Messages in this thread |  | | | Date | Tue, 3 Nov 2009 19:16:26 +0100 | | From | Ingo Molnar <> | | Subject | Re: [PATCH] update fix X86_64 procfs provide stack information for threads |
* Stefani Seibold <stefani@seibold.net> wrote:
> Am Dienstag, den 03.11.2009, 09:28 +0100 schrieb Ingo Molnar: > > > --- linux-2.6.32-rc5/arch/x86/include/asm/processor.h 2009-10-16 02:41:50.000000000 +0200 > > > +++ linux-2.6.32-rc5.new/arch/x86/include/asm/processor.h 2009-11-02 10:39:47.177909657 +0100 > > > @@ -1000,7 +1001,13 @@ > > > #define thread_saved_pc(t) (*(unsigned long *)((t)->thread.sp - 8)) > > > > > > #define task_pt_regs(tsk) ((struct pt_regs *)(tsk)->thread.sp0 - 1) > > > -#define KSTK_ESP(tsk) -1 /* sorry. doesn't work for syscall. */ > > > + > > > +#ifdef CONFIG_IA32_EMULATION > > > +extern unsigned long KSTK_ESP(struct task_struct *task); > > > +#else > > > +#define KSTK_ESP(task) ((task)->thread.usersp) > > > +#endif > > > + > > > #endif /* CONFIG_X86_64 */ > > > > > > extern void start_thread(struct pt_regs *regs, unsigned long new_ip, > > > --- linux-2.6.32-rc5/arch/x86/kernel/process_64.c 2009-10-16 02:41:50.000000000 +0200 > > > +++ linux-2.6.32-rc5.new/arch/x86/kernel/process_64.c 2009-11-02 10:48:23.614936810 +0100 > > > @@ -664,3 +669,11 @@ > > > return do_arch_prctl(current, code, addr); > > > } > > > > > > +#ifdef CONFIG_IA32_EMULATION > > > +unsigned long KSTK_ESP(struct task_struct *task) > > > +{ > > > + return (test_tsk_thread_flag(task, TIF_IA32)) ? \ > > > + (task_pt_regs(task)->sp) : \ > > > + ((task)->thread.usersp); > > > +} > > > +#endif > > > > That's quite ugly. The KSTK_ESP() function should be unconditional and > > the #ifdef should be eliminated. If CONFIG_IA32_EMULATION is turned off > > (whichis rare) then TIF_IA32 wont be set so the function should work > > fine. > > > > Thanks, > > > > Ingo > > Hi Ingo, > > come on, thats not fair. [...]
(Hacking the kernel is rarely 'fair' in the way you seem to be defining it.)
> [...] This would be not the only piece of ugly code in the x86_64 > implementation. It is much better than the previous hack where > KSTK_ESP always returns a wrong hard coded value. That is really > ugly!!!! > > It took me 6 hours to analyze the x64_64 code, most of them written in > assembler. I think it is a first solution, which makes the procfs > stack information work on this architecture and that was the goal. > > I will remove the #ifdef's and repost the patch. Please accept this > patch, which make the KSTP_ESP thing on x86_64 better as before. > > I am not a x64_64 bit hacker, i have not the knowledge to make a > perfect solution for this architecture. Also i am not a full time > kernel hacker, i have customers who wait for their projects.
The cleanup isnt really that hard at all, writng your mail probably took more time. I didnt see you complain when we merged your original procfs patch that introduced/exposed this whole issue:
d899bf7: procfs: provide stack information for threads
Fixing followup issues is standard part of the work-with-upstream fairness equation.
Ingo
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