x86, realmode: set real_mode permissions early

PATCH In review Borislav Petkov 3 participants 5 messages Dec 27, 2012 – Dec 28, 2012

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Borislav Petkov

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2012-12-27 18:22 UTC #0 lore raw

PATCH 1/1 x86, realmode: set real_mode permissions early

Quoted 23 lines

commit 77e277cb85290a183bbc1995a1cd839b1c216f25
Subject: [PATCH] x86, realmode: set real_mode permissions early
Author: Yinghai Lu <[email protected]>
Date: Mon Dec 24 18:00:21 2012 -0800
x86, realmode: set real_mode permissions early
We need to set trampoline code to EXEC early before we do smp AP bootings.
Found the problem after switching to #PF handler set page table, and we do not set initial kernel low mapping with EXEC anymore.
Change to use early_initcall instead that will make sure tramopline will have EXEC set.
Signed-off-by Yinghai Lu <[email protected]>
arch/x86/realmode/init.c +0 -0
index 80450261215c..0b7e840ad4d4 100644

arch/x86/realmode/init.c static int __init set_real_mode_permissions(void) · line 114

Quoted 6 lines

arch/x86/realmode/init.c +1 -2

@@ -111,5 +111,4 @@ static int __init set_real_mode_permissions(void)
 
 	return 0;
 }
-
-arch_initcall(set_real_mode_permissions);
+early_initcall(set_real_mode_permissions);

I'm looking at this patch in the -v8 branch: you need to update the comment above that function to say that trampoline code needs to be marked X now earlier.

Thanks.

Signature · 2 lines

Regards/Gruss,
Boris.

Yinghai Lu

2012-12-27 23:56 UTC #1 lore raw

Quoted 24 lines · Borislav Petkov

Quoted 24 lines
commit 77e277cb85290a183bbc1995a1cd839b1c216f25
Subject: [PATCH] x86, realmode: set real_mode permissions early
Author: Yinghai Lu <[email protected]>
Date: Mon Dec 24 18:00:21 2012 -0800
x86, realmode: set real_mode permissions early
We need to set trampoline code to EXEC early before we do smp AP bootings.
Found the problem after switching to #PF handler set page table, and we do not set initial kernel low mapping with EXEC anymore.
Change to use early_initcall instead that will make sure tramopline will have EXEC set.
Signed-off-by Yinghai Lu <[email protected]>
arch/x86/realmode/init.c +0 -0
index 80450261215c..0b7e840ad4d4 100644
@@ -111,5 +111,4 @@ static int __init set_real_mode_permissions(void)
 

Quoted 9 lines

arch/x86/realmode/init.c static int __init set_real_mode_permissions(void) · line 114
Quoted 5 lines
arch/x86/realmode/init.c +1 -2
      return 0;
 }
-
-arch_initcall(set_real_mode_permissions);
+early_initcall(set_real_mode_permissions);
I'm looking at this patch in the -v8 branch: you need to update the comment above that function to say that trampoline code needs to be marked X now earlier.

Not sure if we really need to add such comment in the code.

Peter, what is your idea about this?

Yinghai

H. Peter Anvin

2012-12-28 00:01 UTC #2 lore raw

Quoted 9 lines · Yinghai Lu

Quoted 4 lines
I'm looking at this patch in the -v8 branch: you need to update the comment above that function to say that trampoline code needs to be marked X now earlier.
Not sure if we really need to add such comment in the code.
Peter, what is your idea about this?

It would be good to note why the early_initcall is the right phase.

-hpa

Signature · 2 lines

H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

Yinghai Lu

2012-12-28 00:57 UTC #3 lore raw

Quoted 8 lines · H. Peter Anvin

Quoted 7 lines · Yinghai Lu
Quoted 5 lines
I'm looking at this patch in the -v8 branch: you need to update the comment above that function to say that trampoline code needs to be marked X now earlier.

Quoted 7 lines

Quoted 4 lines
Not sure if we really need to add such comment in the code.
Peter, what is your idea about this?
It would be good to note why the early_initcall is the right phase.

How about:

---
Trampoline will be executed by APs with SMP,
So we need to set it EXEC in do_pre_smp_initcalls and it is early_initcall.
---

H. Peter Anvin

2012-12-28 01:10 UTC #4 lore raw

Seems ok.

Quoted 24 lines · Yinghai Lu

Quoted 8 lines · H. Peter Anvin
Quoted 7 lines · Yinghai Lu
Quoted 5 lines
I'm looking at this patch in the -v8 branch: you need to update the comment above that function to say that trampoline code needs to be marked X now earlier.
Quoted 7 lines
Quoted 4 lines
Not sure if we really need to add such comment in the code.
Peter, what is your idea about this?
It would be good to note why the early_initcall is the right phase.
How about:
---
Trampoline will be executed by APs with SMP,
So we need to set it EXEC in do_pre_smp_initcalls and it is early_initcall.
---

Signature · 1 line

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