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powerpc/booke: Rewrite pmap_sync_icache() a bit

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* Make mmu_booke_sync_icache() use the DMAP on 64-bit prcoesses, no need to
  map the page into the user's address space.  This removes the
  pvh_global_lock from the equation on 64-bit.
* Don't map the page with user-readability on 32-bit.  I don't know what the
  chance of a given user process being able to access the NULL page when
  another process's page is added there, but it doesn't seem like a good
  idea to map it to NULL with user read permissions.
* Only sync as much as we need to.  There are only two significant places
  where pmap_sync_icache is used: proc_rwmem(), and the SIGILL second-chance
  for powerpc.  The SIGILL second chance is likely the most common, and only
  syncs 4 bytes, so avoid the other 127 loop iterations (4096 / 32 byte
  cacheline) in __syncicache().
This commit is contained in:
jhibbits 2019-05-08 16:15:28 +00:00
parent da99db36d7
commit 138efb0cd5
1 changed files with 22 additions and 10 deletions
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32
sys/powerpc/booke/pmap.c
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@ -2871,18 +2871,20 @@ static void
mmu_booke_sync_icache(mmu_t mmu, pmap_t pm, vm_offset_t va, vm_size_t sz)
{
pte_t *pte;
vm_paddr_t pa = 0;
int sync_sz, valid;
#ifndef __powerpc64__
pmap_t pmap;
vm_page_t m;
vm_offset_t addr;
vm_paddr_t pa = 0;
int active, valid;
int active;
#endif
va = trunc_page(va);
sz = round_page(sz);
#ifndef __powerpc64__
rw_wlock(&pvh_global_lock);
pmap = PCPU_GET(curpmap);
active = (pm == kernel_pmap || pm == pmap) ? 1 : 0;
#endif
while (sz > 0) {
PMAP_LOCK(pm);
pte = pte_find(mmu, pm, va);
@ -2890,24 +2892,34 @@ mmu_booke_sync_icache(mmu_t mmu, pmap_t pm, vm_offset_t va, vm_size_t sz)
if (valid)
pa = PTE_PA(pte);
PMAP_UNLOCK(pm);
sync_sz = PAGE_SIZE - (va & PAGE_MASK);
sync_sz = min(sync_sz, sz);
if (valid) {
#ifdef __powerpc64__
pa += (va & PAGE_MASK);
__syncicache((void *)PHYS_TO_DMAP(pa), sync_sz);
#else
if (!active) {
/* Create a mapping in the active pmap. */
addr = 0;
m = PHYS_TO_VM_PAGE(pa);
PMAP_LOCK(pmap);
pte_enter(mmu, pmap, m, addr,
PTE_SR | PTE_VALID | PTE_UR, FALSE);
__syncicache((void *)addr, PAGE_SIZE);
PTE_SR | PTE_VALID, FALSE);
addr += (va & PAGE_MASK);
__syncicache((void *)addr, sync_sz);
pte_remove(mmu, pmap, addr, PTBL_UNHOLD);
PMAP_UNLOCK(pmap);
} else
__syncicache((void *)va, PAGE_SIZE);
__syncicache((void *)va, sync_sz);
#endif
}
va += PAGE_SIZE;
sz -= PAGE_SIZE;
va += sync_sz;
sz -= sync_sz;
}
#ifndef __powerpc64__
rw_wunlock(&pvh_global_lock);
#endif
}
/*