git: 8dc8feb53da0 - main - Clean up a couple of MD warts in vm_fault_populate():
Jason A. Harmening
jah at FreeBSD.org
Wed Mar 31 01:17:38 UTC 2021
The branch main has been updated by jah:
URL: https://cgit.FreeBSD.org/src/commit/?id=8dc8feb53da0c1a2301cb21c87b17a09d12e8fa7
commit 8dc8feb53da0c1a2301cb21c87b17a09d12e8fa7
Author: Jason A. Harmening <jah at FreeBSD.org>
AuthorDate: 2021-03-27 03:10:46 +0000
Commit: Jason A. Harmening <jah at FreeBSD.org>
CommitDate: 2021-03-31 01:15:55 +0000
Clean up a couple of MD warts in vm_fault_populate():
--Eliminate a big ifdef that encompassed all currently-supported
architectures except mips and powerpc32. This applied to the case
in which we've allocated a superpage but the pager-populated range
is insufficient for a superpage mapping. For platforms that don't
support superpages the check should be inexpensive as we shouldn't
get a superpage in the first place. Make the normal-page fallback
logic identical for all platforms and provide a simple implementation
of pmap_ps_enabled() for MIPS and Book-E/AIM32 powerpc.
--Apply the logic for handling pmap_enter() failure if a superpage
mapping can't be supported due to additional protection policy.
Use KERN_PROTECTION_FAILURE instead of KERN_FAILURE for this case,
and note Intel PKU on amd64 as the first example of such protection
policy.
Reviewed by: kib, markj, bdragon
Differential Revision: https://reviews.freebsd.org/D29439
---
sys/amd64/amd64/pmap.c | 2 +-
sys/mips/include/pmap.h | 6 ++++++
sys/powerpc/aim/mmu_oea.c | 8 ++++++++
sys/powerpc/booke/pmap.c | 8 ++++++++
sys/vm/vm_fault.c | 26 +++++++++++++++-----------
5 files changed, 38 insertions(+), 12 deletions(-)
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index fc5f24d2c303..aa8810e05b63 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -7147,7 +7147,7 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde, u_int flags,
*/
if (!pmap_pkru_same(pmap, va, va + NBPDR)) {
pmap_abort_ptp(pmap, va, pdpg);
- return (KERN_FAILURE);
+ return (KERN_PROTECTION_FAILURE);
}
if (va < VM_MAXUSER_ADDRESS && pmap->pm_type == PT_X86) {
newpde &= ~X86_PG_PKU_MASK;
diff --git a/sys/mips/include/pmap.h b/sys/mips/include/pmap.h
index 77f75903ccd5..6678f8264ad7 100644
--- a/sys/mips/include/pmap.h
+++ b/sys/mips/include/pmap.h
@@ -190,6 +190,12 @@ pmap_vmspace_copy(pmap_t dst_pmap __unused, pmap_t src_pmap __unused)
return (0);
}
+static inline bool
+pmap_ps_enabled(pmap_t pmap __unused)
+{
+ return (false);
+}
+
#endif /* _KERNEL */
#endif /* !LOCORE */
diff --git a/sys/powerpc/aim/mmu_oea.c b/sys/powerpc/aim/mmu_oea.c
index 44d8b9518b8e..cb0c905a53f3 100644
--- a/sys/powerpc/aim/mmu_oea.c
+++ b/sys/powerpc/aim/mmu_oea.c
@@ -327,6 +327,7 @@ void moea_scan_init(void);
vm_offset_t moea_quick_enter_page(vm_page_t m);
void moea_quick_remove_page(vm_offset_t addr);
boolean_t moea_page_is_mapped(vm_page_t m);
+bool moea_ps_enabled(pmap_t pmap);
static int moea_map_user_ptr(pmap_t pm,
volatile const void *uaddr, void **kaddr, size_t ulen, size_t *klen);
static int moea_decode_kernel_ptr(vm_offset_t addr,
@@ -370,6 +371,7 @@ static struct pmap_funcs moea_methods = {
.quick_enter_page = moea_quick_enter_page,
.quick_remove_page = moea_quick_remove_page,
.page_is_mapped = moea_page_is_mapped,
+ .ps_enabled = moea_ps_enabled,
/* Internal interfaces */
.bootstrap = moea_bootstrap,
@@ -1122,6 +1124,12 @@ moea_page_is_mapped(vm_page_t m)
return (!LIST_EMPTY(&(m)->md.mdpg_pvoh));
}
+bool
+moea_ps_enabled(pmap_t pmap __unused)
+{
+ return (false);
+}
+
/*
* Map the given physical page at the specified virtual address in the
* target pmap with the protection requested. If specified the page
diff --git a/sys/powerpc/booke/pmap.c b/sys/powerpc/booke/pmap.c
index 6bc96b222db8..6c48584096c5 100644
--- a/sys/powerpc/booke/pmap.c
+++ b/sys/powerpc/booke/pmap.c
@@ -354,6 +354,7 @@ static int mmu_booke_decode_kernel_ptr(vm_offset_t addr,
int *is_user, vm_offset_t *decoded_addr);
static void mmu_booke_page_array_startup(long);
static boolean_t mmu_booke_page_is_mapped(vm_page_t m);
+static bool mmu_booke_ps_enabled(pmap_t pmap);
static struct pmap_funcs mmu_booke_methods = {
/* pmap dispatcher interface */
@@ -396,6 +397,7 @@ static struct pmap_funcs mmu_booke_methods = {
.quick_remove_page = mmu_booke_quick_remove_page,
.page_array_startup = mmu_booke_page_array_startup,
.page_is_mapped = mmu_booke_page_is_mapped,
+ .ps_enabled = mmu_booke_ps_enabled,
/* Internal interfaces */
.bootstrap = mmu_booke_bootstrap,
@@ -1226,6 +1228,12 @@ mmu_booke_page_is_mapped(vm_page_t m)
return (!TAILQ_EMPTY(&(m)->md.pv_list));
}
+static bool
+mmu_booke_ps_enabled(pmap_t pmap __unused)
+{
+ return (false);
+}
+
/*
* Initialize pmap associated with process 0.
*/
diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 585e1544415d..dd112feefdcd 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -542,17 +542,13 @@ vm_fault_populate(struct faultstate *fs)
pidx <= pager_last;
pidx += npages, m = vm_page_next(&m[npages - 1])) {
vaddr = fs->entry->start + IDX_TO_OFF(pidx) - fs->entry->offset;
-#if defined(__aarch64__) || defined(__amd64__) || (defined(__arm__) && \
- __ARM_ARCH >= 6) || defined(__i386__) || defined(__riscv) || \
- defined(__powerpc64__)
+
psind = m->psind;
if (psind > 0 && ((vaddr & (pagesizes[psind] - 1)) != 0 ||
pidx + OFF_TO_IDX(pagesizes[psind]) - 1 > pager_last ||
!pmap_ps_enabled(fs->map->pmap) || fs->wired))
psind = 0;
-#else
- psind = 0;
-#endif
+
npages = atop(pagesizes[psind]);
for (i = 0; i < npages; i++) {
vm_fault_populate_check_page(&m[i]);
@@ -561,8 +557,18 @@ vm_fault_populate(struct faultstate *fs)
VM_OBJECT_WUNLOCK(fs->first_object);
rv = pmap_enter(fs->map->pmap, vaddr, m, fs->prot, fs->fault_type |
(fs->wired ? PMAP_ENTER_WIRED : 0), psind);
-#if defined(__amd64__)
- if (psind > 0 && rv == KERN_FAILURE) {
+
+ /*
+ * pmap_enter() may fail for a superpage mapping if additional
+ * protection policies prevent the full mapping.
+ * For example, this will happen on amd64 if the entire
+ * address range does not share the same userspace protection
+ * key. Revert to single-page mappings if this happens.
+ */
+ MPASS(rv == KERN_SUCCESS ||
+ (psind > 0 && rv == KERN_PROTECTION_FAILURE));
+ if (__predict_false(psind > 0 &&
+ rv == KERN_PROTECTION_FAILURE)) {
for (i = 0; i < npages; i++) {
rv = pmap_enter(fs->map->pmap, vaddr + ptoa(i),
&m[i], fs->prot, fs->fault_type |
@@ -570,9 +576,7 @@ vm_fault_populate(struct faultstate *fs)
MPASS(rv == KERN_SUCCESS);
}
}
-#else
- MPASS(rv == KERN_SUCCESS);
-#endif
+
VM_OBJECT_WLOCK(fs->first_object);
for (i = 0; i < npages; i++) {
if ((fs->fault_flags & VM_FAULT_WIRE) != 0)
More information about the dev-commits-src-main
mailing list