pc, pc64: do page attribute table (PAT) init early in cpuidentify()

the page attribute table was initialized in mmuinit(), which is
too late for bootscreen(). So now we check for PAT support and
insert the write-combine entry early in cpuidentify().

this might have been the cause of some slow EFI framebuffers on
machines with overlapping or insufficient MTRR entries.
This commit is contained in:
cinap_lenrek 2020-05-22 23:58:24 +02:00
parent 0002fd0cf7
commit b86bb35c7d
5 changed files with 13 additions and 25 deletions

View file

@ -749,7 +749,7 @@ cpuidentify(void)
X86type *t, *tab; X86type *t, *tab;
uintptr cr4; uintptr cr4;
ulong regs[4]; ulong regs[4];
vlong mca, mct; vlong mca, mct, pat;
cpuid(Highstdfunc, regs); cpuid(Highstdfunc, regs);
memmove(m->cpuidid, &regs[1], BY2WD); /* bx */ memmove(m->cpuidid, &regs[1], BY2WD); /* bx */
@ -882,6 +882,13 @@ cpuidentify(void)
rdmsr(0x01, &mct); rdmsr(0x01, &mct);
} }
/* IA32_PAT write combining */
if((m->cpuiddx & Pat) != 0 && rdmsr(0x277, &pat) != -1){
pat &= ~(255LL<<(PATWC*8));
pat |= 1LL<<(PATWC*8); /* WC */
wrmsr(0x277, pat);
}
if(m->cpuiddx & Mtrr) if(m->cpuiddx & Mtrr)
mtrrsync(); mtrrsync();

View file

@ -173,3 +173,5 @@
#define getpgcolor(a) 0 #define getpgcolor(a) 0
/* PAT entry used for write combining */
#define PATWC 7

View file

@ -66,11 +66,6 @@ static void memglobal(void);
#define VPTX(va) (((ulong)(va))>>12) #define VPTX(va) (((ulong)(va))>>12)
#define vpd (vpt+VPTX(VPT)) #define vpd (vpt+VPTX(VPT))
enum {
/* PAT entry used for write combining */
PATWC = 7,
};
void void
mmuinit(void) mmuinit(void)
{ {
@ -125,14 +120,6 @@ mmuinit(void)
taskswitch(PADDR(m->pdb), (ulong)m + BY2PG); taskswitch(PADDR(m->pdb), (ulong)m + BY2PG);
ltr(TSSSEL); ltr(TSSSEL);
/* IA32_PAT write combining */
if((MACHP(0)->cpuiddx & Pat) != 0
&& rdmsr(0x277, &v) != -1){
v &= ~(255LL<<(PATWC*8));
v |= 1LL<<(PATWC*8); /* WC */
wrmsr(0x277, v);
}
} }
/* /*

View file

@ -176,5 +176,8 @@
#define getpgcolor(a) 0 #define getpgcolor(a) 0
/* PAT entry used for write combining */
#define PATWC 7
#define RMACH R15 /* m-> */ #define RMACH R15 /* m-> */
#define RUSER R14 /* up-> */ #define RUSER R14 /* up-> */

View file

@ -38,9 +38,6 @@ enum {
PDE = 0, PDE = 0,
MAPBITS = 8*sizeof(m->mmumap[0]), MAPBITS = 8*sizeof(m->mmumap[0]),
/* PAT entry used for write combining */
PATWC = 7,
}; };
static void static void
@ -133,14 +130,6 @@ mmuinit(void)
wrmsr(Star, ((uvlong)UE32SEL << 48) | ((uvlong)KESEL << 32)); wrmsr(Star, ((uvlong)UE32SEL << 48) | ((uvlong)KESEL << 32));
wrmsr(Lstar, (uvlong)syscallentry); wrmsr(Lstar, (uvlong)syscallentry);
wrmsr(Sfmask, 0x200); wrmsr(Sfmask, 0x200);
/* IA32_PAT write combining */
if((MACHP(0)->cpuiddx & Pat) != 0
&& rdmsr(0x277, &v) != -1){
v &= ~(255LL<<(PATWC*8));
v |= 1LL<<(PATWC*8); /* WC */
wrmsr(0x277, v);
}
} }
/* /*