---

yaml
---
r: 321106
b: refs/heads/master
c: 15ac49b
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c5dff4ffd327088d85035bec535b7d0c9ea03151
+refs/heads/master: 15ac49b65024f55c4371a53214879a9c77c4fbf9

trunk/arch/arm/kernel/entry-armv.S

@@ -244,6 +244,19 @@ svc_preempt:
 	b	1b
 #endif
 
+__und_fault:
+	@ Correct the PC such that it is pointing at the instruction
+	@ which caused the fault.  If the faulting instruction was ARM
+	@ the PC will be pointing at the next instruction, and have to
+	@ subtract 4.  Otherwise, it is Thumb, and the PC will be
+	@ pointing at the second half of the Thumb instruction.  We
+	@ have to subtract 2.
+	ldr	r2, [r0, #S_PC]
+	sub	r2, r2, r1
+	str	r2, [r0, #S_PC]
+	b	do_undefinstr
+ENDPROC(__und_fault)
+
 	.align	5
 __und_svc:
 #ifdef CONFIG_KPROBES
@@ -261,25 +274,32 @@ __und_svc:
 	@
 	@  r0 - instruction
 	@
-#ifndef	CONFIG_THUMB2_KERNEL
+#ifndef CONFIG_THUMB2_KERNEL
 	ldr	r0, [r4, #-4]
 #else
+	mov	r1, #2
 	ldrh	r0, [r4, #-2]			@ Thumb instruction at LR - 2
 	cmp	r0, #0xe800			@ 32-bit instruction if xx >= 0
-	ldrhhs	r9, [r4]			@ bottom 16 bits
-	orrhs	r0, r9, r0, lsl #16
+	blo	__und_svc_fault
+	ldrh	r9, [r4]			@ bottom 16 bits
+	add	r4, r4, #2
+	str	r4, [sp, #S_PC]
+	orr	r0, r9, r0, lsl #16
 #endif
-	adr	r9, BSYM(1f)
+	adr	r9, BSYM(__und_svc_finish)
 	mov	r2, r4
 	bl	call_fpe
 
+	mov	r1, #4				@ PC correction to apply
+__und_svc_fault:
 	mov	r0, sp				@ struct pt_regs *regs
-	bl	do_undefinstr
+	bl	__und_fault
 
 	@
 	@ IRQs off again before pulling preserved data off the stack
 	@
-1:	disable_irq_notrace
+__und_svc_finish:
+	disable_irq_notrace
 
 	@
 	@ restore SPSR and restart the instruction
@@ -423,25 +443,33 @@ __und_usr:
 	mov	r2, r4
 	mov	r3, r5
 
+	@ r2 = regs->ARM_pc, which is either 2 or 4 bytes ahead of the
+	@      faulting instruction depending on Thumb mode.
+	@ r3 = regs->ARM_cpsr
 	@
-	@ fall through to the emulation code, which returns using r9 if
-	@ it has emulated the instruction, or the more conventional lr
-	@ if we are to treat this as a real undefined instruction
-	@
-	@  r0 - instruction
+	@ The emulation code returns using r9 if it has emulated the
+	@ instruction, or the more conventional lr if we are to treat
+	@ this as a real undefined instruction
 	@
 	adr	r9, BSYM(ret_from_exception)
-	adr	lr, BSYM(__und_usr_unknown)
+
 	tst	r3, #PSR_T_BIT			@ Thumb mode?
-	itet	eq				@ explicit IT needed for the 1f label
-	subeq	r4, r2, #4			@ ARM instr at LR - 4
-	subne	r4, r2, #2			@ Thumb instr at LR - 2
-1:	ldreqt	r0, [r4]
+	bne	__und_usr_thumb
+	sub	r4, r2, #4			@ ARM instr at LR - 4
+1:	ldrt	r0, [r4]
 #ifdef CONFIG_CPU_ENDIAN_BE8
-	reveq	r0, r0				@ little endian instruction
+	rev	r0, r0				@ little endian instruction
 #endif
-	beq	call_fpe
+	@ r0 = 32-bit ARM instruction which caused the exception
+	@ r2 = PC value for the following instruction (:= regs->ARM_pc)
+	@ r4 = PC value for the faulting instruction
+	@ lr = 32-bit undefined instruction function
+	adr	lr, BSYM(__und_usr_fault_32)
+	b	call_fpe
+
+__und_usr_thumb:
 	@ Thumb instruction
+	sub	r4, r2, #2			@ First half of thumb instr at LR - 2
 #if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
 /*
  * Thumb-2 instruction handling.  Note that because pre-v6 and >= v6 platforms
@@ -455,23 +483,26 @@ __und_usr:
 	ldr	r5, .LCcpu_architecture
 	ldr	r5, [r5]
 	cmp	r5, #CPU_ARCH_ARMv7
-	blo	__und_usr_unknown
+	blo	__und_usr_fault_16		@ 16bit undefined instruction
 /*
  * The following code won't get run unless the running CPU really is v7, so
  * coding round the lack of ldrht on older arches is pointless.  Temporarily
  * override the assembler target arch with the minimum required instead:
  */
 	.arch	armv6t2
 #endif
-2:
- ARM(	ldrht	r5, [r4], #2	)
- THUMB(	ldrht	r5, [r4]	)
- THUMB(	add	r4, r4, #2	)
+2:	ldrht	r5, [r4]
 	cmp	r5, #0xe800			@ 32bit instruction if xx != 0
-	blo	__und_usr_unknown
-3:	ldrht	r0, [r4]
+	blo	__und_usr_fault_16		@ 16bit undefined instruction
+3:	ldrht	r0, [r2]
 	add	r2, r2, #2			@ r2 is PC + 2, make it PC + 4
+	str	r2, [sp, #S_PC]			@ it's a 2x16bit instr, update
 	orr	r0, r0, r5, lsl #16
+	adr	lr, BSYM(__und_usr_fault_32)
+	@ r0 = the two 16-bit Thumb instructions which caused the exception
+	@ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
+	@ r4 = PC value for the first 16-bit Thumb instruction
+	@ lr = 32bit undefined instruction function
 
 #if __LINUX_ARM_ARCH__ < 7
 /* If the target arch was overridden, change it back: */
@@ -482,17 +513,13 @@ __und_usr:
 #endif
 #endif /* __LINUX_ARM_ARCH__ < 7 */
 #else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */
-	b	__und_usr_unknown
+	b	__und_usr_fault_16
 #endif
- UNWIND(.fnend		)
+ UNWIND(.fnend)
 ENDPROC(__und_usr)
 
-	@
-	@ fallthrough to call_fpe
-	@
-
 /*
- * The out of line fixup for the ldrt above.
+ * The out of line fixup for the ldrt instructions above.
  */
 	.pushsection .fixup, "ax"
 	.align	2
@@ -524,11 +551,12 @@ ENDPROC(__und_usr)
  * NEON handler code.
  *
  * Emulators may wish to make use of the following registers:
- *  r0  = instruction opcode.
- *  r2  = PC+4
+ *  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
+ *  r2  = PC value to resume execution after successful emulation
  *  r9  = normal "successful" return address
- *  r10 = this threads thread_info structure.
+ *  r10 = this threads thread_info structure
  *  lr  = unrecognised instruction return address
+ * IRQs disabled, FIQs enabled.
  */
 	@
 	@ Fall-through from Thumb-2 __und_usr
@@ -659,12 +687,17 @@ ENTRY(no_fp)
 	mov	pc, lr
 ENDPROC(no_fp)
 
-__und_usr_unknown:
-	enable_irq
+__und_usr_fault_32:
+	mov	r1, #4
+	b	1f
+__und_usr_fault_16:
+	mov	r1, #2
+1:	enable_irq
 	mov	r0, sp
 	adr	lr, BSYM(ret_from_exception)
-	b	do_undefinstr
-ENDPROC(__und_usr_unknown)
+	b	__und_fault
+ENDPROC(__und_usr_fault_32)
+ENDPROC(__und_usr_fault_16)
 
 	.align	5
 __pabt_usr:

trunk/arch/arm/kernel/traps.c

@@ -370,18 +370,10 @@ static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
 
 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 {
-	unsigned int correction = thumb_mode(regs) ? 2 : 4;
 	unsigned int instr;
 	siginfo_t info;
 	void __user *pc;
 
-	/*
-	 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
-	 * depending whether we're in Thumb mode or not.
-	 * Correct this offset.
-	 */
-	regs->ARM_pc -= correction;
-
 	pc = (void __user *)instruction_pointer(regs);
 
 	if (processor_mode(regs) == SVC_MODE) {

trunk/arch/arm/vfp/entry.S

@@ -7,18 +7,20 @@
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
- *
- * Basic entry code, called from the kernel's undefined instruction trap.
- *  r0  = faulted instruction
- *  r5  = faulted PC+4
- *  r9  = successful return
- *  r10 = thread_info structure
- *  lr  = failure return
  */
 #include <asm/thread_info.h>
 #include <asm/vfpmacros.h>
 #include "../kernel/entry-header.S"
 
+@ VFP entry point.
+@
+@  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
+@  r2  = PC value to resume execution after successful emulation
+@  r9  = normal "successful" return address
+@  r10 = this threads thread_info structure
+@  lr  = unrecognised instruction return address
+@  IRQs disabled.
+@
 ENTRY(do_vfp)
 #ifdef CONFIG_PREEMPT
 	ldr	r4, [r10, #TI_PREEMPT]	@ get preempt count

trunk/arch/arm/vfp/vfphw.S

@@ -61,13 +61,13 @@
 
 @ VFP hardware support entry point.
 @
-@  r0  = faulted instruction
-@  r2  = faulted PC+4
-@  r9  = successful return
+@  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
+@  r2  = PC value to resume execution after successful emulation
+@  r9  = normal "successful" return address
 @  r10 = vfp_state union
 @  r11 = CPU number
-@  lr  = failure return
-
+@  lr  = unrecognised instruction return address
+@  IRQs enabled.
 ENTRY(vfp_support_entry)
 	DBGSTR3	"instr %08x pc %08x state %p", r0, r2, r10
 
@@ -161,9 +161,12 @@ vfp_hw_state_valid:
 					@ exception before retrying branch
 					@ out before setting an FPEXC that
 					@ stops us reading stuff
-	VFPFMXR	FPEXC, r1		@ restore FPEXC last
-	sub	r2, r2, #4
-	str	r2, [sp, #S_PC]		@ retry the instruction
+	VFPFMXR	FPEXC, r1		@ Restore FPEXC last
+	sub	r2, r2, #4		@ Retry current instruction - if Thumb
+	str	r2, [sp, #S_PC]		@ mode it's two 16-bit instructions,
+					@ else it's one 32-bit instruction, so
+					@ always subtract 4 from the following
+					@ instruction address.
 #ifdef CONFIG_PREEMPT
 	get_thread_info	r10
 	ldr	r4, [r10, #TI_PREEMPT]	@ get preempt count