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vgai81x: use vmap() for uncached access to cursor data instead of manipulating kernel page table

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on 386, the kernel memory region is mapped using huge 4MB pages
(when supported by the cpu). so the uncached pte manipulation
does not work to map the cursor data with uncached attribute.

instead, we allocate a memory page using newpage() and map
it globally using vmap(), which maps it uncached.
This commit is contained in:
cinap_lenrek 2019-10-02 00:58:46 +02:00
parent a524fd0646
commit 0ee738ef8c
1 changed files with 16 additions and 17 deletions
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31
sys/src/9/pc/vgai81x.c
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@ -56,7 +56,7 @@ i81xenable(VGAscr* scr)
Pcidev *p;
int size;
Mach *mach0;
ulong *pgtbl, *rp, cursor, *pte, fbuf, fbend;
ulong *pgtbl, *rp, fbuf, fbend;
if(scr->mmio)
return;
@ -90,18 +90,7 @@ i81xenable(VGAscr* scr)
fbuf += BY2PG;
}
/*
* allocate space for the cursor data in system memory.
* must be uncached.
*/
cursor = (ulong)xspanalloc(BY2PG, BY2PG, 0);
mach0 = MACHP(0);
pte = mmuwalk(mach0->pdb, cursor, 2, 0);
if(pte == nil)
panic("i81x cursor mmuwalk");
*pte |= PTEUNCACHED;
scr->storage = cursor;
scr->storage = 0;
scr->blank = i81xblank;
}
@ -123,7 +112,7 @@ i81xcurload(VGAscr* scr, Cursor* curs)
uchar *p;
CursorI81x *hwcurs;
if(scr->mmio == 0)
if(scr->mmio == 0 || scr->storage == 0)
return;
hwcurs = (void*)((uchar*)scr->mmio+hwCur);
@ -192,23 +181,33 @@ i81xcurenable(VGAscr* scr)
{
int i;
uchar *p;
CursorI81x *hwcurs;
i81xenable(scr);
if(scr->mmio == 0)
return;
if(scr->storage == 0){
CursorI81x *hwcurs;
Page *pg = newpage(0, nil, 0);
scr->storage = (uintptr)vmap(pg->pa, BY2PG);
if(scr->storage == 0){
putpage(pg);
return;
}
hwcurs = (void*)((uchar*)scr->mmio+hwCur);
hwcurs->base = pg->pa;
}
/*
* Initialise the 32x32 cursor to be transparent in 2bpp mode.
*/
hwcurs->base = PADDR(scr->storage);
p = (uchar*)scr->storage;
for(i = 0; i < 32/2; i++) {
memset(p, 0xff, 8);
memset(p+8, 0, 8);
p += 16;
}
/*
* Load, locate and enable the 32x32 cursor in 2bpp mode.
*/