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fix rescaling bug (uninitialized read, see bug #254).

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the x_add/x_sub increments were wrong for u/v in the upscaling case.
They shouldn't be left to the caller's discretion, but set up by
WebPRescalerInit to their exact necessary values.

-> Cleaned-up WebPRescalerInit() param list.
-> added safety asserts
-> removed the mips32/mips_r2 variant of "ImportRow" which were buggy prior

Change-Id: I347c75804d835811e7025de92a0758d7929dfc09
This commit is contained in:
Pascal Massimino
2015-08-05 15:11:48 +02:00
parent 99131e7f8c
commit 7df93893dc
8 changed files with 31 additions and 224 deletions
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98
src/dsp/rescaler_mips32.c
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@ -17,103 +17,6 @@
#include "../utils/rescaler.h"
static void ImportRow(WebPRescaler* const wrk,
const uint8_t* const src, int channel) {
const int x_stride = wrk->num_channels;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const int fx_scale = wrk->fx_scale;
const int x_add = wrk->x_add - wrk->x_sub;
const int x_sub = wrk->x_sub;
int* frow = wrk->frow + channel;
int* irow = wrk->irow + channel;
const uint8_t* src1 = src + channel;
int temp1, temp2, temp3;
int base, frac, sum;
int accum, accum1;
const int x_stride1 = x_stride << 2;
int loop_c = x_out_max - channel;
if (!wrk->x_expand) {
__asm__ volatile (
"li %[temp1], 0x8000 \n\t"
"li %[temp2], 0x10000 \n\t"
"li %[sum], 0 \n\t"
"li %[accum], 0 \n\t"
"1: \n\t"
"addu %[accum], %[accum], %[x_add] \n\t"
"blez %[accum], 3f \n\t"
"2: \n\t"
"lbu %[temp3], 0(%[src1]) \n\t"
"subu %[accum], %[accum], %[x_sub] \n\t"
"addu %[src1], %[src1], %[x_stride] \n\t"
"addu %[sum], %[sum], %[temp3] \n\t"
"bgtz %[accum], 2b \n\t"
"3: \n\t"
"lbu %[base], 0(%[src1]) \n\t"
"addu %[src1], %[src1], %[x_stride] \n\t"
"negu %[accum1], %[accum] \n\t"
"mul %[frac], %[base], %[accum1] \n\t"
"addu %[temp3], %[sum], %[base] \n\t"
"mul %[temp3], %[temp3], %[x_sub] \n\t"
"lw %[base], 0(%[irow]) \n\t"
"subu %[loop_c], %[loop_c], %[x_stride] \n\t"
"sll %[accum1], %[frac], 2 \n\t"
"mult %[temp1], %[temp2] \n\t"
"madd %[accum1], %[fx_scale] \n\t"
"mfhi %[sum] \n\t"
"subu %[temp3], %[temp3], %[frac] \n\t"
"sw %[temp3], 0(%[frow]) \n\t"
"add %[base], %[base], %[temp3] \n\t"
"sw %[base], 0(%[irow]) \n\t"
"addu %[irow], %[irow], %[x_stride1] \n\t"
"addu %[frow], %[frow], %[x_stride1] \n\t"
"bgtz %[loop_c], 1b \n\t"
: [accum] "=&r" (accum), [src1] "+r" (src1), [temp3] "=&r" (temp3),
[sum] "=&r" (sum), [base] "=&r" (base), [frac] "=&r" (frac),
[frow] "+r" (frow), [irow] "+r" (irow), [accum1] "=&r" (accum1),
[temp2] "=&r" (temp2), [temp1] "=&r" (temp1)
: [x_stride] "r" (x_stride), [fx_scale] "r" (fx_scale),
[x_sub] "r" (x_sub), [x_add] "r" (x_add),
[loop_c] "r" (loop_c), [x_stride1] "r" (x_stride1)
: "memory", "hi", "lo"
);
} else {
__asm__ volatile (
"lbu %[temp1], 0(%[src1]) \n\t"
"move %[temp2], %[temp1] \n\t"
"li %[accum], 0 \n\t"
"1: \n\t"
"bgez %[accum], 2f \n\t"
"move %[temp2], %[temp1] \n\t"
"addu %[src1], %[x_stride] \n\t"
"lbu %[temp1], 0(%[src1]) \n\t"
"addu %[accum], %[x_add] \n\t"
"2: \n\t"
"subu %[temp3], %[temp2], %[temp1] \n\t"
"mul %[temp3], %[temp3], %[accum] \n\t"
"mul %[base], %[temp1], %[x_add] \n\t"
"subu %[accum], %[accum], %[x_sub] \n\t"
"lw %[frac], 0(%[irow]) \n\t"
"subu %[loop_c], %[loop_c], %[x_stride] \n\t"
"addu %[temp3], %[base], %[temp3] \n\t"
"sw %[temp3], 0(%[frow]) \n\t"
"addu %[frow], %[x_stride1] \n\t"
"addu %[frac], %[temp3] \n\t"
"sw %[frac], 0(%[irow]) \n\t"
"addu %[irow], %[x_stride1] \n\t"
"bgtz %[loop_c], 1b \n\t"
: [src1] "+r" (src1), [accum] "=&r" (accum), [temp1] "=&r" (temp1),
[temp2] "=&r" (temp2), [temp3] "=&r" (temp3), [base] "=&r" (base),
[frac] "=&r" (frac), [frow] "+r" (frow), [irow] "+r" (irow)
: [x_stride] "r" (x_stride), [x_add] "r" (x_add), [x_sub] "r" (x_sub),
[x_stride1] "r" (x_stride1), [loop_c] "r" (loop_c)
: "memory", "hi", "lo"
);
}
}
static void ExportRow(WebPRescaler* const wrk, int x_out) {
if (wrk->y_accum <= 0) {
uint8_t* const dst = wrk->dst;
@ -183,7 +86,6 @@ static void ExportRow(WebPRescaler* const wrk, int x_out) {
extern void WebPRescalerDspInitMIPS32(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInitMIPS32(void) {
WebPRescalerImportRow = ImportRow;
WebPRescalerExportRow = ExportRow;
}