[PATCH 07/31] Add mips-specific parity functions

[PATCH 07/31] Add mips-specific parity functions

[zhaoxiu.zeng]

From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>

Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
---
 arch/mips/include/asm/arch_parity.h | 44 +++++++++++++++++++++++++++++++++++++
 arch/mips/include/asm/bitops.h      |  3 +++
 2 files changed, 47 insertions(+)
 create mode 100644 arch/mips/include/asm/arch_parity.h

diff --git a/arch/mips/include/asm/arch_parity.h b/arch/mips/include/asm/arch_parity.h
new file mode 100644
index 0000000..23b3c23
--- /dev/null
+++ b/arch/mips/include/asm/arch_parity.h
@@ -0,0 +1,44 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ */
+#ifndef _ASM_ARCH_PARITY_H
+#define _ASM_ARCH_PARITY_H
+
+#ifdef ARCH_HAS_USABLE_BUILTIN_POPCOUNT
+
+#include <asm/types.h>
+
+static inline unsigned int __arch_parity32(unsigned int w)
+{
+	return __builtin_popcount(w) & 1;
+}
+
+static inline unsigned int __arch_parity16(unsigned int w)
+{
+	return __arch_parity32(w & 0xffff);
+}
+
+static inline unsigned int __arch_parity8(unsigned int w)
+{
+	return __arch_parity32(w & 0xff);
+}
+
+static inline unsigned int __arch_parity4(unsigned int w)
+{
+	return __arch_parity32(w & 0xf);
+}
+
+static inline unsigned int __arch_parity64(__u64 w)
+{
+	return (unsigned int)__builtin_popcountll(w) & 1;
+}
+
+#else
+#include <asm-generic/bitops/arch_hweight.h>
+#include <asm-generic/bitops/arch_parity.h>
+#endif
+
+#endif /* _ASM_ARCH_PARITY_H */
diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index ce9666c..0b87734 100644
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -626,6 +626,9 @@ static inline int ffs(int word)
 #include <asm/arch_hweight.h>
 #include <asm-generic/bitops/const_hweight.h>
 
+#include <asm/arch_parity.h>
+#include <asm-generic/bitops/const_parity.h>
+
 #include <asm-generic/bitops/le.h>
 #include <asm-generic/bitops/ext2-atomic.h>
 
-- 
2.5.5

[PATCH 13/31] mips: use parity functions in cerr-sb1.c

[zhaoxiu.zeng]

From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>

Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
---
 arch/mips/mm/cerr-sb1.c | 67 +++++++++++++------------------------------------
 1 file changed, 17 insertions(+), 50 deletions(-)

diff --git a/arch/mips/mm/cerr-sb1.c b/arch/mips/mm/cerr-sb1.c
index ee5c1ff..2e7d660 100644
--- a/arch/mips/mm/cerr-sb1.c
+++ b/arch/mips/mm/cerr-sb1.c
@@ -264,27 +264,6 @@ asmlinkage void sb1_cache_error(void)
 #endif
 }
 
-
-/* Parity lookup table. */
-static const uint8_t parity[256] = {
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
-	0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0
-};
-
 /* Masks to select bits for Hamming parity, mask_72_64[i] for bit[i] */
 static const uint64_t mask_72_64[8] = {
 	0x0738C808099264FFULL,
@@ -298,34 +277,28 @@ static const uint64_t mask_72_64[8] = {
 };
 
 /* Calculate the parity on a range of bits */
-static char range_parity(uint64_t dword, int max, int min)
+static inline char range_parity(uint64_t dword, int max, int min)
 {
-	char parity = 0;
-	int i;
-	dword >>= min;
-	for (i=max-min; i>=0; i--) {
-		if (dword & 0x1)
-			parity = !parity;
-		dword >>= 1;
+	int n = max - min + 1;
+	if (__builtin_constant_p(n)) {
+		if (n <= 8)
+			return parity8((unsigned int)(dword >> min) & ((1U << n) - 1));
+		if (n <= 16)
+			return parity16((unsigned int)(dword >> min) & ((1U << n) - 1));
+		if (n <= 32)
+			return parity32((unsigned int)(dword >> min) & ((1U << n) - 1));
 	}
-	return parity;
+	return parity64((dword >> min) & ((1ULL << n) - 1));
 }
 
 /* Calculate the 4-bit even byte-parity for an instruction */
-static unsigned char inst_parity(uint32_t word)
+static inline unsigned char inst_parity(uint32_t word)
 {
-	int i, j;
-	char parity = 0;
-	for (j=0; j<4; j++) {
-		char byte_parity = 0;
-		for (i=0; i<8; i++) {
-			if (word & 0x80000000)
-				byte_parity = !byte_parity;
-			word <<= 1;
-		}
-		parity <<= 1;
-		parity |= byte_parity;
-	}
+	char parity;
+	parity  = parity8(word >> 24) << 3;
+	parity |= parity8(word >> 16) << 2;
+	parity |= parity8(word >> 8) << 1;
+	parity |= parity8(word);
 	return parity;
 }
 
@@ -436,7 +409,6 @@ static uint32_t extract_ic(unsigned short addr, int data)
 static uint8_t dc_ecc(uint64_t dword)
 {
 	uint64_t t;
-	uint32_t w;
 	uint8_t	 p;
 	int	 i;
 
@@ -445,12 +417,7 @@ static uint8_t dc_ecc(uint64_t dword)
 	{
 		p <<= 1;
 		t = dword & mask_72_64[i];
-		w = (uint32_t)(t >> 32);
-		p ^= (parity[w>>24] ^ parity[(w>>16) & 0xFF]
-		      ^ parity[(w>>8) & 0xFF] ^ parity[w & 0xFF]);
-		w = (uint32_t)(t & 0xFFFFFFFF);
-		p ^= (parity[w>>24] ^ parity[(w>>16) & 0xFF]
-		      ^ parity[(w>>8) & 0xFF] ^ parity[w & 0xFF]);
+		p |= parity64(t);
 	}
 	return p;
 }
-- 
2.5.5

Re: [PATCH 07/31] Add mips-specific parity functions

[David Daney]

On 03/26/2016 11:06 PM, zhaoxiu.zeng wrote:
> From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
>

There is nothing MIPS specific here.  Why not put it in asm-generic or 
some similar place where it can be shared by all architectures?

Also, are you sure __builtin_popcount() is available on all GCC versions 
that are supported for building the kernel?

David Daney


> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
> ---
>   arch/mips/include/asm/arch_parity.h | 44 +++++++++++++++++++++++++++++++++++++
>   arch/mips/include/asm/bitops.h      |  3 +++
>   2 files changed, 47 insertions(+)
>   create mode 100644 arch/mips/include/asm/arch_parity.h
>
> diff --git a/arch/mips/include/asm/arch_parity.h b/arch/mips/include/asm/arch_parity.h
> new file mode 100644
> index 0000000..23b3c23
> --- /dev/null
> +++ b/arch/mips/include/asm/arch_parity.h
> @@ -0,0 +1,44 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + */
> +#ifndef _ASM_ARCH_PARITY_H
> +#define _ASM_ARCH_PARITY_H
> +
> +#ifdef ARCH_HAS_USABLE_BUILTIN_POPCOUNT
> +
> +#include <asm/types.h>
> +
> +static inline unsigned int __arch_parity32(unsigned int w)
> +{
> +	return __builtin_popcount(w) & 1;
> +}
> +
> +static inline unsigned int __arch_parity16(unsigned int w)
> +{
> +	return __arch_parity32(w & 0xffff);
> +}
> +
> +static inline unsigned int __arch_parity8(unsigned int w)
> +{
> +	return __arch_parity32(w & 0xff);
> +}
> +
> +static inline unsigned int __arch_parity4(unsigned int w)
> +{
> +	return __arch_parity32(w & 0xf);
> +}
> +
> +static inline unsigned int __arch_parity64(__u64 w)
> +{
> +	return (unsigned int)__builtin_popcountll(w) & 1;
> +}
> +
> +#else
> +#include <asm-generic/bitops/arch_hweight.h>
> +#include <asm-generic/bitops/arch_parity.h>
> +#endif
> +
> +#endif /* _ASM_ARCH_PARITY_H */
> diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
> index ce9666c..0b87734 100644
> --- a/arch/mips/include/asm/bitops.h
> +++ b/arch/mips/include/asm/bitops.h
> @@ -626,6 +626,9 @@ static inline int ffs(int word)
>   #include <asm/arch_hweight.h>
>   #include <asm-generic/bitops/const_hweight.h>
>
> +#include <asm/arch_parity.h>
> +#include <asm-generic/bitops/const_parity.h>
> +
>   #include <asm-generic/bitops/le.h>
>   #include <asm-generic/bitops/ext2-atomic.h>
>
>

Re: [PATCH 07/31] Add mips-specific parity functions

[Zeng Zhaoxiu]

在 2016年03月29日 01:25, David Daney 写道:
> On 03/26/2016 11:06 PM, zhaoxiu.zeng wrote:
>> From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
>>
>
> There is nothing MIPS specific here.  Why not put it in asm-generic or 
> some similar place where it can be shared by all architectures?
>
> Also, are you sure __builtin_popcount() is available on all GCC 
> versions that are supported for building the kernel?
>
> David Daney
>

Refrence to arch_hweight.h.

In the 68th line of 
arch/mips/include/asm/mach-cavium-octeon/cpu-feature-overrides.h, we can 
see:

#ifdef __OCTEON__
/*
  * All gcc versions that have OCTEON support define __OCTEON__ and have the
  *  __builtin_popcount support.
  */
#define ARCH_HAS_USABLE_BUILTIN_POPCOUNT 1
#endif

/*
  * All gcc versions that have OCTEON support define __OCTEON__ and have the
  *  __builtin_popcount support.
  */

>> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
>> ---
>>   arch/mips/include/asm/arch_parity.h | 44 
>> +++++++++++++++++++++++++++++++++++++
>>   arch/mips/include/asm/bitops.h      |  3 +++
>>   2 files changed, 47 insertions(+)
>>   create mode 100644 arch/mips/include/asm/arch_parity.h
>>
>> diff --git a/arch/mips/include/asm/arch_parity.h 
>> b/arch/mips/include/asm/arch_parity.h
>> new file mode 100644
>> index 0000000..23b3c23
>> --- /dev/null
>> +++ b/arch/mips/include/asm/arch_parity.h
>> @@ -0,0 +1,44 @@
>> +/*
>> + * This file is subject to the terms and conditions of the GNU 
>> General Public
>> + * License.  See the file "COPYING" in the main directory of this 
>> archive
>> + * for more details.
>> + *
>> + */
>> +#ifndef _ASM_ARCH_PARITY_H
>> +#define _ASM_ARCH_PARITY_H
>> +
>> +#ifdef ARCH_HAS_USABLE_BUILTIN_POPCOUNT
>> +
>> +#include <asm/types.h>
>> +
>> +static inline unsigned int __arch_parity32(unsigned int w)
>> +{
>> +    return __builtin_popcount(w) & 1;
>> +}
>> +
>> +static inline unsigned int __arch_parity16(unsigned int w)
>> +{
>> +    return __arch_parity32(w & 0xffff);
>> +}
>> +
>> +static inline unsigned int __arch_parity8(unsigned int w)
>> +{
>> +    return __arch_parity32(w & 0xff);
>> +}
>> +
>> +static inline unsigned int __arch_parity4(unsigned int w)
>> +{
>> +    return __arch_parity32(w & 0xf);
>> +}
>> +
>> +static inline unsigned int __arch_parity64(__u64 w)
>> +{
>> +    return (unsigned int)__builtin_popcountll(w) & 1;
>> +}
>> +
>> +#else
>> +#include <asm-generic/bitops/arch_hweight.h>
>> +#include <asm-generic/bitops/arch_parity.h>
>> +#endif
>> +
>> +#endif /* _ASM_ARCH_PARITY_H */
>> diff --git a/arch/mips/include/asm/bitops.h 
>> b/arch/mips/include/asm/bitops.h
>> index ce9666c..0b87734 100644
>> --- a/arch/mips/include/asm/bitops.h
>> +++ b/arch/mips/include/asm/bitops.h
>> @@ -626,6 +626,9 @@ static inline int ffs(int word)
>>   #include <asm/arch_hweight.h>
>>   #include <asm-generic/bitops/const_hweight.h>
>>
>> +#include <asm/arch_parity.h>
>> +#include <asm-generic/bitops/const_parity.h>
>> +
>>   #include <asm-generic/bitops/le.h>
>>   #include <asm-generic/bitops/ext2-atomic.h>
>>
>>
>