On x86_64 we have to be careful with calculating the physical
address of kernel symbols. Both because of compiler odditities
and because the symbols live in a different range of the virtual
address space.
Having a defintition of __pa_symbol that works on both x86_64 and
i386 simplifies writing code that works for both x86_64 and
i386 that has these kinds of dependencies.
So this patch adds the trivial i386 __pa_symbol definition.
Added assembly magic similar to RELOC_HIDE as suggested by Andi Kleen.
Just picked it up from x86_64.
Signed-off-by: Eric W. Biederman <[email protected]>
Signed-off-by: Vivek Goyal <[email protected]>
---
include/asm-i386/page.h | 6 ++++++
1 file changed, 6 insertions(+)
diff -puN include/asm-i386/page.h~i386-define-__pa_symbol include/asm-i386/page.h
--- linux-2.6.18-git17/include/asm-i386/page.h~i386-define-__pa_symbol 2006-10-02 13:17:58.000000000 -0400
+++ linux-2.6.18-git17-root/include/asm-i386/page.h 2006-10-02 14:36:32.000000000 -0400
@@ -124,6 +124,12 @@ extern int page_is_ram(unsigned long pag
#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
#define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
+/* __pa_symbol should be used for C visible symbols.
+ This seems to be the official gcc blessed way to do such arithmetic. */
+#define __pa_symbol(x) \
+ ({unsigned long v; \
+ asm("" : "=r" (v) : "0" (x)); \
+ __pa(v); })
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
#ifdef CONFIG_FLATMEM
_
-
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