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glibc/sysdeps/unix/sysv/linux/i386/sysconf.c

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/* Get file-specific information about a file. Linux version.
Copyright (C) 2003-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <hp-timing.h>
static long int linux_sysconf (int name);
static long int __attribute__ ((noinline))
handle_i486 (int name)
{
/* The processor only has a unified level 1 cache of 8k. */
switch (name)
{
case _SC_LEVEL1_ICACHE_SIZE:
case _SC_LEVEL1_DCACHE_SIZE:
return 8 * 1024;
case _SC_LEVEL1_ICACHE_ASSOC:
case _SC_LEVEL1_DCACHE_ASSOC:
// XXX Anybody know this?
return 0;
case _SC_LEVEL1_ICACHE_LINESIZE:
case _SC_LEVEL1_DCACHE_LINESIZE:
// XXX Anybody know for sure?
return 16;
case _SC_LEVEL2_CACHE_SIZE:
case _SC_LEVEL2_CACHE_ASSOC:
case _SC_LEVEL2_CACHE_LINESIZE:
case _SC_LEVEL3_CACHE_SIZE:
case _SC_LEVEL3_CACHE_ASSOC:
case _SC_LEVEL3_CACHE_LINESIZE:
case _SC_LEVEL4_CACHE_SIZE:
case _SC_LEVEL4_CACHE_ASSOC:
/* Not available. */
break;
default:
assert (! "cannot happen");
}
return -1;
}
static const struct intel_02_cache_info
{
unsigned char idx;
unsigned char assoc;
unsigned char linesize;
unsigned char rel_name;
unsigned int size;
} intel_02_known [] =
{
#define M(sc) ((sc) - _SC_LEVEL1_ICACHE_SIZE)
{ 0x06, 4, 32, M(_SC_LEVEL1_ICACHE_SIZE), 8192 },
{ 0x08, 4, 32, M(_SC_LEVEL1_ICACHE_SIZE), 16384 },
{ 0x09, 4, 32, M(_SC_LEVEL1_ICACHE_SIZE), 32768 },
{ 0x0a, 2, 32, M(_SC_LEVEL1_DCACHE_SIZE), 8192 },
{ 0x0c, 4, 32, M(_SC_LEVEL1_DCACHE_SIZE), 16384 },
{ 0x0d, 4, 64, M(_SC_LEVEL1_DCACHE_SIZE), 16384 },
{ 0x21, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x22, 4, 64, M(_SC_LEVEL3_CACHE_SIZE), 524288 },
{ 0x23, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 1048576 },
{ 0x25, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 2097152 },
{ 0x29, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 4194304 },
{ 0x2c, 8, 64, M(_SC_LEVEL1_DCACHE_SIZE), 32768 },
{ 0x30, 8, 64, M(_SC_LEVEL1_ICACHE_SIZE), 32768 },
{ 0x39, 4, 64, M(_SC_LEVEL2_CACHE_SIZE), 131072 },
{ 0x3a, 6, 64, M(_SC_LEVEL2_CACHE_SIZE), 196608 },
{ 0x3b, 2, 64, M(_SC_LEVEL2_CACHE_SIZE), 131072 },
{ 0x3c, 4, 64, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x3d, 6, 64, M(_SC_LEVEL2_CACHE_SIZE), 393216 },
{ 0x3e, 4, 64, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x3f, 2, 64, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x41, 4, 32, M(_SC_LEVEL2_CACHE_SIZE), 131072 },
{ 0x42, 4, 32, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x43, 4, 32, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x44, 4, 32, M(_SC_LEVEL2_CACHE_SIZE), 1048576 },
{ 0x45, 4, 32, M(_SC_LEVEL2_CACHE_SIZE), 2097152 },
{ 0x46, 4, 64, M(_SC_LEVEL3_CACHE_SIZE), 4194304 },
{ 0x47, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 8388608 },
{ 0x48, 12, 64, M(_SC_LEVEL2_CACHE_SIZE), 3145728 },
{ 0x49, 16, 64, M(_SC_LEVEL2_CACHE_SIZE), 4194304 },
{ 0x4a, 12, 64, M(_SC_LEVEL3_CACHE_SIZE), 6291456 },
{ 0x4b, 16, 64, M(_SC_LEVEL3_CACHE_SIZE), 8388608 },
{ 0x4c, 12, 64, M(_SC_LEVEL3_CACHE_SIZE), 12582912 },
{ 0x4d, 16, 64, M(_SC_LEVEL3_CACHE_SIZE), 16777216 },
{ 0x4e, 24, 64, M(_SC_LEVEL2_CACHE_SIZE), 6291456 },
{ 0x60, 8, 64, M(_SC_LEVEL1_DCACHE_SIZE), 16384 },
{ 0x66, 4, 64, M(_SC_LEVEL1_DCACHE_SIZE), 8192 },
{ 0x67, 4, 64, M(_SC_LEVEL1_DCACHE_SIZE), 16384 },
{ 0x68, 4, 64, M(_SC_LEVEL1_DCACHE_SIZE), 32768 },
{ 0x78, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 1048576 },
{ 0x79, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 131072 },
{ 0x7a, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x7b, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x7c, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 1048576 },
{ 0x7d, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 2097152 },
{ 0x7f, 2, 64, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x82, 8, 32, M(_SC_LEVEL2_CACHE_SIZE), 262144 },
{ 0x83, 8, 32, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x84, 8, 32, M(_SC_LEVEL2_CACHE_SIZE), 1048576 },
{ 0x85, 8, 32, M(_SC_LEVEL2_CACHE_SIZE), 2097152 },
{ 0x86, 4, 64, M(_SC_LEVEL2_CACHE_SIZE), 524288 },
{ 0x87, 8, 64, M(_SC_LEVEL2_CACHE_SIZE), 1048576 },
{ 0xd0, 4, 64, M(_SC_LEVEL3_CACHE_SIZE), 524288 },
{ 0xd1, 4, 64, M(_SC_LEVEL3_CACHE_SIZE), 1048576 },
{ 0xd2, 4, 64, M(_SC_LEVEL3_CACHE_SIZE), 2097152 },
{ 0xd6, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 1048576 },
{ 0xd7, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 2097152 },
{ 0xd8, 8, 64, M(_SC_LEVEL3_CACHE_SIZE), 4194304 },
{ 0xdc, 12, 64, M(_SC_LEVEL3_CACHE_SIZE), 2097152 },
{ 0xdd, 12, 64, M(_SC_LEVEL3_CACHE_SIZE), 4194304 },
{ 0xde, 12, 64, M(_SC_LEVEL3_CACHE_SIZE), 8388608 },
{ 0xe2, 16, 64, M(_SC_LEVEL3_CACHE_SIZE), 2097152 },
{ 0xe3, 16, 64, M(_SC_LEVEL3_CACHE_SIZE), 4194304 },
{ 0xe4, 16, 64, M(_SC_LEVEL3_CACHE_SIZE), 8388608 },
{ 0xea, 24, 64, M(_SC_LEVEL3_CACHE_SIZE), 12582912 },
{ 0xeb, 24, 64, M(_SC_LEVEL3_CACHE_SIZE), 18874368 },
{ 0xec, 24, 64, M(_SC_LEVEL3_CACHE_SIZE), 25165824 },
};
#define nintel_02_known (sizeof (intel_02_known) / sizeof (intel_02_known[0]))
static int
intel_02_known_compare (const void *p1, const void *p2)
{
const struct intel_02_cache_info *i1;
const struct intel_02_cache_info *i2;
i1 = (const struct intel_02_cache_info *) p1;
i2 = (const struct intel_02_cache_info *) p2;
if (i1->idx == i2->idx)
return 0;
return i1->idx < i2->idx ? -1 : 1;
}
static long int
__attribute__ ((noinline))
intel_check_word (int name, unsigned int value, bool *has_level_2,
bool *no_level_2_or_3)
{
if ((value & 0x80000000) != 0)
/* The register value is reserved. */
return 0;
/* Fold the name. The _SC_ constants are always in the order SIZE,
ASSOC, LINESIZE. */
int folded_rel_name = (M(name) / 3) * 3;
while (value != 0)
{
unsigned int byte = value & 0xff;
if (byte == 0x40)
{
*no_level_2_or_3 = true;
if (folded_rel_name == M(_SC_LEVEL3_CACHE_SIZE))
/* No need to look further. */
break;
}
else if (byte == 0xff)
{
/* CPUID leaf 0x4 contains all the information. We need to
iterate over it. */
unsigned int eax;
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
unsigned int round = 0;
while (1)
{
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (4), "2" (round));
enum { null = 0, data = 1, inst = 2, uni = 3 } type = eax & 0x1f;
if (type == null)
/* That was the end. */
break;
unsigned int level = (eax >> 5) & 0x7;
if ((level == 1 && type == data
&& folded_rel_name == M(_SC_LEVEL1_DCACHE_SIZE))
|| (level == 1 && type == inst
&& folded_rel_name == M(_SC_LEVEL1_ICACHE_SIZE))
|| (level == 2 && folded_rel_name == M(_SC_LEVEL2_CACHE_SIZE))
|| (level == 3 && folded_rel_name == M(_SC_LEVEL3_CACHE_SIZE))
|| (level == 4 && folded_rel_name == M(_SC_LEVEL4_CACHE_SIZE)))
{
unsigned int offset = M(name) - folded_rel_name;
if (offset == 0)
/* Cache size. */
return (((ebx >> 22) + 1)
* (((ebx >> 12) & 0x3ff) + 1)
* ((ebx & 0xfff) + 1)
* (ecx + 1));
if (offset == 1)
return (ebx >> 22) + 1;
assert (offset == 2);
return (ebx & 0xfff) + 1;
}
++round;
}
/* There is no other cache information anywhere else. */
break;
}
else
{
if (byte == 0x49 && folded_rel_name == M(_SC_LEVEL3_CACHE_SIZE))
{
/* Intel reused this value. For family 15, model 6 it
specifies the 3rd level cache. Otherwise the 2nd
level cache. */
unsigned int eax;
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (1));
unsigned int family = ((eax >> 20) & 0xff) + ((eax >> 8) & 0xf);
unsigned int model = ((((eax >>16) & 0xf) << 4)
+ ((eax >> 4) & 0xf));
if (family == 15 && model == 6)
{
/* The level 3 cache is encoded for this model like
the level 2 cache is for other models. Pretend
the caller asked for the level 2 cache. */
name = (_SC_LEVEL2_CACHE_SIZE
+ (name - _SC_LEVEL3_CACHE_SIZE));
folded_rel_name = M(_SC_LEVEL2_CACHE_SIZE);
}
}
struct intel_02_cache_info *found;
struct intel_02_cache_info search;
search.idx = byte;
found = bsearch (&search, intel_02_known, nintel_02_known,
sizeof (intel_02_known[0]), intel_02_known_compare);
if (found != NULL)
{
if (found->rel_name == folded_rel_name)
{
unsigned int offset = M(name) - folded_rel_name;
if (offset == 0)
/* Cache size. */
return found->size;
if (offset == 1)
return found->assoc;
assert (offset == 2);
return found->linesize;
}
if (found->rel_name == M(_SC_LEVEL2_CACHE_SIZE))
*has_level_2 = true;
}
}
/* Next byte for the next round. */
value >>= 8;
}
/* Nothing found. */
return 0;
}
static long int __attribute__ ((noinline))
handle_intel (int name, unsigned int maxidx)
{
if (maxidx < 2)
{
// XXX Do such processors exist? When we know we can fill in some
// values.
return 0;
}
/* OK, we can use the CPUID instruction to get all info about the
caches. */
unsigned int cnt = 0;
unsigned int max = 1;
long int result = 0;
bool no_level_2_or_3 = false;
bool has_level_2 = false;
while (cnt++ < max)
{
unsigned int eax;
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (2));
/* The low byte of EAX in the first round contain the number of
rounds we have to make. At least one, the one we are already
doing. */
if (cnt == 1)
{
max = eax & 0xff;
eax &= 0xffffff00;
}
/* Process the individual registers' value. */
result = intel_check_word (name, eax, &has_level_2, &no_level_2_or_3);
if (result != 0)
return result;
result = intel_check_word (name, ebx, &has_level_2, &no_level_2_or_3);
if (result != 0)
return result;
result = intel_check_word (name, ecx, &has_level_2, &no_level_2_or_3);
if (result != 0)
return result;
result = intel_check_word (name, edx, &has_level_2, &no_level_2_or_3);
if (result != 0)
return result;
}
if (name >= _SC_LEVEL2_CACHE_SIZE && name <= _SC_LEVEL3_CACHE_LINESIZE
&& no_level_2_or_3)
return -1;
return 0;
}
static long int __attribute__ ((noinline))
handle_amd (int name)
{
unsigned int eax;
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (0x80000000));
if (name >= _SC_LEVEL3_CACHE_SIZE)
return 0;
unsigned int fn = 0x80000005 + (name >= _SC_LEVEL2_CACHE_SIZE);
if (eax < fn)
return 0;
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (fn));
if (name < _SC_LEVEL1_DCACHE_SIZE)
{
name += _SC_LEVEL1_DCACHE_SIZE - _SC_LEVEL1_ICACHE_SIZE;
ecx = edx;
}
switch (name)
{
case _SC_LEVEL1_DCACHE_SIZE:
return (ecx >> 14) & 0x3fc00;
case _SC_LEVEL1_DCACHE_ASSOC:
ecx >>= 16;
if ((ecx & 0xff) == 0xff)
/* Fully associative. */
return (ecx << 2) & 0x3fc00;
return ecx & 0xff;
case _SC_LEVEL1_DCACHE_LINESIZE:
return ecx & 0xff;
case _SC_LEVEL2_CACHE_SIZE:
return (ecx & 0xf000) == 0 ? 0 : (ecx >> 6) & 0x3fffc00;
case _SC_LEVEL2_CACHE_ASSOC:
ecx >>= 12;
switch (ecx & 0xf)
{
case 0:
case 1:
case 2:
case 4:
return ecx & 0xf;
case 6:
return 8;
case 8:
return 16;
case 0xf:
return (ecx << 6) & 0x3fffc00;
default:
return 0;
}
case _SC_LEVEL2_CACHE_LINESIZE:
return (ecx & 0xf000) == 0 ? 0 : ecx & 0xff;
default:
assert (! "cannot happen");
}
return -1;
}
static int
i386_i486_test (void)
{
int eflags;
int ac;
asm volatile ("pushfl;\n\t"
"popl %0;\n\t"
"movl $0x240000, %1;\n\t"
"xorl %0, %1;\n\t"
"pushl %1;\n\t"
"popfl;\n\t"
"pushfl;\n\t"
"popl %1;\n\t"
"xorl %0, %1;\n\t"
"pushl %0;\n\t"
"popfl"
: "=r" (eflags), "=r" (ac));
return ac;
}
/* Get the value of the system variable NAME. */
long int
__sysconf (int name)
{
/* All the remainder, except the cache information, is handled in
the generic code. */
if (name < _SC_LEVEL1_ICACHE_SIZE || name > _SC_LEVEL4_CACHE_LINESIZE)
return linux_sysconf (name);
/* Recognize i386 and compatible. These don't have any cache on
board. */
int ac = i386_i486_test ();
if (ac == 0)
/* This is an i386. */
// XXX Is this true for all brands?
return -1;
/* Detect i486, the last Intel processor without CPUID. */
if ((ac & (1 << 21)) == 0)
{
/* No CPUID. */
// XXX Fill in info about other brands. For now only Intel.
return handle_i486 (name);
}
/* Find out what brand of processor. */
unsigned int eax;
unsigned int ebx;
unsigned int ecx;
unsigned int edx;
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
: "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
: "0" (0));
/* This spells out "GenuineIntel". */
if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
return handle_intel (name, eax);
/* This spells out "AuthenticAMD". */
if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
return handle_amd (name);
// XXX Fill in more vendors.
/* CPU not known, we have no information. */
return 0;
}
/* Now the generic Linux version. */
#undef __sysconf
#define __sysconf static linux_sysconf
#include "../sysconf.c"
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