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    Subject[PATCH] fbmem: Fix fb_read, fb_write unaligned accesses.
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    Date
    Apologies for corrupted patch. I'll try again.
    Comments? I'd also appreciate if somebody familiar with sbus on sparc
    could check this patch is sane since I know virtually nothing about sbus
    and am not in a position to compile for sparc, let alone test on it:

    fb_{read,write} access the framebuffer using lots of fb_{read,write}l's
    but don't check that the file position is aligned which can cause
    problems on some architectures which do not support unaligned accesses.

    Since the operations are essentially memcpy_{from,to}io, new
    fb_memcpy_{from,to}fb macros have been defined and these are used
    instead.

    For Sparc, fb_{read,write} macros use sbus_{read,write}, so this defines
    new sbus_memcpy_{from,to}io functions the same as memcpy_{from,to}io but
    using sbus_{read,write}b instead of {read,write}b.

    Signed-off-by: James Hogan <james@albanarts.com>
    ---
    arch/sparc/include/asm/io_32.h | 31 +++++++++++++++++++++++++++
    arch/sparc/include/asm/io_64.h | 31 +++++++++++++++++++++++++++
    drivers/video/fbmem.c | 46 ++++++++++++---------------------------
    include/linux/fb.h | 6 +++++
    4 files changed, 82 insertions(+), 32 deletions(-)

    diff --git a/arch/sparc/include/asm/io_32.h b/arch/sparc/include/asm/io_32.h
    index 2889574..c2ced21 100644
    --- a/arch/sparc/include/asm/io_32.h
    +++ b/arch/sparc/include/asm/io_32.h
    @@ -208,6 +208,21 @@ _memset_io(volatile void __iomem *dst, int c, __kernel_size_t n)
    #define memset_io(d,c,sz) _memset_io(d,c,sz)

    static inline void
    +_sbus_memcpy_fromio(void *dst, const volatile void __iomem *src,
    + __kernel_size_t n)
    +{
    + char *d = dst;
    +
    + while (n--) {
    + char tmp = sbus_readb(src);
    + *d++ = tmp;
    + src++;
    + }
    +}
    +
    +#define sbus_memcpy_fromio(d, s, sz) _sbus_memcpy_fromio(d, s, sz)
    +
    +static inline void
    _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
    {
    char *d = dst;
    @@ -222,6 +237,22 @@ _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
    #define memcpy_fromio(d,s,sz) _memcpy_fromio(d,s,sz)

    static inline void
    +_sbus_memcpy_toio(volatile void __iomem *dst, const void *src,
    + __kernel_size_t n)
    +{
    + const char *s = src;
    + volatile void __iomem *d = dst;
    +
    + while (n--) {
    + char tmp = *s++;
    + sbus_writeb(tmp, d);
    + d++;
    + }
    +}
    +
    +#define sbus_memcpy_toio(d, s, sz) _sbus_memcpy_toio(d, s, sz)
    +
    +static inline void
    _memcpy_toio(volatile void __iomem *dst, const void *src, __kernel_size_t n)
    {
    const char *s = src;
    diff --git a/arch/sparc/include/asm/io_64.h b/arch/sparc/include/asm/io_64.h
    index 9517d06..9c89654 100644
    --- a/arch/sparc/include/asm/io_64.h
    +++ b/arch/sparc/include/asm/io_64.h
    @@ -419,6 +419,21 @@ _memset_io(volatile void __iomem *dst, int c, __kernel_size_t n)
    #define memset_io(d,c,sz) _memset_io(d,c,sz)

    static inline void
    +_sbus_memcpy_fromio(void *dst, const volatile void __iomem *src,
    + __kernel_size_t n)
    +{
    + char *d = dst;
    +
    + while (n--) {
    + char tmp = sbus_readb(src);
    + *d++ = tmp;
    + src++;
    + }
    +}
    +
    +#define sbus_memcpy_fromio(d, s, sz) _sbus_memcpy_fromio(d, s, sz)
    +
    +static inline void
    _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
    {
    char *d = dst;
    @@ -433,6 +448,22 @@ _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
    #define memcpy_fromio(d,s,sz) _memcpy_fromio(d,s,sz)

    static inline void
    +_sbus_memcpy_toio(volatile void __iomem *dst, const void *src,
    + __kernel_size_t n)
    +{
    + const char *s = src;
    + volatile void __iomem *d = dst;
    +
    + while (n--) {
    + char tmp = *s++;
    + sbus_writeb(tmp, d);
    + d++;
    + }
    +}
    +
    +#define sbus_memcpy_toio(d, s, sz) _sbus_memcpy_toio(d, s, sz)
    +
    +static inline void
    _memcpy_toio(volatile void __iomem *dst, const void *src, __kernel_size_t n)
    {
    const char *s = src;
    diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
    index b066475..925f25d 100644
    --- a/drivers/video/fbmem.c
    +++ b/drivers/video/fbmem.c
    @@ -697,9 +697,9 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
    struct inode *inode = file->f_path.dentry->d_inode;
    int fbidx = iminor(inode);
    struct fb_info *info = registered_fb[fbidx];
    - u32 *buffer, *dst;
    - u32 __iomem *src;
    - int c, i, cnt = 0, err = 0;
    + u8 *buffer, *dst;
    + u8 __iomem *src;
    + int c, cnt = 0, err = 0;
    unsigned long total_size;

    if (!info || ! info->screen_base)
    @@ -730,7 +730,7 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
    if (!buffer)
    return -ENOMEM;

    - src = (u32 __iomem *) (info->screen_base + p);
    + src = (u8 __iomem *) (info->screen_base + p);

    if (info->fbops->fb_sync)
    info->fbops->fb_sync(info);
    @@ -738,17 +738,9 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
    while (count) {
    c = (count > PAGE_SIZE) ? PAGE_SIZE : count;
    dst = buffer;
    - for (i = c >> 2; i--; )
    - *dst++ = fb_readl(src++);
    - if (c & 3) {
    - u8 *dst8 = (u8 *) dst;
    - u8 __iomem *src8 = (u8 __iomem *) src;
    -
    - for (i = c & 3; i--;)
    - *dst8++ = fb_readb(src8++);
    -
    - src = (u32 __iomem *) src8;
    - }
    + fb_memcpy_fromfb(dst, src, c);
    + dst += c;
    + src += c;

    if (copy_to_user(buf, buffer, c)) {
    err = -EFAULT;
    @@ -772,9 +764,9 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
    struct inode *inode = file->f_path.dentry->d_inode;
    int fbidx = iminor(inode);
    struct fb_info *info = registered_fb[fbidx];
    - u32 *buffer, *src;
    - u32 __iomem *dst;
    - int c, i, cnt = 0, err = 0;
    + u8 *buffer, *src;
    + u8 __iomem *dst;
    + int c, cnt = 0, err = 0;
    unsigned long total_size;

    if (!info || !info->screen_base)
    @@ -811,7 +803,7 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
    if (!buffer)
    return -ENOMEM;

    - dst = (u32 __iomem *) (info->screen_base + p);
    + dst = (u8 __iomem *) (info->screen_base + p);

    if (info->fbops->fb_sync)
    info->fbops->fb_sync(info);
    @@ -825,19 +817,9 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
    break;
    }

    - for (i = c >> 2; i--; )
    - fb_writel(*src++, dst++);
    -
    - if (c & 3) {
    - u8 *src8 = (u8 *) src;
    - u8 __iomem *dst8 = (u8 __iomem *) dst;
    -
    - for (i = c & 3; i--; )
    - fb_writeb(*src8++, dst8++);
    -
    - dst = (u32 __iomem *) dst8;
    - }
    -
    + fb_memcpy_tofb(dst, src, c);
    + dst += c;
    + src += c;
    *ppos += c;
    buf += c;
    cnt += c;
    diff --git a/include/linux/fb.h b/include/linux/fb.h
    index f0268de..7fca3dc 100644
    --- a/include/linux/fb.h
    +++ b/include/linux/fb.h
    @@ -931,6 +931,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
    #define fb_writel sbus_writel
    #define fb_writeq sbus_writeq
    #define fb_memset sbus_memset_io
    +#define fb_memcpy_fromfb sbus_memcpy_fromio
    +#define fb_memcpy_tofb sbus_memcpy_toio

    #elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) || defined(__hppa__) || defined(__sh__) || defined(__powerpc__) || defined(__avr32__) || defined(__bfin__)

    @@ -943,6 +945,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
    #define fb_writel __raw_writel
    #define fb_writeq __raw_writeq
    #define fb_memset memset_io
    +#define fb_memcpy_fromfb memcpy_fromio
    +#define fb_memcpy_tofb memcpy_toio

    #else

    @@ -955,6 +959,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
    #define fb_writel(b,addr) (*(volatile u32 *) (addr) = (b))
    #define fb_writeq(b,addr) (*(volatile u64 *) (addr) = (b))
    #define fb_memset memset
    +#define fb_memcpy_fromfb memcpy
    +#define fb_memcpy_tofb memcpy

    #endif

    --
    1.7.2.3


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