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| author | Alexander Duyck | 2012-11-16 22:55:46 +0100 |
|---|---|---|
| committer | H. Peter Anvin | 2012-11-17 01:42:09 +0100 |
| commit | 7d74275d39def4d3ccc8cf4725388bf79ef13861 (patch) | |
| tree | afe6ed01aad5df44f82aa576151eeabd2e9b66b6 /arch/x86/mm | |
| parent | x86: Improve __phys_addr performance by making use of carry flags and inlining (diff) | |
| download | kernel-qcow2-linux-7d74275d39def4d3ccc8cf4725388bf79ef13861.tar.gz kernel-qcow2-linux-7d74275d39def4d3ccc8cf4725388bf79ef13861.tar.xz kernel-qcow2-linux-7d74275d39def4d3ccc8cf4725388bf79ef13861.zip | |
x86: Make it so that __pa_symbol can only process kernel symbols on x86_64
I submitted an earlier patch that make __phys_addr an inline. This obviously
results in an increase in the code size. One step I can take to reduce that
is to make it so that the __pa_symbol call does a direct translation for
kernel addresses instead of covering all of virtual memory.
On my system this reduced the size for __pa_symbol from 5 instructions
totalling 30 bytes to 3 instructions totalling 16 bytes.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Link: http://lkml.kernel.org/r/20121116215356.8521.92472.stgit@ahduyck-cp1.jf.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/physaddr.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/mm/physaddr.c b/arch/x86/mm/physaddr.c index fd40d75109ef..c73feddd518d 100644 --- a/arch/x86/mm/physaddr.c +++ b/arch/x86/mm/physaddr.c @@ -28,6 +28,17 @@ unsigned long __phys_addr(unsigned long x) return x; } EXPORT_SYMBOL(__phys_addr); + +unsigned long __phys_addr_symbol(unsigned long x) +{ + unsigned long y = x - __START_KERNEL_map; + + /* only check upper bounds since lower bounds will trigger carry */ + VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE); + + return y + phys_base; +} +EXPORT_SYMBOL(__phys_addr_symbol); #endif bool __virt_addr_valid(unsigned long x) |