ARM: add support for hw-breakpoints [v3]

index 5f4f480..42da2f8 100644
@@ -84,6 +84,9 @@ void arm_notify_die(const char *str, struct pt_regs *regs, struct siginfo *info,
 void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
 				       struct pt_regs *),
 		     int sig, const char *name);
+void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int,
+				       struct pt_regs *),
+		     int sig, const char *name);
 
 #define xchg(ptr,x) \
 	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

index 92f5801..a71b410 100644
@@ -572,6 +572,17 @@ static struct fsr_info ifsr_info[] = {
 	{ do_bad,		SIGBUS,  0,		"unknown 31"			   },
 };
 
+void __init
+hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
+			int sig, const char *name)
+{
+	if (nr >= 0 && nr < ARRAY_SIZE(ifsr_info)) {
+		ifsr_info[nr].fn   = fn;
+		ifsr_info[nr].sig  = sig;
+		ifsr_info[nr].name = name;
+	}
+}
+
 asmlinkage void __exception
 do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
 {

new file mode 100644
index 0000000..c995219
@@ -0,0 +1,117 @@
+#ifndef _ARM_HW_BREAKPOINT_H
+#define _ARM_HW_BREAKPOINT_H
+
+#ifdef __KERNEL__
+struct arch_hw_breakpoint_ctrl {
+		u32 __reserved	: 19,
+		len		: 8,
+		type		: 2,
+		privilege	: 2,
+		enabled		: 1;
+};
+
+struct arch_hw_breakpoint {
+	u32	address;
+	u32	trigger;
+	struct arch_hw_breakpoint_ctrl ctrl;
+};
+
+static inline u32 encode_ctrl_reg(struct arch_hw_breakpoint_ctrl ctrl)
+{
+	return (ctrl.len << 5) | (ctrl.type << 3) |
+		(ctrl.privilege << 1) | ctrl.enabled;
+}
+
+static inline void decode_ctrl_reg(u32 reg,
+				   struct arch_hw_breakpoint_ctrl *ctrl)
+{
+	ctrl->enabled	= reg & 0x1;
+	reg >>= 1;
+	ctrl->privilege	= reg & 0x3;
+	reg >>= 2;
+	ctrl->type	= reg & 0x3;
+	reg >>= 2;
+	ctrl->len	= reg & 0xff;
+}
+
+/* Debug architecture numbers. */
+#define ARM_DEBUG_ARCH_V6	1
+#define ARM_DEBUG_ARCH_V6_1	2
+#define ARM_DEBUG_ARCH_V7_ECP14	3
+#define ARM_DEBUG_ARCH_V7_MM	4
+
+/* Breakpoint */
+#define ARM_BREAKPOINT_EXECUTE	0
+
+/* Watchpoints */
+#define ARM_BREAKPOINT_LOAD	1
+#define ARM_BREAKPOINT_STORE	2
+
+/* Privilege Levels */
+#define ARM_BREAKPOINT_PRIV	1
+#define ARM_BREAKPOINT_USER	2
+
+/* Lengths */
+#define ARM_BREAKPOINT_LEN_1	0x1
+#define ARM_BREAKPOINT_LEN_2	0x3
+#define ARM_BREAKPOINT_LEN_4	0xf
+#define ARM_BREAKPOINT_LEN_8	0xff
+
+/* Limits */
+#define ARM_MAX_BRP		16
+#define ARM_MAX_WRP		16
+#define ARM_MAX_HBP_SLOTS	(ARM_MAX_BRP + ARM_MAX_WRP)
+
+/* DSCR method of entry bits. */
+#define ARM_DSCR_MOE(x)			((x >> 2) & 0xf)
+#define ARM_ENTRY_BREAKPOINT		0x1
+#define ARM_ENTRY_ASYNC_WATCHPOINT	0x2
+#define ARM_ENTRY_SYNC_WATCHPOINT	0xa
+
+/* DSCR monitor/halting bits. */
+#define ARM_DSCR_HDBGEN		(1 << 14)
+#define ARM_DSCR_MDBGEN		(1 << 15)
+
+/* opcode2 numbers for the co-processor instructions. */
+#define ARM_OP2_BVR		4
+#define ARM_OP2_BCR		5
+#define ARM_OP2_WVR		6
+#define ARM_OP2_WCR		7
+
+/* Base register numbers for the debug registers. */
+#define ARM_BASE_BVR		64
+#define ARM_BASE_BCR		80
+#define ARM_BASE_WVR		96
+#define ARM_BASE_WCR		112
+
+/* Accessor macros for the debug registers. */
+#define ARM_DBG_READ(M, OP2, VAL) do {\
+	asm volatile("mrc p14, 0, %0, c0," #M ", " #OP2 : "=r" (VAL));\
+} while (0)
+
+#define ARM_DBG_WRITE(M, OP2, VAL) do {\
+	asm volatile("mcr p14, 0, %0, c0," #M ", " #OP2 : : "r" (VAL));\
+} while (0)
+
+struct notifier_block;
+struct perf_event;
+struct pmu;
+struct task_struct;
+
+extern struct pmu perf_ops_bp;
+extern int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
+				  int *gen_len, int *gen_type);
+extern int arch_check_bp_in_kernelspace(struct perf_event *bp);
+extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
+extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+					   unsigned long val, void *data);
+extern u8 arch_get_debug_arch(void);
+extern u8 arch_get_max_wp_len(void);
+
+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 hw_breakpoint_slots(int type);
+
+#endif	/* __KERNEL__ */
+#endif	/* _ARM_HW_BREAKPOINT_H */

721 lines not on this page · raw message

index 6a89567..dbd33c3 100644
@@ -19,6 +19,7 @@
 
 #ifdef __KERNEL__
 
+#include <asm/hw_breakpoint.h>
 #include <asm/ptrace.h>
 #include <asm/types.h>
 

@@ -41,6 +42,9 @@ struct debug_entry {
 struct debug_info {
 	int			nsaved;
 	struct debug_entry	bp[2];
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	struct perf_event	*hbp[ARM_MAX_HBP_SLOTS];
+#endif
 };
 
 struct thread_struct {

index 9dcb11e..21560e4 100644
@@ -29,6 +29,8 @@
 #define PTRACE_SETCRUNCHREGS	26
 #define PTRACE_GETVFPREGS	27
 #define PTRACE_SETVFPREGS	28
+#define PTRACE_GETHBPREGS	29
+#define PTRACE_SETHBPREGS	30
 
 /*
  * PSR bits

index b249cd7..5d5faec 100644
@@ -647,6 +647,19 @@ out:
 	return ret;
 }
 
+static int hw_breakpoint_thread_notify(struct notifier_block *self,
+				       unsigned long cmd, void *t)
+{
+	if (cmd == THREAD_NOTIFY_FLUSH)
+		flush_ptrace_hw_breakpoint(current);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block hw_breakpoint_thread_notifier_block = {
+	.notifier_call = hw_breakpoint_thread_notify,
+};
+
 /*
  * One-time initialisation.
  */

214 lines not on this page · raw message