diff options
| author | Jonathan Gray <jsg@cvs.openbsd.org> | 2015-11-06 02:49:07 +0000 |
|---|---|---|
| committer | Jonathan Gray <jsg@cvs.openbsd.org> | 2015-11-06 02:49:07 +0000 |
| commit | 7db32e4e50839a3209b01641e31c79ac7a10d1a2 (patch) | |
| tree | 02296f5d05718cf0a590dcf1f98cffb961d41d15 /sys/arch | |
| parent | da1fb06330d1bb7cebaa88631cc83bcdcd468475 (diff) | |
Only read/write cr4 if we have a bit to set after testing the various
cpuid based flags.
Unlike amd64 there is no CR4_DEFAULT used here, cr4 does not exist
on most/all? 486s and cr4 access traps on Cyrix 5x86 processors.
Should fix a regression introduced in rev 1.65 encountered
by 'Ppractivus' on a 5x86.
"looks good" guenther@
Diffstat (limited to 'sys/arch')
| -rw-r--r-- | sys/arch/i386/i386/cpu.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/sys/arch/i386/i386/cpu.c b/sys/arch/i386/i386/cpu.c index 7a978aae1a8..df06c49c2d2 100644 --- a/sys/arch/i386/i386/cpu.c +++ b/sys/arch/i386/i386/cpu.c @@ -1,4 +1,4 @@ -/* $OpenBSD: cpu.c,v 1.67 2015/07/18 19:21:03 sf Exp $ */ +/* $OpenBSD: cpu.c,v 1.68 2015/11/06 02:49:06 jsg Exp $ */ /* $NetBSD: cpu.c,v 1.1.2.7 2000/06/26 02:04:05 sommerfeld Exp $ */ /*- @@ -354,7 +354,7 @@ cpu_attach(struct device *parent, struct device *self, void *aux) void cpu_init(struct cpu_info *ci) { - u_int cr4; + u_int cr4 = 0; /* configure the CPU if needed */ if (ci->cpu_setup != NULL) @@ -372,7 +372,6 @@ cpu_init(struct cpu_info *ci) */ lcr0(rcr0() | CR0_WP); - cr4 = rcr4(); if (cpu_feature & CPUID_PGE) cr4 |= CR4_PGE; /* enable global TLB caching */ @@ -395,7 +394,9 @@ cpu_init(struct cpu_info *ci) if (cpu_feature & (CPUID_SSE|CPUID_SSE2)) cr4 |= CR4_OSXMMEXCPT; } - lcr4(cr4); + /* no cr4 on most 486s */ + if (cr4 != 0) + lcr4(rcr4()|cr4); #ifdef MULTIPROCESSOR ci->ci_flags |= CPUF_RUNNING; |