Commit 309ee042 authored by Russell King's avatar Russell King
Browse files

ARM: use aliases for registers in entry-common 



Use aliases for the saved (and preserved) PSR and PC values so that we
can control which registers are used.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent fed3c155

arch/arm/kernel/entry-common.S

+14 −10
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ 


#include "entry-header.S"



saved_psr	.req	r8

saved_pc	.req	lr



	.align	5

#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
@@ -141,9 +143,9 @@ ENTRY(vector_swi) 
 ARM(	stmdb	r8, {sp, lr}^		)	@ Calling sp, lr

 THUMB(	mov	r8, sp			)

 THUMB(	store_user_sp_lr r8, r10, S_SP	)	@ calling sp, lr

	mrs	r8, spsr			@ called from non-FIQ mode, so ok.

	str	lr, [sp, #S_PC]			@ Save calling PC

	str	r8, [sp, #S_PSR]		@ Save CPSR

	mrs	saved_psr, spsr			@ called from non-FIQ mode, so ok.

	str	saved_pc, [sp, #S_PC]		@ Save calling PC

	str	saved_psr, [sp, #S_PSR]		@ Save CPSR

	str	r0, [sp, #S_OLD_R0]		@ Save OLD_R0

#endif

	zero_fp
@@ -163,11 +165,11 @@ ENTRY(vector_swi) 
	 * value to determine if it is an EABI or an old ABI call.

	 */

#ifdef CONFIG_ARM_THUMB

	tst	r8, #PSR_T_BIT

	tst	saved_psr, #PSR_T_BIT

	movne	r10, #0				@ no thumb OABI emulation

 USER(	ldreq	r10, [lr, #-4]		)	@ get SWI instruction

 USER(	ldreq	r10, [saved_pc, #-4]	)	@ get SWI instruction

#else

 USER(	ldr	r10, [lr, #-4]		)	@ get SWI instruction

 USER(	ldr	r10, [saved_pc, #-4]	)	@ get SWI instruction

#endif

 ARM_BE8(rev	r10, r10)			@ little endian instruction
@@ -178,15 +180,17 @@ ENTRY(vector_swi) 
	 */

#elif defined(CONFIG_ARM_THUMB)

	/* Legacy ABI only, possibly thumb mode. */

	tst	r8, #PSR_T_BIT			@ this is SPSR from save_user_regs

	tst	saved_psr, #PSR_T_BIT		@ this is SPSR from save_user_regs

	addne	scno, r7, #__NR_SYSCALL_BASE	@ put OS number in

 USER(	ldreq	scno, [lr, #-4]		)

 USER(	ldreq	scno, [saved_pc, #-4]	)



#else

	/* Legacy ABI only. */

 USER(	ldr	scno, [lr, #-4]		)	@ get SWI instruction

 USER(	ldr	scno, [saved_pc, #-4]	)	@ get SWI instruction

#endif



	/* saved_psr and saved_pc are now dead */



	uaccess_disable tbl



	adr	tbl, sys_call_table		@ load syscall table pointer
@@ -234,7 +238,7 @@ local_restart: 
	 * current task.

	 */

9001:

	sub	lr, lr, #4

	sub	lr, saved_pc, #4

	str	lr, [sp, #S_PC]

	b	ret_fast_syscall

#endif