vm/vm_phys: add segment allocation function

Architecture specific code sometimes has constraints on the location of some
data structures in physical memory. This interface provides a simple way to
allocate physical memory from segments that fulfill these constraints. If
they are stronger, or needed by machine independent code, another (more
complicated) interface will be needed.

1 files changed, 14 insertions, 7 deletions

diff --git a/vm/vm_phys.c b/vm/vm_phys.c
index 7d8e6810..80b9c7b1 100644
--- a/vm/vm_phys.c
+++ b/vm/vm_phys.c
@@ -127,8 +127,7 @@ struct vm_phys_boot_seg {
 int vm_phys_ready;
 
 /*
- * Segment lists, ordered by priority (higher priority lists have lower
- * numerical priorities).
+ * Segment lists, ordered by priority.
  */
 static struct list vm_phys_seg_lists[VM_NR_PHYS_SEGLIST];
 
@@ -451,7 +450,7 @@ vm_phys_seg_free(struct vm_phys_seg *seg, struct vm_page *page,
 void __init
 vm_phys_load(const char *name, phys_addr_t start, phys_addr_t end,
              phys_addr_t avail_start, phys_addr_t avail_end,
-             unsigned int seglist_prio)
+             unsigned int seg_index, unsigned int seglist_prio)
 {
     struct vm_phys_boot_seg *boot_seg;
     struct vm_phys_seg *seg;
@@ -460,6 +459,7 @@ vm_phys_load(const char *name, phys_addr_t start, phys_addr_t end,
 
     assert(name != NULL);
     assert(start < end);
+    assert(seg_index < ARRAY_SIZE(vm_phys_segs));
     assert(seglist_prio < ARRAY_SIZE(vm_phys_seg_lists));
 
     if (!vm_phys_load_initialized) {
@@ -470,12 +470,11 @@ vm_phys_load(const char *name, phys_addr_t start, phys_addr_t end,
         vm_phys_load_initialized = 1;
     }
 
-    if (vm_phys_segs_size >= ARRAY_SIZE(vm_phys_segs))
-        panic("vm_phys: too many physical segments");
+    assert(vm_phys_segs_size < ARRAY_SIZE(vm_phys_segs));
 
+    boot_seg = &vm_phys_boot_segs[seg_index];
+    seg = &vm_phys_segs[seg_index];
     seg_list = &vm_phys_seg_lists[seglist_prio];
-    seg = &vm_phys_segs[vm_phys_segs_size];
-    boot_seg = &vm_phys_boot_segs[vm_phys_segs_size];
 
     list_insert_tail(seg_list, &seg->node);
     seg->start = start;
@@ -602,6 +601,14 @@ vm_phys_alloc(unsigned int order)
     return NULL;
 }
 
+struct vm_page *
+vm_phys_alloc_seg(unsigned int order, unsigned int seg_index)
+{
+    assert(seg_index < vm_phys_segs_size);
+
+    return vm_phys_seg_alloc(&vm_phys_segs[seg_index], order);
+}
+
 void
 vm_phys_free(struct vm_page *page, unsigned int order)
 {