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[librm] Mark virt_offset, text16, data16, rm_cs, and rm_ds as constant 

The physical locations of .textdata, .text16 and .data16 are constant
from the point of view of C code.  Mark the relevant variables as
constant to allow gcc to optimise out redundant reads.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/45/head
Michael Brown 2016-02-21 11:13:04 +00:00
parent 5fbfe50ccb
commit b6ebafe1bb
1 changed files with 5 additions and 5 deletions
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10
src/arch/x86/include/librm.h
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@ -79,7 +79,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
"call prot_call\n\t" "call prot_call\n\t"
/* Variables in librm.S */ /* Variables in librm.S */
extern unsigned long virt_offset; extern const unsigned long virt_offset;
/** /**
* Convert physical address to user pointer * Convert physical address to user pointer
@ -170,8 +170,8 @@ UACCESS_INLINE ( librm, memchr_user ) ( userptr_t buffer, off_t offset,
* *
*/ */
extern char *data16; extern char * const data16;
extern char *text16; extern char * const text16;
#define __data16( variable ) \ #define __data16( variable ) \
__attribute__ (( section ( ".data16" ) )) \ __attribute__ (( section ( ".data16" ) )) \
@ -216,9 +216,9 @@ extern char *text16;
/* Variables in librm.S, present in the normal data segment */ /* Variables in librm.S, present in the normal data segment */
extern uint16_t rm_sp; extern uint16_t rm_sp;
extern uint16_t rm_ss; extern uint16_t rm_ss;
extern uint16_t __text16 ( rm_cs ); extern const uint16_t __text16 ( rm_cs );
#define rm_cs __use_text16 ( rm_cs ) #define rm_cs __use_text16 ( rm_cs )
extern uint16_t __text16 ( rm_ds ); extern const uint16_t __text16 ( rm_ds );
#define rm_ds __use_text16 ( rm_ds ) #define rm_ds __use_text16 ( rm_ds )
extern uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size ); extern uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size );