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authorK.Prasad <prasad@linux.vnet.ibm.com>2012-10-28 19:13:15 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-11-15 06:00:23 +0400
commit6c7a2856ade6a58c20038024247d16a12a8d2323 (patch)
tree87d43dc2aeaded2c7d9cc9faaa2ce326334f2360
parent16b86bf2520ed29712ca7462dbfe76c856b445e9 (diff)
downloadlinux-6c7a2856ade6a58c20038024247d16a12a8d2323.tar.xz
powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags
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> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--Documentation/powerpc/ptrace.txt16
-rw-r--r--arch/powerpc/kernel/ptrace.c78
2 files changed, 90 insertions, 4 deletions
diff --git a/Documentation/powerpc/ptrace.txt b/Documentation/powerpc/ptrace.txt
index f4a5499b7bc6..f2a7a3919772 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 79d8e56470df..140238aad718 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,