On Mon, 2007-08-27 at 18:48 +0000, Pavel Machek wrote: > Hi! > > > To support jumping back from kexeced kernel, before executing the new > > kernel, the devices are put into quiescent state (to be fully > > implemented), and the state of devices and CPU is saved. After jumping > > back from kexeced kernel, the state of devices and CPU are restored > > accordingly. The devices/CPU state save/restore code of software > > suspend is called to implement corresponding function. > > > > Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx> > > Looks quite ok to me... > > > > Index: linux-2.6.23-rc3/include/asm-i386/kexec.h > > =================================================================== > > --- linux-2.6.23-rc3.orig/include/asm-i386/kexec.h 2007-08-25 21:56:54.000000000 +0800 > > +++ linux-2.6.23-rc3/include/asm-i386/kexec.h 2007-08-25 21:57:00.000000000 +0800 > > @@ -94,6 +94,10 @@ > > unsigned long start_address, > > unsigned int has_pae) ATTRIB_NORET; > > > > +#ifdef CONFIG_KEXEC_JUMP > > +extern asmlinkage int machine_kexec_real_jump(void *buf); > > +#endif > > Is it really neccessery to have ifdef here? It is not necessary. I will fix it in the next version. > > +#ifdef CONFIG_KEXEC_JUMP > > +#define KEXEC_JUMP_FLAG_IS_KEXECED_KERNEL 0x1 > > +#endif /* CONFIG_KEXEC_JUMP */ > > And here? ... It would be nice to use slightly shorter identifier. > 'KJUMP_IS_KEXECED' should be enough. Yes, that is nicer. I will fix it. > > +/* > > + * Must be relocatable PIC code callable as a C function > > + */ > > +#define HALF_PAGE_ALIGNED (1 << (PAGE_SHIFT-1)) > > + > > +#define EBX 0x0 > > +#define ESI 0x4 > > +#define EDI 0x8 > > +#define EBP 0xc > > +#define ESP 0x10 > > +#define CR0 0x14 > > +#define CR3 0x18 > > +#define CR4 0x1c > > +#define FLAG 0x20 > > +#define RET 0x24 > > Hmm, is this enough? Should it use struct ptregs for normal registers? > What about segment registers -- they could change between kernel > version. Should some kind of 'version of kjump protocol' be > introduced? All "preserve" registers defined in ABI are saved, I think that is sufficient. The "swsusp_arch_suspend" saves only these registers too. An extensible inter-kernel kjump protocol and corresponding version number seems sensible. I will work on this. > > What about CX/DX/fpu state? GDT pointer? > > Actually I think that you _do_ need to save FPU. You should probably > use relevant swsusp parts here. Before and after "machine_kexec_jump" is called, the save_processor_state() and restore_processor_state() are called, where the MTRR/FPU/GDT/IDT/TR/segments/cr are saved and restored. These two functions come from swsusp. Thanks swsusp guys. :) Best Regards, Huang Ying _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
