powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers

This is a rewrite so that we don't assume we are using the DABR throughout the
code.  We now use the arch_hw_breakpoint to store the breakpoint in a generic
manner in the thread_struct, rather than storing the raw DABR value.

The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from
userspace.  We keep this functionality, so that future changes (like the POWER8
DAWR), will still fake the DABR to userspace.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

4 files changed, 37 insertions, 18 deletions

diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
index 32de2577bb6..8d85ffb03e6 100644
--- a/arch/powerpc/include/asm/debug.h
+++ b/arch/powerpc/include/asm/debug.h
@@ -4,6 +4,8 @@
 #ifndef _ASM_POWERPC_DEBUG_H
 #define _ASM_POWERPC_DEBUG_H
 
+#include <asm/hw_breakpoint.h>
+
 struct pt_regs;
 
 extern struct dentry *powerpc_debugfs_root;
@@ -15,7 +17,7 @@ extern int (*__debugger_ipi)(struct pt_regs *regs);
 extern int (*__debugger_bpt)(struct pt_regs *regs);
 extern int (*__debugger_sstep)(struct pt_regs *regs);
 extern int (*__debugger_iabr_match)(struct pt_regs *regs);
-extern int (*__debugger_dabr_match)(struct pt_regs *regs);
+extern int (*__debugger_break_match)(struct pt_regs *regs);
 extern int (*__debugger_fault_handler)(struct pt_regs *regs);
 
 #define DEBUGGER_BOILERPLATE(__NAME) \
@@ -31,7 +33,7 @@ DEBUGGER_BOILERPLATE(debugger_ipi)
 DEBUGGER_BOILERPLATE(debugger_bpt)
 DEBUGGER_BOILERPLATE(debugger_sstep)
 DEBUGGER_BOILERPLATE(debugger_iabr_match)
-DEBUGGER_BOILERPLATE(debugger_dabr_match)
+DEBUGGER_BOILERPLATE(debugger_break_match)
 DEBUGGER_BOILERPLATE(debugger_fault_handler)
 
 #else
@@ -40,17 +42,18 @@ static inline int debugger_ipi(struct pt_regs *regs) { return 0; }
 static inline int debugger_bpt(struct pt_regs *regs) { return 0; }
 static inline int debugger_sstep(struct pt_regs *regs) { return 0; }
 static inline int debugger_iabr_match(struct pt_regs *regs) { return 0; }
-static inline int debugger_dabr_match(struct pt_regs *regs) { return 0; }
+static inline int debugger_break_match(struct pt_regs *regs) { return 0; }
 static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
 #endif
 
-extern int set_dabr(unsigned long dabr, unsigned long dabrx);
+int set_break(struct arch_hw_breakpoint *brk);
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 extern void do_send_trap(struct pt_regs *regs, unsigned long address,
 			 unsigned long error_code, int signal_code, int brkpt);
 #else
-extern void do_dabr(struct pt_regs *regs, unsigned long address,
-		    unsigned long error_code);
+
+extern void do_break(struct pt_regs *regs, unsigned long address,
+		     unsigned long error_code);
 #endif
 
 #endif /* _ASM_POWERPC_DEBUG_H */
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index 423424599da..2c91faf981d 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -24,16 +24,30 @@
 #define _PPC_BOOK3S_64_HW_BREAKPOINT_H
 
 #ifdef	__KERNEL__
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
-
 struct arch_hw_breakpoint {
 	unsigned long	address;
-	unsigned long	dabrx;
-	int		type;
-	u8		len; /* length of the target data symbol */
-	bool		extraneous_interrupt;
+	u16		type;
+	u16		len; /* length of the target data symbol */
 };
 
+/* Note: Don't change the the first 6 bits below as they are in the same order
+ * as the dabr and dabrx.
+ */
+#define HW_BRK_TYPE_READ		0x01
+#define HW_BRK_TYPE_WRITE		0x02
+#define HW_BRK_TYPE_TRANSLATE		0x04
+#define HW_BRK_TYPE_USER		0x08
+#define HW_BRK_TYPE_KERNEL		0x10
+#define HW_BRK_TYPE_HYP			0x20
+#define HW_BRK_TYPE_EXTRANEOUS_IRQ	0x80
+
+/* bits that overlap with the bottom 3 bits of the dabr */
+#define HW_BRK_TYPE_RDWR	(HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)
+#define HW_BRK_TYPE_DABR	(HW_BRK_TYPE_RDWR | HW_BRK_TYPE_TRANSLATE)
+#define HW_BRK_TYPE_PRIV_ALL	(HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \
+				 HW_BRK_TYPE_HYP)
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
 #include <linux/kdebug.h>
 #include <asm/reg.h>
 #include <asm/debug.h>
@@ -62,7 +76,12 @@ extern void ptrace_triggered(struct perf_event *bp,
 			struct perf_sample_data *data, struct pt_regs *regs);
 static inline void hw_breakpoint_disable(void)
 {
-	set_dabr(0, 0);
+	struct arch_hw_breakpoint brk;
+
+	brk.address = 0;
+	brk.type = 0;
+	brk.len = 0;
+	set_break(&brk);
 }
 extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
 
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 37f87f069cb..7938658c168 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -33,6 +33,7 @@
 #include <linux/cache.h>
 #include <asm/ptrace.h>
 #include <asm/types.h>
+#include <asm/hw_breakpoint.h>
 
 /* We do _not_ want to define new machine types at all, those must die
  * in favor of using the device-tree
@@ -225,8 +226,7 @@ struct thread_struct {
 	struct perf_event *last_hit_ubp;
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 #endif
-	unsigned long	dabr;		/* Data address breakpoint register */
-	unsigned long	dabrx;		/*      ... extension  */
+	struct arch_hw_breakpoint hw_brk; /* info on the hardware breakpoint */
 	unsigned long	trap_nr;	/* last trap # on this thread */
 #ifdef CONFIG_ALTIVEC
 	/* Complete AltiVec register set */
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index d111beb1acd..1f59fbb7b05 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -206,9 +206,6 @@
 #define   DAWRX_KERNEL	(1UL << 1)
 #define   DAWRX_HYP	(1UL << 2)
 #define SPRN_DABR	0x3F5	/* Data Address Breakpoint Register */
-#define   DABR_TRANSLATION	(1UL << 2)
-#define   DABR_DATA_WRITE	(1UL << 1)
-#define   DABR_DATA_READ	(1UL << 0)
 #define SPRN_DABR2	0x13D	/* e300 */
 #define SPRN_DABRX	0x3F7	/* Data Address Breakpoint Register Extension */
 #define   DABRX_USER	(1UL << 0)