Thread (46 messages) 46 messages, 5 authors, 2013-08-05
STALE4695d

[PATCH 04/14] ARM: set BE8 if LE in head code

From: Will Deacon <hidden>
Date: 2013-07-24 14:41:19

On Wed, Jul 24, 2013 at 11:27:52AM +0100, Ben Dooks wrote:
quoted hunk ↗ jump to hunk
If we are booting in LE and compiled for BE8, then add code to
set the state to bE8. Since the instruction stream is always LE,
we do not need to do anything special to the instruction.

Also ensure that the secondary processors are started in the same mode.

Note, we do add about 20 bytes to the kernel image, but it seems easier
to do this than adding another configuration to change.

Signed-off-by: Ben Dooks <redacted>
---
 arch/arm/boot/compressed/head.S |    1 +
 arch/arm/kernel/head.S          |    4 ++++
 arch/arm/kernel/sleep.S         |    1 +
 3 files changed, 6 insertions(+)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 4eb8364..4d83bfd 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -135,6 +135,7 @@ start:
 		.word	_edata			@ zImage end address
  THUMB(		.thumb			)
 1:
+ ARM_BE8(	setend	be )			@ go BE8 if LE, no-op if BE8
I find the comment here slightly confusing as it makes it sound like the
macro expands to nothing if we're BE8 (which is clearly not the case).
quoted hunk ↗ jump to hunk
 		mrs	r9, cpsr
 #ifdef CONFIG_ARM_VIRT_EXT
 		bl	__hyp_stub_install	@ get into SVC mode, reversibly
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index e40c0b3b..706c441 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -77,6 +77,7 @@
 
 	__HEAD
 ENTRY(stext)
+ ARM_BE8(setend	be )			@ ensure we are in BE8 mode
Alignment issue here -- please try to align the instruction with the
instructions below (it's awkward to read with all the brackets).
quoted hunk ↗ jump to hunk
 
  THUMB(	adr	r9, BSYM(1f)	)	@ Kernel is always entered in ARM.
  THUMB(	bx	r9		)	@ If this is a Thumb-2 kernel,
@@ -351,6 +352,9 @@ ENTRY(secondary_startup)
 	 * the processor type - there is no need to check the machine type
 	 * as it has already been validated by the primary processor.
 	 */
+
+ ARM_BE8(setend	be)				@ if system starts LE, go BE8
+
 #ifdef CONFIG_ARM_VIRT_EXT
 	bl	__hyp_stub_install_secondary
 #endif
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index 987dcf3..954c28a 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -81,6 +81,7 @@ ENDPROC(cpu_resume_after_mmu)
 	.data
 	.align
 ENTRY(cpu_resume)
+ARM_BE8(setend be)			@ ensure we are in BE mode
Any reason to have three different comments for the same thing? I think you
probably just need to comment the one in head.S.

Will
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