Re: [PATCH 07/15] powerpc/watchpoint: Get watchpoint count dynamically while disabling them
On 3/18/20 12:27 PM, Ravi Bangoria wrote:
On 3/17/20 4:02 PM, Christophe Leroy wrote:
Le 09/03/2020 à 09:57, Ravi Bangoria a écrit :
Instead of disabling only one watchpooint, get num of available
watchpoints dynamically and disable all of them.
Signed-off-by: Ravi Bangoria
---
arch/powerpc/include/asm/hw_breakpoint.h | 15 +++
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h
b/arch/powerpc/include/asm/hw_breakpoint.h
index 980ac7d9f267..ec61e2b7195c 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -75,14 +75,13 @@ extern void ptrace_triggered(struct perf_event *bp,
struct perf_sample_data *data, struct pt_regs *regs);
static inline void hw_breakpoint_disable(void)
{
- struct arch_hw_breakpoint brk;
-
- brk.address = 0;
- brk.type = 0;
- brk.len = 0;
- brk.hw_len = 0;
- if (ppc_breakpoint_available())
- __set_breakpoint(&brk, 0);
+ int i;
+ struct arch_hw_breakpoint null_brk = {0};
+
+ if (ppc_breakpoint_available()) {
I think this test should go into nr_wp_slots() which should return zero when no
breakpoint is available.
Seems possible. Will change it in next version.
Once we move ppc_breakpoint_available() logic into nr_wp_slots(),
'dawr_force_enable' variable is checked in nr_wp_slots() before
it gets initialized in dawr_force_setup():
start_kernel()
|-> perf_event_init()
| init_hw_breakpoint()
| hw_breakpoint_slots()
| nr_wp_slots()
| /* Check dawr_force_enable variable */
|
|-> arch_call_rest_init()
rest_init()
kernel_thread(kernel_init, ...)
...
kernel_init()
kernel_init_freeable()
...
do_one_initcall()
dawr_force_setup()
/* Set dawr_force_enable = true */
Because of this, hw-breakpoint infrastructure is initialized with
no DAWRs. So I'm thinking to keep the code as it is i.e. not moving
ppc_breakpoint_available() test inside nr_wp_slots().
Ravi
Re: [PATCH 07/15] powerpc/watchpoint: Get watchpoint count dynamically while disabling them
On 3/17/20 4:02 PM, Christophe Leroy wrote:
Le 09/03/2020 à 09:57, Ravi Bangoria a écrit :
Instead of disabling only one watchpooint, get num of available
watchpoints dynamically and disable all of them.
Signed-off-by: Ravi Bangoria
---
arch/powerpc/include/asm/hw_breakpoint.h | 15 +++
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h
b/arch/powerpc/include/asm/hw_breakpoint.h
index 980ac7d9f267..ec61e2b7195c 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -75,14 +75,13 @@ extern void ptrace_triggered(struct perf_event *bp,
struct perf_sample_data *data, struct pt_regs *regs);
static inline void hw_breakpoint_disable(void)
{
- struct arch_hw_breakpoint brk;
-
- brk.address = 0;
- brk.type = 0;
- brk.len = 0;
- brk.hw_len = 0;
- if (ppc_breakpoint_available())
- __set_breakpoint(&brk, 0);
+ int i;
+ struct arch_hw_breakpoint null_brk = {0};
+
+ if (ppc_breakpoint_available()) {
I think this test should go into nr_wp_slots() which should return zero when no
breakpoint is available.
Seems possible. Will change it in next version.
Thanks,
Ravi
Re: [PATCH 07/15] powerpc/watchpoint: Get watchpoint count dynamically while disabling them
Le 09/03/2020 à 09:57, Ravi Bangoria a écrit :
Instead of disabling only one watchpooint, get num of available
watchpoints dynamically and disable all of them.
Signed-off-by: Ravi Bangoria
---
arch/powerpc/include/asm/hw_breakpoint.h | 15 +++
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h
b/arch/powerpc/include/asm/hw_breakpoint.h
index 980ac7d9f267..ec61e2b7195c 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -75,14 +75,13 @@ extern void ptrace_triggered(struct perf_event *bp,
struct perf_sample_data *data, struct pt_regs *regs);
static inline void hw_breakpoint_disable(void)
{
- struct arch_hw_breakpoint brk;
-
- brk.address = 0;
- brk.type = 0;
- brk.len = 0;
- brk.hw_len = 0;
- if (ppc_breakpoint_available())
- __set_breakpoint(&brk, 0);
+ int i;
+ struct arch_hw_breakpoint null_brk = {0};
+
+ if (ppc_breakpoint_available()) {
I think this test should go into nr_wp_slots() which should return zero
when no breakpoint is available. This would simplify at least here and
patch 4
Christophe
+ for (i = 0; i < nr_wp_slots(); i++)
+ __set_breakpoint(&null_brk, i);
+ }
}
extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
int hw_breakpoint_handler(struct die_args *args);
