[RFC PATCH 1/3] perf/core: extend perf_regs to include arch specific regs

From: Madhavan Srinivasan
Date: Wed Nov 04 2015 - 15:46:48 EST


As a foundation patch, new structure called arch_misc_regs
added to perf_regs. And perf_reg_value() is modified to expect
perf_regs instead of pt_regs. This way, perf_reg_value() can decide
on the struct to pick based on the register idx.

Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
---
Will really appreciate comments and feedback for the patch

arch/arm/include/asm/ptrace.h | 2 ++
arch/arm/kernel/perf_regs.c | 4 +++-
arch/arm64/include/asm/ptrace.h | 2 ++
arch/arm64/kernel/perf_regs.c | 4 +++-
arch/powerpc/include/uapi/asm/ptrace.h | 2 ++
arch/powerpc/perf/perf_regs.c | 4 +++-
arch/x86/include/asm/ptrace.h | 2 ++
arch/x86/kernel/perf_regs.c | 4 +++-
include/linux/perf_regs.h | 5 +++--
kernel/events/core.c | 6 +++---
10 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 51622ba7c4a6..26cd8dbf1f02 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -17,6 +17,8 @@ struct pt_regs {
unsigned long uregs[18];
};

+struct arch_misc_regs {};
+
#define user_mode(regs) \
(((regs)->ARM_cpsr & 0xf) == 0)

diff --git a/arch/arm/kernel/perf_regs.c b/arch/arm/kernel/perf_regs.c
index 592dda3f21ff..18999abbadbe 100644
--- a/arch/arm/kernel/perf_regs.c
+++ b/arch/arm/kernel/perf_regs.c
@@ -6,8 +6,10 @@
#include <asm/perf_regs.h>
#include <asm/ptrace.h>

-u64 perf_reg_value(struct pt_regs *regs, int idx)
+u64 perf_reg_value(struct perf_regs *p_regs, int idx)
{
+ struct pt_regs *regs = p_regs->regs;
+
if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM_MAX))
return 0;

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 536274ed292e..9a33ab69f19f 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -118,6 +118,8 @@ struct pt_regs {
u64 syscallno;
};

+struct arch_misc_regs {};
+
#define arch_has_single_step() (1)

#ifdef CONFIG_COMPAT
diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c
index 3f62b35fb6f1..8ee80d7c8604 100644
--- a/arch/arm64/kernel/perf_regs.c
+++ b/arch/arm64/kernel/perf_regs.c
@@ -7,8 +7,10 @@
#include <asm/perf_regs.h>
#include <asm/ptrace.h>

-u64 perf_reg_value(struct pt_regs *regs, int idx)
+u64 perf_reg_value(struct perf_regs *p_regs, int idx)
{
+ struct pt_regs *regs = p_regs->regs;
+
if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
return 0;

diff --git a/arch/powerpc/include/uapi/asm/ptrace.h b/arch/powerpc/include/uapi/asm/ptrace.h
index 8036b385417d..0025651ab8bc 100644
--- a/arch/powerpc/include/uapi/asm/ptrace.h
+++ b/arch/powerpc/include/uapi/asm/ptrace.h
@@ -51,6 +51,8 @@ struct pt_regs {
unsigned long result; /* Result of a system call */
};

+struct arch_misc_regs {};
+
#endif /* __ASSEMBLY__ */


diff --git a/arch/powerpc/perf/perf_regs.c b/arch/powerpc/perf/perf_regs.c
index 0520492d4078..f7995b46078a 100644
--- a/arch/powerpc/perf/perf_regs.c
+++ b/arch/powerpc/perf/perf_regs.c
@@ -61,8 +61,10 @@ static unsigned int pt_regs_offset[PERF_REG_POWERPC_MAX] = {
PT_REGS_OFFSET(PERF_REG_POWERPC_DSISR, dsisr),
};

-u64 perf_reg_value(struct pt_regs *regs, int idx)
+u64 perf_reg_value(struct perf_regs *p_regs, int idx)
{
+ struct pt_regs *regs = p_regs->regs;
+
if (WARN_ON_ONCE(idx >= PERF_REG_POWERPC_MAX))
return 0;
return regs_get_register(regs, pt_regs_offset[idx]);
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 6271281f947d..410a2eb885c1 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -67,6 +67,8 @@ struct pt_regs {

#endif /* !__i386__ */

+struct arch_misc_regs {};
+
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt_types.h>
#endif
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index da8cb987b973..c6e41f7f648b 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -55,8 +55,10 @@ static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
#endif
};

-u64 perf_reg_value(struct pt_regs *regs, int idx)
+u64 perf_reg_value(struct perf_regs *p_regs, int idx)
{
+ struct pt_regs *regs = p_regs->regs;
+
if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
return 0;

diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
index a5f98d53d732..7727a30e7d84 100644
--- a/include/linux/perf_regs.h
+++ b/include/linux/perf_regs.h
@@ -4,18 +4,19 @@
struct perf_regs {
__u64 abi;
struct pt_regs *regs;
+ struct arch_misc_regs *arch_regs;
};

#ifdef CONFIG_HAVE_PERF_REGS
#include <asm/perf_regs.h>
-u64 perf_reg_value(struct pt_regs *regs, int idx);
+u64 perf_reg_value(struct perf_regs *p_regs, int idx);
int perf_reg_validate(u64 mask);
u64 perf_reg_abi(struct task_struct *task);
void perf_get_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs,
struct pt_regs *regs_user_copy);
#else
-static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
+static inline u64 perf_reg_value(struct perf_regs *p_regs, int idx)
{
return 0;
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b11756f9b6dc..c04bdad3d365 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4934,7 +4934,7 @@ EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

static void
perf_output_sample_regs(struct perf_output_handle *handle,
- struct pt_regs *regs, u64 mask)
+ struct perf_regs *regs, u64 mask)
{
int bit;

@@ -5331,7 +5331,7 @@ void perf_output_sample(struct perf_output_handle *handle,
if (abi) {
u64 mask = event->attr.sample_regs_user;
perf_output_sample_regs(handle,
- data->regs_user.regs,
+ &data->regs_user,
mask);
}
}
@@ -5363,7 +5363,7 @@ void perf_output_sample(struct perf_output_handle *handle,
u64 mask = event->attr.sample_regs_intr;

perf_output_sample_regs(handle,
- data->regs_intr.regs,
+ &data->regs_intr,
mask);
}
}
--
1.9.1

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