Commit 828e9834 authored by Matthew Leach's avatar Matthew Leach Committed by Catalin Marinas
Browse files

arm64: head: create a new function for setting the boot_cpu_mode flag 



Currently, the code for setting the __cpu_boot_mode flag is munged in
with el2_setup. This makes things difficult on a BE bringup as a
memory access has to have occurred before el2_setup which is the place
that we'd like to set the endianess on the current EL.

Create a new function for setting __cpu_boot_mode and have el2_setup
return the mode the CPU. Also define a new constant in virt.h,
BOOT_CPU_MODE_EL1, for readability.

Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMatthew Leach <matthew.leach@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent e68bedaa

arch/arm64/include/asm/virt.h

+2 −1
Original line number Diff line number Diff line
@@ -18,7 +18,8 @@ 
#ifndef __ASM__VIRT_H

#define __ASM__VIRT_H



#define BOOT_CPU_MODE_EL2	(0x0e12b007)

#define BOOT_CPU_MODE_EL1	(0xe11)

#define BOOT_CPU_MODE_EL2	(0xe12)



#ifndef __ASSEMBLY__

#include <asm/cacheflush.h>

arch/arm64/kernel/head.S

+25 −9
Original line number Diff line number Diff line
@@ -123,8 +123,9 @@ 


ENTRY(stext)

	mov	x21, x0				// x21=FDT

	bl	el2_setup			// Drop to EL1, w20=cpu_boot_mode

	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET

	bl	el2_setup			// Drop to EL1

	bl	set_cpu_boot_mode_flag

	mrs	x22, midr_el1			// x22=cpuid

	mov	x0, x22

	bl	lookup_processor_type
@@ -150,21 +151,20 @@ ENDPROC(stext) 
/*

 * If we're fortunate enough to boot at EL2, ensure that the world is

 * sane before dropping to EL1.

 *

 * Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x20 if

 * booted in EL1 or EL2 respectively.

 */

ENTRY(el2_setup)

	mrs	x0, CurrentEL

	cmp	x0, #PSR_MODE_EL2t

	ccmp	x0, #PSR_MODE_EL2h, #0x4, ne

	ldr	x0, =__boot_cpu_mode		// Compute __boot_cpu_mode

	add	x0, x0, x28

	b.eq	1f

	str	wzr, [x0]			// Remember we don't have EL2...

	mov	w20, #BOOT_CPU_MODE_EL1		// This cpu booted in EL1

	ret



	/* Hyp configuration. */

1:	ldr	w1, =BOOT_CPU_MODE_EL2

	str	w1, [x0, #4]			// This CPU has EL2

	mov	x0, #(1 << 31)			// 64-bit EL1

1:	mov	x0, #(1 << 31)			// 64-bit EL1

	msr	hcr_el2, x0



	/* Generic timers. */
@@ -204,9 +204,24 @@ ENTRY(el2_setup) 
		      PSR_MODE_EL1h)

	msr	spsr_el2, x0

	msr	elr_el2, lr

	mov	w20, #BOOT_CPU_MODE_EL2		// This CPU booted in EL2

	eret

ENDPROC(el2_setup)



/*

 * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed

 * in x20. See arch/arm64/include/asm/virt.h for more info.

 */

ENTRY(set_cpu_boot_mode_flag)

	ldr	x1, =__boot_cpu_mode		// Compute __boot_cpu_mode

	add	x1, x1, x28

	cmp	w20, #BOOT_CPU_MODE_EL2

	b.ne	1f

	add	x1, x1, #4

1:	str	w20, [x1]			// This CPU has booted in EL1

	ret

ENDPROC(set_cpu_boot_mode_flag)



/*

 * We need to find out the CPU boot mode long after boot, so we need to

 * store it in a writable variable.
@@ -234,8 +249,9 @@ ENTRY(__boot_cpu_mode) 
	 * cores are held until we're ready for them to initialise.

	 */

ENTRY(secondary_holding_pen)

	bl	__calc_phys_offset		// x24=phys offset

	bl	el2_setup			// Drop to EL1

	bl	el2_setup			// Drop to EL1, w20=cpu_boot_mode

	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET

	bl	set_cpu_boot_mode_flag

	mrs	x0, mpidr_el1

	ldr     x1, =MPIDR_HWID_BITMASK

	and	x0, x0, x1

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