mewin/libpng
1
0
Fork 0
mirror of https://git.code.sf.net/p/libpng/code.git synced 2025-07-10 18:04:09 +02:00
Code Issues Projects Releases Wiki Activity

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

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
contrib/mips-msa/linux.c
View File

@ -1,67 +1,55 @@
/* contrib/mips-msa/linux.c
*
* Copyright (c) 2020 Cosmin Truta
* Copyright (c) 2020-2023 Cosmin Truta
* Copyright (c) 2016 Glenn Randers-Pehrson
* Written by Mandar Sahastrabuddhe, 2016.
* Updated by Sui Jingfeng, 2021.
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* 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
* 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 <string.h>
#include <elf.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
static int
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";
char word[10];
if (f != NULL)
fd = open("/proc/self/auxv", O_RDONLY);
if (fd >= 0)
{
while(!feof(f))
while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
{
int ch = fgetc(f);
static int i = 0;
while(!(ch <= 32))
if (aux.a_type == AT_HWCAP)
{
word[i++] = ch;
ch = fgetc(f);
uint64_t hwcap = aux.a_un.a_val;
has_msa = (hwcap >> 1) & 1;
break;
}
int val = strcmp(string, word);
if (val == 0) {
fclose(f);
return 1;
}
i = 0;
memset(word, 0, 10);
}
fclose(f);
close(fd);
}
#ifdef PNG_WARNINGS_SUPPORTED
else
png_warning(png_ptr, "/proc/cpuinfo open failed");
png_warning(png_ptr, "/proc/self/auxv open failed");
#endif
return 0;
return has_msa;
}