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linux-next/arch/x86/include/asm/page.h
Namhyung Kim 8fd49936a8 x86: Document __phys_reloc_hide() usage in __pa_symbol()
Until all supported versions of gcc recognize
-fno-strict-overflow, we should keep the RELOC_HIDE() magic in
__pa_symbol(). Comment it.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
LKML-Reference: <1281508661-29507-1-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-11 08:43:49 +02:00

72 lines
2.0 KiB
C

#ifndef _ASM_X86_PAGE_H
#define _ASM_X86_PAGE_H
#include <linux/types.h>
#ifdef __KERNEL__
#include <asm/page_types.h>
#ifdef CONFIG_X86_64
#include <asm/page_64.h>
#else
#include <asm/page_32.h>
#endif /* CONFIG_X86_64 */
#ifndef __ASSEMBLY__
struct page;
static inline void clear_user_page(void *page, unsigned long vaddr,
struct page *pg)
{
clear_page(page);
}
static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
struct page *topage)
{
copy_page(to, from);
}
#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \
alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr)
#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
#define __pa(x) __phys_addr((unsigned long)(x))
#define __pa_nodebug(x) __phys_addr_nodebug((unsigned long)(x))
/* __pa_symbol should be used for C visible symbols.
This seems to be the official gcc blessed way to do such arithmetic. */
/*
* We need __phys_reloc_hide() here because gcc may assume that there is no
* overflow during __pa() calculation and can optimize it unexpectedly.
* Newer versions of gcc provide -fno-strict-overflow switch to handle this
* case properly. Once all supported versions of gcc understand it, we can
* remove this Voodoo magic stuff. (i.e. once gcc3.x is deprecated)
*/
#define __pa_symbol(x) __pa(__phys_reloc_hide((unsigned long)(x)))
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define __boot_va(x) __va(x)
#define __boot_pa(x) __pa(x)
/*
* virt_to_page(kaddr) returns a valid pointer if and only if
* virt_addr_valid(kaddr) returns true.
*/
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
extern bool __virt_addr_valid(unsigned long kaddr);
#define virt_addr_valid(kaddr) __virt_addr_valid((unsigned long) (kaddr))
#endif /* __ASSEMBLY__ */
#include <asm-generic/memory_model.h>
#include <asm-generic/getorder.h>
#define __HAVE_ARCH_GATE_AREA 1
#endif /* __KERNEL__ */
#endif /* _ASM_X86_PAGE_H */