[PATCH] x86: Clean up files of Intel Processor Trace

[PATCH] x86: Clean up files of Intel Processor Trace

[Takao Indoh]

This patch just cleans up some files of Intel Processor Trace, does not
change its behavior. Removing unused definition, replace a constant
value with macro, etc.

Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
---
 arch/x86/kernel/cpu/intel_pt.h            |   33 +++++-----------------------
 arch/x86/kernel/cpu/perf_event_intel_pt.c |   14 ++++++------
 2 files changed, 13 insertions(+), 34 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_pt.h b/arch/x86/kernel/cpu/intel_pt.h
index 1c338b0..6b48ba8 100644
--- a/arch/x86/kernel/cpu/intel_pt.h
+++ b/arch/x86/kernel/cpu/intel_pt.h
@@ -25,32 +25,11 @@
  */
 #define TOPA_PMI_MARGIN 512
 
-/*
- * Table of Physical Addresses bits
- */
-enum topa_sz {
-	TOPA_4K	= 0,
-	TOPA_8K,
-	TOPA_16K,
-	TOPA_32K,
-	TOPA_64K,
-	TOPA_128K,
-	TOPA_256K,
-	TOPA_512K,
-	TOPA_1MB,
-	TOPA_2MB,
-	TOPA_4MB,
-	TOPA_8MB,
-	TOPA_16MB,
-	TOPA_32MB,
-	TOPA_64MB,
-	TOPA_128MB,
-	TOPA_SZ_END,
-};
+#define TOPA_SHIFT PAGE_SHIFT
 
-static inline unsigned int sizes(enum topa_sz tsz)
+static inline unsigned int sizes(unsigned int tsz)
 {
-	return 1 << (tsz + 12);
+	return 1 << (tsz + TOPA_SHIFT);
 };
 
 struct topa_entry {
@@ -66,8 +45,8 @@ struct topa_entry {
 	u64	rsvd4	: 16;
 };
 
-#define TOPA_SHIFT 12
-#define PT_CPUID_LEAVES 2
+#define PT_CPUID_LEAVES		2
+#define PT_CPUID_REGS_NUM	4 /* number of regsters (eax, ebx, ecx, edx) */
 
 enum pt_capabilities {
 	PT_CAP_max_subleaf = 0,
@@ -79,7 +58,7 @@ enum pt_capabilities {
 
 struct pt_pmu {
 	struct pmu		pmu;
-	u32			caps[4 * PT_CPUID_LEAVES];
+	u32			caps[PT_CPUID_REGS_NUM * PT_CPUID_LEAVES];
 };
 
 /**
diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
index 183de71..1e7d89e 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
@@ -37,9 +37,9 @@ static struct pt_pmu pt_pmu;
 
 enum cpuid_regs {
 	CR_EAX = 0,
+	CR_EBX,
 	CR_ECX,
-	CR_EDX,
-	CR_EBX
+	CR_EDX
 };
 
 /*
@@ -73,7 +73,7 @@ static struct pt_cap_desc {
 static u32 pt_cap_get(enum pt_capabilities cap)
 {
 	struct pt_cap_desc *cd = &pt_caps[cap];
-	u32 c = pt_pmu.caps[cd->leaf * 4 + cd->reg];
+	u32 c = pt_pmu.caps[cd->leaf * PT_CPUID_REGS_NUM + cd->reg];
 	unsigned int shift = __ffs(cd->mask);
 
 	return (c & cd->mask) >> shift;
@@ -129,10 +129,10 @@ static int __init pt_pmu_hw_init(void)
 
 	for (i = 0; i < PT_CPUID_LEAVES; i++) {
 		cpuid_count(20, i,
-			    &pt_pmu.caps[CR_EAX + i*4],
-			    &pt_pmu.caps[CR_EBX + i*4],
-			    &pt_pmu.caps[CR_ECX + i*4],
-			    &pt_pmu.caps[CR_EDX + i*4]);
+			    &pt_pmu.caps[CR_EAX + i*PT_CPUID_REGS_NUM],
+			    &pt_pmu.caps[CR_EBX + i*PT_CPUID_REGS_NUM],
+			    &pt_pmu.caps[CR_ECX + i*PT_CPUID_REGS_NUM],
+			    &pt_pmu.caps[CR_EDX + i*PT_CPUID_REGS_NUM]);
 	}
 
 	ret = -ENOMEM;
-- 
1.7.1

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Alexander Shishkin]

Takao Indoh <indou.takao@jp.fujitsu.com> writes:

> This patch just cleans up some files of Intel Processor Trace, does not
> change its behavior. Removing unused definition, replace a constant
> value with macro, etc.
>
> Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
> ---
>  arch/x86/kernel/cpu/intel_pt.h            |   33 +++++-----------------------
>  arch/x86/kernel/cpu/perf_event_intel_pt.c |   14 ++++++------
>  2 files changed, 13 insertions(+), 34 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/intel_pt.h b/arch/x86/kernel/cpu/intel_pt.h
> index 1c338b0..6b48ba8 100644
> --- a/arch/x86/kernel/cpu/intel_pt.h
> +++ b/arch/x86/kernel/cpu/intel_pt.h
> @@ -25,32 +25,11 @@
>   */
>  #define TOPA_PMI_MARGIN 512
>  
> -/*
> - * Table of Physical Addresses bits
> - */
> -enum topa_sz {
> -	TOPA_4K	= 0,
> -	TOPA_8K,
> -	TOPA_16K,
> -	TOPA_32K,
> -	TOPA_64K,
> -	TOPA_128K,
> -	TOPA_256K,
> -	TOPA_512K,
> -	TOPA_1MB,
> -	TOPA_2MB,
> -	TOPA_4MB,
> -	TOPA_8MB,
> -	TOPA_16MB,
> -	TOPA_32MB,
> -	TOPA_64MB,
> -	TOPA_128MB,
> -	TOPA_SZ_END,
> -};
> +#define TOPA_SHIFT PAGE_SHIFT

Even though TOPA_SHIFT happens to be the same as PAGE_SHIFT, it is a
property of a separate hardware block, not mmu. PAGE_SHIFT is 12, but
12 is not always PAGE_SHIFT.

> -static inline unsigned int sizes(enum topa_sz tsz)
> +static inline unsigned int sizes(unsigned int tsz)
>  {
> -	return 1 << (tsz + 12);
> +	return 1 << (tsz + TOPA_SHIFT);
>  };
>  
>  struct topa_entry {
> @@ -66,8 +45,8 @@ struct topa_entry {
>  	u64	rsvd4	: 16;
>  };
>  
> -#define TOPA_SHIFT 12
> -#define PT_CPUID_LEAVES 2
> +#define PT_CPUID_LEAVES		2
> +#define PT_CPUID_REGS_NUM	4 /* number of regsters (eax, ebx, ecx, edx) */
>  
>  enum pt_capabilities {
>  	PT_CAP_max_subleaf = 0,
> @@ -79,7 +58,7 @@ enum pt_capabilities {
>  
>  struct pt_pmu {
>  	struct pmu		pmu;
> -	u32			caps[4 * PT_CPUID_LEAVES];
> +	u32			caps[PT_CPUID_REGS_NUM * PT_CPUID_LEAVES];
>  };
>  
>  /**
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> index 183de71..1e7d89e 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> @@ -37,9 +37,9 @@ static struct pt_pmu pt_pmu;
>  
>  enum cpuid_regs {
>  	CR_EAX = 0,
> +	CR_EBX,
>  	CR_ECX,
> -	CR_EDX,
> -	CR_EBX
> +	CR_EDX
>  };

This doesn't seem necessary.

Thanks,
--
Alex

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Peter Zijlstra]

On Mon, Aug 03, 2015 at 12:03:13PM +0300, Alexander Shishkin wrote:
> Takao Indoh <indou.takao@jp.fujitsu.com> writes:

> Even though TOPA_SHIFT happens to be the same as PAGE_SHIFT, it is a
> property of a separate hardware block, not mmu. PAGE_SHIFT is 12, but
> 12 is not always PAGE_SHIFT.

PAGE_SHIFT is _always_ 12 on x86. Changing that will require changing
the page table format, a rather unlikely thing to go happen.

> > diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> > index 183de71..1e7d89e 100644
> > --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
> > +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> > @@ -37,9 +37,9 @@ static struct pt_pmu pt_pmu;
> >  
> >  enum cpuid_regs {
> >  	CR_EAX = 0,
> > +	CR_EBX,
> >  	CR_ECX,
> > -	CR_EDX,
> > -	CR_EBX
> > +	CR_EDX
> >  };
> 
> This doesn't seem necessary.

For those of us suffering OCDs and all, its a good change though. The
alfabet song does go: A, B, C, D etc.. after all. Not: A, C, D, B ...

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Alexander Shishkin]

On 3 August 2015 at 12:08, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, Aug 03, 2015 at 12:03:13PM +0300, Alexander Shishkin wrote:
>> Takao Indoh <indou.takao@jp.fujitsu.com> writes:
>
>> Even though TOPA_SHIFT happens to be the same as PAGE_SHIFT, it is a
>> property of a separate hardware block, not mmu. PAGE_SHIFT is 12, but
>> 12 is not always PAGE_SHIFT.
>
> PAGE_SHIFT is _always_ 12 on x86. Changing that will require changing
> the page table format, a rather unlikely thing to go happen.

Of course. Yet that doesn't justify turning every 12 into PAGE_SHIFT
is what I'm saying.

Oh, look, it's PAGE_SHIFT o'clock on x86, time for lunch. :)

Regards,
--
Alex

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Takao Indoh]

On 2015/08/03 18:44, Alexander Shishkin wrote:
> On 3 August 2015 at 12:08, Peter Zijlstra <peterz@infradead.org> wrote:
>> On Mon, Aug 03, 2015 at 12:03:13PM +0300, Alexander Shishkin wrote:
>>> Takao Indoh <indou.takao@jp.fujitsu.com> writes:
>>
>>> Even though TOPA_SHIFT happens to be the same as PAGE_SHIFT, it is a
>>> property of a separate hardware block, not mmu. PAGE_SHIFT is 12, but
>>> 12 is not always PAGE_SHIFT.
>>
>> PAGE_SHIFT is _always_ 12 on x86. Changing that will require changing
>> the page table format, a rather unlikely thing to go happen.
> 
> Of course. Yet that doesn't justify turning every 12 into PAGE_SHIFT
> is what I'm saying.
> 
> Oh, look, it's PAGE_SHIFT o'clock on x86, time for lunch. :)

I thought the base address of output region is page aligned. I took a
look at Intel SDM again, it just says the base address is 4K-aligned
physical address, does not mention page size. So, logically TOPA_SHIFT
and PAGE_SHIFT are different things and I'll remove this change in next
version.

Thanks,
Takao Indoh

> 
> Regards,
> --
> Alex
> 

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Borislav Petkov]

On Mon, Aug 03, 2015 at 11:08:07AM +0200, Peter Zijlstra wrote:
> For those of us suffering OCDs and all, its a good change though. The
> alfabet song does go: A, B, C, D etc.. after all. Not: A, C, D, B ...

... except that x86 encoding orders regs like it was originally: AX,
CX, DX, BX, ... Don't ask me why - looks like someone thought that the
C (count) and D (double precision - AX extension) registers were more
important than B (base).

Or someone was simply illiterate.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH] x86: Clean up files of Intel Processor Trace

[Takao Indoh]

On 2015/08/03 20:03, Borislav Petkov wrote:
> On Mon, Aug 03, 2015 at 11:08:07AM +0200, Peter Zijlstra wrote:
>> For those of us suffering OCDs and all, its a good change though. The
>> alfabet song does go: A, B, C, D etc.. after all. Not: A, C, D, B ...
> 
> ... except that x86 encoding orders regs like it was originally: AX,
> CX, DX, BX, ... Don't ask me why - looks like someone thought that the
> C (count) and D (double precision - AX extension) registers were more
> important than B (base).
> 
> Or someone was simply illiterate.
> 

I thought this was typo. If it is intentional, I'll keep it intact.

Thanks,
Takao Indoh