[PATCH 0/3] powerpc/ptrace: hw breakpoint book3s repost and cleanups

[PATCH 0/3] powerpc/ptrace: hw breakpoint book3s repost and cleanups

[Michael Neuling]

This is a repost of K.Prasad hw breakpoint support for book3s and some
other junk I found along the way.

K.Prasad (1):
  powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new
    PPC ptrace flags

Michael Neuling (2):
  powerpc/ptrace: Fix spelling mistake
  powerpc/ptrace: Remove unused addr parameter in ppc_del_hwdebug()

 Documentation/powerpc/ptrace.txt |   16 +++++++
 arch/powerpc/kernel/ptrace.c     |   86 ++++++++++++++++++++++++++++++++++----
 2 files changed, 94 insertions(+), 8 deletions(-)

-- 
1.7.9.5

[PATCH 1/3] powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags

[Michael Neuling]

From: "K.Prasad" <prasad@linux.vnet.ibm.com>

PPC_PTRACE_GETHWDBGINFO, PPC_PTRACE_SETHWDEBUG and PPC_PTRACE_DELHWDEBUG are
PowerPC specific ptrace flags that use the watchpoint register. While they are
targeted primarily towards BookE users, user-space applications such as GDB
have started using them for BookS too. This patch enables the use of generic
hardware breakpoint interfaces for these new flags.

Apart from the usual benefits of using generic hw-breakpoint interfaces, these
changes allow debuggers (such as GDB) to use a common set of ptrace flags for
their watchpoint needs and allow more precise breakpoint specification (length
of the variable can be specified).

Mikey added: rebased and added dbginfo.features around #ifdef
             CONFIG_HAVE_HW_BREAKPOINT

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
---
 Documentation/powerpc/ptrace.txt |   16 ++++++++
 arch/powerpc/kernel/ptrace.c     |   78 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 90 insertions(+), 4 deletions(-)

diff --git a/Documentation/powerpc/ptrace.txt b/Documentation/powerpc/ptrace.txt
index f4a5499..f2a7a39 100644
--- a/Documentation/powerpc/ptrace.txt
+++ b/Documentation/powerpc/ptrace.txt
@@ -127,6 +127,22 @@ Some examples of using the structure to:
   p.addr2           = (uint64_t) end_range;
   p.condition_value = 0;
 
+- set a watchpoint in server processors (BookS)
+
+  p.version         = 1;
+  p.trigger_type    = PPC_BREAKPOINT_TRIGGER_RW;
+  p.addr_mode       = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE;
+  or
+  p.addr_mode       = PPC_BREAKPOINT_MODE_EXACT;
+
+  p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;
+  p.addr            = (uint64_t) begin_range;
+  /* For PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE addr2 needs to be specified, where
+   * addr2 - addr <= 8 Bytes.
+   */
+  p.addr2           = (uint64_t) end_range;
+  p.condition_value = 0;
+
 3. PTRACE_DELHWDEBUG
 
 Takes an integer which identifies an existing breakpoint or watchpoint
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 79d8e56..140238a 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -1338,6 +1338,12 @@ static int set_dac_range(struct task_struct *child,
 static long ppc_set_hwdebug(struct task_struct *child,
 		     struct ppc_hw_breakpoint *bp_info)
 {
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int len = 0;
+	struct thread_struct *thread = &(child->thread);
+	struct perf_event *bp;
+	struct perf_event_attr attr;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
 #ifndef CONFIG_PPC_ADV_DEBUG_REGS
 	unsigned long dabr;
 #endif
@@ -1381,13 +1387,9 @@ static long ppc_set_hwdebug(struct task_struct *child,
 	 */
 	if ((bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_RW) == 0 ||
 	    (bp_info->trigger_type & ~PPC_BREAKPOINT_TRIGGER_RW) != 0 ||
-	    bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT ||
 	    bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)
 		return -EINVAL;
 
-	if (child->thread.dabr)
-		return -ENOSPC;
-
 	if ((unsigned long)bp_info->addr >= TASK_SIZE)
 		return -EIO;
 
@@ -1397,6 +1399,50 @@ static long ppc_set_hwdebug(struct task_struct *child,
 		dabr |= DABR_DATA_READ;
 	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
 		dabr |= DABR_DATA_WRITE;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	if (ptrace_get_breakpoints(child) < 0)
+		return -ESRCH;
+
+	/*
+	 * Check if the request is for 'range' breakpoints. We can
+	 * support it if range < 8 bytes.
+	 */
+	if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE) {
+		len = bp_info->addr2 - bp_info->addr;
+	} else if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) {
+		ptrace_put_breakpoints(child);
+		return -EINVAL;
+	}
+	bp = thread->ptrace_bps[0];
+	if (bp) {
+		ptrace_put_breakpoints(child);
+		return -ENOSPC;
+	}
+
+	/* Create a new breakpoint request if one doesn't exist already */
+	hw_breakpoint_init(&attr);
+	attr.bp_addr = (unsigned long)bp_info->addr & ~HW_BREAKPOINT_ALIGN;
+	attr.bp_len = len;
+	arch_bp_generic_fields(dabr & (DABR_DATA_WRITE | DABR_DATA_READ),
+								&attr.bp_type);
+
+	thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,
+					       ptrace_triggered, NULL, child);
+	if (IS_ERR(bp)) {
+		thread->ptrace_bps[0] = NULL;
+		ptrace_put_breakpoints(child);
+		return PTR_ERR(bp);
+	}
+
+	ptrace_put_breakpoints(child);
+	return 1;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
+	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
+		return -EINVAL;
+
+	if (child->thread.dabr)
+		return -ENOSPC;
 
 	child->thread.dabr = dabr;
 	child->thread.dabrx = DABRX_ALL;
@@ -1407,6 +1453,11 @@ static long ppc_set_hwdebug(struct task_struct *child,
 
 static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)
 {
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int ret = 0;
+	struct thread_struct *thread = &(child->thread);
+	struct perf_event *bp;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 	int rc;
 
@@ -1426,10 +1477,25 @@ static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)
 #else
 	if (data != 1)
 		return -EINVAL;
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	if (ptrace_get_breakpoints(child) < 0)
+		return -ESRCH;
+
+	bp = thread->ptrace_bps[0];
+	if (bp) {
+		unregister_hw_breakpoint(bp);
+		thread->ptrace_bps[0] = NULL;
+	} else
+		ret = -ENOENT;
+	ptrace_put_breakpoints(child);
+	return ret;
+#else /* CONFIG_HAVE_HW_BREAKPOINT */
 	if (child->thread.dabr == 0)
 		return -ENOENT;
 
 	child->thread.dabr = 0;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
 
 	return 0;
 #endif
@@ -1536,7 +1602,11 @@ long arch_ptrace(struct task_struct *child, long request,
 		dbginfo.data_bp_alignment = 4;
 #endif
 		dbginfo.sizeof_condition = 0;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+		dbginfo.features = PPC_DEBUG_FEATURE_DATA_BP_RANGE;
+#else
 		dbginfo.features = 0;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
 
 		if (!access_ok(VERIFY_WRITE, datavp,
-- 
1.7.9.5

[PATCH 2/3] powerpc/ptrace: Fix spelling mistake

[Michael Neuling]

s/intruction/instruction/

Signed-off-by: Michael Neuling <mikey@neuling.org>
---
 arch/powerpc/kernel/ptrace.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 140238a..7dd32d1 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -1037,7 +1037,7 @@ void ptrace_disable(struct task_struct *child)
 }
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
-static long set_intruction_bp(struct task_struct *child,
+static long set_instruction_bp(struct task_struct *child,
 			      struct ppc_hw_breakpoint *bp_info)
 {
 	int slot;
@@ -1371,7 +1371,7 @@ static long ppc_set_hwdebug(struct task_struct *child,
 		if ((bp_info->trigger_type != PPC_BREAKPOINT_TRIGGER_EXECUTE) ||
 		    (bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE))
 			return -EINVAL;
-		return set_intruction_bp(child, bp_info);
+		return set_instruction_bp(child, bp_info);
 	}
 	if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
 		return set_dac(child, bp_info);
-- 
1.7.9.5

[PATCH 3/3] powerpc/ptrace: Remove unused addr parameter in ppc_del_hwdebug()

[Michael Neuling]

Signed-off-by: Michael Neuling <mikey@neuling.org>
---
 arch/powerpc/kernel/ptrace.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 7dd32d1..817b411 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -1451,7 +1451,7 @@ static long ppc_set_hwdebug(struct task_struct *child,
 #endif /* !CONFIG_PPC_ADV_DEBUG_DVCS */
 }
 
-static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)
+static long ppc_del_hwdebug(struct task_struct *child, long data)
 {
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	int ret = 0;
@@ -1633,7 +1633,7 @@ long arch_ptrace(struct task_struct *child, long request,
 	}
 
 	case PPC_PTRACE_DELHWDEBUG: {
-		ret = ppc_del_hwdebug(child, addr, data);
+		ret = ppc_del_hwdebug(child, data);
 		break;
 	}
 
-- 
1.7.9.5