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authorAndrew Turner <andrew@FreeBSD.org>2021-01-15 18:48:43 +0000
committerAndrew Turner <andrew@FreeBSD.org>2021-01-15 19:08:01 +0000
commitf64329bcdc4f7cf41c03bfbcf7e6a7525dad68fd (patch)
tree8e5c3dda51df7ccc4f81a7256f6d2b2a9af3993e
parent7c84a7405beede34cd07cf7753d72d1098532baf (diff)
downloadsrc-f64329bcdc4f7cf41c03bfbcf7e6a7525dad68fd.tar.gz
src-f64329bcdc4f7cf41c03bfbcf7e6a7525dad68fd.zip
Extract the logic from pmap_kextract
This allows us to use it when we only need to check if the virtual address is valid. For example when checking if an address in the DMAP region is mapped. Reviewed by: kib, markj Sponsored by: Innovate UK Differential Revision: https://reviews.freebsd.org/D27621
-rw-r--r--sys/arm64/arm64/pmap.c73
-rw-r--r--sys/arm64/include/armreg.h1
-rw-r--r--sys/arm64/include/pmap.h1
3 files changed, 62 insertions, 13 deletions
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index 86ab5cb43ae9..d4047fc84096 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -1365,16 +1365,42 @@ pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
return (m);
}
-vm_paddr_t
-pmap_kextract(vm_offset_t va)
+/*
+ * Walks the page tables to translate a kernel virtual address to a
+ * physical address. Returns true if the kva is valid and stores the
+ * physical address in pa if it is not NULL.
+ */
+bool
+pmap_klookup(vm_offset_t va, vm_paddr_t *pa)
{
pt_entry_t *pte, tpte;
+ register_t intr;
+ uint64_t par;
+
+ /*
+ * Disable interrupts so we don't get interrupted between asking
+ * for address translation, and getting the result back.
+ */
+ intr = intr_disable();
+ par = arm64_address_translate_s1e1r(va);
+ intr_restore(intr);
+
+ if (PAR_SUCCESS(par)) {
+ if (pa != NULL)
+ *pa = (par & PAR_PA_MASK) | (va & PAR_LOW_MASK);
+ return (true);
+ }
+
+ /*
+ * Fall back to walking the page table. The address translation
+ * instruction may fail when the page is in a break-before-make
+ * sequence. As we only clear the valid bit in said sequence we
+ * can walk the page table to find the physical address.
+ */
- if (va >= DMAP_MIN_ADDRESS && va < DMAP_MAX_ADDRESS)
- return (DMAP_TO_PHYS(va));
pte = pmap_l1(kernel_pmap, va);
if (pte == NULL)
- return (0);
+ return (false);
/*
* A concurrent pmap_update_entry() will clear the entry's valid bit
@@ -1384,20 +1410,41 @@ pmap_kextract(vm_offset_t va)
*/
tpte = pmap_load(pte);
if (tpte == 0)
- return (0);
- if ((tpte & ATTR_DESCR_TYPE_MASK) == ATTR_DESCR_TYPE_BLOCK)
- return ((tpte & ~ATTR_MASK) | (va & L1_OFFSET));
+ return (false);
+ if ((tpte & ATTR_DESCR_TYPE_MASK) == ATTR_DESCR_TYPE_BLOCK) {
+ if (pa != NULL)
+ *pa = (tpte & ~ATTR_MASK) | (va & L1_OFFSET);
+ return (true);
+ }
pte = pmap_l1_to_l2(&tpte, va);
tpte = pmap_load(pte);
if (tpte == 0)
- return (0);
- if ((tpte & ATTR_DESCR_TYPE_MASK) == ATTR_DESCR_TYPE_BLOCK)
- return ((tpte & ~ATTR_MASK) | (va & L2_OFFSET));
+ return (false);
+ if ((tpte & ATTR_DESCR_TYPE_MASK) == ATTR_DESCR_TYPE_BLOCK) {
+ if (pa != NULL)
+ *pa = (tpte & ~ATTR_MASK) | (va & L2_OFFSET);
+ return (true);
+ }
pte = pmap_l2_to_l3(&tpte, va);
tpte = pmap_load(pte);
if (tpte == 0)
+ return (false);
+ if (pa != NULL)
+ *pa = (tpte & ~ATTR_MASK) | (va & L3_OFFSET);
+ return (true);
+}
+
+vm_paddr_t
+pmap_kextract(vm_offset_t va)
+{
+ vm_paddr_t pa;
+
+ if (va >= DMAP_MIN_ADDRESS && va < DMAP_MAX_ADDRESS)
+ return (DMAP_TO_PHYS(va));
+
+ if (pmap_klookup(va, &pa) == false)
return (0);
- return ((tpte & ~ATTR_MASK) | (va & L3_OFFSET));
+ return (pa);
}
/***************************************************
@@ -6833,7 +6880,7 @@ pmap_fault(pmap_t pmap, uint64_t esr, uint64_t far)
* critical section. Therefore, we must check the
* address without acquiring the kernel pmap's lock.
*/
- if (pmap_kextract(far) != 0)
+ if (pmap_klookup(far, NULL))
rv = KERN_SUCCESS;
} else {
PMAP_LOCK(pmap);
diff --git a/sys/arm64/include/armreg.h b/sys/arm64/include/armreg.h
index 35a8f6dd488b..201d7559320b 100644
--- a/sys/arm64/include/armreg.h
+++ b/sys/arm64/include/armreg.h
@@ -743,6 +743,7 @@
#define PAR_F (0x1 << PAR_F_SHIFT)
#define PAR_SUCCESS(x) (((x) & PAR_F) == 0)
/* When PAR_F == 0 (success) */
+#define PAR_LOW_MASK 0xfff
#define PAR_SH_SHIFT 7
#define PAR_SH_MASK (0x3 << PAR_SH_SHIFT)
#define PAR_NS_SHIFT 9
diff --git a/sys/arm64/include/pmap.h b/sys/arm64/include/pmap.h
index 059d188ff847..b05fee999c73 100644
--- a/sys/arm64/include/pmap.h
+++ b/sys/arm64/include/pmap.h
@@ -167,6 +167,7 @@ void pmap_bootstrap(vm_offset_t, vm_offset_t, vm_paddr_t, vm_size_t);
int pmap_change_attr(vm_offset_t va, vm_size_t size, int mode);
void pmap_kenter(vm_offset_t sva, vm_size_t size, vm_paddr_t pa, int mode);
void pmap_kenter_device(vm_offset_t, vm_size_t, vm_paddr_t);
+bool pmap_klookup(vm_offset_t va, vm_paddr_t *pa);
vm_paddr_t pmap_kextract(vm_offset_t va);
void pmap_kremove(vm_offset_t);
void pmap_kremove_device(vm_offset_t, vm_size_t);