[PATCH] Remove zero page mapping from all architectures to allow detection of NULL pointer dereferences.
Signed-off-by: Mark Cave-Ayland mark.cave-ayland@ilande.co.uk --- openbios-devel/arch/ppc/qemu/ofmem.c | 7 ++++--- openbios-devel/arch/sparc32/lib.c | 6 +++--- openbios-devel/arch/sparc64/ofmem_sparc64.c | 4 ++-- 3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/openbios-devel/arch/ppc/qemu/ofmem.c b/openbios-devel/arch/ppc/qemu/ofmem.c index 0161a17..429f43b 100644 --- a/openbios-devel/arch/ppc/qemu/ofmem.c +++ b/openbios-devel/arch/ppc/qemu/ofmem.c @@ -549,9 +549,10 @@ ofmem_init(void) { ofmem_t *ofmem = ofmem_arch_get_private();
- ofmem_claim_phys(0, get_ram_bottom(), 0); - ofmem_claim_virt(0, get_ram_bottom(), 0); - ofmem_map(0, 0, get_ram_bottom(), 0); + /* Map the memory (don't map page 0 to allow catching of NULL dereferences) */ + ofmem_claim_phys(PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0); + ofmem_claim_virt(PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0); + ofmem_map(PAGE_SIZE, PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0);
/* Map everything at the top of physical RAM 1:1, minus the OpenBIOS ROM in RAM copy */ ofmem_claim_phys(get_ram_top(), get_hash_base() + HASH_SIZE - get_ram_top(), 0); diff --git a/openbios-devel/arch/sparc32/lib.c b/openbios-devel/arch/sparc32/lib.c index c0df654..4ff3619 100644 --- a/openbios-devel/arch/sparc32/lib.c +++ b/openbios-devel/arch/sparc32/lib.c @@ -403,9 +403,9 @@ init_mmu_swift(void) 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 diff --git a/openbios-devel/arch/sparc64/ofmem_sparc64.c b/openbios-devel/arch/sparc64/ofmem_sparc64.c index 50224e6..ece51f9 100644 --- a/openbios-devel/arch/sparc64/ofmem_sparc64.c +++ b/openbios-devel/arch/sparc64/ofmem_sparc64.c @@ -365,8 +365,8 @@ void ofmem_init( void ) /* inherit translations set up by entry.S */ ofmem_walk_boot_map(remap_page_range);
- /* Map the memory */ - ofmem_map_page_range(0, 0, qemu_mem_size, 0x36); + /* Map the memory (don't map page 0 to allow catching of NULL dereferences) */ + ofmem_map_page_range(PAGE_SIZE, PAGE_SIZE, qemu_mem_size - PAGE_SIZE, 0x36);
if (!(retained->magic == RETAIN_MAGIC)) { OFMEM_TRACE("ofmem_init: no retained magic found, creating\n");
On Tue, Apr 9, 2013 at 9:33 PM, Mark Cave-Ayland mark.cave-ayland@ilande.co.uk wrote:
Signed-off-by: Mark Cave-Ayland mark.cave-ayland@ilande.co.uk
openbios-devel/arch/ppc/qemu/ofmem.c | 7 ++++--- openbios-devel/arch/sparc32/lib.c | 6 +++--- openbios-devel/arch/sparc64/ofmem_sparc64.c | 4 ++-- 3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/openbios-devel/arch/ppc/qemu/ofmem.c b/openbios-devel/arch/ppc/qemu/ofmem.c index 0161a17..429f43b 100644 --- a/openbios-devel/arch/ppc/qemu/ofmem.c +++ b/openbios-devel/arch/ppc/qemu/ofmem.c @@ -549,9 +549,10 @@ ofmem_init(void) { ofmem_t *ofmem = ofmem_arch_get_private();
- ofmem_claim_phys(0, get_ram_bottom(), 0);
- ofmem_claim_virt(0, get_ram_bottom(), 0);
- ofmem_map(0, 0, get_ram_bottom(), 0);
- /* Map the memory (don't map page 0 to allow catching of NULL dereferences) */
- ofmem_claim_phys(PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0);
- ofmem_claim_virt(PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0);
- ofmem_map(PAGE_SIZE, PAGE_SIZE, get_ram_bottom() - PAGE_SIZE, 0);
You seem not to like my
#define LOWMEM_START PAGE_SIZE
? I think it would have made distinguishing between the page size and the offset parameters more obvious.
Artyom
/* Map everything at the top of physical RAM 1:1, minus the OpenBIOS ROM in RAM copy */ ofmem_claim_phys(get_ram_top(), get_hash_base() + HASH_SIZE - get_ram_top(), 0);diff --git a/openbios-devel/arch/sparc32/lib.c b/openbios-devel/arch/sparc32/lib.c index c0df654..4ff3619 100644 --- a/openbios-devel/arch/sparc32/lib.c +++ b/openbios-devel/arch/sparc32/lib.c @@ -403,9 +403,9 @@ init_mmu_swift(void) 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
diff --git a/openbios-devel/arch/sparc64/ofmem_sparc64.c b/openbios-devel/arch/sparc64/ofmem_sparc64.c index 50224e6..ece51f9 100644 --- a/openbios-devel/arch/sparc64/ofmem_sparc64.c +++ b/openbios-devel/arch/sparc64/ofmem_sparc64.c @@ -365,8 +365,8 @@ void ofmem_init( void ) /* inherit translations set up by entry.S */ ofmem_walk_boot_map(remap_page_range);
/* Map the memory */ofmem_map_page_range(0, 0, qemu_mem_size, 0x36);
/* Map the memory (don't map page 0 to allow catching of NULL dereferences) */ofmem_map_page_range(PAGE_SIZE, PAGE_SIZE, qemu_mem_size - PAGE_SIZE, 0x36); if (!(retained->magic == RETAIN_MAGIC)) { OFMEM_TRACE("ofmem_init: no retained magic found, creating\n");-- 1.7.10.4
-- OpenBIOS http://openbios.org/ Mailinglist: http://lists.openbios.org/mailman/listinfo Free your System - May the Forth be with you
-- Regards, Artyom Tarasenko
linux/sparc and solaris/sparc under qemu blog: http://tyom.blogspot.com/search/label/qemu
-
Artyom Tarasenko -
Mark Cave-Ayland