arch/arm64/mm/proc.S - arm/linux - Git at Google

 /*
  * Based on arch/arm/mm/proc.S
  *
  * Copyright (C) 2001 Deep Blue Solutions Ltd.
  * Copyright (C) 2012 ARM Ltd.
  * Author: Catalin Marinas <catalin.marinas@arm.com>
  *
  * 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.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/init.h>
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/hwcap.h>
 #include <asm/pgtable.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/cpufeature.h>
 #include <asm/alternative.h>

 #ifdef CONFIG_ARM64_64K_PAGES
 #define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
 #elif defined(CONFIG_ARM64_16K_PAGES)
 #define TCR_TG_FLAGS	TCR_TG0_16K | TCR_TG1_16K
 #else /* CONFIG_ARM64_4K_PAGES */
 #define TCR_TG_FLAGS	TCR_TG0_4K | TCR_TG1_4K
 #endif

 #define TCR_SMP_FLAGS	TCR_SHARED

 /* PTWs cacheable, inner/outer WBWA */
 #define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA

 #define MAIR(attr, mt)	((attr) << ((mt) * 8))

 /*
  *	cpu_do_idle()
  *
  *	Idle the processor (wait for interrupt).
  */
 ENTRY(cpu_do_idle)
 	dsb	sy				// WFI may enter a low-power mode
 	wfi
 	ret
 ENDPROC(cpu_do_idle)

 #ifdef CONFIG_CPU_PM
 /**
  * cpu_do_suspend - save CPU registers context
  *
  * x0: virtual address of context pointer
  */
 ENTRY(cpu_do_suspend)
 	mrs	x2, tpidr_el0
 	mrs	x3, tpidrro_el0
 	mrs	x4, contextidr_el1
 	mrs	x5, cpacr_el1
 	mrs	x6, tcr_el1
 	mrs	x7, vbar_el1
 	mrs	x8, mdscr_el1
 	mrs	x9, oslsr_el1
 	mrs	x10, sctlr_el1
 	mrs	x11, tpidr_el1
 	mrs	x12, sp_el0
 	stp	x2, x3, [x0]
 	stp	x4, xzr, [x0, #16]
 	stp	x5, x6, [x0, #32]
 	stp	x7, x8, [x0, #48]
 	stp	x9, x10, [x0, #64]
 	stp	x11, x12, [x0, #80]
 	ret
 ENDPROC(cpu_do_suspend)

 /**
  * cpu_do_resume - restore CPU register context
  *
  * x0: Address of context pointer
  */
 	.pushsection ".idmap.text", "ax"
 ENTRY(cpu_do_resume)
 	ldp	x2, x3, [x0]
 	ldp	x4, x5, [x0, #16]
 	ldp	x6, x8, [x0, #32]
 	ldp	x9, x10, [x0, #48]
 	ldp	x11, x12, [x0, #64]
 	ldp	x13, x14, [x0, #80]
 	msr	tpidr_el0, x2
 	msr	tpidrro_el0, x3
 	msr	contextidr_el1, x4
 	msr	cpacr_el1, x6

 	/* Don't change t0sz here, mask those bits when restoring */
 	mrs	x5, tcr_el1
 	bfi	x8, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

 	msr	tcr_el1, x8
 	msr	vbar_el1, x9

 	/*
 	 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
 	 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
 	 * exception. Mask them until local_dbg_restore() in cpu_suspend()
 	 * resets them.
 	 */
 	disable_dbg
 	msr	mdscr_el1, x10

 	msr	sctlr_el1, x12
 	msr	tpidr_el1, x13
 	msr	sp_el0, x14
 	/*
 	 * Restore oslsr_el1 by writing oslar_el1
 	 */
 	ubfx	x11, x11, #1, #1
 	msr	oslar_el1, x11
 	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
 	isb
 	ret
 ENDPROC(cpu_do_resume)
 	.popsection
 #endif

 /*
  *	cpu_do_switch_mm(pgd_phys, tsk)
  *
  *	Set the translation table base pointer to be pgd_phys.
  *
  *	- pgd_phys - physical address of new TTB
  */
 ENTRY(cpu_do_switch_mm)
 	pre_ttbr0_update_workaround x0, x2, x3
 	mmid	x1, x1				// get mm->context.id
 	bfi	x0, x1, #48, #16		// set the ASID
 	msr	ttbr0_el1, x0			// set TTBR0
 	isb
 	post_ttbr0_update_workaround
 	ret
 ENDPROC(cpu_do_switch_mm)

 	.pushsection ".idmap.text", "ax"
 /*
  * void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
  *
  * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
  * called by anything else. It can only be executed from a TTBR0 mapping.
  */
 ENTRY(idmap_cpu_replace_ttbr1)
 	mrs	x2, daif
 	msr	daifset, #0xf

 	adrp	x1, empty_zero_page
 	msr	ttbr1_el1, x1
 	isb

 	tlbi	vmalle1
 	dsb	nsh
 	isb

 	msr	ttbr1_el1, x0
 	isb

 	msr	daif, x2

 	ret
 ENDPROC(idmap_cpu_replace_ttbr1)
 	.popsection

 /*
  *	__cpu_setup
  *
  *	Initialise the processor for turning the MMU on.  Return in x0 the
  *	value of the SCTLR_EL1 register.
  */
 	.pushsection ".idmap.text", "ax"
 ENTRY(__cpu_setup)
 	tlbi	vmalle1				// Invalidate local TLB
 	dsb	nsh

 	mov	x0, #3 << 20
 	msr	cpacr_el1, x0			// Enable FP/ASIMD
 	mov	x0, #1 << 12			// Reset mdscr_el1 and disable
 	msr	mdscr_el1, x0			// access to the DCC from EL0
 	isb					// Unmask debug exceptions now,
 	enable_dbg				// since this is per-cpu
 	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
 	/*
 	 * Memory region attributes for LPAE:
 	 *
 	 *   n = AttrIndx[2:0]
 	 *			n	MAIR
 	 *   DEVICE_nGnRnE	000	00000000
 	 *   DEVICE_nGnRE	001	00000100
 	 *   DEVICE_GRE		010	00001100
 	 *   NORMAL_NC		011	01000100
 	 *   NORMAL		100	11111111
 	 *   NORMAL_WT		101	10111011
 	 */
 	ldr	x5, =MAIR(0x00, MT_DEVICE_nGnRnE) | \
 		     MAIR(0x04, MT_DEVICE_nGnRE) | \
 		     MAIR(0x0c, MT_DEVICE_GRE) | \
 		     MAIR(0x44, MT_NORMAL_NC) | \
 		     MAIR(0xff, MT_NORMAL) | \
 		     MAIR(0xbb, MT_NORMAL_WT)
 	msr	mair_el1, x5
 	/*
 	 * Prepare SCTLR
 	 */
 	adr	x5, crval
 	ldp	w5, w6, [x5]
 	mrs	x0, sctlr_el1
 	bic	x0, x0, x5			// clear bits
 	orr	x0, x0, x6			// set bits
 	/*
 	 * Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
 	 * both user and kernel.
 	 */
 	ldr	x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
 			TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0
 	tcr_set_idmap_t0sz	x10, x9

 	/*
 	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the IPS bits in
 	 * TCR_EL1.
 	 */
 	mrs	x9, ID_AA64MMFR0_EL1
 	bfi	x10, x9, #32, #3
 #ifdef CONFIG_ARM64_HW_AFDBM
 	/*
 	 * Hardware update of the Access and Dirty bits.
 	 */
 	mrs	x9, ID_AA64MMFR1_EL1
 	and	x9, x9, #0xf
 	cbz	x9, 2f
 	cmp	x9, #2
 	b.lt	1f
 	orr	x10, x10, #TCR_HD		// hardware Dirty flag update
 1:	orr	x10, x10, #TCR_HA		// hardware Access flag update
 2:
 #endif	/* CONFIG_ARM64_HW_AFDBM */
 	msr	tcr_el1, x10
 	ret					// return to head.S
 ENDPROC(__cpu_setup)

 	/*
 	 * We set the desired value explicitly, including those of the
 	 * reserved bits. The values of bits EE & E0E were set early in
 	 * el2_setup, which are left untouched below.
 	 *
 	 *                 n n            T
 	 *       U E      WT T UD     US IHBS
 	 *       CE0      XWHW CZ     ME TEEA S
 	 * .... .IEE .... NEAI TE.I ..AD DEN0 ACAM
 	 * 0011 0... 1101 ..0. ..0. 10.. .0.. .... < hardware reserved
 	 * .... .1.. .... 01.1 11.1 ..01 0.01 1101 < software settings
 	 */
 	.type	crval, #object
 crval:
 	.word	0xfcffffff			// clear
 	.word	0x34d5d91d			// set
 	.popsection
	/*
	* Based on arch/arm/mm/proc.S
	*
	* Copyright (C) 2001 Deep Blue Solutions Ltd.
	* Copyright (C) 2012 ARM Ltd.
	* Author: Catalin Marinas <catalin.marinas@arm.com>
	*
	* 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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/init.h>
	#include <linux/linkage.h>
	#include <asm/assembler.h>
	#include <asm/asm-offsets.h>
	#include <asm/hwcap.h>
	#include <asm/pgtable.h>
	#include <asm/pgtable-hwdef.h>
	#include <asm/cpufeature.h>
	#include <asm/alternative.h>

	#ifdef CONFIG_ARM64_64K_PAGES
	#define TCR_TG_FLAGS TCR_TG0_64K \| TCR_TG1_64K
	#elif defined(CONFIG_ARM64_16K_PAGES)
	#define TCR_TG_FLAGS TCR_TG0_16K \| TCR_TG1_16K
	#else /* CONFIG_ARM64_4K_PAGES */
	#define TCR_TG_FLAGS TCR_TG0_4K \| TCR_TG1_4K
	#endif

	#define TCR_SMP_FLAGS TCR_SHARED

	/* PTWs cacheable, inner/outer WBWA */
	#define TCR_CACHE_FLAGS TCR_IRGN_WBWA \| TCR_ORGN_WBWA

	#define MAIR(attr, mt) ((attr) << ((mt) * 8))

	/*
	* cpu_do_idle()
	*
	* Idle the processor (wait for interrupt).
	*/
	ENTRY(cpu_do_idle)
	dsb sy // WFI may enter a low-power mode
	wfi
	ret
	ENDPROC(cpu_do_idle)

	#ifdef CONFIG_CPU_PM
	/**
	* cpu_do_suspend - save CPU registers context
	*
	* x0: virtual address of context pointer
	*/
	ENTRY(cpu_do_suspend)
	mrs x2, tpidr_el0
	mrs x3, tpidrro_el0
	mrs x4, contextidr_el1
	mrs x5, cpacr_el1
	mrs x6, tcr_el1
	mrs x7, vbar_el1
	mrs x8, mdscr_el1
	mrs x9, oslsr_el1
	mrs x10, sctlr_el1
	mrs x11, tpidr_el1
	mrs x12, sp_el0
	stp x2, x3, [x0]
	stp x4, xzr, [x0, #16]
	stp x5, x6, [x0, #32]
	stp x7, x8, [x0, #48]
	stp x9, x10, [x0, #64]
	stp x11, x12, [x0, #80]
	ret
	ENDPROC(cpu_do_suspend)

	/**
	* cpu_do_resume - restore CPU register context
	*
	* x0: Address of context pointer
	*/
	.pushsection ".idmap.text", "ax"
	ENTRY(cpu_do_resume)
	ldp x2, x3, [x0]
	ldp x4, x5, [x0, #16]
	ldp x6, x8, [x0, #32]
	ldp x9, x10, [x0, #48]
	ldp x11, x12, [x0, #64]
	ldp x13, x14, [x0, #80]
	msr tpidr_el0, x2
	msr tpidrro_el0, x3
	msr contextidr_el1, x4
	msr cpacr_el1, x6

	/* Don't change t0sz here, mask those bits when restoring */
	mrs x5, tcr_el1
	bfi x8, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

	msr tcr_el1, x8
	msr vbar_el1, x9

	/*
	* __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
	* debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
	* exception. Mask them until local_dbg_restore() in cpu_suspend()
	* resets them.
	*/
	disable_dbg
	msr mdscr_el1, x10

	msr sctlr_el1, x12
	msr tpidr_el1, x13
	msr sp_el0, x14
	/*
	* Restore oslsr_el1 by writing oslar_el1
	*/
	ubfx x11, x11, #1, #1
	msr oslar_el1, x11
	reset_pmuserenr_el0 x0 // Disable PMU access from EL0
	isb
	ret
	ENDPROC(cpu_do_resume)
	.popsection
	#endif

	/*
	* cpu_do_switch_mm(pgd_phys, tsk)
	*
	* Set the translation table base pointer to be pgd_phys.
	*
	* - pgd_phys - physical address of new TTB
	*/
	ENTRY(cpu_do_switch_mm)
	pre_ttbr0_update_workaround x0, x2, x3
	mmid x1, x1 // get mm->context.id
	bfi x0, x1, #48, #16 // set the ASID
	msr ttbr0_el1, x0 // set TTBR0
	isb
	post_ttbr0_update_workaround
	ret
	ENDPROC(cpu_do_switch_mm)

	.pushsection ".idmap.text", "ax"
	/*
	* void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
	*
	* This is the low-level counterpart to cpu_replace_ttbr1, and should not be
	* called by anything else. It can only be executed from a TTBR0 mapping.
	*/
	ENTRY(idmap_cpu_replace_ttbr1)
	mrs x2, daif
	msr daifset, #0xf

	adrp x1, empty_zero_page
	msr ttbr1_el1, x1
	isb

	tlbi vmalle1
	dsb nsh
	isb

	msr ttbr1_el1, x0
	isb

	msr daif, x2

	ret
	ENDPROC(idmap_cpu_replace_ttbr1)
	.popsection

	/*
	* __cpu_setup
	*
	* Initialise the processor for turning the MMU on. Return in x0 the
	* value of the SCTLR_EL1 register.
	*/
	.pushsection ".idmap.text", "ax"
	ENTRY(__cpu_setup)
	tlbi vmalle1 // Invalidate local TLB
	dsb nsh

	mov x0, #3 << 20
	msr cpacr_el1, x0 // Enable FP/ASIMD
	mov x0, #1 << 12 // Reset mdscr_el1 and disable
	msr mdscr_el1, x0 // access to the DCC from EL0
	isb // Unmask debug exceptions now,
	enable_dbg // since this is per-cpu
	reset_pmuserenr_el0 x0 // Disable PMU access from EL0
	/*
	* Memory region attributes for LPAE:
	*
	* n = AttrIndx[2:0]
	* n MAIR
	* DEVICE_nGnRnE 000 00000000
	* DEVICE_nGnRE 001 00000100
	* DEVICE_GRE 010 00001100
	* NORMAL_NC 011 01000100
	* NORMAL 100 11111111
	* NORMAL_WT 101 10111011
	*/
	ldr x5, =MAIR(0x00, MT_DEVICE_nGnRnE) \| \
	MAIR(0x04, MT_DEVICE_nGnRE) \| \
	MAIR(0x0c, MT_DEVICE_GRE) \| \
	MAIR(0x44, MT_NORMAL_NC) \| \
	MAIR(0xff, MT_NORMAL) \| \
	MAIR(0xbb, MT_NORMAL_WT)
	msr mair_el1, x5
	/*
	* Prepare SCTLR
	*/
	adr x5, crval
	ldp w5, w6, [x5]
	mrs x0, sctlr_el1
	bic x0, x0, x5 // clear bits
	orr x0, x0, x6 // set bits
	/*
	* Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
	* both user and kernel.
	*/
	ldr x10, =TCR_TxSZ(VA_BITS) \| TCR_CACHE_FLAGS \| TCR_SMP_FLAGS \| \
	TCR_TG_FLAGS \| TCR_ASID16 \| TCR_TBI0
	tcr_set_idmap_t0sz x10, x9

	/*
	* Read the PARange bits from ID_AA64MMFR0_EL1 and set the IPS bits in
	* TCR_EL1.
	*/
	mrs x9, ID_AA64MMFR0_EL1
	bfi x10, x9, #32, #3
	#ifdef CONFIG_ARM64_HW_AFDBM
	/*
	* Hardware update of the Access and Dirty bits.
	*/
	mrs x9, ID_AA64MMFR1_EL1
	and x9, x9, #0xf
	cbz x9, 2f
	cmp x9, #2
	b.lt 1f
	orr x10, x10, #TCR_HD // hardware Dirty flag update
	1: orr x10, x10, #TCR_HA // hardware Access flag update
	2:
	#endif /* CONFIG_ARM64_HW_AFDBM */
	msr tcr_el1, x10
	ret // return to head.S
	ENDPROC(__cpu_setup)

	/*
	* We set the desired value explicitly, including those of the
	* reserved bits. The values of bits EE & E0E were set early in
	* el2_setup, which are left untouched below.
	*
	* n n T
	* U E WT T UD US IHBS
	* CE0 XWHW CZ ME TEEA S
	* .... .IEE .... NEAI TE.I ..AD DEN0 ACAM
	* 0011 0... 1101 ..0. ..0. 10.. .0.. .... < hardware reserved
	* .... .1.. .... 01.1 11.1 ..01 0.01 1101 < software settings
	*/
	.type crval, #object
	crval:
	.word 0xfcffffff // clear
	.word 0x34d5d91d // set
	.popsection