# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1302064964 -10800
# Node ID 9939a6d7a45a1ea08d4094cffa302a1890c726d8
# Parent  53588744382ceb01121a3b06759e638749a0509a
protected critical sections in VM and the physical memory manager by disabling interrupts

diff -r 53588744382c -r 9939a6d7a45a src/intr-asm.S
--- a/src/intr-asm.S	Tue Apr 05 02:09:02 2011 +0300
+++ b/src/intr-asm.S	Wed Apr 06 07:42:44 2011 +0300
@@ -17,6 +17,28 @@
 	lidt (lim)
 	ret
 
+/* get_intr_state()
+ * returns 1 if interrutps are enabled, 0 if disabled */
+	.globl get_intr_state
+get_intr_state:
+	pushf
+	popl %eax
+	shr $9, %eax  /* bit 9 of eflags is IF */
+	andl $1, %eax
+	ret
+
+/* set_intr_state(int state)
+ * enables interrupts if the argument is non-zero, disables them otherwise */
+	.globl set_intr_state
+set_intr_state:
+	cmpl $0, 4(%esp)
+	jz 0f
+	sti
+	ret
+0:	cli
+	ret
+
+
 /* interrupt entry with error code macro
  * this macro generates an interrupt entry point for the
  * exceptions which include error codes in the stack frame
diff -r 53588744382c -r 9939a6d7a45a src/intr.h
--- a/src/intr.h	Tue Apr 05 02:09:02 2011 +0300
+++ b/src/intr.h	Wed Apr 06 07:42:44 2011 +0300
@@ -2,6 +2,7 @@
 #define INTR_H_
 
 #include <inttypes.h>
+#include "asmops.h"
 
 typedef void (*intr_func_t)(int, uint32_t);
 
@@ -10,4 +11,8 @@
 
 void interrupt(int intr_num, intr_func_t func);
 
+/* defined in intr-asm.S */
+int get_intr_state(void);
+void set_intr_state(int s);
+
 #endif	/* INTR_H_ */
diff -r 53588744382c -r 9939a6d7a45a src/mem.c
--- a/src/mem.c	Tue Apr 05 02:09:02 2011 +0300
+++ b/src/mem.c	Wed Apr 06 07:42:44 2011 +0300
@@ -3,6 +3,7 @@
 #include "mem.h"
 #include "panic.h"
 #include "vm.h"
+#include "intr.h"
 
 #define FREE		0
 #define USED		1
@@ -120,7 +121,10 @@
  */
 uint32_t alloc_phys_page(void)
 {
-	int i, idx, max;
+	int i, idx, max, intr_state;
+
+	intr_state = get_intr_state();
+	disable_intr();
 
 	idx = last_alloc_idx;
 	max = bmsize / 4;
@@ -139,6 +143,8 @@
 					last_alloc_idx = idx;
 
 					printf("alloc_phys_page() -> %x (page: %d)\n", PAGE_TO_ADDR(pg), pg);
+
+					set_intr_state(intr_state);
 					return PAGE_TO_ADDR(pg);
 				}
 			}
@@ -147,6 +153,7 @@
 		idx++;
 	}
 
+	set_intr_state(intr_state);
 	return 0;
 }
 
@@ -163,6 +170,9 @@
 	int pg = ADDR_TO_PAGE(addr);
 	int bmidx = BM_IDX(pg);
 
+	int intr_state = get_intr_state();
+	disable_intr();
+
 	if(!IS_FREE(pg)) {
 		panic("free_phys_page(%d): I thought that was already free!\n", pg);
 	}
@@ -171,6 +181,8 @@
 	if(bmidx < last_alloc_idx) {
 		last_alloc_idx = bmidx;
 	}
+
+	set_intr_state(intr_state);
 }
 
 /* this is only ever used by the VM init code to find out what the extends of
diff -r 53588744382c -r 9939a6d7a45a src/vm.c
--- a/src/vm.c	Tue Apr 05 02:09:02 2011 +0300
+++ b/src/vm.c	Wed Apr 06 07:42:44 2011 +0300
@@ -97,13 +97,17 @@
 int map_page(int vpage, int ppage, unsigned int attr)
 {
 	uint32_t *pgtbl;
-	int diridx, pgidx, pgon;
+	int diridx, pgidx, pgon, intr_state;
+
+	intr_state = get_intr_state();
+	disable_intr();
 
 	pgon = get_paging_status();
 
 	if(ppage < 0) {
 		uint32_t addr = alloc_phys_page();
 		if(!addr) {
+			set_intr_state(intr_state);
 			return -1;
 		}
 		ppage = ADDR_TO_PAGE(addr);
@@ -129,6 +133,7 @@
 	pgtbl[pgidx] = PAGE_TO_ADDR(ppage) | (attr & ATTR_PGTBL_MASK) | PG_PRESENT;
 	flush_tlb_page(vpage);
 
+	set_intr_state(intr_state);
 	return 0;
 }
 
@@ -138,6 +143,9 @@
 	int diridx = PAGE_TO_PGTBL(vpage);
 	int pgidx = PAGE_TO_PGTBL_PG(vpage);
 
+	int intr_state = get_intr_state();
+	disable_intr();
+
 	if(!(pgdir[diridx] & PG_PRESENT)) {
 		goto err;
 	}
@@ -149,9 +157,11 @@
 	pgtbl[pgidx] = 0;
 	flush_tlb_page(vpage);
 
-	return;
+	if(0) {
 err:
-	printf("unmap_page(%d): page already not mapped\n", vpage);
+		printf("unmap_page(%d): page already not mapped\n", vpage);
+	}
+	set_intr_state(intr_state);
 }
 
 /* if ppg_start is -1, we allocate physical pages to map with alloc_phys_page() */
@@ -217,9 +227,12 @@
  */
 int pgalloc(int num, int area)
 {
-	int ret = -1;
+	int intr_state, ret = -1;
 	struct page_range *node, *prev, dummy;
 
+	intr_state = get_intr_state();
+	disable_intr();
+
 	dummy.next = pglist[area];
 	node = pglist[area];
 	prev = &dummy;
@@ -252,14 +265,18 @@
 		}
 	}
 
+	set_intr_state(intr_state);
 	return ret;
 }
 
 void pgfree(int start, int num)
 {
-	int area, end;
+	int area, end, intr_state;
 	struct page_range *node, *new, *prev, *next;
 
+	intr_state = get_intr_state();
+	disable_intr();
+
 	if(!(new = alloc_node())) {
 		panic("pgfree: can't allocate new page_range node to add the freed pages\n");
 	}
@@ -295,6 +312,7 @@
 	}
 
 	coalesce(prev, new, next);
+	set_intr_state(intr_state);
 }
 
 static void coalesce(struct page_range *low, struct page_range *mid, struct page_range *high)
@@ -382,8 +400,14 @@
 
 void dbg_print_vm(int area)
 {
-	struct page_range *node = pglist[area];
-	int last = area == MEM_USER ? 0 : ADDR_TO_PAGE(KMEM_START);
+	struct page_range *node;
+	int last, intr_state;
+
+	intr_state = get_intr_state();
+	disable_intr();
+
+	node = pglist[area];
+	last = area == MEM_USER ? 0 : ADDR_TO_PAGE(KMEM_START);
 
 	printf("%s vm space\n", area == MEM_USER ? "user" : "kernel");
 
@@ -402,4 +426,6 @@
 		last = node->end;
 		node = node->next;
 	}
+
+	set_intr_state(intr_state);
 }