From: Ingo Molnar <[EMAIL PROTECTED]> provide an optimized assembly version of sys_umem_add(). It is about 2 times faster than the C version.
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]> Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]> --- arch/i386/lib/getuser.S | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) Index: linux/arch/i386/lib/getuser.S =================================================================== --- linux.orig/arch/i386/lib/getuser.S +++ linux/arch/i386/lib/getuser.S @@ -11,6 +11,33 @@ #include <asm/thread_info.h> /* + * Optimized user-memory arithmetics system-call: + */ + +.text +.align 4 +.globl sys_umem_add +sys_umem_add: + movl 0x4(%esp), %ecx # uptr + movl 0x8(%esp), %edx # inc + + cmpl $__PAGE_OFFSET, %ecx # access_ok(uptr) + jae bad_sys_umem_add + +1: addl %edx, (%ecx) # *uptr += inc +2: movl (%ecx), %eax # return *uptr + ret + +bad_sys_umem_add: + movl $-14, %eax + ret + +.section __ex_table,"a" + .long 1b, bad_sys_umem_add + .long 2b, bad_sys_umem_add +.previous + +/* * copy_uatom() - copy a syslet_atom from user-space into kernel-space: */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
