Re: current as segment register was Re: Using %cr2 to reference "current"

[Keith Owens]

On 06 Nov 2001 20:02:09 +0100, 
Andi Kleen <[e-mail]> wrote:
>One nasty thing is that lea doesn't work on segment registers. It needs
>an quite ugly inline assembly mess similar to get/put_user to implement
>read/write/add_pda functions for the fundamental types. To implement
>that properly without hardcoded offsets it is also needed to have an
>offset.c like many other ports that puts structure offsets at compile
>time into an include file.

Already done in kbuild 2.5, it creates arch/i386/asm-offsets.h.
Currently containing this list, which can easily be expanded.

#ifndef __ASM_OFFSETS_H__
#define __ASM_OFFSETS_H__
/*
 * DO NOT MODIFY
 *
 * This file was generated by arch/i386/Makefile.in.
 *
 */

state                =   0                      /* 0x0     offsetof(struct task_struct, state) */
flags                =   4                      /* 0x4     offsetof(struct task_struct, flags) */
sigpending           =   8                      /* 0x8     offsetof(struct task_struct, sigpending) */
addr_limit           =  12                      /* 0xc     offsetof(struct task_struct, addr_limit) */
exec_domain          =  16                      /* 0x10    offsetof(struct task_struct, exec_domain) */
need_resched         =  20                      /* 0x14    offsetof(struct task_struct, need_resched) */
tsk_ptrace           =  24                      /* 0x18    offsetof(struct task_struct, ptrace) */
processor            =  52                      /* 0x34    offsetof(struct task_struct, processor) */

ENOSYS               =  38                      /* 0x26    ENOSYS */

#endif