[OpenBIOS] [commit] r1123 - trunk/openbios-devel/arch/sparc32

[repository service]

Author: mcayland
Date: Fri Apr 19 09:04:32 2013
New Revision: 1123
URL: http://tracker.coreboot.org/trac/openbios/changeset/1123

Log:
SPARC32: Remove zero page mapping from MMU to enable detection of NULL pointer dereferences

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
Acked-by: Artyom Tarasenko <atar4qemu at gmail.com>

Modified:
   trunk/openbios-devel/arch/sparc32/lib.c
   trunk/openbios-devel/arch/sparc32/ofmem_sparc32.c

Modified: trunk/openbios-devel/arch/sparc32/lib.c
==============================================================================
--- trunk/openbios-devel/arch/sparc32/lib.c	Fri Apr 19 09:04:25 2013	(r1122)
+++ trunk/openbios-devel/arch/sparc32/lib.c	Fri Apr 19 09:04:32 2013	(r1123)
@@ -393,9 +393,9 @@
     ofmem_arch_map_pages(pa, va, size, ofmem_arch_default_translation_mode(pa));
     ofmem_map_page_range(pa, va, size, ofmem_arch_default_translation_mode(pa));
 
-    // 1:1 mapping for RAM
-    ofmem_arch_map_pages(0, 0, LOWMEMSZ, ofmem_arch_default_translation_mode(0));
-    ofmem_map_page_range(0, 0, LOWMEMSZ, ofmem_arch_default_translation_mode(0));
+    // 1:1 mapping for RAM (don't map page 0 to allow catching of NULL dereferences)                                                                                                                                            
+    ofmem_arch_map_pages(PAGE_SIZE, PAGE_SIZE, LOWMEMSZ - PAGE_SIZE, ofmem_arch_default_translation_mode(0));                                                                                                                   
+    ofmem_map_page_range(PAGE_SIZE, PAGE_SIZE, LOWMEMSZ - PAGE_SIZE, ofmem_arch_default_translation_mode(0));
 
     /*
      * Flush cache

Modified: trunk/openbios-devel/arch/sparc32/ofmem_sparc32.c
==============================================================================
--- trunk/openbios-devel/arch/sparc32/ofmem_sparc32.c	Fri Apr 19 09:04:25 2013	(r1122)
+++ trunk/openbios-devel/arch/sparc32/ofmem_sparc32.c	Fri Apr 19 09:04:32 2013	(r1123)
@@ -238,6 +238,9 @@
 	memset(&s_ofmem_data, 0, sizeof(s_ofmem_data));
 	s_ofmem_data.ofmem.ramsize = qemu_mem_size;
 	
+	/* Mark the first page as non-free */
+	ofmem_claim_virt(0, PAGE_SIZE, 0);
+	
 	/* Claim reserved physical addresses at top of RAM */
 	ofmem_claim_phys(ofmem_arch_get_phys_top(), s_ofmem_data.ofmem.ramsize - ofmem_arch_get_phys_top(), 0);