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multiboot2: Set min address for mbi allocation to 0x1000

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In some cases GRUB2 allocates multiboot2 structure at 0 address, that is
a confusing behavior. Consumers of that structure can have internal NULL-checks
that will throw an error when get a pointer to data allocated at address 0.
To prevent that, define min address for mbi allocation on x86 and x86_64
platforms.

Signed-off-by: Lukasz Hawrylko <lukasz.hawrylko@linux.intel.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Lukasz Hawrylko 2019-12-16 11:15:55 +01:00 committed by Daniel Kiper
parent 7e28ca82bb
commit 0f3f5b7c13
1 changed files with 7 additions and 1 deletions
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8
grub-core/loader/multiboot_mbi2.c
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@ -48,6 +48,12 @@
#define HAS_VGA_TEXT 0
#endif
#if defined (__i386__) || defined (__x86_64__)
#define MBI_MIN_ADDR 0x1000
#else
#define MBI_MIN_ADDR 0
#endif
struct module
{
struct module *next;
@ -708,7 +714,7 @@ grub_multiboot2_make_mbi (grub_uint32_t *target)
COMPILE_TIME_ASSERT (MULTIBOOT_TAG_ALIGN % sizeof (grub_properly_aligned_t) == 0);
err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
0, 0xffffffff - bufsize,
MBI_MIN_ADDR, 0xffffffff - bufsize,
bufsize, MULTIBOOT_TAG_ALIGN,
GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)