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authorLinus Torvalds <torvalds@linux-foundation.org>2010-08-13 10:35:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-13 10:35:48 -0700
commitc029b55af7d6b02b993e8a5add78d062da7a3940 (patch)
treeeda9177a8d42324927424b3c42a99606ac6a4080 /arch/x86/include
parent96054569190bdec375fe824e48ca1f4e3b53dd36 (diff)
parent417484d47e115774745ef025bce712a102b6f86f (diff)
Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, asm: Use a lower case name for the end macro in atomic64_386_32.S x86, asm: Refactor atomic64_386_32.S to support old binutils and be cleaner x86: Document __phys_reloc_hide() usage in __pa_symbol() x86, apic: Map the local apic when parsing the MP table.
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/page.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 625c3f0e741a..8ca82839288a 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -37,6 +37,13 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
#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))