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acpi: do not skip BIOS scan if EBDA length is zero

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EBDA layout is not standardized so we cannot assume first two bytes
are length. Neither is it required by ACPI standard. HP 8710W is known
to contain zeroes here.

Closes: 45002
This commit is contained in:
Andrei Borzenkov 2015-05-08 06:15:16 +03:00
parent 6a5c78c8c8
commit 07258815e9
2 changed files with 10 additions and 4 deletions
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4
grub-core/commands/acpi.c
View file

@ -180,8 +180,10 @@ grub_acpi_create_ebda (void)
struct grub_acpi_rsdp_v20 *v2;
ebda = (grub_uint8_t *) (grub_addr_t) ((*((grub_uint16_t *)0x40e)) << 4);
grub_dprintf ("acpi", "EBDA @%p\n", ebda);
if (ebda)
ebda_kb_len = *(grub_uint16_t *) ebda;
grub_dprintf ("acpi", "EBDA length 0x%x\n", ebda_kb_len);
if (ebda_kb_len > 16)
ebda_kb_len = 0;
ctx.ebda_len = (ebda_kb_len + 1) << 10;
@ -495,6 +497,8 @@ grub_cmd_acpi (struct grub_extcmd_context *ctxt, int argc, char **args)
if (! rsdp)
rsdp = grub_machine_acpi_get_rsdpv1 ();
grub_dprintf ("acpi", "RSDP @%p\n", rsdp);
if (rsdp)
{
grub_uint32_t *entry_ptr;

10
grub-core/commands/i386/pc/acpi.c
View file

@ -29,14 +29,15 @@ grub_machine_acpi_get_rsdpv1 (void)
grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
ebda_len = * (grub_uint16_t *) ebda;
if (! ebda_len)
return 0;
if (! ebda_len) /* FIXME do we really need this check? */
goto scan_bios;
for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
&& ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
return (struct grub_acpi_rsdp_v10 *) ptr;
scan_bios:
grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
ptr += 16)
@ -56,8 +57,8 @@ grub_machine_acpi_get_rsdpv2 (void)
grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
ebda_len = * (grub_uint16_t *) ebda;
if (! ebda_len)
return 0;
if (! ebda_len) /* FIXME do we really need this check? */
goto scan_bios;
for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
@ -67,6 +68,7 @@ grub_machine_acpi_get_rsdpv2 (void)
== 0)
return (struct grub_acpi_rsdp_v20 *) ptr;
scan_bios:
grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
ptr += 16)