/* * __put_user functions. * * (C) Copyright 1998 Linus Torvalds * (C) Copyright 2005 Andi Kleen * * These functions have a non-standard call interface * to make them more efficient, especially as they * return an error value in addition to the "real" * return value. */ /* * __put_user_X * * Inputs: %rcx contains the address * %rdx contains new value * * Outputs: %rax is error code (0 or -EFAULT) * * %r8 is destroyed. * * These functions should not modify any other registers, * as they get called from within inline assembly. */ #include <linux/linkage.h> #include <asm/dwarf2.h> #include <asm/page.h> #include <asm/errno.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> .text ENTRY(__put_user_1) CFI_STARTPROC GET_THREAD_INFO(%r8) cmpq threadinfo_addr_limit(%r8),%rcx jae bad_put_user 1: movb %dl,(%rcx) xorl %eax,%eax ret CFI_ENDPROC ENDPROC(__put_user_1) ENTRY(__put_user_2) CFI_STARTPROC GET_THREAD_INFO(%r8) addq $1,%rcx jc 20f cmpq threadinfo_addr_limit(%r8),%rcx jae 20f decq %rcx 2: movw %dx,(%rcx) xorl %eax,%eax ret 20: decq %rcx jmp bad_put_user CFI_ENDPROC ENDPROC(__put_user_2) ENTRY(__put_user_4) CFI_STARTPROC GET_THREAD_INFO(%r8) addq $3,%rcx jc 30f cmpq threadinfo_addr_limit(%r8),%rcx jae 30f subq $3,%rcx 3: movl %edx,(%rcx) xorl %eax,%eax ret 30: subq $3,%rcx jmp bad_put_user CFI_ENDPROC ENDPROC(__put_user_4) ENTRY(__put_user_8) CFI_STARTPROC GET_THREAD_INFO(%r8) addq $7,%rcx jc 40f cmpq threadinfo_addr_limit(%r8),%rcx jae 40f subq $7,%rcx 4: movq %rdx,(%rcx) xorl %eax,%eax ret 40: subq $7,%rcx jmp bad_put_user CFI_ENDPROC ENDPROC(__put_user_8) bad_put_user: CFI_STARTPROC movq $(-EFAULT),%rax ret CFI_ENDPROC END(bad_put_user) .section __ex_table,"a" .quad 1b,bad_put_user .quad 2b,bad_put_user .quad 3b,bad_put_user .quad 4b,bad_put_user .previous