[haiku-commits] Re: r42068 - haiku/trunk/src/system/boot/platform/bios_ia32
- From: Stefano Ceccherini <stefano.ceccherini@xxxxxxxxx>
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Fri, 10 Jun 2011 10:00:42 +0200
2011/6/9 Axel Dörfler <axeld@xxxxxxxxxxxxxxxx>:
> stefano.ceccherini@xxxxxxxxx wrote:
>> Log:
>> Map B_PAGE_SIZE, and not just acpi_description_header (was actually a
>> regression), since the tables are bigger than that.
>> Accessing unmapped memory was doing bad things on XenServer.
>
> That doesn't make any sense at all: the minimum mapping size is B_PAGE_SIZE;
> if you map less it will be automatically expanded to it. So unless the header
> is larger than B_PAGE_SIZE, this change doesn't really change anything.
> Please revert.
>
> Bye,
> Axel.
acpi_descriptor_header, as defined in
headers/private/kernel/arch/x86/arch_acpi.h
typedef struct acpi_descriptor_header {
char signature[4]; /* table identifier as ASCII
string */
uint32 length; /* length in bytes of
the entire table */
uint8 revision;
uint8 checksum; /* checksum of entire
table */
char oem_id[6]; /* not null terminated
*/
char oem_table_id[8]; /* oem supplied table
identifier */
uint32 oem_revision; /* oem supplied revision number
*/
char creator_id[4]; /* creator / asl compiler id */
uint32 creator_revision; /* compiler revision */
} _PACKED acpi_descriptor_header;
is 36 bytes.
Given that with B_PAGE_SIZE in the mmu_map_physical_memory() call
xenserver boots haiku, and with sizeof(acpi_description_header) it
reboots, I guess something doesn't work correctly.
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