On Tuesday, 21 August 2007 16:37, Rafael J. Wysocki wrote: > On Tuesday, 21 August 2007 09:57, Pavel Machek wrote: > > Hi! > > > > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > Make it possible to restore a hibernation image on x86_64 with the help of a > > > kernel different from the one in the image. > > > > Looks mostly ok to me. > > > > Should this be split in half (generic support, x86-64 support) and be > > done last in the series, so that suspend still works when bisecting? > > Yes, I can do that, but the x86-64 support must go at least before the 4/4 > patch which depends on it. > > > > done: > > > + /* jump to the restore_registers address from the image header */ > > > + jmpq *%rax > > > > So this is where the change from kernel text 1 to kernel text 2 > > happens, right? > > Yes. > > > I see you are using %r10 for something here, perhaps that should be > > commented? > > %r10 is used to store the address of the data to copy into the skipped page. > I'll try to add a comment for that. > > > > +.balign PAGE_SIZE > > > +ENTRY(restore_registers) > > > + /* we are in the image kernel's text now */ > > > + testq %r10, %r10 > > > + jz 1f > > > + /* copy the skipped page */ > > > + movq %r10, %rsi > > > + movq %r9, %rdi > > > + movq $(PAGE_SIZE >> 3), %rcx > > > + rep > > > + movsq > > > > > @@ -84,10 +127,7 @@ done: > > > movq %rcx, %cr3 > > > movq %rax, %cr4; # turn PGE back on > > > > > > - movl $24, %eax > > > - movl %eax, %ds > > > - > > > - /* We don't restore %rax, it must be 0 anyway */ > > > + /* restore GPRs (we don't restore %rax, it must be 0 anyway) */ > > > movq $saved_context, %rax > > > movq pt_regs_rsp(%rax), %rsp > > > movq pt_regs_rbp(%rax), %rbp > > > > Hmm, in the old code, we knew we don't have to restore %ds, because it > > is constant for one kernel. Now, we rely on %ds being constant accross > > kernels. Not nice, and should be at least documented. > > Well, in fact we rely on it all the time (eg. the > "movq mmu_cr4_features(%rip), %rax" above wouldn't work if that's not true), > but I can keep the old code here just fine. ;-) Well, I was wrong. The new code doesn't work without this change and I'm not exactly sure why. Greetings, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
