[PATCH] arm64: Clear the stack

On Tue, Jul 03, 2018 at 01:14:41PM +0100, Mark Rutland wrote:

On Mon, Jul 02, 2018 at 11:48:05AM -0700, Laura Abbott wrote:

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On 07/02/2018 06:02 AM, Alexander Popov wrote:

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On 29.06.2018 22:05, Laura Abbott wrote:

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Implementation of stackleak based heavily on the x86 version

Signed-off-by: Laura Abbott <redacted>
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Changes since last time:
- Minor name change in entry.S
- Converted to use the generic interfaces so there's minimal additions.
- Added the fast syscall path.
- Addition of on_thread_stack and current_top_of_stack
- Disable stackleak on hyp per suggestion
- Added a define for check_alloca. I'm still not sure about keeping it
   since the x86 version got reworked?

I've mostly kept this as one patch with a minimal commit text. I can
split it up and elaborate more before final merging.
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diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index ec2ee720e33e..31c9da7d401e 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S

@@ -401,6 +401,11 @@ tsk	.req	x28		// current thread_info
  	.text
+	.macro	stackleak_erase

Could you rename the macro to STACKLEAK_ERASE for similarity with x86?

Mark Rutland had previously asked for this to be lowercase.
I really don't care one way or the other so I'll defer to
someone else to have the final word.

Will, Catalin, could you chime in either way?

I'd previously asked for lower-case for consistency with our other
assembly macros.

I'd keep it lowercase as the other arm64 macros in this file.

-- 
Catalin