x86, realmode: Pointer walk cleanups, pull out invariant use of __pa()
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
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index a44f457..bad628a 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -29,12 +29,10 @@
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 @@
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. */