forked from mirrors/linux
framebuffer: fix cfb_copyarea
The function cfb_copyarea is buggy when the copy operation is not aligned on long boundary (4 bytes on 32-bit machines, 8 bytes on 64-bit machines). How to reproduce: - use x86-64 machine - use a framebuffer driver without acceleration (for example uvesafb) - set the framebuffer to 8-bit depth (for example fbset -a 1024x768-60 -depth 8) - load a font with character width that is not a multiple of 8 pixels note: the console-tools package cannot load a font that has width different from 8 pixels. You need to install the packages "kbd" and "console-terminus" and use the program "setfont" to set font width (for example: setfont Uni2-Terminus20x10) - move some text left and right on the bash command line and you get a screen corruption To expose more bugs, put this line to the end of uvesafb_init_info: info->flags |= FBINFO_HWACCEL_COPYAREA | FBINFO_READS_FAST; - Now framebuffer console will use cfb_copyarea for console scrolling. You get a screen corruption when console is scrolled. This patch is a rewrite of cfb_copyarea. It fixes the bugs, with this patch, console scrolling in 8-bit depth with a font width that is not a multiple of 8 pixels works fine. The cfb_copyarea code was very buggy and it looks like it was written and never tried with non-8-pixel font. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
This commit is contained in:
Mikulas Patocka
Tomi Valkeinen
parent
a772d47366
commit
00a9d699bc
1 changed files with 78 additions and 75 deletions
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@ -43,13 +43,22 @@
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*/
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static void
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bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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const unsigned long __iomem *src, int src_idx, int bits,
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bitcpy(struct fb_info *p, unsigned long __iomem *dst, unsigned dst_idx,
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const unsigned long __iomem *src, unsigned src_idx, int bits,
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unsigned n, u32 bswapmask)
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{
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unsigned long first, last;
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int const shift = dst_idx-src_idx;
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int left, right;
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#if 0
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/*
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* If you suspect bug in this function, compare it with this simple
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* memmove implementation.
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*/
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fb_memmove((char *)dst + ((dst_idx & (bits - 1))) / 8,
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(char *)src + ((src_idx & (bits - 1))) / 8, n / 8);
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return;
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#endif
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first = fb_shifted_pixels_mask_long(p, dst_idx, bswapmask);
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last = ~fb_shifted_pixels_mask_long(p, (dst_idx+n) % bits, bswapmask);
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@ -98,9 +107,8 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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unsigned long d0, d1;
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int m;
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right = shift & (bits - 1);
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left = -shift & (bits - 1);
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bswapmask &= shift;
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int const left = shift & (bits - 1);
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int const right = -shift & (bits - 1);
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if (dst_idx+n <= bits) {
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// Single destination word
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@ -110,15 +118,15 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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if (shift > 0) {
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// Single source word
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d0 >>= right;
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d0 <<= left;
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} else if (src_idx+n <= bits) {
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// Single source word
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d0 <<= left;
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d0 >>= right;
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} else {
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// 2 source words
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d1 = FB_READL(src + 1);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0<<left | d1>>right;
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d0 = d0 >> right | d1 << left;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
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@ -135,60 +143,59 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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if (shift > 0) {
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// Single source word
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d1 = d0;
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d0 >>= right;
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dst++;
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d0 <<= left;
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n -= bits - dst_idx;
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} else {
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// 2 source words
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d1 = FB_READL(src++);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0<<left | d1>>right;
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dst++;
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d0 = d0 >> right | d1 << left;
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n -= bits - dst_idx;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
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d0 = d1;
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dst++;
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// Main chunk
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m = n % bits;
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n /= bits;
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while ((n >= 4) && !bswapmask) {
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d1 = FB_READL(src++);
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FB_WRITEL(d0 << left | d1 >> right, dst++);
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FB_WRITEL(d0 >> right | d1 << left, dst++);
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d0 = d1;
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d1 = FB_READL(src++);
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FB_WRITEL(d0 << left | d1 >> right, dst++);
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FB_WRITEL(d0 >> right | d1 << left, dst++);
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d0 = d1;
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d1 = FB_READL(src++);
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FB_WRITEL(d0 << left | d1 >> right, dst++);
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FB_WRITEL(d0 >> right | d1 << left, dst++);
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d0 = d1;
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d1 = FB_READL(src++);
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FB_WRITEL(d0 << left | d1 >> right, dst++);
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FB_WRITEL(d0 >> right | d1 << left, dst++);
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d0 = d1;
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n -= 4;
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}
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while (n--) {
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d1 = FB_READL(src++);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0 << left | d1 >> right;
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d0 = d0 >> right | d1 << left;
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(d0, dst++);
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d0 = d1;
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}
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// Trailing bits
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if (last) {
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if (m <= right) {
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if (m) {
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if (m <= bits - right) {
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// Single source word
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d0 <<= left;
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d0 >>= right;
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} else {
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// 2 source words
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d1 = FB_READL(src);
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d1 = fb_rev_pixels_in_long(d1,
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bswapmask);
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d0 = d0<<left | d1>>right;
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d0 = d0 >> right | d1 << left;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), last), dst);
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@ -202,43 +209,46 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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*/
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static void
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bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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const unsigned long __iomem *src, int src_idx, int bits,
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bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, unsigned dst_idx,
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const unsigned long __iomem *src, unsigned src_idx, int bits,
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unsigned n, u32 bswapmask)
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{
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unsigned long first, last;
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int shift;
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dst += (n-1)/bits;
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src += (n-1)/bits;
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if ((n-1) % bits) {
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dst_idx += (n-1) % bits;
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dst += dst_idx >> (ffs(bits) - 1);
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dst_idx &= bits - 1;
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src_idx += (n-1) % bits;
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src += src_idx >> (ffs(bits) - 1);
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src_idx &= bits - 1;
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}
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#if 0
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/*
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* If you suspect bug in this function, compare it with this simple
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* memmove implementation.
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*/
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fb_memmove((char *)dst + ((dst_idx & (bits - 1))) / 8,
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(char *)src + ((src_idx & (bits - 1))) / 8, n / 8);
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return;
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#endif
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dst += (dst_idx + n - 1) / bits;
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src += (src_idx + n - 1) / bits;
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dst_idx = (dst_idx + n - 1) % bits;
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src_idx = (src_idx + n - 1) % bits;
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shift = dst_idx-src_idx;
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first = fb_shifted_pixels_mask_long(p, bits - 1 - dst_idx, bswapmask);
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last = ~fb_shifted_pixels_mask_long(p, bits - 1 - ((dst_idx-n) % bits),
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bswapmask);
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first = ~fb_shifted_pixels_mask_long(p, (dst_idx + 1) % bits, bswapmask);
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last = fb_shifted_pixels_mask_long(p, (bits + dst_idx + 1 - n) % bits, bswapmask);
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if (!shift) {
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// Same alignment for source and dest
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if ((unsigned long)dst_idx+1 >= n) {
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// Single word
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if (last)
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first &= last;
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FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
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if (first)
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last &= first;
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FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst);
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} else {
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// Multiple destination words
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// Leading bits
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if (first != ~0UL) {
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if (first) {
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FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
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dst--;
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src--;
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@ -262,7 +272,7 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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FB_WRITEL(FB_READL(src--), dst--);
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// Trailing bits
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if (last)
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if (last != -1UL)
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FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst);
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}
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} else {
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@ -270,29 +280,28 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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unsigned long d0, d1;
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int m;
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int const left = -shift & (bits-1);
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int const right = shift & (bits-1);
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bswapmask &= shift;
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int const left = shift & (bits-1);
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int const right = -shift & (bits-1);
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if ((unsigned long)dst_idx+1 >= n) {
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// Single destination word
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if (last)
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first &= last;
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if (first)
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last &= first;
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d0 = FB_READL(src);
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if (shift < 0) {
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// Single source word
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d0 <<= left;
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d0 >>= right;
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} else if (1+(unsigned long)src_idx >= n) {
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// Single source word
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d0 >>= right;
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d0 <<= left;
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} else {
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// 2 source words
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d1 = FB_READL(src - 1);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0>>right | d1<<left;
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d0 = d0 << left | d1 >> right;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
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FB_WRITEL(comp(d0, FB_READL(dst), last), dst);
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} else {
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// Multiple destination words
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/** We must always remember the last value read, because in case
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@ -307,12 +316,12 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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if (shift < 0) {
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// Single source word
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d1 = d0;
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d0 <<= left;
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d0 >>= right;
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} else {
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// 2 source words
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d1 = FB_READL(src--);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0>>right | d1<<left;
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d0 = d0 << left | d1 >> right;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
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@ -325,39 +334,39 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
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n /= bits;
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while ((n >= 4) && !bswapmask) {
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d1 = FB_READL(src--);
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FB_WRITEL(d0 >> right | d1 << left, dst--);
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FB_WRITEL(d0 << left | d1 >> right, dst--);
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d0 = d1;
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d1 = FB_READL(src--);
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FB_WRITEL(d0 >> right | d1 << left, dst--);
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FB_WRITEL(d0 << left | d1 >> right, dst--);
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d0 = d1;
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d1 = FB_READL(src--);
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FB_WRITEL(d0 >> right | d1 << left, dst--);
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FB_WRITEL(d0 << left | d1 >> right, dst--);
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d0 = d1;
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d1 = FB_READL(src--);
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FB_WRITEL(d0 >> right | d1 << left, dst--);
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FB_WRITEL(d0 << left | d1 >> right, dst--);
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d0 = d1;
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n -= 4;
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}
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while (n--) {
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d1 = FB_READL(src--);
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d1 = fb_rev_pixels_in_long(d1, bswapmask);
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d0 = d0 >> right | d1 << left;
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d0 = d0 << left | d1 >> right;
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(d0, dst--);
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d0 = d1;
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}
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// Trailing bits
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if (last) {
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if (m <= left) {
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if (m) {
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if (m <= bits - left) {
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// Single source word
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d0 >>= right;
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d0 <<= left;
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} else {
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// 2 source words
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d1 = FB_READL(src);
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d1 = fb_rev_pixels_in_long(d1,
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bswapmask);
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d0 = d0>>right | d1<<left;
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d0 = d0 << left | d1 >> right;
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}
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d0 = fb_rev_pixels_in_long(d0, bswapmask);
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FB_WRITEL(comp(d0, FB_READL(dst), last), dst);
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@ -371,9 +380,9 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
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u32 dx = area->dx, dy = area->dy, sx = area->sx, sy = area->sy;
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u32 height = area->height, width = area->width;
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unsigned long const bits_per_line = p->fix.line_length*8u;
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unsigned long __iomem *dst = NULL, *src = NULL;
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unsigned long __iomem *base = NULL;
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int bits = BITS_PER_LONG, bytes = bits >> 3;
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int dst_idx = 0, src_idx = 0, rev_copy = 0;
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unsigned dst_idx = 0, src_idx = 0, rev_copy = 0;
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u32 bswapmask = fb_compute_bswapmask(p);
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if (p->state != FBINFO_STATE_RUNNING)
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@ -389,7 +398,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
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// split the base of the framebuffer into a long-aligned address and the
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// index of the first bit
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dst = src = (unsigned long __iomem *)((unsigned long)p->screen_base & ~(bytes-1));
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base = (unsigned long __iomem *)((unsigned long)p->screen_base & ~(bytes-1));
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dst_idx = src_idx = 8*((unsigned long)p->screen_base & (bytes-1));
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// add offset of source and target area
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dst_idx += dy*bits_per_line + dx*p->var.bits_per_pixel;
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@ -402,20 +411,14 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
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while (height--) {
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dst_idx -= bits_per_line;
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src_idx -= bits_per_line;
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dst += dst_idx >> (ffs(bits) - 1);
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dst_idx &= (bytes - 1);
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src += src_idx >> (ffs(bits) - 1);
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src_idx &= (bytes - 1);
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bitcpy_rev(p, dst, dst_idx, src, src_idx, bits,
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bitcpy_rev(p, base + (dst_idx / bits), dst_idx % bits,
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base + (src_idx / bits), src_idx % bits, bits,
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width*p->var.bits_per_pixel, bswapmask);
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}
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} else {
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while (height--) {
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dst += dst_idx >> (ffs(bits) - 1);
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dst_idx &= (bytes - 1);
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src += src_idx >> (ffs(bits) - 1);
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src_idx &= (bytes - 1);
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bitcpy(p, dst, dst_idx, src, src_idx, bits,
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bitcpy(p, base + (dst_idx / bits), dst_idx % bits,
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base + (src_idx / bits), src_idx % bits, bits,
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width*p->var.bits_per_pixel, bswapmask);
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dst_idx += bits_per_line;
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src_idx += bits_per_line;
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