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>

1 files changed, 26 insertions, 7 deletions

diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index 423424599dad..2c91faf981db 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);