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Avoid calling CPUID function 0x02 if the CPU reports no support for

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it.  The former code used to hang older Intel CPUs by trying to get
non-existent TLB info 2^32 times.

Reduce code duplication around the calls to CPUID 0x02 by using
do-while loops.

PR:		i386/92977
Tested by:	cy
This commit is contained in:
Yaroslav Tykhiy 2006-02-09 09:10:54 +00:00
parent c1fd993af9
commit 84d8f1b027
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=155466
1 changed files with 22 additions and 47 deletions
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69
sys/i386/i386/identcpu.c
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@ -1235,34 +1235,23 @@ print_INTEL_info(void)
u_int rounds, regnum;
u_int nwaycode, nway;
do_cpuid(0x2, regs);
if (cpu_high >= 2) {
rounds = 0;
do {
do_cpuid(0x2, regs);
if (rounds == 0 && (rounds = (regs[0] & 0xff)) == 0)
break; /* we have a buggy CPU */
rounds = (regs[0] & 0xff) - 1;
for (regnum = 0; regnum <= 3; ++regnum) {
if ((regs[regnum] & (1<<31)) == 0) {
if (regnum != 0)
print_INTEL_TLB(regs[regnum] & 0xff);
print_INTEL_TLB((regs[regnum] >> 8) & 0xff);
print_INTEL_TLB((regs[regnum] >> 16) & 0xff);
print_INTEL_TLB((regs[regnum] >> 24) & 0xff);
}
}
while (rounds > 0) {
do_cpuid(0x2, regs);
for (regnum = 0; regnum <= 3; ++regnum) {
if ((regs[regnum] & (1<<31)) == 0) {
for (regnum = 0; regnum <= 3; ++regnum) {
if (regs[regnum] & (1<<31))
continue;
if (regnum != 0)
print_INTEL_TLB(regs[regnum] & 0xff);
print_INTEL_TLB((regs[regnum] >> 8) & 0xff);
print_INTEL_TLB((regs[regnum] >> 16) & 0xff);
print_INTEL_TLB((regs[regnum] >> 24) & 0xff);
}
}
--rounds;
} while (--rounds > 0);
}
if (cpu_exthigh >= 0x80000006) {
@ -1451,28 +1440,16 @@ setPQL2_INTEL(int *const size, int *const ways)
u_int regs[4];
u_int nwaycode;
do_cpuid(0x2, regs);
rounds = (regs[0] & 0xff) - 1;
if (cpu_high >= 2) {
rounds = 0;
do {
do_cpuid(0x2, regs);
if (rounds == 0 && (rounds = (regs[0] & 0xff)) == 0)
break; /* we have a buggy CPU */
for (regnum = 0; regnum <= 3; ++regnum) {
if ((regs[regnum] & (1<<31)) == 0) {
if (regnum != 0)
get_INTEL_TLB(regs[regnum] & 0xff,
size, ways);
get_INTEL_TLB((regs[regnum] >> 8) & 0xff,
size, ways);
get_INTEL_TLB((regs[regnum] >> 16) & 0xff,
size, ways);
get_INTEL_TLB((regs[regnum] >> 24) & 0xff,
size, ways);
}
}
while (rounds > 0) {
do_cpuid(0x2, regs);
for (regnum = 0; regnum <= 3; ++regnum) {
if ((regs[regnum] & (1<<31)) == 0) {
for (regnum = 0; regnum <= 3; ++regnum) {
if (regs[regnum] & (1<<31))
continue;
if (regnum != 0)
get_INTEL_TLB(regs[regnum] & 0xff,
size, ways);
@ -1482,11 +1459,9 @@ setPQL2_INTEL(int *const size, int *const ways)
size, ways);
get_INTEL_TLB((regs[regnum] >> 24) & 0xff,
size, ways);
}
}
--rounds;
}
}
} while (--rounds > 0);
}
if (cpu_exthigh >= 0x80000006) {
do_cpuid(0x80000006, regs);