2008-11-30 02:41:47

by Harvey Harrison

[permalink] [raw]
Subject: [PATCH-mm 4/7] sh: wire up arch overrides for unaligned access on the SH4a

Signed-off-by: Harvey Harrison <[email protected]>
---
arch/sh/include/asm/unaligned-sh4a.h | 258 ----------------------------------
arch/sh/include/asm/unaligned.h | 76 ++++++++--
2 files changed, 61 insertions(+), 273 deletions(-)

diff --git a/arch/sh/include/asm/unaligned-sh4a.h b/arch/sh/include/asm/unaligned-sh4a.h
deleted file mode 100644
index d8f8977..0000000
--- a/arch/sh/include/asm/unaligned-sh4a.h
+++ /dev/null
@@ -1,258 +0,0 @@
-#ifndef __ASM_SH_UNALIGNED_SH4A_H
-#define __ASM_SH_UNALIGNED_SH4A_H
-
-/*
- * SH-4A has support for unaligned 32-bit loads, and 32-bit loads only.
- * Support for 16 and 64-bit accesses are done through shifting and
- * masking relative to the endianness. Unaligned stores are not supported
- * by the instruction encoding, so these continue to use the packed
- * struct.
- *
- * The same note as with the movli.l/movco.l pair applies here, as long
- * as the load is gauranteed to be inlined, nothing else will hook in to
- * r0 and we get the return value for free.
- *
- * NOTE: Due to the fact we require r0 encoding, care should be taken to
- * avoid mixing these heavily with other r0 consumers, such as the atomic
- * ops. Failure to adhere to this can result in the compiler running out
- * of spill registers and blowing up when building at low optimization
- * levels. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34777.
- */
-#include <linux/types.h>
-#include <asm/byteorder.h>
-
-static __always_inline u32 __get_unaligned_cpu32(const u8 *p)
-{
- unsigned long unaligned;
-
- __asm__ __volatile__ (
- "movua.l @%1, %0\n\t"
- : "=z" (unaligned)
- : "r" (p)
- );
-
- return unaligned;
-}
-
-struct __una_u16 { u16 x __attribute__((packed)); };
-struct __una_u32 { u32 x __attribute__((packed)); };
-struct __una_u64 { u64 x __attribute__((packed)); };
-
-static inline u16 __get_unaligned_cpu16(const u8 *p)
-{
-#ifdef __LITTLE_ENDIAN
- return __get_unaligned_cpu32(p) & 0xffff;
-#else
- return __get_unaligned_cpu32(p) >> 16;
-#endif
-}
-
-/*
- * Even though movua.l supports auto-increment on the read side, it can
- * only store to r0 due to instruction encoding constraints, so just let
- * the compiler sort it out on its own.
- */
-static inline u64 __get_unaligned_cpu64(const u8 *p)
-{
-#ifdef __LITTLE_ENDIAN
- return (u64)__get_unaligned_cpu32(p + 4) << 32 |
- __get_unaligned_cpu32(p);
-#else
- return (u64)__get_unaligned_cpu32(p) << 32 |
- __get_unaligned_cpu32(p + 4);
-#endif
-}
-
-static inline u16 get_unaligned_le16(const void *p)
-{
- return le16_to_cpu(__get_unaligned_cpu16(p));
-}
-
-static inline u32 get_unaligned_le32(const void *p)
-{
- return le32_to_cpu(__get_unaligned_cpu32(p));
-}
-
-static inline u64 get_unaligned_le64(const void *p)
-{
- return le64_to_cpu(__get_unaligned_cpu64(p));
-}
-
-static inline u16 get_unaligned_be16(const void *p)
-{
- return be16_to_cpu(__get_unaligned_cpu16(p));
-}
-
-static inline u32 get_unaligned_be32(const void *p)
-{
- return be32_to_cpu(__get_unaligned_cpu32(p));
-}
-
-static inline u64 get_unaligned_be64(const void *p)
-{
- return be64_to_cpu(__get_unaligned_cpu64(p));
-}
-
-static inline void __put_le16_noalign(u8 *p, u16 val)
-{
- *p++ = val;
- *p++ = val >> 8;
-}
-
-static inline void __put_le32_noalign(u8 *p, u32 val)
-{
- __put_le16_noalign(p, val);
- __put_le16_noalign(p + 2, val >> 16);
-}
-
-static inline void __put_le64_noalign(u8 *p, u64 val)
-{
- __put_le32_noalign(p, val);
- __put_le32_noalign(p + 4, val >> 32);
-}
-
-static inline void __put_be16_noalign(u8 *p, u16 val)
-{
- *p++ = val >> 8;
- *p++ = val;
-}
-
-static inline void __put_be32_noalign(u8 *p, u32 val)
-{
- __put_be16_noalign(p, val >> 16);
- __put_be16_noalign(p + 2, val);
-}
-
-static inline void __put_be64_noalign(u8 *p, u64 val)
-{
- __put_be32_noalign(p, val >> 32);
- __put_be32_noalign(p + 4, val);
-}
-
-static inline void put_unaligned_le16(u16 val, void *p)
-{
-#ifdef __LITTLE_ENDIAN
- ((struct __una_u16 *)p)->x = val;
-#else
- __put_le16_noalign(p, val);
-#endif
-}
-
-static inline void put_unaligned_le32(u32 val, void *p)
-{
-#ifdef __LITTLE_ENDIAN
- ((struct __una_u32 *)p)->x = val;
-#else
- __put_le32_noalign(p, val);
-#endif
-}
-
-static inline void put_unaligned_le64(u64 val, void *p)
-{
-#ifdef __LITTLE_ENDIAN
- ((struct __una_u64 *)p)->x = val;
-#else
- __put_le64_noalign(p, val);
-#endif
-}
-
-static inline void put_unaligned_be16(u16 val, void *p)
-{
-#ifdef __BIG_ENDIAN
- ((struct __una_u16 *)p)->x = val;
-#else
- __put_be16_noalign(p, val);
-#endif
-}
-
-static inline void put_unaligned_be32(u32 val, void *p)
-{
-#ifdef __BIG_ENDIAN
- ((struct __una_u32 *)p)->x = val;
-#else
- __put_be32_noalign(p, val);
-#endif
-}
-
-static inline void put_unaligned_be64(u64 val, void *p)
-{
-#ifdef __BIG_ENDIAN
- ((struct __una_u64 *)p)->x = val;
-#else
- __put_be64_noalign(p, val);
-#endif
-}
-
-/*
- * Cause a link-time error if we try an unaligned access other than
- * 1,2,4 or 8 bytes long
- */
-extern void __bad_unaligned_access_size(void);
-
-#define __get_unaligned_le(ptr) ((__force typeof(*(ptr)))({ \
- __builtin_choose_expr(sizeof(*(ptr)) == 1, *(ptr), \
- __builtin_choose_expr(sizeof(*(ptr)) == 2, get_unaligned_le16((ptr)), \
- __builtin_choose_expr(sizeof(*(ptr)) == 4, get_unaligned_le32((ptr)), \
- __builtin_choose_expr(sizeof(*(ptr)) == 8, get_unaligned_le64((ptr)), \
- __bad_unaligned_access_size())))); \
- }))
-
-#define __get_unaligned_be(ptr) ((__force typeof(*(ptr)))({ \
- __builtin_choose_expr(sizeof(*(ptr)) == 1, *(ptr), \
- __builtin_choose_expr(sizeof(*(ptr)) == 2, get_unaligned_be16((ptr)), \
- __builtin_choose_expr(sizeof(*(ptr)) == 4, get_unaligned_be32((ptr)), \
- __builtin_choose_expr(sizeof(*(ptr)) == 8, get_unaligned_be64((ptr)), \
- __bad_unaligned_access_size())))); \
- }))
-
-#define __put_unaligned_le(val, ptr) ({ \
- void *__gu_p = (ptr); \
- switch (sizeof(*(ptr))) { \
- case 1: \
- *(u8 *)__gu_p = (__force u8)(val); \
- break; \
- case 2: \
- put_unaligned_le16((__force u16)(val), __gu_p); \
- break; \
- case 4: \
- put_unaligned_le32((__force u32)(val), __gu_p); \
- break; \
- case 8: \
- put_unaligned_le64((__force u64)(val), __gu_p); \
- break; \
- default: \
- __bad_unaligned_access_size(); \
- break; \
- } \
- (void)0; })
-
-#define __put_unaligned_be(val, ptr) ({ \
- void *__gu_p = (ptr); \
- switch (sizeof(*(ptr))) { \
- case 1: \
- *(u8 *)__gu_p = (__force u8)(val); \
- break; \
- case 2: \
- put_unaligned_be16((__force u16)(val), __gu_p); \
- break; \
- case 4: \
- put_unaligned_be32((__force u32)(val), __gu_p); \
- break; \
- case 8: \
- put_unaligned_be64((__force u64)(val), __gu_p); \
- break; \
- default: \
- __bad_unaligned_access_size(); \
- break; \
- } \
- (void)0; })
-
-#ifdef __LITTLE_ENDIAN
-# define get_unaligned __get_unaligned_le
-# define put_unaligned __put_unaligned_le
-#else
-# define get_unaligned __get_unaligned_be
-# define put_unaligned __put_unaligned_be
-#endif
-
-#endif /* __ASM_SH_UNALIGNED_SH4A_H */
diff --git a/arch/sh/include/asm/unaligned.h b/arch/sh/include/asm/unaligned.h
index 8c0ad5e..ac91e0d 100644
--- a/arch/sh/include/asm/unaligned.h
+++ b/arch/sh/include/asm/unaligned.h
@@ -1,24 +1,70 @@
#ifndef _ASM_SH_UNALIGNED_H
#define _ASM_SH_UNALIGNED_H

+#include <linux/types.h>
+#include <asm/byteorder.h>
+
#ifdef CONFIG_CPU_SH4A
-/* SH-4A can handle unaligned loads in a relatively neutered fashion. */
-#include <asm/unaligned-sh4a.h>
-#else
-/* Otherwise, SH can't handle unaligned accesses. */
-#ifdef __LITTLE_ENDIAN__
-# include <linux/unaligned/le_struct.h>
-# include <linux/unaligned/be_byteshift.h>
-# include <linux/unaligned/generic.h>
-# define get_unaligned __get_unaligned_le
-# define put_unaligned __put_unaligned_le
+/*
+ * SH-4A has support for unaligned 32-bit loads, and 32-bit loads only.
+ * Support for 16 and 64-bit accesses are done through shifting and
+ * masking relative to the endianness. Unaligned stores are not supported
+ * by the instruction encoding, so these continue to use the packed
+ * struct.
+ *
+ * The same note as with the movli.l/movco.l pair applies here, as long
+ * as the load is gauranteed to be inlined, nothing else will hook in to
+ * r0 and we get the return value for free.
+ *
+ * NOTE: Due to the fact we require r0 encoding, care should be taken to
+ * avoid mixing these heavily with other r0 consumers, such as the atomic
+ * ops. Failure to adhere to this can result in the compiler running out
+ * of spill registers and blowing up when building at low optimization
+ * levels. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34777.
+ */
+
+static inline u32 __arch_load_cpu32_noalign(const u8 *p)
+{
+ unsigned long unaligned;
+
+ __asm__ __volatile__ (
+ "movua.l @%1, %0\n\t"
+ : "=z" (unaligned)
+ : "r" (p)
+ );
+
+ return unaligned;
+}
+#define __arch_load_cpu32_noalign __arch_load_cpu32_noalign
+
+static inline u16 __arch_load_cpu16_noalign(const u8 *p)
+{
+#ifdef __LITTLE_ENDIAN
+ return __arch_load_cpu32_noalign(p) & 0xffff;
#else
-# include <linux/unaligned/be_struct.h>
-# include <linux/unaligned/le_byteshift.h>
-# include <linux/unaligned/generic.h>
-# define get_unaligned __get_unaligned_be
-# define put_unaligned __put_unaligned_be
+ return __arch_load_cpu32_noalign(p) >> 16;
#endif
+}
+#define __arch_load_cpu16_noalign __arch_load_cpu16_noalign
+
+/*
+ * Even though movua.l supports auto-increment on the read side, it can
+ * only store to r0 due to instruction encoding constraints, so just let
+ * the compiler sort it out on its own.
+ */
+static inline u64 __arch_load_cpu64_noalign(const u8 *p)
+{
+#ifdef __LITTLE_ENDIAN
+ return (u64)__arch_load_cpu32_noalign(p + 4) << 32 |
+ __arch_load_cpu32_noalign(p);
+#else
+ return (u64)__arch_load_cpu32_noalign(p) << 32 |
+ __arch_load_cpu32_noalign(p + 4);
#endif
+}
+#define __arch_load_cpu64_noalign __arch_load_cpu64_noalign
+
+#endif /* CONFIG_CPU_SH4A */

+#include <linux/unaligned.h>
#endif /* _ASM_SH_UNALIGNED_H */
--
1.6.0.4.1044.g77718


2008-12-01 06:53:04

by Paul Mundt

[permalink] [raw]
Subject: Re: [PATCH-mm 4/7] sh: wire up arch overrides for unaligned access on the SH4a

On Sat, Nov 29, 2008 at 06:40:30PM -0800, Harvey Harrison wrote:
> Signed-off-by: Harvey Harrison <[email protected]>
> ---
> arch/sh/include/asm/unaligned-sh4a.h | 258 ----------------------------------
> arch/sh/include/asm/unaligned.h | 76 ++++++++--
> 2 files changed, 61 insertions(+), 273 deletions(-)
>
Acked-by: Paul Mundt <[email protected]>

Thanks for looking at this!

2008-12-01 07:14:33

by Harvey Harrison

[permalink] [raw]
Subject: Re: [PATCH-mm 4/7] sh: wire up arch overrides for unaligned access on the SH4a

On Mon, 2008-12-01 at 15:51 +0900, Paul Mundt wrote:
> On Sat, Nov 29, 2008 at 06:40:30PM -0800, Harvey Harrison wrote:
> > Signed-off-by: Harvey Harrison <[email protected]>
> > ---
> > arch/sh/include/asm/unaligned-sh4a.h | 258 ----------------------------------
> > arch/sh/include/asm/unaligned.h | 76 ++++++++--
> > 2 files changed, 61 insertions(+), 273 deletions(-)
> >
> Acked-by: Paul Mundt <[email protected]>
>
> Thanks for looking at this!

No worries, I've also CC'd the AVR32 maintainer as I think his arch
could do something similar as that arch also provides limited
unaligned access that might be worth adding an override for.

Cheers,

Harvey