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

 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * 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>
  */

 #include <linux/init.h>
 #include <linux/linkage.h>
 #include <linux/pgtable.h>
 #include <linux/cfi_types.h>
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/asm_pointer_auth.h>
 #include <asm/hwcap.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/cpufeature.h>
 #include <asm/alternative.h>
 #include <asm/smp.h>
 #include <asm/sysreg.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

 #ifdef CONFIG_RANDOMIZE_BASE
 #define TCR_KASLR_FLAGS	TCR_NFD1
 #else
 #define TCR_KASLR_FLAGS	0
 #endif

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

 #ifdef CONFIG_KASAN_SW_TAGS
 #define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1
 #else
 #define TCR_KASAN_SW_FLAGS 0
 #endif

 #ifdef CONFIG_KASAN_HW_TAGS
 #define TCR_MTE_FLAGS TCR_TCMA1 | TCR_TBI1 | TCR_TBID1
 #elif defined(CONFIG_ARM64_MTE)
 /*
  * The mte_zero_clear_page_tags() implementation uses DC GZVA, which relies on
  * TBI being enabled at EL1.
  */
 #define TCR_MTE_FLAGS TCR_TBI1 | TCR_TBID1
 #else
 #define TCR_MTE_FLAGS 0
 #endif

 /*
  * Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
  * changed during mte_cpu_setup to Normal Tagged if the system supports MTE.
  */
 #define MAIR_EL1_SET							\
 	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) |	\
 	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) |	\
 	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) |		\
 	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) |			\
 	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))

 #ifdef CONFIG_CPU_PM
 /**
  * cpu_do_suspend - save CPU registers context
  *
  * x0: virtual address of context pointer
  *
  * This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
  */
 SYM_FUNC_START(cpu_do_suspend)
 	mrs	x2, tpidr_el0
 	mrs	x3, tpidrro_el0
 	mrs	x4, contextidr_el1
 	mrs	x5, osdlr_el1
 	mrs	x6, cpacr_el1
 	mrs	x7, tcr_el1
 	mrs	x8, vbar_el1
 	mrs	x9, mdscr_el1
 	mrs	x10, oslsr_el1
 	mrs	x11, sctlr_el1
 	get_this_cpu_offset x12
 	mrs	x13, sp_el0
 	stp	x2, x3, [x0]
 	stp	x4, x5, [x0, #16]
 	stp	x6, x7, [x0, #32]
 	stp	x8, x9, [x0, #48]
 	stp	x10, x11, [x0, #64]
 	stp	x12, x13, [x0, #80]
 	/*
 	 * Save x18 as it may be used as a platform register, e.g. by shadow
 	 * call stack.
 	 */
 	str	x18, [x0, #96]
 	ret
 SYM_FUNC_END(cpu_do_suspend)

 /**
  * cpu_do_resume - restore CPU register context
  *
  * x0: Address of context pointer
  */
 SYM_FUNC_START(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]
 	/*
 	 * Restore x18, as it may be used as a platform register, and clear
 	 * the buffer to minimize the risk of exposure when used for shadow
 	 * call stack.
 	 */
 	ldr	x18, [x0, #96]
 	str	xzr, [x0, #96]
 	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	x7, tcr_el1
 	bfi	x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

 	msr	tcr_el1, x8
 	msr	vbar_el1, x9
 	msr	mdscr_el1, x10

 	msr	sctlr_el1, x12
 	set_this_cpu_offset x13
 	msr	sp_el0, x14
 	/*
 	 * Restore oslsr_el1 by writing oslar_el1
 	 */
 	msr	osdlr_el1, x5
 	ubfx	x11, x11, #1, #1
 	msr	oslar_el1, x11
 	reset_pmuserenr_el0 x0			// Disable PMU access from EL0
 	reset_amuserenr_el0 x0			// Disable AMU access from EL0

 alternative_if ARM64_HAS_RAS_EXTN
 	msr_s	SYS_DISR_EL1, xzr
 alternative_else_nop_endif

 	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
 	isb
 	ret
 SYM_FUNC_END(cpu_do_resume)
 #endif

 	.pushsection ".idmap.text", "a"

 .macro	__idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
 	adrp	\tmp1, reserved_pg_dir
 	phys_to_ttbr \tmp2, \tmp1
 	offset_ttbr1 \tmp2, \tmp1
 	msr	ttbr1_el1, \tmp2
 	isb
 	tlbi	vmalle1
 	dsb	nsh
 	isb
 .endm

 /*
  * void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
  *
  * 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.
  */
 SYM_TYPED_FUNC_START(idmap_cpu_replace_ttbr1)
 	__idmap_cpu_set_reserved_ttbr1 x1, x3

 	offset_ttbr1 x0, x3
 	msr	ttbr1_el1, x0
 	isb

 	ret
 SYM_FUNC_END(idmap_cpu_replace_ttbr1)
 SYM_FUNC_ALIAS(__pi_idmap_cpu_replace_ttbr1, idmap_cpu_replace_ttbr1)
 	.popsection

 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0

 #define KPTI_NG_PTE_FLAGS	(PTE_ATTRINDX(MT_NORMAL) | PTE_TYPE_PAGE | \
 				 PTE_AF | PTE_SHARED | PTE_UXN | PTE_WRITE)

 	.pushsection ".idmap.text", "a"

 	.macro	pte_to_phys, phys, pte
 	and	\phys, \pte, #PTE_ADDR_LOW
 #ifdef CONFIG_ARM64_PA_BITS_52
 	and	\pte, \pte, #PTE_ADDR_HIGH
 	orr	\phys, \phys, \pte, lsl #PTE_ADDR_HIGH_SHIFT
 #endif
 	.endm

 	.macro	kpti_mk_tbl_ng, type, num_entries
 	add	end_\type\()p, cur_\type\()p, #\num_entries * 8
 .Ldo_\type:
 	ldr	\type, [cur_\type\()p], #8	// Load the entry and advance
 	tbz	\type, #0, .Lnext_\type		// Skip invalid and
 	tbnz	\type, #11, .Lnext_\type	// non-global entries
 	orr	\type, \type, #PTE_NG		// Same bit for blocks and pages
 	str	\type, [cur_\type\()p, #-8]	// Update the entry
 	.ifnc	\type, pte
 	tbnz	\type, #1, .Lderef_\type
 	.endif
 .Lnext_\type:
 	cmp	cur_\type\()p, end_\type\()p
 	b.ne	.Ldo_\type
 	.endm

 	/*
 	 * Dereference the current table entry and map it into the temporary
 	 * fixmap slot associated with the current level.
 	 */
 	.macro	kpti_map_pgtbl, type, level
 	str	xzr, [temp_pte, #8 * (\level + 2)]	// break before make
 	dsb	nshst
 	add	pte, temp_pte, #PAGE_SIZE * (\level + 2)
 	lsr	pte, pte, #12
 	tlbi	vaae1, pte
 	dsb	nsh
 	isb

 	phys_to_pte pte, cur_\type\()p
 	add	cur_\type\()p, temp_pte, #PAGE_SIZE * (\level + 2)
 	orr	pte, pte, pte_flags
 	str	pte, [temp_pte, #8 * (\level + 2)]
 	dsb	nshst
 	.endm

 /*
  * void __kpti_install_ng_mappings(int cpu, int num_secondaries, phys_addr_t temp_pgd,
  *				   unsigned long temp_pte_va)
  *
  * Called exactly once from stop_machine context by each CPU found during boot.
  */
 	.pushsection	".data", "aw", %progbits
 SYM_DATA(__idmap_kpti_flag, .long 1)
 	.popsection

 SYM_TYPED_FUNC_START(idmap_kpti_install_ng_mappings)
 	cpu		.req	w0
 	temp_pte	.req	x0
 	num_cpus	.req	w1
 	pte_flags	.req	x1
 	temp_pgd_phys	.req	x2
 	swapper_ttb	.req	x3
 	flag_ptr	.req	x4
 	cur_pgdp	.req	x5
 	end_pgdp	.req	x6
 	pgd		.req	x7
 	cur_pudp	.req	x8
 	end_pudp	.req	x9
 	cur_pmdp	.req	x11
 	end_pmdp	.req	x12
 	cur_ptep	.req	x14
 	end_ptep	.req	x15
 	pte		.req	x16
 	valid		.req	x17
 	cur_p4dp	.req	x19
 	end_p4dp	.req	x20

 	mov	x5, x3				// preserve temp_pte arg
 	mrs	swapper_ttb, ttbr1_el1
 	adr_l	flag_ptr, __idmap_kpti_flag

 	cbnz	cpu, __idmap_kpti_secondary

 #if CONFIG_PGTABLE_LEVELS > 4
 	stp	x29, x30, [sp, #-32]!
 	mov	x29, sp
 	stp	x19, x20, [sp, #16]
 #endif

 	/* We're the boot CPU. Wait for the others to catch up */
 	sevl
 1:	wfe
 	ldaxr	w17, [flag_ptr]
 	eor	w17, w17, num_cpus
 	cbnz	w17, 1b

 	/* Switch to the temporary page tables on this CPU only */
 	__idmap_cpu_set_reserved_ttbr1 x8, x9
 	offset_ttbr1 temp_pgd_phys, x8
 	msr	ttbr1_el1, temp_pgd_phys
 	isb

 	mov	temp_pte, x5
 	mov_q	pte_flags, KPTI_NG_PTE_FLAGS

 	/* Everybody is enjoying the idmap, so we can rewrite swapper. */

 #ifdef CONFIG_ARM64_LPA2
 	/*
 	 * If LPA2 support is configured, but 52-bit virtual addressing is not
 	 * enabled at runtime, we will fall back to one level of paging less,
 	 * and so we have to walk swapper_pg_dir as if we dereferenced its
 	 * address from a PGD level entry, and terminate the PGD level loop
 	 * right after.
 	 */
 	adrp	pgd, swapper_pg_dir	// walk &swapper_pg_dir at the next level
 	mov	cur_pgdp, end_pgdp	// must be equal to terminate the PGD loop
 alternative_if_not ARM64_HAS_VA52
 	b	.Lderef_pgd		// skip to the next level
 alternative_else_nop_endif
 	/*
 	 * LPA2 based 52-bit virtual addressing requires 52-bit physical
 	 * addressing to be enabled as well. In this case, the shareability
 	 * bits are repurposed as physical address bits, and should not be
 	 * set in pte_flags.
 	 */
 	bic	pte_flags, pte_flags, #PTE_SHARED
 #endif

 	/* PGD */
 	adrp		cur_pgdp, swapper_pg_dir
 	kpti_map_pgtbl	pgd, -1
 	kpti_mk_tbl_ng	pgd, PTRS_PER_PGD

 	/* Ensure all the updated entries are visible to secondary CPUs */
 	dsb	ishst

 	/* We're done: fire up swapper_pg_dir again */
 	__idmap_cpu_set_reserved_ttbr1 x8, x9
 	msr	ttbr1_el1, swapper_ttb
 	isb

 	/* Set the flag to zero to indicate that we're all done */
 	str	wzr, [flag_ptr]
 #if CONFIG_PGTABLE_LEVELS > 4
 	ldp	x19, x20, [sp, #16]
 	ldp	x29, x30, [sp], #32
 #endif
 	ret

 .Lderef_pgd:
 	/* P4D */
 	.if		CONFIG_PGTABLE_LEVELS > 4
 	p4d		.req	x30
 	pte_to_phys	cur_p4dp, pgd
 	kpti_map_pgtbl	p4d, 0
 	kpti_mk_tbl_ng	p4d, PTRS_PER_P4D
 	b		.Lnext_pgd
 	.else		/* CONFIG_PGTABLE_LEVELS <= 4 */
 	p4d		.req	pgd
 	.set		.Lnext_p4d, .Lnext_pgd
 	.endif

 .Lderef_p4d:
 	/* PUD */
 	.if		CONFIG_PGTABLE_LEVELS > 3
 	pud		.req	x10
 	pte_to_phys	cur_pudp, p4d
 	kpti_map_pgtbl	pud, 1
 	kpti_mk_tbl_ng	pud, PTRS_PER_PUD
 	b		.Lnext_p4d
 	.else		/* CONFIG_PGTABLE_LEVELS <= 3 */
 	pud		.req	pgd
 	.set		.Lnext_pud, .Lnext_pgd
 	.endif

 .Lderef_pud:
 	/* PMD */
 	.if		CONFIG_PGTABLE_LEVELS > 2
 	pmd		.req	x13
 	pte_to_phys	cur_pmdp, pud
 	kpti_map_pgtbl	pmd, 2
 	kpti_mk_tbl_ng	pmd, PTRS_PER_PMD
 	b		.Lnext_pud
 	.else		/* CONFIG_PGTABLE_LEVELS <= 2 */
 	pmd		.req	pgd
 	.set		.Lnext_pmd, .Lnext_pgd
 	.endif

 .Lderef_pmd:
 	/* PTE */
 	pte_to_phys	cur_ptep, pmd
 	kpti_map_pgtbl	pte, 3
 	kpti_mk_tbl_ng	pte, PTRS_PER_PTE
 	b		.Lnext_pmd

 	.unreq	cpu
 	.unreq	temp_pte
 	.unreq	num_cpus
 	.unreq	pte_flags
 	.unreq	temp_pgd_phys
 	.unreq	cur_pgdp
 	.unreq	end_pgdp
 	.unreq	pgd
 	.unreq	cur_pudp
 	.unreq	end_pudp
 	.unreq	pud
 	.unreq	cur_pmdp
 	.unreq	end_pmdp
 	.unreq	pmd
 	.unreq	cur_ptep
 	.unreq	end_ptep
 	.unreq	pte
 	.unreq	valid
 	.unreq	cur_p4dp
 	.unreq	end_p4dp
 	.unreq	p4d

 	/* Secondary CPUs end up here */
 __idmap_kpti_secondary:
 	/* Uninstall swapper before surgery begins */
 	__idmap_cpu_set_reserved_ttbr1 x16, x17

 	/* Increment the flag to let the boot CPU we're ready */
 1:	ldxr	w16, [flag_ptr]
 	add	w16, w16, #1
 	stxr	w17, w16, [flag_ptr]
 	cbnz	w17, 1b

 	/* Wait for the boot CPU to finish messing around with swapper */
 	sevl
 1:	wfe
 	ldxr	w16, [flag_ptr]
 	cbnz	w16, 1b

 	/* All done, act like nothing happened */
 	msr	ttbr1_el1, swapper_ttb
 	isb
 	ret

 	.unreq	swapper_ttb
 	.unreq	flag_ptr
 SYM_FUNC_END(idmap_kpti_install_ng_mappings)
 	.popsection
 #endif

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

 	msr	cpacr_el1, xzr			// Reset cpacr_el1
 	mov	x1, #1 << 12			// Reset mdscr_el1 and disable
 	msr	mdscr_el1, x1			// access to the DCC from EL0
 	reset_pmuserenr_el0 x1			// Disable PMU access from EL0
 	reset_amuserenr_el0 x1			// Disable AMU access from EL0

 	/*
 	 * Default values for VMSA control registers. These will be adjusted
 	 * below depending on detected CPU features.
 	 */
 	mair	.req	x17
 	tcr	.req	x16
 	mov_q	mair, MAIR_EL1_SET
 	mov_q	tcr, TCR_T0SZ(IDMAP_VA_BITS) | TCR_T1SZ(VA_BITS_MIN) | TCR_CACHE_FLAGS | \
 		     TCR_SHARED | TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
 		     TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS | TCR_MTE_FLAGS

 	tcr_clear_errata_bits tcr, x9, x5

 #ifdef CONFIG_ARM64_VA_BITS_52
 	mov		x9, #64 - VA_BITS
 alternative_if ARM64_HAS_VA52
 	tcr_set_t1sz	tcr, x9
 #ifdef CONFIG_ARM64_LPA2
 	orr		tcr, tcr, #TCR_DS
 #endif
 alternative_else_nop_endif
 #endif

 	/*
 	 * Set the IPS bits in TCR_EL1.
 	 */
 	tcr_compute_pa_size tcr, #TCR_IPS_SHIFT, x5, x6
 #ifdef CONFIG_ARM64_HW_AFDBM
 	/*
 	 * Enable hardware update of the Access Flags bit.
 	 * Hardware dirty bit management is enabled later,
 	 * via capabilities.
 	 */
 	mrs	x9, ID_AA64MMFR1_EL1
 	and	x9, x9, ID_AA64MMFR1_EL1_HAFDBS_MASK
 	cbz	x9, 1f
 	orr	tcr, tcr, #TCR_HA		// hardware Access flag update
 1:
 #endif	/* CONFIG_ARM64_HW_AFDBM */
 	msr	mair_el1, mair
 	msr	tcr_el1, tcr

 	mrs_s	x1, SYS_ID_AA64MMFR3_EL1
 	ubfx	x1, x1, #ID_AA64MMFR3_EL1_S1PIE_SHIFT, #4
 	cbz	x1, .Lskip_indirection

 	/*
 	 * The PROT_* macros describing the various memory types may resolve to
 	 * C expressions if they include the PTE_MAYBE_* macros, and so they
 	 * can only be used from C code. The PIE_E* constants below are also
 	 * defined in terms of those macros, but will mask out those
 	 * PTE_MAYBE_* constants, whether they are set or not. So #define them
 	 * as 0x0 here so we can evaluate the PIE_E* constants in asm context.
 	 */

 #define PTE_MAYBE_NG		0
 #define PTE_MAYBE_SHARED	0

 	mov_q	x0, PIE_E0
 	msr	REG_PIRE0_EL1, x0
 	mov_q	x0, PIE_E1
 	msr	REG_PIR_EL1, x0

 #undef PTE_MAYBE_NG
 #undef PTE_MAYBE_SHARED

 	mov	x0, TCR2_EL1x_PIE
 	msr	REG_TCR2_EL1, x0

 .Lskip_indirection:

 	/*
 	 * Prepare SCTLR
 	 */
 	mov_q	x0, INIT_SCTLR_EL1_MMU_ON
 	ret					// return to head.S

 	.unreq	mair
 	.unreq	tcr
 SYM_FUNC_END(__cpu_setup)
	/* SPDX-License-Identifier: GPL-2.0-only */
	/*
	* 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>
	*/

	#include <linux/init.h>
	#include <linux/linkage.h>
	#include <linux/pgtable.h>
	#include <linux/cfi_types.h>
	#include <asm/assembler.h>
	#include <asm/asm-offsets.h>
	#include <asm/asm_pointer_auth.h>
	#include <asm/hwcap.h>
	#include <asm/kernel-pgtable.h>
	#include <asm/pgtable-hwdef.h>
	#include <asm/cpufeature.h>
	#include <asm/alternative.h>
	#include <asm/smp.h>
	#include <asm/sysreg.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

	#ifdef CONFIG_RANDOMIZE_BASE
	#define TCR_KASLR_FLAGS TCR_NFD1
	#else
	#define TCR_KASLR_FLAGS 0
	#endif

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

	#ifdef CONFIG_KASAN_SW_TAGS
	#define TCR_KASAN_SW_FLAGS TCR_TBI1 \| TCR_TBID1
	#else
	#define TCR_KASAN_SW_FLAGS 0
	#endif

	#ifdef CONFIG_KASAN_HW_TAGS
	#define TCR_MTE_FLAGS TCR_TCMA1 \| TCR_TBI1 \| TCR_TBID1
	#elif defined(CONFIG_ARM64_MTE)
	/*
	* The mte_zero_clear_page_tags() implementation uses DC GZVA, which relies on
	* TBI being enabled at EL1.
	*/
	#define TCR_MTE_FLAGS TCR_TBI1 \| TCR_TBID1
	#else
	#define TCR_MTE_FLAGS 0
	#endif

	/*
	* Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
	* changed during mte_cpu_setup to Normal Tagged if the system supports MTE.
	*/
	#define MAIR_EL1_SET \
	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) \| \
	MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) \| \
	MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) \| \
	MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) \| \
	MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))

	#ifdef CONFIG_CPU_PM
	/**
	* cpu_do_suspend - save CPU registers context
	*
	* x0: virtual address of context pointer
	*
	* This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
	*/
	SYM_FUNC_START(cpu_do_suspend)
	mrs x2, tpidr_el0
	mrs x3, tpidrro_el0
	mrs x4, contextidr_el1
	mrs x5, osdlr_el1
	mrs x6, cpacr_el1
	mrs x7, tcr_el1
	mrs x8, vbar_el1
	mrs x9, mdscr_el1
	mrs x10, oslsr_el1
	mrs x11, sctlr_el1
	get_this_cpu_offset x12
	mrs x13, sp_el0
	stp x2, x3, [x0]
	stp x4, x5, [x0, #16]
	stp x6, x7, [x0, #32]
	stp x8, x9, [x0, #48]
	stp x10, x11, [x0, #64]
	stp x12, x13, [x0, #80]
	/*
	* Save x18 as it may be used as a platform register, e.g. by shadow
	* call stack.
	*/
	str x18, [x0, #96]
	ret
	SYM_FUNC_END(cpu_do_suspend)

	/**
	* cpu_do_resume - restore CPU register context
	*
	* x0: Address of context pointer
	*/
	SYM_FUNC_START(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]
	/*
	* Restore x18, as it may be used as a platform register, and clear
	* the buffer to minimize the risk of exposure when used for shadow
	* call stack.
	*/
	ldr x18, [x0, #96]
	str xzr, [x0, #96]
	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 x7, tcr_el1
	bfi x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

	msr tcr_el1, x8
	msr vbar_el1, x9
	msr mdscr_el1, x10

	msr sctlr_el1, x12
	set_this_cpu_offset x13
	msr sp_el0, x14
	/*
	* Restore oslsr_el1 by writing oslar_el1
	*/
	msr osdlr_el1, x5
	ubfx x11, x11, #1, #1
	msr oslar_el1, x11
	reset_pmuserenr_el0 x0 // Disable PMU access from EL0
	reset_amuserenr_el0 x0 // Disable AMU access from EL0

	alternative_if ARM64_HAS_RAS_EXTN
	msr_s SYS_DISR_EL1, xzr
	alternative_else_nop_endif

	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
	isb
	ret
	SYM_FUNC_END(cpu_do_resume)
	#endif

	.pushsection ".idmap.text", "a"

	.macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
	adrp \tmp1, reserved_pg_dir
	phys_to_ttbr \tmp2, \tmp1
	offset_ttbr1 \tmp2, \tmp1
	msr ttbr1_el1, \tmp2
	isb
	tlbi vmalle1
	dsb nsh
	isb
	.endm

	/*
	* void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
	*
	* 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.
	*/
	SYM_TYPED_FUNC_START(idmap_cpu_replace_ttbr1)
	__idmap_cpu_set_reserved_ttbr1 x1, x3

	offset_ttbr1 x0, x3
	msr ttbr1_el1, x0
	isb

	ret
	SYM_FUNC_END(idmap_cpu_replace_ttbr1)
	SYM_FUNC_ALIAS(__pi_idmap_cpu_replace_ttbr1, idmap_cpu_replace_ttbr1)
	.popsection

	#ifdef CONFIG_UNMAP_KERNEL_AT_EL0

	#define KPTI_NG_PTE_FLAGS (PTE_ATTRINDX(MT_NORMAL) \| PTE_TYPE_PAGE \| \
	PTE_AF \| PTE_SHARED \| PTE_UXN \| PTE_WRITE)

	.pushsection ".idmap.text", "a"

	.macro pte_to_phys, phys, pte
	and \phys, \pte, #PTE_ADDR_LOW
	#ifdef CONFIG_ARM64_PA_BITS_52
	and \pte, \pte, #PTE_ADDR_HIGH
	orr \phys, \phys, \pte, lsl #PTE_ADDR_HIGH_SHIFT
	#endif
	.endm

	.macro kpti_mk_tbl_ng, type, num_entries
	add end_\type\()p, cur_\type\()p, #\num_entries * 8
	.Ldo_\type:
	ldr \type, [cur_\type\()p], #8 // Load the entry and advance
	tbz \type, #0, .Lnext_\type // Skip invalid and
	tbnz \type, #11, .Lnext_\type // non-global entries
	orr \type, \type, #PTE_NG // Same bit for blocks and pages
	str \type, [cur_\type\()p, #-8] // Update the entry
	.ifnc \type, pte
	tbnz \type, #1, .Lderef_\type
	.endif
	.Lnext_\type:
	cmp cur_\type\()p, end_\type\()p
	b.ne .Ldo_\type
	.endm

	/*
	* Dereference the current table entry and map it into the temporary
	* fixmap slot associated with the current level.
	*/
	.macro kpti_map_pgtbl, type, level
	str xzr, [temp_pte, #8 * (\level + 2)] // break before make
	dsb nshst
	add pte, temp_pte, #PAGE_SIZE * (\level + 2)
	lsr pte, pte, #12
	tlbi vaae1, pte
	dsb nsh
	isb

	phys_to_pte pte, cur_\type\()p
	add cur_\type\()p, temp_pte, #PAGE_SIZE * (\level + 2)
	orr pte, pte, pte_flags
	str pte, [temp_pte, #8 * (\level + 2)]
	dsb nshst
	.endm

	/*
	* void __kpti_install_ng_mappings(int cpu, int num_secondaries, phys_addr_t temp_pgd,
	* unsigned long temp_pte_va)
	*
	* Called exactly once from stop_machine context by each CPU found during boot.
	*/
	.pushsection ".data", "aw", %progbits
	SYM_DATA(__idmap_kpti_flag, .long 1)
	.popsection

	SYM_TYPED_FUNC_START(idmap_kpti_install_ng_mappings)
	cpu .req w0
	temp_pte .req x0
	num_cpus .req w1
	pte_flags .req x1
	temp_pgd_phys .req x2
	swapper_ttb .req x3
	flag_ptr .req x4
	cur_pgdp .req x5
	end_pgdp .req x6
	pgd .req x7
	cur_pudp .req x8
	end_pudp .req x9
	cur_pmdp .req x11
	end_pmdp .req x12
	cur_ptep .req x14
	end_ptep .req x15
	pte .req x16
	valid .req x17
	cur_p4dp .req x19
	end_p4dp .req x20

	mov x5, x3 // preserve temp_pte arg
	mrs swapper_ttb, ttbr1_el1
	adr_l flag_ptr, __idmap_kpti_flag

	cbnz cpu, __idmap_kpti_secondary

	#if CONFIG_PGTABLE_LEVELS > 4
	stp x29, x30, [sp, #-32]!
	mov x29, sp
	stp x19, x20, [sp, #16]
	#endif

	/* We're the boot CPU. Wait for the others to catch up */
	sevl
	1: wfe
	ldaxr w17, [flag_ptr]
	eor w17, w17, num_cpus
	cbnz w17, 1b

	/* Switch to the temporary page tables on this CPU only */
	__idmap_cpu_set_reserved_ttbr1 x8, x9
	offset_ttbr1 temp_pgd_phys, x8
	msr ttbr1_el1, temp_pgd_phys
	isb

	mov temp_pte, x5
	mov_q pte_flags, KPTI_NG_PTE_FLAGS

	/* Everybody is enjoying the idmap, so we can rewrite swapper. */

	#ifdef CONFIG_ARM64_LPA2
	/*
	* If LPA2 support is configured, but 52-bit virtual addressing is not
	* enabled at runtime, we will fall back to one level of paging less,
	* and so we have to walk swapper_pg_dir as if we dereferenced its
	* address from a PGD level entry, and terminate the PGD level loop
	* right after.
	*/
	adrp pgd, swapper_pg_dir // walk &swapper_pg_dir at the next level
	mov cur_pgdp, end_pgdp // must be equal to terminate the PGD loop
	alternative_if_not ARM64_HAS_VA52
	b .Lderef_pgd // skip to the next level
	alternative_else_nop_endif
	/*
	* LPA2 based 52-bit virtual addressing requires 52-bit physical
	* addressing to be enabled as well. In this case, the shareability
	* bits are repurposed as physical address bits, and should not be
	* set in pte_flags.
	*/
	bic pte_flags, pte_flags, #PTE_SHARED
	#endif

	/* PGD */
	adrp cur_pgdp, swapper_pg_dir
	kpti_map_pgtbl pgd, -1
	kpti_mk_tbl_ng pgd, PTRS_PER_PGD

	/* Ensure all the updated entries are visible to secondary CPUs */
	dsb ishst

	/* We're done: fire up swapper_pg_dir again */
	__idmap_cpu_set_reserved_ttbr1 x8, x9
	msr ttbr1_el1, swapper_ttb
	isb

	/* Set the flag to zero to indicate that we're all done */
	str wzr, [flag_ptr]
	#if CONFIG_PGTABLE_LEVELS > 4
	ldp x19, x20, [sp, #16]
	ldp x29, x30, [sp], #32
	#endif
	ret

	.Lderef_pgd:
	/* P4D */
	.if CONFIG_PGTABLE_LEVELS > 4
	p4d .req x30
	pte_to_phys cur_p4dp, pgd
	kpti_map_pgtbl p4d, 0
	kpti_mk_tbl_ng p4d, PTRS_PER_P4D
	b .Lnext_pgd
	.else /* CONFIG_PGTABLE_LEVELS <= 4 */
	p4d .req pgd
	.set .Lnext_p4d, .Lnext_pgd
	.endif

	.Lderef_p4d:
	/* PUD */
	.if CONFIG_PGTABLE_LEVELS > 3
	pud .req x10
	pte_to_phys cur_pudp, p4d
	kpti_map_pgtbl pud, 1
	kpti_mk_tbl_ng pud, PTRS_PER_PUD
	b .Lnext_p4d
	.else /* CONFIG_PGTABLE_LEVELS <= 3 */
	pud .req pgd
	.set .Lnext_pud, .Lnext_pgd
	.endif

	.Lderef_pud:
	/* PMD */
	.if CONFIG_PGTABLE_LEVELS > 2
	pmd .req x13
	pte_to_phys cur_pmdp, pud
	kpti_map_pgtbl pmd, 2
	kpti_mk_tbl_ng pmd, PTRS_PER_PMD
	b .Lnext_pud
	.else /* CONFIG_PGTABLE_LEVELS <= 2 */
	pmd .req pgd
	.set .Lnext_pmd, .Lnext_pgd
	.endif

	.Lderef_pmd:
	/* PTE */
	pte_to_phys cur_ptep, pmd
	kpti_map_pgtbl pte, 3
	kpti_mk_tbl_ng pte, PTRS_PER_PTE
	b .Lnext_pmd

	.unreq cpu
	.unreq temp_pte
	.unreq num_cpus
	.unreq pte_flags
	.unreq temp_pgd_phys
	.unreq cur_pgdp
	.unreq end_pgdp
	.unreq pgd
	.unreq cur_pudp
	.unreq end_pudp
	.unreq pud
	.unreq cur_pmdp
	.unreq end_pmdp
	.unreq pmd
	.unreq cur_ptep
	.unreq end_ptep
	.unreq pte
	.unreq valid
	.unreq cur_p4dp
	.unreq end_p4dp
	.unreq p4d

	/* Secondary CPUs end up here */
	__idmap_kpti_secondary:
	/* Uninstall swapper before surgery begins */
	__idmap_cpu_set_reserved_ttbr1 x16, x17

	/* Increment the flag to let the boot CPU we're ready */
	1: ldxr w16, [flag_ptr]
	add w16, w16, #1
	stxr w17, w16, [flag_ptr]
	cbnz w17, 1b

	/* Wait for the boot CPU to finish messing around with swapper */
	sevl
	1: wfe
	ldxr w16, [flag_ptr]
	cbnz w16, 1b

	/* All done, act like nothing happened */
	msr ttbr1_el1, swapper_ttb
	isb
	ret

	.unreq swapper_ttb
	.unreq flag_ptr
	SYM_FUNC_END(idmap_kpti_install_ng_mappings)
	.popsection
	#endif

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

	msr cpacr_el1, xzr // Reset cpacr_el1
	mov x1, #1 << 12 // Reset mdscr_el1 and disable
	msr mdscr_el1, x1 // access to the DCC from EL0
	reset_pmuserenr_el0 x1 // Disable PMU access from EL0
	reset_amuserenr_el0 x1 // Disable AMU access from EL0

	/*
	* Default values for VMSA control registers. These will be adjusted
	* below depending on detected CPU features.
	*/
	mair .req x17
	tcr .req x16
	mov_q mair, MAIR_EL1_SET
	mov_q tcr, TCR_T0SZ(IDMAP_VA_BITS) \| TCR_T1SZ(VA_BITS_MIN) \| TCR_CACHE_FLAGS \| \
	TCR_SHARED \| TCR_TG_FLAGS \| TCR_KASLR_FLAGS \| TCR_ASID16 \| \
	TCR_TBI0 \| TCR_A1 \| TCR_KASAN_SW_FLAGS \| TCR_MTE_FLAGS

	tcr_clear_errata_bits tcr, x9, x5

	#ifdef CONFIG_ARM64_VA_BITS_52
	mov x9, #64 - VA_BITS
	alternative_if ARM64_HAS_VA52
	tcr_set_t1sz tcr, x9
	#ifdef CONFIG_ARM64_LPA2
	orr tcr, tcr, #TCR_DS
	#endif
	alternative_else_nop_endif
	#endif

	/*
	* Set the IPS bits in TCR_EL1.
	*/
	tcr_compute_pa_size tcr, #TCR_IPS_SHIFT, x5, x6
	#ifdef CONFIG_ARM64_HW_AFDBM
	/*
	* Enable hardware update of the Access Flags bit.
	* Hardware dirty bit management is enabled later,
	* via capabilities.
	*/
	mrs x9, ID_AA64MMFR1_EL1
	and x9, x9, ID_AA64MMFR1_EL1_HAFDBS_MASK
	cbz x9, 1f
	orr tcr, tcr, #TCR_HA // hardware Access flag update
	1:
	#endif /* CONFIG_ARM64_HW_AFDBM */
	msr mair_el1, mair
	msr tcr_el1, tcr

	mrs_s x1, SYS_ID_AA64MMFR3_EL1
	ubfx x1, x1, #ID_AA64MMFR3_EL1_S1PIE_SHIFT, #4
	cbz x1, .Lskip_indirection

	/*
	* The PROT_* macros describing the various memory types may resolve to
	* C expressions if they include the PTE_MAYBE_* macros, and so they
	* can only be used from C code. The PIE_E* constants below are also
	* defined in terms of those macros, but will mask out those
	* PTE_MAYBE_* constants, whether they are set or not. So #define them
	* as 0x0 here so we can evaluate the PIE_E* constants in asm context.
	*/

	#define PTE_MAYBE_NG 0
	#define PTE_MAYBE_SHARED 0

	mov_q x0, PIE_E0
	msr REG_PIRE0_EL1, x0
	mov_q x0, PIE_E1
	msr REG_PIR_EL1, x0

	#undef PTE_MAYBE_NG
	#undef PTE_MAYBE_SHARED

	mov x0, TCR2_EL1x_PIE
	msr REG_TCR2_EL1, x0

	.Lskip_indirection:

	/*
	* Prepare SCTLR
	*/
	mov_q x0, INIT_SCTLR_EL1_MMU_ON
	ret // return to head.S

	.unreq mair
	.unreq tcr
	SYM_FUNC_END(__cpu_setup)