Commit 22893aa2 authored Apr 03, 2018 by Vladimir Murzin Committed by Russell King May 19, 2018

ARM: 8755/1: NOMMU: Reorganise __setup_mpu



Currently, we have mixed code placement between .head.text and .text
depends on configuration we are building:

_text                           M       R(UP)   R(SMP)
======================================================
 __setup_mpu                    __HEAD  __HEAD  text
 __after_proc_init              __HEAD  __HEAD  text
 __mmap_switched                text    text    text

We are going to support another variant of MPU which is different to
PMSAv7 in sense overlapping MPU regions are not allowed, so this patch
makes boundaries between these sections precise and consistent:

_text                           M       R(UP)   R(SMP)
======================================================
 __setup_mpu                    __HEAD  __HEAD  __HEAD
 __after_proc_init              text    text    text
 __mmap_switched                text    text    text

Additionally, it paves a path to postpone MPU activation till
__after_proc_init where we do set SCTLR anyway and can return
directly to __mmap_switched.

Tested-by: Szemz? András <sza@esh.hu>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

parent 9cfb541a

arch/arm/kernel/head-nommu.S

+5 −2

Original line number	Diff line number	Diff line
		@@ -75,8 +75,8 @@ ENTRY(stext)
		ldr r12, [r10, #PROCINFO_INITFUNC]
		add r12, r12, r10
		ret r12
		1: bl __after_proc_init
		b __mmap_switched
		1: ldr lr, =__mmap_switched
		b __after_proc_init
		ENDPROC(stext)

		#ifdef CONFIG_SMP
		@@ -123,6 +123,7 @@ __secondary_data:
		/*
		* Set the Control Register and Read the process ID.
		*/
		.text
		__after_proc_init:
		#ifdef CONFIG_CPU_CP15
		/*
		@@ -202,6 +203,7 @@ ENDPROC(__after_proc_init)
		*
		* r6: Value to be written to DRSR (and IRSR if required) for PMSAv7_RAM_REGION
		*/
		__HEAD

		ENTRY(__setup_mpu)

		@@ -301,6 +303,7 @@ ENDPROC(__setup_pmsa_v7)
		* r6: pointer at mpu_rgn_info
		*/

		.text
		ENTRY(__secondary_setup_mpu)
		/* Use MPU region info supplied by __cpu_up */
		ldr r6, [r7] @ get secondary_data.mpu_rgn_info

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