lkml.org 
[lkml]   [2008]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: ftraced and suspend to ram
    Date
    On Friday, 22 of August 2008, Steven Rostedt wrote:
    >
    > On Fri, 22 Aug 2008, Rafael J. Wysocki wrote:
    > > > > tracing. Certainly all the assembly functions.
    > > >
    > > > I'm looking into that now too. Are the functions in arch/x86/power/cpu*.c
    > > > the suspend to ram code?
    > >
    > > They contain code executed during suspend to RAM, but such code is also:
    > > - in all files under arch/x86/kernel/acpi/
    > > - in main.c, console.c under kernel/power
    > > - in all files under drivers/acpi/sleep
    > > - in drivers/acpi/hardware/hwsleep.c
    > >
    > > Generally, ACPI is heavily involved and I'm not the right person to ask which
    > > of the ACPI functions should get the 'notrace' thing. Also, I'm not sure about
    > > the device drivers' ->suspend() and ->resume() callbacks, especially for
    > > sysdevs and ->suspend_late(), ->resume_early() for platform devices and PCI.
    > >
    > > Well, how exactly suspend to RAM is broken by ftrace?
    > >
    >
    > I know that the smp_processor_id may be defined in the %fs register, but
    > if ftrace is called before the %fs is set up, it may crash because it
    > uses smp_processor_id.

    The wake-up code is the most interesting for you, then. It's located in
    arch/x86/kernel/acpi/ , but on x86-64 it also uses trampoline code in
    trampoline_64.S (this is assembly, though).

    On x86-64, wakeup_long64 in wakeup_64.S is where we get from the real-mode
    wake-up code, but under arch/x86/kernel/acpi/realmode there are some C files
    containing functions executed in real mode. Everything in there and everything
    referred to from there should be 'notrace' IMO.

    Thanks,
    Rafael



    \
     
     \ /
      Last update: 2008-08-22 23:11    [W:0.034 / U:58.164 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site