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SubjectRe: swsusp_restore crap
Date
Hi,

On Tuesday, 15 of March 2005 13:02, Pavel Machek wrote:
> Hi!
>
> > > > > Please kill that swsusp_restore() call that itself calls
> > > > > flush_tlb_global(), it's junk. First, the flush_tlb_global() thing is
> > > > > arch specific, and that's all swsusp_restore() does. Then, the asm just
> > > > > calls this before returning to C code, so it makes no sense to have a
> > > > > hook there. The x86 asm can have it's own call to some arch stuff if it
> > > > > wants or just do the tlb flush in asm...
> > > >
> > > > Better, here is a patch... (note: flush_tlb_global() is an x86'ism,
> > > > doesn't exist on ppc, thus breaks compile, and that has nothing to do in
> > > > the generic code imho, it should be clearly defined as the
> > > > responsibility of the asm code).
> > >
> > > x86-64 needs this, too.... Otherwise it looks okay.
> >
> > It breaks compilation on i386 either, because nr_copy_pages_check
> > is static in swsusp.c. May I propose the following patch instead (tested on
> > x86-64 and i386)?
>
>
> > +asmlinkage int __swsusp_flush_tlb(void)
> > +{
> > + swsusp_restore_check();
>
> Someone will certainly forget this one, and it is probably
> nicer/easier to just move BUG_ON into swsusp_suspend(), just after
> restore_processor_state() or something like that...

... in which case __swsusp_flush_tlb() would only contain a "call" to
__flush_tlb_global(), but this is a macro on both x86-64 and i386, so we can
drop the __swsusp_flush_tlb() altogether and do it in assembly (before the
GPRs are restored, perhaps). Patch follows.

Greets,
Rafael


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff -Nrup linux-2.6.11-bk10-a/arch/i386/power/swsusp.S linux-2.6.11-bk10-b/arch/i386/power/swsusp.S
--- linux-2.6.11-bk10-a/arch/i386/power/swsusp.S 2005-03-15 09:20:53.000000000 +0100
+++ linux-2.6.11-bk10-b/arch/i386/power/swsusp.S 2005-03-15 15:37:25.000000000 +0100
@@ -51,6 +51,15 @@ copy_loop:
.p2align 4,,7

done:
+ /* Flush TLB, including "global" things (vmalloc) */
+ movl mmu_cr4_features, %eax
+ movl %eax, %edx
+ andl $~(1<<7), %edx; # PGE
+ movl %edx, %cr4; # turn off PGE
+ movl %cr3, %ecx; # flush TLB
+ movl %ecx, %cr3
+ movl %eax, %cr4; # turn PGE back on
+
movl saved_context_esp, %esp
movl saved_context_ebp, %ebp
movl saved_context_ebx, %ebx
@@ -58,5 +67,5 @@ done:
movl saved_context_edi, %edi

pushl saved_context_eflags ; popfl
- call swsusp_restore
+
ret
diff -Nrup linux-2.6.11-bk10-a/arch/x86_64/kernel/suspend_asm.S linux-2.6.11-bk10-b/arch/x86_64/kernel/suspend_asm.S
--- linux-2.6.11-bk10-a/arch/x86_64/kernel/suspend_asm.S 2005-03-15 09:20:53.000000000 +0100
+++ linux-2.6.11-bk10-b/arch/x86_64/kernel/suspend_asm.S 2005-03-15 15:36:29.000000000 +0100
@@ -69,6 +69,14 @@ loop:
movq pbe_next(%rdx), %rdx
jmp loop
done:
+ /* Flush TLB, including "global" things (vmalloc) */
+ movq %rax, %rdx; # mmu_cr4_features(%rip)
+ andq $~(1<<7), %rdx; # PGE
+ movq %rdx, %cr4; # turn off PGE
+ movq %cr3, %rcx; # flush TLB
+ movq %rcx, %cr3
+ movq %rax, %cr4; # turn PGE back on
+
movl $24, %eax
movl %eax, %ds

@@ -89,5 +97,5 @@ done:
movq saved_context_r14(%rip), %r14
movq saved_context_r15(%rip), %r15
pushq saved_context_eflags(%rip) ; popfq
- call swsusp_restore
+
ret
diff -Nrup linux-2.6.11-bk10-a/kernel/power/swsusp.c linux-2.6.11-bk10-b/kernel/power/swsusp.c
--- linux-2.6.11-bk10-a/kernel/power/swsusp.c 2005-03-15 09:21:23.000000000 +0100
+++ linux-2.6.11-bk10-b/kernel/power/swsusp.c 2005-03-15 15:35:44.000000000 +0100
@@ -900,22 +900,13 @@ int swsusp_suspend(void)
error = swsusp_arch_suspend();
/* Restore control flow magically appears here */
restore_processor_state();
+ BUG_ON (nr_copy_pages_check != nr_copy_pages);
restore_highmem();
device_power_up();
local_irq_enable();
return error;
}

-
-asmlinkage int swsusp_restore(void)
-{
- BUG_ON (nr_copy_pages_check != nr_copy_pages);
-
- /* Even mappings of "global" things (vmalloc) need to be fixed */
- __flush_tlb_global();
- return 0;
-}
-
int swsusp_resume(void)
{
int error;
--
- Would you tell me, please, which way I ought to go from here?
- That depends a good deal on where you want to get to.
-- Lewis Carroll "Alice's Adventures in Wonderland"
-
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