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Subject[PATCH v4 3/8] x86: Make it so that __pa_symbol can only process kernel symbols on x86_64
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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>
---
v4: Dropped y>x check in debug version of __phys_addr_symbol since we already
checked for y >= KERNEL_IMAGE_SIZE.

arch/x86/include/asm/page.h | 3 ++-
arch/x86/include/asm/page_32.h | 1 +
arch/x86/include/asm/page_64.h | 3 +++
arch/x86/mm/physaddr.c | 11 +++++++++++
4 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 8ca8283..3698a6a 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -44,7 +44,8 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
* 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 __pa_symbol(x) \
+ __phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))

#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))

diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h
index da4e762..4d550d0 100644
--- a/arch/x86/include/asm/page_32.h
+++ b/arch/x86/include/asm/page_32.h
@@ -15,6 +15,7 @@ extern unsigned long __phys_addr(unsigned long);
#else
#define __phys_addr(x) __phys_addr_nodebug(x)
#endif
+#define __phys_addr_symbol(x) __phys_addr(x)
#define __phys_reloc_hide(x) RELOC_HIDE((x), 0)

#ifdef CONFIG_FLATMEM
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 5138174..0f1ddee 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -21,8 +21,11 @@ static inline unsigned long __phys_addr_nodebug(unsigned long x)

#ifdef CONFIG_DEBUG_VIRTUAL
extern unsigned long __phys_addr(unsigned long);
+extern unsigned long __phys_addr_symbol(unsigned long);
#else
#define __phys_addr(x) __phys_addr_nodebug(x)
+#define __phys_addr_symbol(x) \
+ ((unsigned long)(x) - __START_KERNEL_map + phys_base)
#endif

#define __phys_reloc_hide(x) (x)
diff --git a/arch/x86/mm/physaddr.c b/arch/x86/mm/physaddr.c
index fd40d75..c73fedd 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)


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