On Sat, Feb 05, 2022 at 02:26:48PM +0100, Mark Kettenis wrote:
> > Date: Sat, 5 Feb 2022 22:34:10 +1100
> > From: Jonathan Gray <[email protected]>
> > 
> > On Sat, Feb 05, 2022 at 11:44:03AM +0100, Mark Kettenis wrote:
> > > We want to get rid of the uvm_km_valloc() interfaces in favour of
> > > km_alloc().  This changes the calls in drm(4) over.  The kv_physwait
> > > struct is made static to prevent collission with a symbol in
> > > vm_machdep.c on some architectures.  The goal is to move this into
> > > uvm/uvm_km.c eventually.
> > > 
> > > Just to make sure I didn't screw the conversion up somehow a few tests
> > > on a mix of inteldrm(4) and amdgpu(4) systems would be good.
> > > 
> > > ok?
> > > 
> > > 
> > > Index: dev/pci/drm/drm_linux.c
> > > ===================================================================
> > > RCS file: /cvs/src/sys/dev/pci/drm/drm_linux.c,v
> > > retrieving revision 1.89
> > > diff -u -p -r1.89 drm_linux.c
> > > --- dev/pci/drm/drm_linux.c       21 Jan 2022 23:49:36 -0000      1.89
> > > +++ dev/pci/drm/drm_linux.c       5 Feb 2022 10:40:22 -0000
> > > @@ -564,6 +564,11 @@ __pagevec_release(struct pagevec *pvec)
> > >   pagevec_reinit(pvec);
> > >  }
> > >  
> > > +static struct kmem_va_mode kv_physwait = {
> > > + .kv_map = &phys_map,
> > > + .kv_wait = 1,
> > > +};
> > > +
> > >  void *
> > >  kmap(struct vm_page *pg)
> > >  {
> > > @@ -572,7 +577,7 @@ kmap(struct vm_page *pg)
> > >  #if defined (__HAVE_PMAP_DIRECT)
> > >   va = pmap_map_direct(pg);
> > >  #else
> > > - va = uvm_km_valloc_wait(phys_map, PAGE_SIZE);
> > > + va = (vaddr_t)km_alloc(PAGE_SIZE, &kv_physwait, &kp_none, &kd_waitok);
> > >   pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg), PROT_READ | PROT_WRITE);
> > >   pmap_update(pmap_kernel());
> > >  #endif
> > > @@ -589,7 +594,7 @@ kunmap_va(void *addr)
> > >  #else
> > >   pmap_kremove(va, PAGE_SIZE);
> > >   pmap_update(pmap_kernel());
> > > - uvm_km_free_wakeup(phys_map, va, PAGE_SIZE);
> > > + km_free((void *)va, PAGE_SIZE, &kv_physwait, &kp_none);
> > >  #endif
> > >  }
> > >  
> > > @@ -624,7 +629,8 @@ vmap(struct vm_page **pages, unsigned in
> > >   paddr_t pa;
> > >   int i;
> > >  
> > > - va = uvm_km_valloc(kernel_map, PAGE_SIZE * npages);
> > > + va = (vaddr_t)km_alloc(PAGE_SIZE * npages, &kv_any, &kp_none,
> > > +     &kd_nowait);
> > 
> > this could be kd_waitok as the linux vmap() uses might_sleep()
> > but I suppose that would be a change in behaviour/different diff
> 
> Actually that doesn't make a difference.  Specifying kd_waitok will
> only make it wait for physical pages.  But we're passing kp_none so no
> physical pages are allocated.
> 
> Yes, this is confusing and continues to trip people up.

ah right

tested by starting X and chromium on

amd64
amdgpu0: VEGA10 56 CU rev 0x01
inteldrm0: msi, BROADWELL, gen 8

i386
X and crack-attack (chromium won't start due to illegal instruction)
radeondrm0: RV200
inteldrm0: apic 1 int 16, I85X, gen 2

ok jsg@

> 
> > 
> > >   if (va == 0)
> > >           return NULL;
> > >   for (i = 0; i < npages; i++) {
> > > @@ -645,7 +651,7 @@ vunmap(void *addr, size_t size)
> > >  
> > >   pmap_remove(pmap_kernel(), va, va + size);
> > >   pmap_update(pmap_kernel());
> > > - uvm_km_free(kernel_map, va, size);
> > > + km_free((void *)va, size, &kv_any, &kp_none);
> > >  }
> > >  
> > >  bool
> > > 
> > > 
> > 
> 
> 

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