From: Ben Gras <ben@minix3.org>
Date: Fri, 1 Feb 2013 16:48:40 +0000 (+0100)
Subject: vm: fix sanity checks on arm
X-Git-Tag: v3.2.1~35
X-Git-Url: http://zhaoyanbai.com/repos/?a=commitdiff_plain;h=b7ea9f3fd103f1fd36bf11f4330facffcc5bb89b;p=minix.git

vm: fix sanity checks on arm

The 'polarity' of the RW bit is inversed on ARM, causing one
of the sanity check compensations to fail. ARM now runs basic
stuff with sanity checks passing.

Change-Id: Iee28ab63e430e759f204eeb204b24c301d5ea3c9
---

diff --git a/servers/vm/arch/i386/pagetable.c b/servers/vm/arch/i386/pagetable.c
index 0d51fd2ba..30cf912fb 100644
--- a/servers/vm/arch/i386/pagetable.c
+++ b/servers/vm/arch/i386/pagetable.c
@@ -171,15 +171,10 @@ static u32_t findhole(int pages)
 	assert(pages > 0);
 #endif
 
-#if SANITYCHECKS
-	curv = ((u32_t) random()) % ((vmax - vmin)/VM_PAGE_SIZE);
-	curv *= VM_PAGE_SIZE;
-	curv += vmin;
-#else
 	curv = lastv;
 	if(curv < vmin || curv >= vmax)
 		curv = vmin;
-#endif
+
 	try_restart = 1;
 
 	/* Start looking for a free page starting at vmin. */
@@ -958,10 +953,17 @@ int pt_writemap(struct vmproc * vmp,
 			maskedentry &= ~(I386_VM_ACC|I386_VM_DIRTY);
 #endif
 			/* Verify pagetable entry. */
+#if defined(__i386__)
 			if(entry & ARCH_VM_PTE_RW) {
 				/* If we expect a writable page, allow a readonly page. */
 				maskedentry |= ARCH_VM_PTE_RW;
 			}
+#elif defined(__arm__)
+			if(!(entry & ARCH_VM_PTE_RO)) {
+				/* If we expect a writable page, allow a readonly page. */
+				maskedentry &= ~ARCH_VM_PTE_RO;
+			}
+#endif
 			if(maskedentry != entry) {
 				printf("pt_writemap: mismatch: ");
 #if defined(__i386__)
@@ -979,6 +981,8 @@ int pt_writemap(struct vmproc * vmp,
 				printf(" masked %s; ",
 					ptestr(maskedentry));
 				printf(" expected %s\n", ptestr(entry));
+				printf("found 0x%x, wanted 0x%x\n", 
+					pt->pt_pt[pde][pte], entry);
 				ret = EFAULT;
 				goto resume_exit;
 			}