diff mbox

[16/22] arm64/debug: Make use of the system wide safe value

Message ID 1442413280-31885-17-git-send-email-suzuki.poulose@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Suzuki K Poulose Sept. 16, 2015, 2:21 p.m. UTC 
From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>

Use the system wide value of ID_AA64DFR0 to make safer decisions

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/include/asm/hw_breakpoint.h |   14 ++------------
 arch/arm64/kernel/debug-monitors.c     |    6 ++++--
 arch/arm64/kernel/hw_breakpoint.c      |   19 ++++++++++++++++++-
 3 files changed, 24 insertions(+), 15 deletions(-)

Comments

Vladimir Murzin Sept. 29, 2015, 12:17 p.m. UTC | #1 
On 16/09/15 15:21, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>
> 
> Use the system wide value of ID_AA64DFR0 to make safer decisions
> 
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
> ---
>  arch/arm64/include/asm/hw_breakpoint.h |   14 ++------------
>  arch/arm64/kernel/debug-monitors.c     |    6 ++++--
>  arch/arm64/kernel/hw_breakpoint.c      |   19 ++++++++++++++++++-
>  3 files changed, 24 insertions(+), 15 deletions(-)
> 

Looks like this patch introduces build-time regression if
CONFIG_PERF_EVENTS is not set:

> arch/arm64/kvm/built-in.o: In function `kvm_arm_setup_debug':
> /work/tools/linux/arch/arm64/kvm/debug.c:173: undefined reference to `get_num_brps'
> /work/tools/linux/arch/arm64/kvm/debug.c:177: undefined reference to `get_num_wrps'
> arch/arm64/kvm/built-in.o: In function `kvm_arm_clear_debug':
> /work/tools/linux/arch/arm64/kvm/debug.c:208: undefined reference to `get_num_brps'
> /work/tools/linux/arch/arm64/kvm/debug.c:212: undefined reference to `get_num_wrps'
> arch/arm64/kvm/built-in.o: In function `kvm_arch_dev_ioctl_check_extension':
> /work/tools/linux/arch/arm64/kvm/reset.c:78: undefined reference to `get_num_wrps'
> /work/tools/linux/arch/arm64/kvm/reset.c:75: undefined reference to `get_num_brps'
> make: *** [vmlinux] Error 1

Vladimir
Suzuki K Poulose Sept. 29, 2015, 12:46 p.m. UTC | #2 
On 29/09/15 13:17, Vladimir Murzin wrote:
> On 16/09/15 15:21, Suzuki K. Poulose wrote:
>> From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>
>>
>> Use the system wide value of ID_AA64DFR0 to make safer decisions
>>
>> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
>> ---
>>   arch/arm64/include/asm/hw_breakpoint.h |   14 ++------------
>>   arch/arm64/kernel/debug-monitors.c     |    6 ++++--
>>   arch/arm64/kernel/hw_breakpoint.c      |   19 ++++++++++++++++++-
>>   3 files changed, 24 insertions(+), 15 deletions(-)
>>
>
> Looks like this patch introduces build-time regression if
> CONFIG_PERF_EVENTS is not set:
>
>> arch/arm64/kvm/built-in.o: In function `kvm_arm_setup_debug':
>> /work/tools/linux/arch/arm64/kvm/debug.c:173: undefined reference to `get_num_brps'
>> /work/tools/linux/arch/arm64/kvm/debug.c:177: undefined reference to `get_num_wrps'
>> arch/arm64/kvm/built-in.o: In function `kvm_arm_clear_debug':
>> /work/tools/linux/arch/arm64/kvm/debug.c:208: undefined reference to `get_num_brps'
>> /work/tools/linux/arch/arm64/kvm/debug.c:212: undefined reference to `get_num_wrps'
>> arch/arm64/kvm/built-in.o: In function `kvm_arch_dev_ioctl_check_extension':
>> /work/tools/linux/arch/arm64/kvm/reset.c:78: undefined reference to `get_num_wrps'
>> /work/tools/linux/arch/arm64/kvm/reset.c:75: undefined reference to `get_num_brps'
>> make: *** [vmlinux] Error 1
>
> Vladimir
>

Thanks for pointing this out. I will fix it by moving the get_num_xrps() definition
back to hw_breakpoint.h.

Suzuki
Suzuki K Poulose Sept. 30, 2015, 4:13 p.m. UTC | #3 
On 29/09/15 13:17, Vladimir Murzin wrote:
> On 16/09/15 15:21, Suzuki K. Poulose wrote:
>> From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>
>>
>> Use the system wide value of ID_AA64DFR0 to make safer decisions
>>
>> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
>> ---
>>   arch/arm64/include/asm/hw_breakpoint.h |   14 ++------------
>>   arch/arm64/kernel/debug-monitors.c     |    6 ++++--
>>   arch/arm64/kernel/hw_breakpoint.c      |   19 ++++++++++++++++++-
>>   3 files changed, 24 insertions(+), 15 deletions(-)
>>
>
> Looks like this patch introduces build-time regression if
> CONFIG_PERF_EVENTS is not set:
>
>> arch/arm64/kvm/built-in.o: In function `kvm_arm_setup_debug':
>> /work/tools/linux/arch/arm64/kvm/debug.c:173: undefined reference to `get_num_brps'
>> /work/tools/linux/arch/arm64/kvm/debug.c:177: undefined reference to `get_num_wrps'
>> arch/arm64/kvm/built-in.o: In function `kvm_arm_clear_debug':
>> /work/tools/linux/arch/arm64/kvm/debug.c:208: undefined reference to `get_num_brps'
>> /work/tools/linux/arch/arm64/kvm/debug.c:212: undefined reference to `get_num_wrps'
>> arch/arm64/kvm/built-in.o: In function `kvm_arch_dev_ioctl_check_extension':
>> /work/tools/linux/arch/arm64/kvm/reset.c:78: undefined reference to `get_num_wrps'
>> /work/tools/linux/arch/arm64/kvm/reset.c:75: undefined reference to `get_num_brps'
>> make: *** [vmlinux] Error 1

The fixed series is available here :

git://linux-arm.org/linux-skp.git cpu-ftr/v1.1-4.3-rc3


I will wait for some more comments/review before I sent the updated
version to the list.

Thanks
Suzuki
diff mbox

Patch

diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h
index 4c47cb2..0251768 100644
--- a/arch/arm64/include/asm/hw_breakpoint.h
+++ b/arch/arm64/include/asm/hw_breakpoint.h
@@ -119,6 +119,8 @@  extern int arch_install_hw_breakpoint(struct perf_event *bp);
 extern void arch_uninstall_hw_breakpoint(struct perf_event *bp);
 extern void hw_breakpoint_pmu_read(struct perf_event *bp);
 extern int hw_breakpoint_slots(int type);
+extern int get_num_brps(void);
+extern int get_num_wrps(void);
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 extern void hw_breakpoint_thread_switch(struct task_struct *next);
@@ -134,17 +136,5 @@  static inline void ptrace_hw_copy_thread(struct task_struct *task)
 
 extern struct pmu perf_ops_bp;
 
-/* Determine number of BRP registers available. */
-static inline int get_num_brps(void)
-{
-	return ((read_cpuid(ID_AA64DFR0_EL1) >> 12) & 0xf) + 1;
-}
-
-/* Determine number of WRP registers available. */
-static inline int get_num_wrps(void)
-{
-	return ((read_cpuid(ID_AA64DFR0_EL1) >> 20) & 0xf) + 1;
-}
-
 #endif	/* __KERNEL__ */
 #endif	/* __ASM_BREAKPOINT_H */
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 9b3b62a..9ca5f77 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -26,14 +26,16 @@ 
 #include <linux/stat.h>
 #include <linux/uaccess.h>
 
-#include <asm/debug-monitors.h>
+#include <asm/cpufeature.h>
 #include <asm/cputype.h>
+#include <asm/debug-monitors.h>
 #include <asm/system_misc.h>
 
 /* Determine debug architecture. */
 u8 debug_monitors_arch(void)
 {
-	return read_cpuid(ID_AA64DFR0_EL1) & 0xf;
+	return cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
+						ID_AA64DFR0_DEBUGVER_SHIFT);
 }
 
 /*
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index c97040e..1fa0476 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -28,11 +28,12 @@ 
 #include <linux/ptrace.h>
 #include <linux/smp.h>
 
+#include <asm/cpufeature.h>
+#include <asm/cputype.h>
 #include <asm/current.h>
 #include <asm/debug-monitors.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/traps.h>
-#include <asm/cputype.h>
 #include <asm/system_misc.h>
 
 /* Breakpoint currently in use for each BRP. */
@@ -48,6 +49,22 @@  static DEFINE_PER_CPU(int, stepping_kernel_bp);
 static int core_num_brps;
 static int core_num_wrps;
 
+/* Determine number of BRP registers available. */
+int get_num_brps(void)
+{
+	return 1 +
+	      	cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
+						ID_AA64DFR0_BRPS_SHIFT);
+}
+
+/* Determine number of WRP registers available. */
+int get_num_wrps(void)
+{
+	return 1 +
+	      	cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
+						ID_AA64DFR0_WRPS_SHIFT);
+}
+
 int hw_breakpoint_slots(int type)
 {
 	/*