2014-01-22 18:29:45

by Christopher Covington

[permalink] [raw]
Subject: [PATCH] ARM: hw_breakpoint: Add ARMv8 support

Add the trivial support necessary to get hardware breakpoints
working for GDB on ARMv8 simulators running in AArch32 mode.

Signed-off-by: Christopher Covington <[email protected]>
---
arch/arm/include/asm/hw_breakpoint.h | 1 +
arch/arm/kernel/hw_breakpoint.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
index eef55ea..8e427c7 100644
--- a/arch/arm/include/asm/hw_breakpoint.h
+++ b/arch/arm/include/asm/hw_breakpoint.h
@@ -51,6 +51,7 @@ static inline void decode_ctrl_reg(u32 reg,
#define ARM_DEBUG_ARCH_V7_ECP14 3
#define ARM_DEBUG_ARCH_V7_MM 4
#define ARM_DEBUG_ARCH_V7_1 5
+#define ARM_DEBUG_ARCH_V8 6

/* Breakpoint */
#define ARM_BREAKPOINT_EXECUTE 0
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 3d44660..45fbcaf 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -257,6 +257,7 @@ static int enable_monitor_mode(void)
break;
case ARM_DEBUG_ARCH_V7_ECP14:
case ARM_DEBUG_ARCH_V7_1:
+ case ARM_DEBUG_ARCH_V8:
ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN));
isb();
break;
--
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hosted by the Linux Foundation.


2014-01-24 15:58:27

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH] ARM: hw_breakpoint: Add ARMv8 support

Hi Christopher,

On Wed, Jan 22, 2014 at 06:29:25PM +0000, Christopher Covington wrote:
> Add the trivial support necessary to get hardware breakpoints
> working for GDB on ARMv8 simulators running in AArch32 mode.
>
> Signed-off-by: Christopher Covington <[email protected]>
> ---
> arch/arm/include/asm/hw_breakpoint.h | 1 +
> arch/arm/kernel/hw_breakpoint.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
> index eef55ea..8e427c7 100644
> --- a/arch/arm/include/asm/hw_breakpoint.h
> +++ b/arch/arm/include/asm/hw_breakpoint.h
> @@ -51,6 +51,7 @@ static inline void decode_ctrl_reg(u32 reg,
> #define ARM_DEBUG_ARCH_V7_ECP14 3
> #define ARM_DEBUG_ARCH_V7_MM 4
> #define ARM_DEBUG_ARCH_V7_1 5
> +#define ARM_DEBUG_ARCH_V8 6
>
> /* Breakpoint */
> #define ARM_BREAKPOINT_EXECUTE 0
> diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
> index 3d44660..45fbcaf 100644
> --- a/arch/arm/kernel/hw_breakpoint.c
> +++ b/arch/arm/kernel/hw_breakpoint.c
> @@ -257,6 +257,7 @@ static int enable_monitor_mode(void)
> break;
> case ARM_DEBUG_ARCH_V7_ECP14:
> case ARM_DEBUG_ARCH_V7_1:
> + case ARM_DEBUG_ARCH_V8:
> ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN));
> isb();
> break;

I'm slightly uneasy about this, mainly because I've not spent much time
looking at the AArch32 side of ARMv8 debug and I know that a fair amount
has changed since 7.1. Furthermore, the arch/arm/ kernel hasn't grown any v8
features yet and it's not clear whether that's a road down which people wish
to take it.

Anyway, assuming this works, can you please update debug_exception_updates_fsr
to return true for ARMv8 cores?

Will

2014-01-28 18:26:32

by Christopher Covington

[permalink] [raw]
Subject: [PATCH v2] ARM: hw_breakpoint: Add ARMv8 support

Add the trivial support necessary to get hardware breakpoints
working for GDB on ARMv8 simulators running in AArch32 mode.

Signed-off-by: Christopher Covington <[email protected]>
---

v2: modify debug_exception_updates_fsr

arch/arm/include/asm/hw_breakpoint.h | 1 +
arch/arm/kernel/hw_breakpoint.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
index eef55ea..8e427c7 100644
--- a/arch/arm/include/asm/hw_breakpoint.h
+++ b/arch/arm/include/asm/hw_breakpoint.h
@@ -51,6 +51,7 @@ static inline void decode_ctrl_reg(u32 reg,
#define ARM_DEBUG_ARCH_V7_ECP14 3
#define ARM_DEBUG_ARCH_V7_MM 4
#define ARM_DEBUG_ARCH_V7_1 5
+#define ARM_DEBUG_ARCH_V8 6

/* Breakpoint */
#define ARM_BREAKPOINT_EXECUTE 0
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 3d44660..a711b27 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -167,7 +167,7 @@ static int debug_arch_supported(void)
/* Can we determine the watchpoint access type from the fsr? */
static int debug_exception_updates_fsr(void)
{
- return 0;
+ return get_debug_arch() == ARM_DEBUG_ARCH_V8;
}

/* Determine number of WRP registers available. */
@@ -257,6 +257,7 @@ static int enable_monitor_mode(void)
break;
case ARM_DEBUG_ARCH_V7_ECP14:
case ARM_DEBUG_ARCH_V7_1:
+ case ARM_DEBUG_ARCH_V8:
ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN));
isb();
break;
--
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by the Linux Foundation.

2014-01-28 18:39:27

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v2] ARM: hw_breakpoint: Add ARMv8 support

On Tue, Jan 28, 2014 at 06:26:23PM +0000, Christopher Covington wrote:
> Add the trivial support necessary to get hardware breakpoints
> working for GDB on ARMv8 simulators running in AArch32 mode.
>
> Signed-off-by: Christopher Covington <[email protected]>
> ---
>
> v2: modify debug_exception_updates_fsr
>
> arch/arm/include/asm/hw_breakpoint.h | 1 +
> arch/arm/kernel/hw_breakpoint.c | 3 ++-
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
> index eef55ea..8e427c7 100644
> --- a/arch/arm/include/asm/hw_breakpoint.h
> +++ b/arch/arm/include/asm/hw_breakpoint.h
> @@ -51,6 +51,7 @@ static inline void decode_ctrl_reg(u32 reg,
> #define ARM_DEBUG_ARCH_V7_ECP14 3
> #define ARM_DEBUG_ARCH_V7_MM 4
> #define ARM_DEBUG_ARCH_V7_1 5
> +#define ARM_DEBUG_ARCH_V8 6
>
> /* Breakpoint */
> #define ARM_BREAKPOINT_EXECUTE 0
> diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
> index 3d44660..a711b27 100644
> --- a/arch/arm/kernel/hw_breakpoint.c
> +++ b/arch/arm/kernel/hw_breakpoint.c
> @@ -167,7 +167,7 @@ static int debug_arch_supported(void)
> /* Can we determine the watchpoint access type from the fsr? */
> static int debug_exception_updates_fsr(void)
> {
> - return 0;
> + return get_debug_arch() == ARM_DEBUG_ARCH_V8;

I'd probably make that >= to save on future changes.

With that change:

Acked-by: Will Deacon <[email protected]>

Will

2014-01-28 18:52:00

by Christopher Covington

[permalink] [raw]
Subject: [PATCH v3] ARM: hw_breakpoint: Add ARMv8 support

Add the trivial support necessary to get hardware breakpoints
working for GDB on ARMv8 simulators running in AArch32 mode.

Acked-by: Will Deacon <[email protected]>
Signed-off-by: Christopher Covington <[email protected]>
---

v3: assume for now that ARMv9 and later will update FSR

v2: modify debug_exception_updates_fsr

arch/arm/include/asm/hw_breakpoint.h | 1 +
arch/arm/kernel/hw_breakpoint.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
index eef55ea..8e427c7 100644
--- a/arch/arm/include/asm/hw_breakpoint.h
+++ b/arch/arm/include/asm/hw_breakpoint.h
@@ -51,6 +51,7 @@ static inline void decode_ctrl_reg(u32 reg,
#define ARM_DEBUG_ARCH_V7_ECP14 3
#define ARM_DEBUG_ARCH_V7_MM 4
#define ARM_DEBUG_ARCH_V7_1 5
+#define ARM_DEBUG_ARCH_V8 6

/* Breakpoint */
#define ARM_BREAKPOINT_EXECUTE 0
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 3d44660..9da35c6 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -167,7 +167,7 @@ static int debug_arch_supported(void)
/* Can we determine the watchpoint access type from the fsr? */
static int debug_exception_updates_fsr(void)
{
- return 0;
+ return get_debug_arch() >= ARM_DEBUG_ARCH_V8;
}

/* Determine number of WRP registers available. */
@@ -257,6 +257,7 @@ static int enable_monitor_mode(void)
break;
case ARM_DEBUG_ARCH_V7_ECP14:
case ARM_DEBUG_ARCH_V7_1:
+ case ARM_DEBUG_ARCH_V8:
ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN));
isb();
break;
--
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by the Linux Foundation.

2014-01-29 10:57:55

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v3] ARM: hw_breakpoint: Add ARMv8 support

Hi Christopher,

On Tue, Jan 28, 2014 at 06:51:51PM +0000, Christopher Covington wrote:
> Add the trivial support necessary to get hardware breakpoints
> working for GDB on ARMv8 simulators running in AArch32 mode.
>
> Acked-by: Will Deacon <[email protected]>
> Signed-off-by: Christopher Covington <[email protected]>
> ---
>
> v3: assume for now that ARMv9 and later will update FSR

Please can you stick this into the patch system? I don't have any other
hw_breakpoint changes queued, so I doubt I'll send a pull for 3.15.

Cheers,

Will

2014-01-29 14:00:18

by Christopher Covington

[permalink] [raw]
Subject: Re: [PATCH v3] ARM: hw_breakpoint: Add ARMv8 support

Hi Will,

On 01/29/2014 05:57 AM, Will Deacon wrote:
> Hi Christopher,
>
> On Tue, Jan 28, 2014 at 06:51:51PM +0000, Christopher Covington wrote:
>> Add the trivial support necessary to get hardware breakpoints
>> working for GDB on ARMv8 simulators running in AArch32 mode.
>>
>> Acked-by: Will Deacon <[email protected]>
>> Signed-off-by: Christopher Covington <[email protected]>
>> ---
>>
>> v3: assume for now that ARMv9 and later will update FSR
>
> Please can you stick this into the patch system? I don't have any other
> hw_breakpoint changes queued, so I doubt I'll send a pull for 3.15.

Thanks for your review. Sounds good; will do.

Regards,
Christopher

--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.