backported fixes from 256boss

[bootcensus] / src / mem.c

diff --git a/src/mem.c b/src/mem.c
index 4125fe4..a013607 100644 (file)
--- a/src/mem.c
+++ b/src/mem.c
@@ -17,6 +17,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 #include <stdio.h>
 #include <string.h>
+#include "config.h"
 #include "panic.h"
 #include "mem.h"
 #include "intr.h"
@@ -37,6 +38,8 @@ struct mem_range {
        uint32_t size;
 };
 
+void move_stack(uint32_t newaddr);     /* defined in startup.s */
+
 static void mark_page(int pg, int used);
 static void add_memory(uint32_t start, size_t size);
 
@@ -63,7 +66,7 @@ static int bmsize, last_alloc_idx;
 
 void init_mem(void)
 {
-       int i, pg, max_pg = 0;
+       int i, pg, max_used_pg, end_pg = 0;
        uint32_t used_end, start, end, sz, total = 0, rem;
        const char *suffix[] = {"bytes", "KB", "MB", "GB"};
 
@@ -107,8 +110,8 @@ void init_mem(void)
                total += sz;
 
                pg = ADDR_TO_PAGE(end);
-               if(max_pg < pg) {
-                       max_pg = pg;
+               if(end_pg < pg) {
+                       end_pg = pg;
                }
        }
 
@@ -123,21 +126,29 @@ void init_mem(void)
        /* size of the useful part of the bitmap in bytes padded to 4-byte
         * boundaries to allow 32bit at a time operations.
         */
-       bmsize = (max_pg / 32 + 1) * 4;
+       bmsize = (end_pg / 32) * 4;
 
        /* mark all pages occupied by the bitmap as used */
        used_end = (uint32_t)bitmap + bmsize - 1;
 
-       max_pg = ADDR_TO_PAGE(used_end);
-       printf("marking pages up to %x (page: %d) as used\n", used_end, max_pg);
-       for(i=0; i<=max_pg; i++) {
+       max_used_pg = ADDR_TO_PAGE(used_end);
+       printf("marking pages up to %x (page: %d) as used\n", used_end, max_used_pg);
+       for(i=0; i<=max_used_pg; i++) {
                mark_page(i, USED);
        }
+
+#ifdef MOVE_STACK_RAMTOP
+       /* allocate space for the stack at the top of RAM and move it there */
+       if((pg = alloc_ppages(STACK_PAGES, MEM_STACK)) != -1) {
+               printf("moving stack-top to: %x (%d pages)\n", PAGE_TO_ADDR(end_pg) - 4, STACK_PAGES);
+               move_stack(PAGE_TO_ADDR(pg + STACK_PAGES) - 4);
+       }
+#endif
 }
 
-int alloc_ppage(void)
+int alloc_ppage(int area)
 {
-       return alloc_ppages(1);
+       return alloc_ppages(1, area);
 }
 
 /* free_ppage marks the physical page, free in the allocation bitmap.
@@ -167,26 +178,34 @@ void free_ppage(int pg)
 }
 
 
-int alloc_ppages(int count)
+int alloc_ppages(int count, int area)
 {
-       int i, pg, idx, max, intr_state, found_free = 0;
+       int i, dir, pg, idx, max, intr_state, found_free = 0;
 
        intr_state = get_intr_flag();
        disable_intr();
 
-       idx = last_alloc_idx;
-       max = bmsize / 4;
+       if(area == MEM_STACK) {
+               idx = (bmsize - 1) / 4;
+               max = -1;
+               dir = -1;
+       } else {
+               idx = last_alloc_idx;
+               max = bmsize / 4;
+               dir = 1;
+       }
 
-       while(idx <= max) {
+       while(idx != max) {
                /* if at least one bit is 0 then we have at least
                 * one free page. find it and try to allocate a range starting from there
                 */
                if(bitmap[idx] != 0xffffffff) {
-                       for(i=0; i<32; i++) {
-                               pg = idx * 32 + i;
+                       pg = idx * 32;
+                       if(dir < 0) pg += 31;
 
+                       for(i=0; i<32; i++) {
                                if(IS_FREE(pg)) {
-                                       if(!found_free) {
+                                       if(!found_free && dir > 0) {
                                                last_alloc_idx = idx;
                                                found_free = 1;
                                        }
@@ -196,9 +215,10 @@ int alloc_ppages(int count)
                                                return pg;
                                        }
                                }
+                               pg += dir;
                        }
                }
-               idx++;
+               idx += dir;
        }
 
        set_intr_flag(intr_state);
@@ -278,3 +298,17 @@ static void mark_page(int pg, int used)
        }
 }
 
+void print_page_bitmap(void)
+{
+       int i;
+
+       for(i=0; i<bmsize/4; i++) {
+               if((i & 3) == 0) {
+                       uint32_t pg = i * 32;
+                       uint32_t addr = PAGE_TO_ADDR(pg);
+                       printf("\n%5d [%08x]:", (int)pg, (unsigned long)addr);
+               }
+               printf(" %08x", bitmap[i]);
+       }
+       printf("\n");
+}