---

yaml
---
r: 258226
b: refs/heads/master
c: 540b573
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c7e89b16eb90e7bdf0d71bd5ba265ce8d424f30b
+refs/heads/master: 540b573875bd26dfe39aa18d22dc195f275fc0df

trunk/Documentation/arm/Booting

@@ -164,3 +164,8 @@ In either case, the following conditions must be met:
 - The boot loader is expected to call the kernel image by jumping
   directly to the first instruction of the kernel image.
 
+  On CPUs supporting the ARM instruction set, the entry must be
+  made in ARM state, even for a Thumb-2 kernel.
+
+  On CPUs supporting only the Thumb instruction set such as
+  Cortex-M class CPUs, the entry must be made in Thumb state.

trunk/arch/arm/boot/compressed/head.S

@@ -353,7 +353,8 @@ not_relocated:	mov	r0, #0
 		mov	r0, #0			@ must be zero
 		mov	r1, r7			@ restore architecture number
 		mov	r2, r8			@ restore atags pointer
-		mov	pc, r4			@ call kernel
+ ARM(		mov	pc, r4	)		@ call kernel
+ THUMB(		bx	r4	)		@ entry point is always ARM
 
 		.align	2
 		.type	LC0, #object

trunk/arch/arm/kernel/head-nommu.S

@@ -32,8 +32,16 @@
  * numbers for r1.
  *
  */
+	.arm
+
 	__HEAD
 ENTRY(stext)
+
+ THUMB(	adr	r9, BSYM(1f)	)	@ Kernel is always entered in ARM.
+ THUMB(	bx	r9		)	@ If this is a Thumb-2 kernel,
+ THUMB(	.thumb			)	@ switch to Thumb now.
+ THUMB(1:			)
+
 	setmode	PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
 						@ and irqs disabled
 #ifndef CONFIG_CPU_CP15

trunk/arch/arm/kernel/head.S

@@ -71,8 +71,16 @@
  * crap here - that's what the boot loader (or in extreme, well justified
  * circumstances, zImage) is for.
  */
+	.arm
+
 	__HEAD
 ENTRY(stext)
+
+ THUMB(	adr	r9, BSYM(1f)	)	@ Kernel is always entered in ARM.
+ THUMB(	bx	r9		)	@ If this is a Thumb-2 kernel,
+ THUMB(	.thumb			)	@ switch to Thumb now.
+ THUMB(1:			)
+
 	setmode	PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
 						@ and irqs disabled
 	mrc	p15, 0, r9, c0, c0		@ get processor id