From 00a9d699bc85052d2d3ed56251cd928024ce06a3 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 23 Jan 2014 14:39:29 -0500 Subject: [PATCH] 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 Cc: stable@vger.kernel.org Signed-off-by: Tomi Valkeinen --- drivers/video/cfbcopyarea.c | 153 ++++++++++++++++++------------------ 1 file changed, 78 insertions(+), 75 deletions(-) diff --git a/drivers/video/cfbcopyarea.c b/drivers/video/cfbcopyarea.c index bb5a96b1645d..bcb57235fcc7 100644 --- a/drivers/video/cfbcopyarea.c +++ b/drivers/video/cfbcopyarea.c @@ -43,13 +43,22 @@ */ static void -bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, - const unsigned long __iomem *src, int src_idx, int bits, +bitcpy(struct fb_info *p, unsigned long __iomem *dst, unsigned dst_idx, + const unsigned long __iomem *src, unsigned src_idx, int bits, unsigned n, u32 bswapmask) { unsigned long first, last; int const shift = dst_idx-src_idx; - int left, right; + +#if 0 + /* + * If you suspect bug in this function, compare it with this simple + * memmove implementation. + */ + fb_memmove((char *)dst + ((dst_idx & (bits - 1))) / 8, + (char *)src + ((src_idx & (bits - 1))) / 8, n / 8); + return; +#endif first = fb_shifted_pixels_mask_long(p, dst_idx, bswapmask); last = ~fb_shifted_pixels_mask_long(p, (dst_idx+n) % bits, bswapmask); @@ -98,9 +107,8 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, unsigned long d0, d1; int m; - right = shift & (bits - 1); - left = -shift & (bits - 1); - bswapmask &= shift; + int const left = shift & (bits - 1); + int const right = -shift & (bits - 1); if (dst_idx+n <= bits) { // Single destination word @@ -110,15 +118,15 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, d0 = fb_rev_pixels_in_long(d0, bswapmask); if (shift > 0) { // Single source word - d0 >>= right; + d0 <<= left; } else if (src_idx+n <= bits) { // Single source word - d0 <<= left; + d0 >>= right; } else { // 2 source words d1 = FB_READL(src + 1); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0<>right; + d0 = d0 >> right | d1 << left; } d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(comp(d0, FB_READL(dst), first), dst); @@ -135,60 +143,59 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, if (shift > 0) { // Single source word d1 = d0; - d0 >>= right; - dst++; + d0 <<= left; n -= bits - dst_idx; } else { // 2 source words d1 = FB_READL(src++); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0<>right; - dst++; + d0 = d0 >> right | d1 << left; n -= bits - dst_idx; } d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(comp(d0, FB_READL(dst), first), dst); d0 = d1; + dst++; // Main chunk m = n % bits; n /= bits; while ((n >= 4) && !bswapmask) { d1 = FB_READL(src++); - FB_WRITEL(d0 << left | d1 >> right, dst++); + FB_WRITEL(d0 >> right | d1 << left, dst++); d0 = d1; d1 = FB_READL(src++); - FB_WRITEL(d0 << left | d1 >> right, dst++); + FB_WRITEL(d0 >> right | d1 << left, dst++); d0 = d1; d1 = FB_READL(src++); - FB_WRITEL(d0 << left | d1 >> right, dst++); + FB_WRITEL(d0 >> right | d1 << left, dst++); d0 = d1; d1 = FB_READL(src++); - FB_WRITEL(d0 << left | d1 >> right, dst++); + FB_WRITEL(d0 >> right | d1 << left, dst++); d0 = d1; n -= 4; } while (n--) { d1 = FB_READL(src++); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0 << left | d1 >> right; + d0 = d0 >> right | d1 << left; d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(d0, dst++); d0 = d1; } // Trailing bits - if (last) { - if (m <= right) { + if (m) { + if (m <= bits - right) { // Single source word - d0 <<= left; + d0 >>= right; } else { // 2 source words d1 = FB_READL(src); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0<>right; + d0 = d0 >> right | d1 << left; } d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(comp(d0, FB_READL(dst), last), dst); @@ -202,43 +209,46 @@ bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, */ static void -bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, - const unsigned long __iomem *src, int src_idx, int bits, +bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, unsigned dst_idx, + const unsigned long __iomem *src, unsigned src_idx, int bits, unsigned n, u32 bswapmask) { unsigned long first, last; int shift; - dst += (n-1)/bits; - src += (n-1)/bits; - if ((n-1) % bits) { - dst_idx += (n-1) % bits; - dst += dst_idx >> (ffs(bits) - 1); - dst_idx &= bits - 1; - src_idx += (n-1) % bits; - src += src_idx >> (ffs(bits) - 1); - src_idx &= bits - 1; - } +#if 0 + /* + * If you suspect bug in this function, compare it with this simple + * memmove implementation. + */ + fb_memmove((char *)dst + ((dst_idx & (bits - 1))) / 8, + (char *)src + ((src_idx & (bits - 1))) / 8, n / 8); + return; +#endif + + dst += (dst_idx + n - 1) / bits; + src += (src_idx + n - 1) / bits; + dst_idx = (dst_idx + n - 1) % bits; + src_idx = (src_idx + n - 1) % bits; shift = dst_idx-src_idx; - first = fb_shifted_pixels_mask_long(p, bits - 1 - dst_idx, bswapmask); - last = ~fb_shifted_pixels_mask_long(p, bits - 1 - ((dst_idx-n) % bits), - bswapmask); + first = ~fb_shifted_pixels_mask_long(p, (dst_idx + 1) % bits, bswapmask); + last = fb_shifted_pixels_mask_long(p, (bits + dst_idx + 1 - n) % bits, bswapmask); if (!shift) { // Same alignment for source and dest if ((unsigned long)dst_idx+1 >= n) { // Single word - if (last) - first &= last; - FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst); + if (first) + last &= first; + FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst); } else { // Multiple destination words // Leading bits - if (first != ~0UL) { + if (first) { FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst); dst--; src--; @@ -262,7 +272,7 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, FB_WRITEL(FB_READL(src--), dst--); // Trailing bits - if (last) + if (last != -1UL) FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst); } } else { @@ -270,29 +280,28 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, unsigned long d0, d1; int m; - int const left = -shift & (bits-1); - int const right = shift & (bits-1); - bswapmask &= shift; + int const left = shift & (bits-1); + int const right = -shift & (bits-1); if ((unsigned long)dst_idx+1 >= n) { // Single destination word - if (last) - first &= last; + if (first) + last &= first; d0 = FB_READL(src); if (shift < 0) { // Single source word - d0 <<= left; + d0 >>= right; } else if (1+(unsigned long)src_idx >= n) { // Single source word - d0 >>= right; + d0 <<= left; } else { // 2 source words d1 = FB_READL(src - 1); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0>>right | d1<> right; } d0 = fb_rev_pixels_in_long(d0, bswapmask); - FB_WRITEL(comp(d0, FB_READL(dst), first), dst); + FB_WRITEL(comp(d0, FB_READL(dst), last), dst); } else { // Multiple destination words /** We must always remember the last value read, because in case @@ -307,12 +316,12 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, if (shift < 0) { // Single source word d1 = d0; - d0 <<= left; + d0 >>= right; } else { // 2 source words d1 = FB_READL(src--); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0>>right | d1<> right; } d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(comp(d0, FB_READL(dst), first), dst); @@ -325,39 +334,39 @@ bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx, n /= bits; while ((n >= 4) && !bswapmask) { d1 = FB_READL(src--); - FB_WRITEL(d0 >> right | d1 << left, dst--); + FB_WRITEL(d0 << left | d1 >> right, dst--); d0 = d1; d1 = FB_READL(src--); - FB_WRITEL(d0 >> right | d1 << left, dst--); + FB_WRITEL(d0 << left | d1 >> right, dst--); d0 = d1; d1 = FB_READL(src--); - FB_WRITEL(d0 >> right | d1 << left, dst--); + FB_WRITEL(d0 << left | d1 >> right, dst--); d0 = d1; d1 = FB_READL(src--); - FB_WRITEL(d0 >> right | d1 << left, dst--); + FB_WRITEL(d0 << left | d1 >> right, dst--); d0 = d1; n -= 4; } while (n--) { d1 = FB_READL(src--); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0 >> right | d1 << left; + d0 = d0 << left | d1 >> right; d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(d0, dst--); d0 = d1; } // Trailing bits - if (last) { - if (m <= left) { + if (m) { + if (m <= bits - left) { // Single source word - d0 >>= right; + d0 <<= left; } else { // 2 source words d1 = FB_READL(src); d1 = fb_rev_pixels_in_long(d1, bswapmask); - d0 = d0>>right | d1<> right; } d0 = fb_rev_pixels_in_long(d0, bswapmask); FB_WRITEL(comp(d0, FB_READL(dst), last), dst); @@ -371,9 +380,9 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) u32 dx = area->dx, dy = area->dy, sx = area->sx, sy = area->sy; u32 height = area->height, width = area->width; unsigned long const bits_per_line = p->fix.line_length*8u; - unsigned long __iomem *dst = NULL, *src = NULL; + unsigned long __iomem *base = NULL; int bits = BITS_PER_LONG, bytes = bits >> 3; - int dst_idx = 0, src_idx = 0, rev_copy = 0; + unsigned dst_idx = 0, src_idx = 0, rev_copy = 0; u32 bswapmask = fb_compute_bswapmask(p); if (p->state != FBINFO_STATE_RUNNING) @@ -389,7 +398,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) // split the base of the framebuffer into a long-aligned address and the // index of the first bit - dst = src = (unsigned long __iomem *)((unsigned long)p->screen_base & ~(bytes-1)); + base = (unsigned long __iomem *)((unsigned long)p->screen_base & ~(bytes-1)); dst_idx = src_idx = 8*((unsigned long)p->screen_base & (bytes-1)); // add offset of source and target area dst_idx += dy*bits_per_line + dx*p->var.bits_per_pixel; @@ -402,20 +411,14 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) while (height--) { dst_idx -= bits_per_line; src_idx -= bits_per_line; - dst += dst_idx >> (ffs(bits) - 1); - dst_idx &= (bytes - 1); - src += src_idx >> (ffs(bits) - 1); - src_idx &= (bytes - 1); - bitcpy_rev(p, dst, dst_idx, src, src_idx, bits, + bitcpy_rev(p, base + (dst_idx / bits), dst_idx % bits, + base + (src_idx / bits), src_idx % bits, bits, width*p->var.bits_per_pixel, bswapmask); } } else { while (height--) { - dst += dst_idx >> (ffs(bits) - 1); - dst_idx &= (bytes - 1); - src += src_idx >> (ffs(bits) - 1); - src_idx &= (bytes - 1); - bitcpy(p, dst, dst_idx, src, src_idx, bits, + bitcpy(p, base + (dst_idx / bits), dst_idx % bits, + base + (src_idx / bits), src_idx % bits, bits, width*p->var.bits_per_pixel, bswapmask); dst_idx += bits_per_line; src_idx += bits_per_line; -- 2.39.2