Linux Virtualization - May 2018 - [PATCH v3 11/27] x86/power/64: Adapt assembly for PIE support

On Wed 2018-05-23 12:54:05, Thomas Garnier wrote:
> Change the assembly code to use only relative references of symbols for the
> kernel to be PIE compatible.
> 
> Position Independent Executable (PIE) support will allow to extended the
> KASLR randomization range below the -2G memory limit.
> 
> Signed-off-by: Thomas Garnier <thgarnie at google.com>
Again, was this tested?
> diff --git a/arch/x86/power/hibernate_asm_64.S
b/arch/x86/power/hibernate_asm_64.S
> index ce8da3a0412c..6fdd7bbc3c33 100644
> --- a/arch/x86/power/hibernate_asm_64.S
> +++ b/arch/x86/power/hibernate_asm_64.S
> @@ -24,7 +24,7 @@
>  #include <asm/frame.h>
>  
>  ENTRY(swsusp_arch_suspend)
> -	movq	$saved_context, %rax
> +	leaq	saved_context(%rip), %rax
>  	movq	%rsp, pt_regs_sp(%rax)
>  	movq	%rbp, pt_regs_bp(%rax)
>  	movq	%rsi, pt_regs_si(%rax)
> @@ -115,7 +115,7 @@ ENTRY(restore_registers)
>  	movq	%rax, %cr4;  # turn PGE back on
>  
>  	/* We don't restore %rax, it must be 0 anyway */
> -	movq	$saved_context, %rax
> +	leaq	saved_context(%rip), %rax
>  	movq	pt_regs_sp(%rax), %rsp
>  	movq	pt_regs_bp(%rax), %rbp
>  	movq	pt_regs_si(%rax), %rsi
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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On Thu, May 24, 2018 at 4:04 AM Pavel Machek <pavel at ucw.cz> wrote:
> On Wed 2018-05-23 12:54:05, Thomas Garnier wrote:
> > Change the assembly code to use only relative references of symbols
for
the
> > kernel to be PIE compatible.
> >
> > Position Independent Executable (PIE) support will allow to extended
the
> > KASLR randomization range below the -2G memory limit.
> >
> > Signed-off-by: Thomas Garnier <thgarnie at google.com>
> Again, was this tested?
Hibernation was tested as much as I can with qemu and my dedicated machine.
Any specific test you think I should use?

> > diff --git a/arch/x86/power/hibernate_asm_64.S
b/arch/x86/power/hibernate_asm_64.S
> > index ce8da3a0412c..6fdd7bbc3c33 100644
> > --- a/arch/x86/power/hibernate_asm_64.S
> > +++ b/arch/x86/power/hibernate_asm_64.S
> > @@ -24,7 +24,7 @@
> >  #include <asm/frame.h>
> >
> >  ENTRY(swsusp_arch_suspend)
> > -     movq    $saved_context, %rax
> > +     leaq    saved_context(%rip), %rax
> >       movq    %rsp, pt_regs_sp(%rax)
> >       movq    %rbp, pt_regs_bp(%rax)
> >       movq    %rsi, pt_regs_si(%rax)
> > @@ -115,7 +115,7 @@ ENTRY(restore_registers)
> >       movq    %rax, %cr4;  # turn PGE back on
> >
> >       /* We don't restore %rax, it must be 0 anyway */
> > -     movq    $saved_context, %rax
> > +     leaq    saved_context(%rip), %rax
> >       movq    pt_regs_sp(%rax), %rsp
> >       movq    pt_regs_bp(%rax), %rbp
> >       movq    pt_regs_si(%rax), %rsi
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html



-- 
Thomas

On Thu 2018-05-24 09:37:20, Thomas Garnier wrote:
> On Thu, May 24, 2018 at 4:04 AM Pavel Machek <pavel at ucw.cz> wrote:
> 
> > On Wed 2018-05-23 12:54:05, Thomas Garnier wrote:
> > > Change the assembly code to use only relative references of
symbols for
> the
> > > kernel to be PIE compatible.
> > >
> > > Position Independent Executable (PIE) support will allow to
extended the
> > > KASLR randomization range below the -2G memory limit.
> > >
> > > Signed-off-by: Thomas Garnier <thgarnie at google.com>
> 
> > Again, was this tested?
> 
> Hibernation was tested as much as I can with qemu and my dedicated
>machine.
Ok, good.

Acked-by: Pavel Machek <pavel at ucw.cz>
> Any specific test you think I should use?
Hibernation working should be good enough test for this.

Thanks,
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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