Re: syscall descriptor table

[Jiri Slaby]

On 04/05/2012 11:55 PM, Xin Tong wrote:
> Can anyone please describe to me how x86 syscall works ( i.e. how it
> is dispatched to the correct function) on x86 ?
> 
> mov $1, %eax   ;; __NR_exit = 1
> mov $42, %ebx  ;; status = 42
> sysenter       ;; perform the syscall!
> 
> what does the sysenter instruction do ? what is the difference aganst int 0x80.

Please refer to some processor manual. For example: Intel 64 and IA-32
Architectures Software Developer’s Manual. For the entry point see
ia32_sysenter_target in arch/x86/kernel/entry_32.S for x86_32 or
arch/x86/ia32/ia32entry.S for x86_64 with 32-bit binary.

regards,
-- 
js
suse labs

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