git: f803dd1e24ea - stable/13 - Add pmap_change_prot on arm64
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Date: Mon, 25 Oct 2021 13:54:51 UTC
The branch stable/13 has been updated by andrew:
URL: https://cgit.FreeBSD.org/src/commit/?id=f803dd1e24eaa37bb0fd6395fb5312265f94f9f5
commit f803dd1e24eaa37bb0fd6395fb5312265f94f9f5
Author: Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2021-09-20 16:49:18 +0000
Commit: Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2021-10-25 13:46:44 +0000
Add pmap_change_prot on arm64
Support changing the protection of preloaded kernel modules by
implementing pmap_change_prot on arm64 and calling it from
preload_protect.
Reviewed by: alc (previous version)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32026
(cherry picked from commit a85ce4ad7272ffa4b4649b0ed463341b743e815f)
---
sys/arm64/arm64/pmap.c | 94 +++++++++++++++++++++++++++++++++++++++++-------
sys/arm64/include/pmap.h | 1 +
sys/kern/link_elf.c | 2 +-
3 files changed, 83 insertions(+), 14 deletions(-)
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index cdd1ed49fc7d..3fa3a4b62711 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -382,7 +382,8 @@ static pv_entry_t pmap_pvh_remove(struct md_page *pvh, pmap_t pmap,
static void pmap_abort_ptp(pmap_t pmap, vm_offset_t va, vm_page_t mpte);
static bool pmap_activate_int(pmap_t pmap);
static void pmap_alloc_asid(pmap_t pmap);
-static int pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode);
+static int pmap_change_props_locked(vm_offset_t va, vm_size_t size,
+ vm_prot_t prot, int mode);
static pt_entry_t *pmap_demote_l1(pmap_t pmap, pt_entry_t *l1, vm_offset_t va);
static pt_entry_t *pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2,
vm_offset_t va, struct rwlock **lockp);
@@ -6127,17 +6128,41 @@ pmap_change_attr(vm_offset_t va, vm_size_t size, int mode)
int error;
PMAP_LOCK(kernel_pmap);
- error = pmap_change_attr_locked(va, size, mode);
+ error = pmap_change_props_locked(va, size, PROT_NONE, mode);
+ PMAP_UNLOCK(kernel_pmap);
+ return (error);
+}
+
+/*
+ * Changes the specified virtual address range's protections to those
+ * specified by "prot". Like pmap_change_attr(), protections for aliases
+ * in the direct map are updated as well. Protections on aliasing mappings may
+ * be a subset of the requested protections; for example, mappings in the direct
+ * map are never executable.
+ */
+int
+pmap_change_prot(vm_offset_t va, vm_size_t size, vm_prot_t prot)
+{
+ int error;
+
+ /* Only supported within the kernel map. */
+ if (va < VM_MIN_KERNEL_ADDRESS)
+ return (EINVAL);
+
+ PMAP_LOCK(kernel_pmap);
+ error = pmap_change_props_locked(va, size, prot, -1);
PMAP_UNLOCK(kernel_pmap);
return (error);
}
static int
-pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode)
+pmap_change_props_locked(vm_offset_t va, vm_size_t size, vm_prot_t prot,
+ int mode)
{
vm_offset_t base, offset, tmpva;
pt_entry_t l3, *pte, *newpte;
- int lvl;
+ pt_entry_t bits, mask;
+ int lvl, rv;
PMAP_LOCK_ASSERT(kernel_pmap, MA_OWNED);
base = trunc_page(va);
@@ -6148,12 +6173,44 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode)
!(base >= VM_MIN_KERNEL_ADDRESS && base < VM_MAX_KERNEL_ADDRESS))
return (EINVAL);
+ bits = 0;
+ mask = 0;
+ if (mode != -1) {
+ bits = ATTR_S1_IDX(mode);
+ mask = ATTR_S1_IDX_MASK;
+ if (mode == VM_MEMATTR_DEVICE) {
+ mask |= ATTR_S1_XN;
+ bits |= ATTR_S1_XN;
+ }
+ }
+ if (prot != VM_PROT_NONE) {
+ /* Don't mark the DMAP as executable. It never is on arm64. */
+ if (VIRT_IN_DMAP(base)) {
+ prot &= ~VM_PROT_EXECUTE;
+ /*
+ * XXX Mark the DMAP as writable for now. We rely
+ * on this in ddb & dtrace to insert breakpoint
+ * instructions.
+ */
+ prot |= VM_PROT_WRITE;
+ }
+
+ if ((prot & VM_PROT_WRITE) == 0) {
+ bits |= ATTR_S1_AP(ATTR_S1_AP_RO);
+ }
+ if ((prot & VM_PROT_EXECUTE) == 0) {
+ bits |= ATTR_S1_PXN;
+ }
+ bits |= ATTR_S1_UXN;
+ mask |= ATTR_S1_AP_MASK | ATTR_S1_XN;
+ }
+
for (tmpva = base; tmpva < base + size; ) {
pte = pmap_pte(kernel_pmap, tmpva, &lvl);
if (pte == NULL)
return (EINVAL);
- if ((pmap_load(pte) & ATTR_S1_IDX_MASK) == ATTR_S1_IDX(mode)) {
+ if ((pmap_load(pte) & mask) == bits) {
/*
* We already have the correct attribute,
* ignore this entry.
@@ -6194,14 +6251,23 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode)
case 3:
/* Update the entry */
l3 = pmap_load(pte);
- l3 &= ~ATTR_S1_IDX_MASK;
- l3 |= ATTR_S1_IDX(mode);
- if (mode == VM_MEMATTR_DEVICE)
- l3 |= ATTR_S1_XN;
+ l3 &= ~mask;
+ l3 |= bits;
pmap_update_entry(kernel_pmap, pte, l3, tmpva,
PAGE_SIZE);
+ if (!VIRT_IN_DMAP(tmpva)) {
+ /*
+ * Keep the DMAP memory in sync.
+ */
+ rv = pmap_change_props_locked(
+ PHYS_TO_DMAP(l3 & ~ATTR_MASK),
+ L3_SIZE, prot, mode);
+ if (rv != 0)
+ return (rv);
+ }
+
/*
* If moving to a non-cacheable entry flush
* the cache.
@@ -6363,12 +6429,14 @@ pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2, vm_offset_t va,
/*
* If the page table page is missing and the mapping
* is for a kernel address, the mapping must belong to
- * the direct map. Page table pages are preallocated
- * for every other part of the kernel address space,
- * so the direct map region is the only part of the
+ * either the direct map or the early kernel memory.
+ * Page table pages are preallocated for every other
+ * part of the kernel address space, so the direct map
+ * region and early kernel memory are the only parts of the
* kernel address space that must be handled here.
*/
- KASSERT(!ADDR_IS_KERNEL(va) || VIRT_IN_DMAP(va),
+ KASSERT(!ADDR_IS_KERNEL(va) || VIRT_IN_DMAP(va) ||
+ (va >= VM_MIN_KERNEL_ADDRESS && va < kernel_vm_end),
("pmap_demote_l2: No saved mpte for va %#lx", va));
/*
diff --git a/sys/arm64/include/pmap.h b/sys/arm64/include/pmap.h
index da739bb765e8..11a0388ab350 100644
--- a/sys/arm64/include/pmap.h
+++ b/sys/arm64/include/pmap.h
@@ -167,6 +167,7 @@ extern vm_offset_t virtual_end;
void pmap_activate_vm(pmap_t);
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);
+int pmap_change_prot(vm_offset_t va, vm_size_t size, vm_prot_t prot);
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);
diff --git a/sys/kern/link_elf.c b/sys/kern/link_elf.c
index ea21bf447a55..2faaa003380a 100644
--- a/sys/kern/link_elf.c
+++ b/sys/kern/link_elf.c
@@ -769,7 +769,7 @@ parse_vnet(elf_file_t ef)
static int
preload_protect(elf_file_t ef, vm_prot_t prot)
{
-#ifdef __amd64__
+#if defined(__aarch64__) || defined(__amd64__)
Elf_Ehdr *hdr;
Elf_Phdr *phdr, *phlimit;
vm_prot_t nprot;