Sui Jingfeng 2ed5a70bca mips: Implement the run-time MIPS MSA discovery function correctly
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>
2023-12-20 21:09:27 +02:00

56 lines
1.2 KiB
C

/* contrib/mips-msa/linux.c
*
* 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
*
* 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
*/
#include <elf.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
static int
png_have_msa(png_structp png_ptr)
{
Elf64_auxv_t aux;
int fd;
int has_msa = 0;
fd = open("/proc/self/auxv", O_RDONLY);
if (fd >= 0)
{
while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
{
if (aux.a_type == AT_HWCAP)
{
uint64_t hwcap = aux.a_un.a_val;
has_msa = (hwcap >> 1) & 1;
break;
}
}
close(fd);
}
#ifdef PNG_WARNINGS_SUPPORTED
else
png_warning(png_ptr, "/proc/self/auxv open failed");
#endif
return has_msa;
}