[v3,11/27] x86/power/64: Adapt assembly for PIE support
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Message ID 20180523195421.180248-12-thgarnie@google.com
State New
Headers show

Commit Message

Thomas Garnier May 23, 2018, 7:54 p.m. UTC
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@google.com>
---
 arch/x86/power/hibernate_asm_64.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Pavel Machek May 24, 2018, 11:03 a.m. UTC | #1
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@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
Thomas Garnier May 24, 2018, 4:37 p.m. UTC | #2
On Thu, May 24, 2018 at 4:04 AM Pavel Machek <pavel@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@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
Pavel Machek May 25, 2018, 9:10 a.m. UTC | #3
On Thu 2018-05-24 09:37:20, Thomas Garnier wrote:
> On Thu, May 24, 2018 at 4:04 AM Pavel Machek <pavel@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@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@ucw.cz>

> Any specific test you think I should use?

Hibernation working should be good enough test for this.

Thanks,
								Pavel

Patch
diff mbox

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