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mips: Implement the run-time MIPS MSA discovery function correctly

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The old implementation of png_have_msa() caused a bus error,
if a word in /proc/cpuinfo was longer than 10 characters.

In the original implementation, `word[10]` was too short, and
`word[i++] = ch` caused a stack smash if the characters between
spaces were more than 10.

And also, fclose(f) should be called before leaving.

For example on loongson ls3a4000 cpu platform:

$ cat /proc/cpuinfo

system type             : Generic Loongson64 System
machine                 : loongson,loongson64g-4core-ls7a
processor               : 0
cpu model               : ICT Loongson-3 V0.1  FPU V0.1
BogoMIPS                : 3594.02
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 2112
extra interrupt vector  : no
hardware watchpoint     : no
isa                     : mips1 mips2 mips3 mips4 mips5 mips32r1 mips32r2 mips64r1 mips64r2
ASEs implemented        : vz msa loongson-mmi loongson-cam loongson-ext loongson-ext2
shadow register sets    : 1
kscratch registers      : 6
package                 : 0
core                    : 0
VCED exceptions         : not available
VCEI exceptions         : not available
processor               : 1
cpu model               : ICT Loongson-3 V0.1  FPU V0.1
BogoMIPS                : 3611.26
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 2112
extra interrupt vector  : no
hardware watchpoint     : no
isa                     : mips1 mips2 mips3 mips4 mips5 mips32r1 mips32r2 mips64r1 mips64r2
ASEs implemented        : vz msa loongson-mmi loongson-cam loongson-ext loongson-ext2
shadow register sets    : 1
kscratch registers      : 6
package                 : 0
core                    : 1
VCED exceptions         : not available
VCEI exceptions         : not available

Co-authored-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: Sui Jingfeng <15330273260@189.cn>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
This commit is contained in:
Sui Jingfeng 2021-11-12 00:06:50 +08:00 committed by Cosmin Truta
parent 85f866dea3
commit 2ed5a70bca
1 changed files with 24 additions and 36 deletions
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60
contrib/mips-msa/linux.c
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@ -1,67 +1,55 @@
/* contrib/mips-msa/linux.c /* contrib/mips-msa/linux.c
* *
* Copyright (c) 2020 Cosmin Truta * Copyright (c) 2020-2023 Cosmin Truta
* Copyright (c) 2016 Glenn Randers-Pehrson * Copyright (c) 2016 Glenn Randers-Pehrson
* Written by Mandar Sahastrabuddhe, 2016. * Written by Mandar Sahastrabuddhe, 2016.
* Updated by Sui Jingfeng, 2021.
* *
* This code is released under the libpng license. * This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer * For conditions of distribution and use, see the disclaimer
* and license in png.h * and license in png.h
* *
* SEE contrib/mips-msa/README before reporting bugs * On Linux, png_have_msa is implemented by reading the pseudo-file
* "/proc/self/auxv".
*
* See contrib/mips-msa/README before reporting bugs.
* *
* STATUS: SUPPORTED * STATUS: SUPPORTED
* BUG REPORTS: png-mng-implement@sourceforge.net * BUG REPORTS: png-mng-implement@sourceforge.net
*
* png_have_msa implemented for Linux by reading the widely available
* pseudo-file /proc/cpuinfo.
*
* This code is strict ANSI-C and is probably moderately portable; it does
* however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
*/ */
#include <stdio.h> #include <elf.h>
#include <string.h> #include <fcntl.h>
#include <stdlib.h> #include <stdlib.h>
#include <unistd.h>
static int static int
png_have_msa(png_structp png_ptr) png_have_msa(png_structp png_ptr)
{ {
FILE *f = fopen("/proc/cpuinfo", "rb"); Elf64_auxv_t aux;
int fd;
int has_msa = 0;
char *string = "msa"; fd = open("/proc/self/auxv", O_RDONLY);
char word[10]; if (fd >= 0)
if (f != NULL)
{ {
while(!feof(f)) while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
{ {
int ch = fgetc(f); if (aux.a_type == AT_HWCAP)
static int i = 0;
while(!(ch <= 32))
{ {
word[i++] = ch; uint64_t hwcap = aux.a_un.a_val;
ch = fgetc(f);
has_msa = (hwcap >> 1) & 1;
break;
} }
int val = strcmp(string, word);
if (val == 0) {
fclose(f);
return 1;
}
i = 0;
memset(word, 0, 10);
} }
close(fd);
fclose(f);
} }
#ifdef PNG_WARNINGS_SUPPORTED #ifdef PNG_WARNINGS_SUPPORTED
else else
png_warning(png_ptr, "/proc/cpuinfo open failed"); png_warning(png_ptr, "/proc/self/auxv open failed");
#endif #endif
return 0;
return has_msa;
} }