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platform: relax rom scanning alignment for ahci platforms 

The PCI-3.0 Firmware specification allows for option-roms to have
512-byte alignment rather than 2048-byte.  As there does not appear to
be a reliable method to detect a PCI-3.0 compliant BIOS from userspace
we allow the imsm platform detection code to presume that a system
modern enough to have an Intel AHCI controller does not have
dangerous/legacy ISA regions in the option-ROM memory space.

An environment variable to disable this behaviour, IMSM_SAFE_OROM_SCAN,
is added in case this presumption is ever proven wrong.

Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-07-31 17:11:41 -07:00
parent 148acb7baa
commit 969c255511
3 changed files with 28 additions and 7 deletions
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7
platform-intel.c
View File

@ -157,6 +157,7 @@ static int scan(const void *start, const void *end)
const struct imsm_orom *find_imsm_orom(void)
{
static int populated = 0;
unsigned long align;
/* it's static data so we only need to read it once */
if (populated)
@ -184,7 +185,11 @@ const struct imsm_orom *find_imsm_orom(void)
return NULL;
/* scan option-rom memory looking for an imsm signature */
if (probe_roms_init() != 0)
if (check_env("IMSM_SAFE_OROM_SCAN"))
align = 2048;
else
align = 512;
if (probe_roms_init(align) != 0)
return NULL;
probe_roms();
populated = scan_adapter_roms(scan);

26
probe_roms.c
View File

@ -32,6 +32,8 @@ static void *rom_mem = MAP_FAILED;
static int rom_fd = -1;
const static int rom_len = 0xf0000 - 0xc0000; /* option-rom memory region */
static int _sigbus;
static unsigned long rom_align;
#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
static void sigbus(int sig)
@ -76,11 +78,20 @@ void probe_roms_exit(void)
}
}
int probe_roms_init(void)
int probe_roms_init(unsigned long align)
{
int fd;
int rc = 0;
/* valid values are 2048 and 512. 512 is for PCI-3.0 compliant
* systems, or systems that do not have dangerous/legacy ISA
* devices. 2048 should always be safe
*/
if (align == 512 || align == 2048)
rom_align = align;
else
return -1;
if (signal(SIGBUS, sigbus) == SIG_ERR)
rc = -1;
if (rc == 0) {
@ -208,6 +219,11 @@ int scan_adapter_roms(scan_fn fn)
return found;
}
static unsigned long align(unsigned long addr, unsigned long alignment)
{
return (addr + alignment - 1) & ~(alignment - 1);
}
void probe_roms(void)
{
const void *rom;
@ -220,7 +236,7 @@ void probe_roms(void)
/* video rom */
upper = adapter_rom_resources[0].start;
for (start = video_rom_resource.start; start < upper; start += 2048) {
for (start = video_rom_resource.start; start < upper; start += rom_align) {
rom = isa_bus_to_virt(start);
if (!romsignature(rom))
continue;
@ -239,7 +255,7 @@ void probe_roms(void)
break;
}
start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
start = align(video_rom_resource.end + 1, rom_align);
if (start < upper)
start = upper;
@ -255,7 +271,7 @@ void probe_roms(void)
}
/* check for adapter roms on 2k boundaries */
for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += rom_align) {
rom = isa_bus_to_virt(start);
if (!romsignature(rom))
continue;
@ -273,7 +289,7 @@ void probe_roms(void)
adapter_rom_resources[i].start = start;
adapter_rom_resources[i].end = start + length - 1;
start = adapter_rom_resources[i++].end & ~2047UL;
start = adapter_rom_resources[i++].end & ~(rom_align - 1);
}
}

2
probe_roms.h
View File

@ -18,7 +18,7 @@
*/
void probe_roms_exit(void);
int probe_roms_init(void);
int probe_roms_init(unsigned long align);
typedef int (*scan_fn)(const void *start, const void *end);
int scan_adapter_roms(scan_fn fn);
void probe_roms(void);