3, DT_DBREAKC_SAVE + _index * 4 + .set _index, _index + 1 + .endr + + movi a0, XCHAL_EXCM_LEVEL + 1 + xsr a0, icountlevel + s32i a0, a3, DT_ICOUNT_LEVEL_SAVE + + movi a0, 0xfffffffe + xsr a0, icount + s32i a0, a3, DT_ICOUNT_SAVE + + l32i a0, a3, DT_DEBUG_SAVE + xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL + rfi XCHAL_DEBUGLEVEL +#else + /* Debug exception while in exception mode. Should not happen. */ 1: j 1b // FIXME!! +#endif ENDPROC(debug_exception) diff --git a/arch/xtensa/kernel/hw_breakpoint.c b/arch/xtensa/kernel/hw_breakpoint.c new file mode 100644 index 000000000000..b35656ab7dbd --- /dev/null +++ b/arch/xtensa/kernel/hw_breakpoint.c @@ -0,0 +1,317 @@ +/* + * 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. + */ + +#include <linux/hw_breakpoint.h> +#include <linux/log2.h> +#include <linux/percpu.h> +#include <linux/perf_event.h> +#include <variant/core.h> + +/* 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 1c85323f01d7..5bbfed81c97b 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -24,6 +24,7 @@ #include <linux/unistd.h> #include <linux/ptrace.h> #include <linux/elf.h> +#include <linux/hw_breakpoint.h> #include <linux/init.h> #include <linux/prctl.h> #include <linux/init_task.h> @@ -43,6 +44,7 @@ #include <linux/atomic.h> #include <asm/asm-offsets.h> #include <asm/regs.h> +#include <asm/hw_breakpoint.h> 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 4d54b481123b..a651f3a628ee 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -13,21 +13,23 @@ * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca> */ +#include <linux/errno.h> +#include <linux/hw_breakpoint.h> #include <linux/kernel.h> -#include <linux/sched.h> #include <linux/mm.h> -#include <linux/errno.h> +#include <linux/perf_event.h> #include <linux/ptrace.h> -#include <linux/smp.h> +#include <linux/sched.h> #include <linux/security.h> #include <linux/signal.h> +#include <linux/smp.h> -#include <asm/pgtable.h> +#include <asm/coprocessor.h> +#include <asm/elf.h> #include <asm/page.h> -#include <asm/uaccess.h> +#include <asm/pgtable.h> #include <asm/ptrace.h> -#include <asm/elf.h> -#include <asm/coprocessor.h> +#include <asm/uaccess.h> 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 e4764f216a7a..d02fc304b31c 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -39,6 +39,7 @@ #include <asm/pgtable.h> #include <asm/processor.h> #include <asm/traps.h> +#include <asm/hw_breakpoint.h> /* * 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 */ |