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Commit be0d9b6c7aeaad1683059c00131cabd4c894c17c

Authored by Antonino A. Daplas
Committed by Linus Torvalds
1 parent 7275b4b6bc
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[PATCH] fbdev: Fix incorrect unaligned access in little-endian machines 

The drawing function cfbfillrect does not work correctly when access is not
unsigned-long aligned.  It manifests as extra lines of pixels that are not
complete drawn.  Reversing the shift operator solves the problem, so I would
presume that this bug would manifest only on little endian machines.  The
function cfbcopyarea may also have this bug.

Aligned access should present no problems.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 4 changed files with 36 additions and 36 deletions Side-by-side Diff

drivers/video/cfbcopyarea.c
Diff comments   View file @ be0d9b6
... ... @@ -64,8 +64,8 @@
64 64 int const shift = dst_idx-src_idx;
65 65 int left, right;
66 66  
67   - first = ~0UL >> dst_idx;
68   - last = ~(~0UL >> ((dst_idx+n) % bits));
  67 + first = FB_SHIFT_HIGH(~0UL, dst_idx);
  68 + last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
69 69  
70 70 if (!shift) {
71 71 // Same alignment for source and dest
... ... @@ -216,8 +216,8 @@
216 216  
217 217 shift = dst_idx-src_idx;
218 218  
219   - first = ~0UL << (bits - 1 - dst_idx);
220   - last = ~(~0UL << (bits - 1 - ((dst_idx-n) % bits)));
  219 + first = FB_SHIFT_LOW(~0UL, bits - 1 - dst_idx);
  220 + last = ~(FB_SHIFT_LOW(~0UL, bits - 1 - ((dst_idx-n) % bits)));
221 221  
222 222 if (!shift) {
223 223 // Same alignment for source and dest
drivers/video/cfbfillrect.c
Diff comments   View file @ be0d9b6
... ... @@ -110,8 +110,8 @@
110 110 if (!n)
111 111 return;
112 112  
113   - first = ~0UL >> dst_idx;
114   - last = ~(~0UL >> ((dst_idx+n) % bits));
  113 + first = FB_SHIFT_HIGH(~0UL, dst_idx);
  114 + last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
115 115  
116 116 if (dst_idx+n <= bits) {
117 117 // Single word
... ... @@ -167,8 +167,8 @@
167 167 if (!n)
168 168 return;
169 169  
170   - first = ~0UL >> dst_idx;
171   - last = ~(~0UL >> ((dst_idx+n) % bits));
  170 + first = FB_SHIFT_HIGH(~0UL, dst_idx);
  171 + last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
172 172  
173 173 if (dst_idx+n <= bits) {
174 174 // Single word
... ... @@ -221,8 +221,8 @@
221 221 if (!n)
222 222 return;
223 223  
224   - first = ~0UL >> dst_idx;
225   - last = ~(~0UL >> ((dst_idx+n) % bits));
  224 + first = FB_SHIFT_HIGH(~0UL, dst_idx);
  225 + last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
226 226  
227 227 if (dst_idx+n <= bits) {
228 228 // Single word
... ... @@ -290,8 +290,8 @@
290 290 if (!n)
291 291 return;
292 292  
293   - first = ~0UL >> dst_idx;
294   - last = ~(~0UL >> ((dst_idx+n) % bits));
  293 + first = FB_SHIFT_HIGH(~0UL, dst_idx);
  294 + last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
295 295  
296 296 if (dst_idx+n <= bits) {
297 297 // Single word
drivers/video/cfbimgblt.c
Diff comments   View file @ be0d9b6
... ... @@ -76,18 +76,6 @@
76 76 #define FB_WRITEL fb_writel
77 77 #define FB_READL fb_readl
78 78  
79   -#if defined (__BIG_ENDIAN)
80   -#define LEFT_POS(bpp) (32 - bpp)
81   -#define SHIFT_HIGH(val, bits) ((val) >> (bits))
82   -#define SHIFT_LOW(val, bits) ((val) << (bits))
83   -#define BIT_NR(b) (7 - (b))
84   -#else
85   -#define LEFT_POS(bpp) (0)
86   -#define SHIFT_HIGH(val, bits) ((val) << (bits))
87   -#define SHIFT_LOW(val, bits) ((val) >> (bits))
88   -#define BIT_NR(b) (b)
89   -#endif
90   -
91 79 static inline void color_imageblit(const struct fb_image *image,
92 80 struct fb_info *p, u8 __iomem *dst1,
93 81 u32 start_index,
... ... @@ -109,7 +97,7 @@
109 97 val = 0;
110 98  
111 99 if (start_index) {
112   - u32 start_mask = ~(SHIFT_HIGH(~(u32)0, start_index));
  100 + u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0, start_index));
113 101 val = FB_READL(dst) & start_mask;
114 102 shift = start_index;
115 103 }
116 104  
117 105  
... ... @@ -119,20 +107,20 @@
119 107 color = palette[*src];
120 108 else
121 109 color = *src;
122   - color <<= LEFT_POS(bpp);
123   - val |= SHIFT_HIGH(color, shift);
  110 + color <<= FB_LEFT_POS(bpp);
  111 + val |= FB_SHIFT_HIGH(color, shift);
124 112 if (shift >= null_bits) {
125 113 FB_WRITEL(val, dst++);
126 114  
127 115 val = (shift == null_bits) ? 0 :
128   - SHIFT_LOW(color, 32 - shift);
  116 + FB_SHIFT_LOW(color, 32 - shift);
129 117 }
130 118 shift += bpp;
131 119 shift &= (32 - 1);
132 120 src++;
133 121 }
134 122 if (shift) {
135   - u32 end_mask = SHIFT_HIGH(~(u32)0, shift);
  123 + u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
136 124  
137 125 FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
138 126 }
... ... @@ -162,8 +150,8 @@
162 150 u32 i, j, l;
163 151  
164 152 dst2 = (u32 __iomem *) dst1;
165   - fgcolor <<= LEFT_POS(bpp);
166   - bgcolor <<= LEFT_POS(bpp);
  153 + fgcolor <<= FB_LEFT_POS(bpp);
  154 + bgcolor <<= FB_LEFT_POS(bpp);
167 155  
168 156 for (i = image->height; i--; ) {
169 157 shift = val = 0;
170 158  
171 159  
... ... @@ -174,21 +162,21 @@
174 162  
175 163 /* write leading bits */
176 164 if (start_index) {
177   - u32 start_mask = ~(SHIFT_HIGH(~(u32)0, start_index));
  165 + u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0,start_index));
178 166 val = FB_READL(dst) & start_mask;
179 167 shift = start_index;
180 168 }
181 169  
182 170 while (j--) {
183 171 l--;
184   - color = (*s & 1 << (BIT_NR(l))) ? fgcolor : bgcolor;
185   - val |= SHIFT_HIGH(color, shift);
  172 + color = (*s & 1 << (FB_BIT_NR(l))) ? fgcolor : bgcolor;
  173 + val |= FB_SHIFT_HIGH(color, shift);
186 174  
187 175 /* Did the bitshift spill bits to the next long? */
188 176 if (shift >= null_bits) {
189 177 FB_WRITEL(val, dst++);
190 178 val = (shift == null_bits) ? 0 :
191   - SHIFT_LOW(color,32 - shift);
  179 + FB_SHIFT_LOW(color,32 - shift);
192 180 }
193 181 shift += bpp;
194 182 shift &= (32 - 1);
... ... @@ -197,7 +185,7 @@
197 185  
198 186 /* write trailing bits */
199 187 if (shift) {
200   - u32 end_mask = SHIFT_HIGH(~(u32)0, shift);
  188 + u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
201 189  
202 190 FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
203 191 }
... ... @@ -835,6 +835,18 @@
835 835  
836 836 #endif
837 837  
  838 +#if defined (__BIG_ENDIAN)
  839 +#define FB_LEFT_POS(bpp) (32 - bpp)
  840 +#define FB_SHIFT_HIGH(val, bits) ((val) >> (bits))
  841 +#define FB_SHIFT_LOW(val, bits) ((val) << (bits))
  842 +#define FB_BIT_NR(b) (7 - (b))
  843 +#else
  844 +#define FB_LEFT_POS(bpp) (0)
  845 +#define FB_SHIFT_HIGH(val, bits) ((val) << (bits))
  846 +#define FB_SHIFT_LOW(val, bits) ((val) >> (bits))
  847 +#define FB_BIT_NR(b) (b)
  848 +#endif
  849 +
838 850 /*
839 851 * `Generic' versions of the frame buffer device operations
840 852 */