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-rw-r--r--src/vmem.c131
1 files changed, 75 insertions, 56 deletions
diff --git a/src/vmem.c b/src/vmem.c
index 261ef42..52e7bd2 100644
--- a/src/vmem.c
+++ b/src/vmem.c
@@ -14,11 +14,23 @@
#include <kmi/vmem.h>
#include <arch/vmem.h>
-stat_t init_uvmem(struct tcb *t, vm_t base, vm_t top)
+stat_t init_uvmem(struct tcb *t)
{
t->uvmem.owner = t->tid;
t->uvmem.vmem = t->proc.vmem;
- return init_region(&t->uvmem.region, base, top);
+
+ stat_t ret = OK;
+ if ((ret = init_region(&t->uvmem.region, UVMEM_START, UVMEM_END)))
+ return ret;
+
+ /* if a user really wants to use the first page for something, they'll
+ * have to free it first, 'accepting' that no null-page is dangerous. */
+ size_t size = 0;
+ vm_t v = alloc_fixed_region(&t->uvmem.region,
+ UVMEM_START, BASE_PAGE_SIZE, &size,
+ MR_NONBACKED);
+ assert(v == UVMEM_START && size == BASE_PAGE_SIZE);
+ return OK;
}
/**
@@ -40,6 +52,12 @@ static stat_t __copy_mapped_region(struct tcb *d, struct tcb *s,
size_t size = end - start;
vm_t v = alloc_fixed_region(&d->uvmem.region, start, size, &size,
m->flags);
+ if (ERR_CODE(v))
+ return v;
+
+ if (is_set(m->flags, MR_NONBACKED))
+ return v;
+
assert(v == start);
/* note that we use uvmem.vmem instead of proc.vmem, this is just to
@@ -76,6 +94,8 @@ static stat_t __copy_shared_region(struct tcb *d, struct mem_region *m)
size_t size = end - start;
vm_t v = alloc_fixed_region(&d->uvmem.region, start, size, &size,
m->flags);
+ if (ERR_CODE(v))
+ return v;
assert(v == start);
stat_t res = clone_region(d->uvmem.vmem, s->uvmem.vmem, start, v, size,
@@ -107,8 +127,11 @@ static vm_t __clone_shared_region(struct tcb *d, struct tcb *s,
reference_proc(s);
size_t size = end - start;
- vm_t v = alloc_shared_region(&d->uvmem.region, size, &size, m->flags,
- s->rid);
+ vm_t v = alloc_shared_region(&d->uvmem.region, size, &size,
+ MR_NONBACKED | m->flags, s->rid);
+ if (ERR_CODE(v))
+ return v;
+
stat_t res = clone_region(d->uvmem.vmem, s->uvmem.vmem, start, v, size,
flags);
if (res == OK)
@@ -118,7 +141,7 @@ static vm_t __clone_shared_region(struct tcb *d, struct tcb *s,
unreference_proc(s);
free_region(&d->uvmem.region, v);
unmap_fixed_region(d->uvmem.vmem, v, size);
- return NULL;
+ return res;
}
/**
@@ -127,44 +150,23 @@ static vm_t __clone_shared_region(struct tcb *d, struct tcb *s,
* @param t Current thread.
* @param m Memory region to free.
*/
-static void __free_private_mapping(struct tcb *t, struct mem_region *m)
+static void __free_mapping(struct tcb *t, struct mem_region *m)
{
+ struct tcb *owner = get_tcb(m->pid);
+ if (owner)
+ unreference_proc(owner);
+
+ if (is_set(m->flags, MR_NONBACKED))
+ return;
+
pm_t start = __addr(m->start);
pm_t end = __addr(m->end);
size_t size = end - start;
- unmap_region(t->proc.vmem, start, size);
-}
-
-/**
- * Unmap shared region and free associated physical pages if they're not being
- * used by the other process.
- *
- * @param t Current thread.
- * @param m Memory region to free.
- */
-static void __free_shared_mapping(struct tcb *t, struct mem_region *m)
-{
- vm_t start = __addr(m->start);
- vm_t end = __addr(m->end);
- unreference_proc(get_tcb(m->pid));
-
- size_t bytes = end - start;
- unmap_fixed_region(t->proc.vmem, start, bytes);
-}
-
-/**
- * Convenience function for freeing mapped regions.
- *
- * @param t Thread to work in.
- * @param m Memory region to free.
- */
-static void __free_mapping(struct tcb *t, struct mem_region *m)
-{
- if (m->pid != 0)
- return __free_shared_mapping(t, m);
-
- return __free_private_mapping(t, m);
+ if (m->pid)
+ unmap_fixed_region(t->proc.vmem, start, size);
+ else
+ unmap_region(t->proc.vmem, start, size);
}
void clear_uvmem(struct tcb *t)
@@ -174,13 +176,11 @@ void clear_uvmem(struct tcb *t)
struct mem_region *m = find_closest_used_region(&t->uvmem.region, 0);
for (; m; m = m->next) {
- if (is_region_kept(m)) {
+ if (is_region_kept(m))
continue;
- }
- if (!is_set(m->flags, MR_USED)) {
+ if (!is_set(m->flags, MR_USED))
continue;
- }
__free_mapping(t, m);
free_known_region(&t->uvmem.region, m);
@@ -243,10 +243,14 @@ vm_t alloc_uvmem(struct tcb *t, size_t size, vmflags_t flags)
assert(t && is_proc(t));
const vm_t v = alloc_region(&t->uvmem.region, size, &size, flags);
- if (map_region(t->proc.vmem, v, size, max_order(), flags)) {
+ if (ERR_CODE(v))
+ return v;
+
+ stat_t ret = OK;
+ if ((ret = map_region(t->proc.vmem, v, size, max_order(), flags))) {
unmap_region(t->proc.vmem, v, size);
free_region(&t->uvmem.region, v);
- return NULL;
+ return ret;
}
return v;
@@ -258,10 +262,14 @@ vm_t alloc_fixed_uvmem(struct tcb *t, vm_t start, size_t size, vmflags_t flags)
const vm_t v = alloc_fixed_region(&t->uvmem.region, start, size, &size,
flags);
- if (map_region(t->proc.vmem, v, size, max_order(), flags)) {
+ if (ERR_CODE(v))
+ return v;
+
+ stat_t ret = OK;
+ if ((ret = map_region(t->proc.vmem, v, size, max_order(), flags))) {
unmap_region(t->proc.vmem, v, size);
free_region(&t->uvmem.region, v);
- return NULL;
+ return ret;
}
return v;
@@ -269,14 +277,20 @@ vm_t alloc_fixed_uvmem(struct tcb *t, vm_t start, size_t size, vmflags_t flags)
vm_t map_fixed_uvmem(struct tcb *t, pm_t start, size_t size, vmflags_t flags)
{
+ assert(is_aligned(start, BASE_PAGE_SIZE));
+
const vm_t v = alloc_region(&t->uvmem.region, size, &size, flags);
- if (map_fixed_region(t->proc.vmem, v, start, size, flags)) {
+ if (ERR_CODE(v))
+ return v;
+
+ stat_t ret = OK;
+ if ((ret = map_fixed_region(t->proc.vmem, v, start, size, flags))) {
unmap_region(t->proc.vmem, v, size);
free_region(&t->uvmem.region, v);
- return NULL;
+ return ret;
}
- return v + (start % BASE_PAGE_SIZE);
+ return v;
}
vm_t alloc_uvpage(struct tcb *t, size_t size, vmflags_t flags, pm_t *startp,
@@ -286,19 +300,20 @@ vm_t alloc_uvpage(struct tcb *t, size_t size, vmflags_t flags, pm_t *startp,
size = order_size(order);
const vm_t v = alloc_region(&t->uvmem.region, size, &size, flags);
- if (!v)
- return 0;
+ if (ERR_CODE(v))
+ return v;
pm_t start = alloc_page(order);
if (!start) {
free_region(&t->uvmem.region, size);
- return 0;
+ return ERR_OOMEM;
}
- if (map_fixed_region(t->proc.vmem, v, start, size, flags)) {
+ stat_t ret = OK;
+ if ((ret = map_fixed_region(t->proc.vmem, v, start, size, flags))) {
unmap_region(t->proc.vmem, v, size);
free_region(&t->uvmem.region, v);
- return NULL;
+ return ret;
}
*startp = (pm_t)__pa(start);
@@ -313,11 +328,15 @@ vm_t alloc_shared_uvmem(struct tcb *s, size_t size, vmflags_t flags)
assert(s && is_proc(s));
const vm_t v = alloc_region(&s->uvmem.region, size, &size,
MR_SHARED | flags);
+ if (ERR_CODE(v))
+ return v;
+
/* use base pages to make clone more likely to succeed */
- if (map_region(s->proc.vmem, v, size, BASE_PAGE, flags)) {
+ stat_t ret = OK;
+ if ((ret = map_region(s->proc.vmem, v, size, BASE_PAGE, flags))) {
unmap_region(s->proc.vmem, v, size);
free_region(&s->uvmem.region, v);
- return NULL;
+ return ret;
}
return v;
generated by cgit v1.3 (git 2.53.0) at 2026-08-27 00:59:54 +0000