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x86, realmode: Pointer walk cleanups, pull out invariant use of __pa()

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The pointer arithmetic in this function was really bizarre, where in
fact all we really wanted was a simple pointer array walk.  Use the
much more idiomatic construction for that (*ptr++).

Factor an invariant use of __pa() out of the relocation loop.  At
least on 64 bits it seems gcc isn't capable of doing that
automatically.

Change the scope of a couple of variables to make it extra obvious
that they are extremely local temp variables.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-rd908t9c8kvcojdabtmm94mb@git.kernel.org
This commit is contained in:
H. Peter Anvin 2013-12-18 15:52:13 -08:00
parent d8af4ce490
commit 7306006f10
1 changed files with 12 additions and 14 deletions
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26
arch/x86/realmode/init.c
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@ -29,12 +29,10 @@ void __init reserve_real_mode(void)
void __init setup_real_mode(void)
{
u16 real_mode_seg;
u32 *rel;
const u32 *rel;
u32 count;
u32 *ptr;
u16 *seg;
int i;
unsigned char *base;
unsigned long phys_base;
struct trampoline_header *trampoline_header;
size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
#ifdef CONFIG_X86_64
@ -46,23 +44,23 @@ void __init setup_real_mode(void)
memcpy(base, real_mode_blob, size);
real_mode_seg = __pa(base) >> 4;
phys_base = __pa(base);
real_mode_seg = phys_base >> 4;
rel = (u32 *) real_mode_relocs;
/* 16-bit segment relocations. */
count = rel[0];
rel = &rel[1];
for (i = 0; i < count; i++) {
seg = (u16 *) (base + rel[i]);
count = *rel++;
while (count--) {
u16 *seg = (u16 *) (base + *rel++);
*seg = real_mode_seg;
}
/* 32-bit linear relocations. */
count = rel[i];
rel = &rel[i + 1];
for (i = 0; i < count; i++) {
ptr = (u32 *) (base + rel[i]);
*ptr += __pa(base);
count = *rel++;
while (count--) {
u32 *ptr = (u32 *) (base + *rel++);
*ptr += phys_base;
}
/* Must be perfomed *after* relocation. */