diff options
| author | Peter Chubb <peter.chubb@nicta.com.au> | 2014-01-16 08:39:06 +1100 |
|---|---|---|
| committer | Simon Horman <horms@verge.net.au> | 2014-01-16 09:21:52 +0900 |
| commit | 0780897b8b06fe40234e3d4eac66ce6031145220 (patch) | |
| tree | 31b0b78869106f15d7f454e06dac5876fbe5d69d /kexec/arch/i386/kexec-multiboot-x86.c | |
| parent | fbd61f27cb637d984b0a15e2d711605d28b3043e (diff) | |
Fix value of mbi->mem_lower for multiboot-x86
In the multiboot header, there is a field, `mem_lower' that is meant to
contain the size of memory starting at zero and ending below 640k.
If your kernel is compiled with CONFIG_X86_RESERVE_LOW non zero
(the usual case), then a hole is inserted into kernel's physical
memory map at zero, so the test to find the size of this region in
kexec/arch/i386/kexec-multiboot-x86.c never succeeds, so the value is
always zero.
On a PC99 architecture, there is always memory at physycal address zero;
assume that a region that starts below 64k actually starts at zero,
and use it for the mem_lower variable.
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'kexec/arch/i386/kexec-multiboot-x86.c')
| -rw-r--r-- | kexec/arch/i386/kexec-multiboot-x86.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/kexec/arch/i386/kexec-multiboot-x86.c b/kexec/arch/i386/kexec-multiboot-x86.c index 2f59d7b..fce7f05 100644 --- a/kexec/arch/i386/kexec-multiboot-x86.c +++ b/kexec/arch/i386/kexec-multiboot-x86.c @@ -258,10 +258,18 @@ int multiboot_x86_load(int argc, char **argv, const char *buf, off_t len, mmap[i].length_high = length >> 32; if (range[i].type == RANGE_RAM) { mmap[i].Type = 1; /* RAM */ - /* Is this the "low" memory? */ - if ((range[i].start == 0) - && (range[i].end > mem_lower)) + /* + * Is this the "low" memory? Can't just test + * against zero, because Linux protects (and + * hides) the first few pages of physical + * memory. + */ + + if ((range[i].start <= 64*1024) + && (range[i].end > mem_lower)) { + range[i].start = 0; mem_lower = range[i].end; + } /* Is this the "high" memory? */ if ((range[i].start <= 0x100000) && (range[i].end > mem_upper + 0x100000)) |