Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1102 insertions, 0 deletions

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
new file mode 100644
index 000000000..62146d48d
--- /dev/null
+++ b/arch/arm64/kernel/entry.S
@@ -0,0 +1,1102 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Low-level exception handling code
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ * Authors:	Catalin Marinas <catalin.marinas@arm.com>
+ *		Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/init.h>
+#include <linux/linkage.h>
+
+#include <asm/alternative.h>
+#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
+#include <asm/asm_pointer_auth.h>
+#include <asm/bug.h>
+#include <asm/cpufeature.h>
+#include <asm/errno.h>
+#include <asm/esr.h>
+#include <asm/irq.h>
+#include <asm/memory.h>
+#include <asm/mmu.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/scs.h>
+#include <asm/thread_info.h>
+#include <asm/asm-uaccess.h>
+#include <asm/unistd.h>
+
+	.macro	clear_gp_regs
+	.irp	n,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29
+	mov	x\n, xzr
+	.endr
+	.endm
+
+	.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
+	.align 7
+.Lventry_start\@:
+	.if	\el == 0
+	/*
+	 * This must be the first instruction of the EL0 vector entries. It is
+	 * skipped by the trampoline vectors, to trigger the cleanup.
+	 */
+	b	.Lskip_tramp_vectors_cleanup\@
+	.if	\regsize == 64
+	mrs	x30, tpidrro_el0
+	msr	tpidrro_el0, xzr
+	.else
+	mov	x30, xzr
+	.endif
+.Lskip_tramp_vectors_cleanup\@:
+	.endif
+
+	sub	sp, sp, #PT_REGS_SIZE
+#ifdef CONFIG_VMAP_STACK
+	/*
+	 * Test whether the SP has overflowed, without corrupting a GPR.
+	 * Task and IRQ stacks are aligned so that SP & (1 << THREAD_SHIFT)
+	 * should always be zero.
+	 */
+	add	sp, sp, x0			// sp' = sp + x0
+	sub	x0, sp, x0			// x0' = sp' - x0 = (sp + x0) - x0 = sp
+	tbnz	x0, #THREAD_SHIFT, 0f
+	sub	x0, sp, x0			// x0'' = sp' - x0' = (sp + x0) - sp = x0
+	sub	sp, sp, x0			// sp'' = sp' - x0 = (sp + x0) - x0 = sp
+	b	el\el\ht\()_\regsize\()_\label
+
+0:
+	/*
+	 * Either we've just detected an overflow, or we've taken an exception
+	 * while on the overflow stack. Either way, we won't return to
+	 * userspace, and can clobber EL0 registers to free up GPRs.
+	 */
+
+	/* Stash the original SP (minus PT_REGS_SIZE) in tpidr_el0. */
+	msr	tpidr_el0, x0
+
+	/* Recover the original x0 value and stash it in tpidrro_el0 */
+	sub	x0, sp, x0
+	msr	tpidrro_el0, x0
+
+	/* Switch to the overflow stack */
+	adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0
+
+	/*
+	 * Check whether we were already on the overflow stack. This may happen
+	 * after panic() re-enables interrupts.
+	 */
+	mrs	x0, tpidr_el0			// sp of interrupted context
+	sub	x0, sp, x0			// delta with top of overflow stack
+	tst	x0, #~(OVERFLOW_STACK_SIZE - 1)	// within range?
+	b.ne	__bad_stack			// no? -> bad stack pointer
+
+	/* We were already on the overflow stack. Restore sp/x0 and carry on. */
+	sub	sp, sp, x0
+	mrs	x0, tpidrro_el0
+#endif
+	b	el\el\ht\()_\regsize\()_\label
+.org .Lventry_start\@ + 128	// Did we overflow the ventry slot?
+	.endm
+
+	.macro tramp_alias, dst, sym, tmp
+	mov_q	\dst, TRAMP_VALIAS
+	adr_l	\tmp, \sym
+	add	\dst, \dst, \tmp
+	adr_l	\tmp, .entry.tramp.text
+	sub	\dst, \dst, \tmp
+	.endm
+
+	/*
+	 * This macro corrupts x0-x3. It is the caller's duty  to save/restore
+	 * them if required.
+	 */
+	.macro	apply_ssbd, state, tmp1, tmp2
+alternative_cb	ARM64_ALWAYS_SYSTEM, spectre_v4_patch_fw_mitigation_enable
+	b	.L__asm_ssbd_skip\@		// Patched to NOP
+alternative_cb_end
+	ldr_this_cpu	\tmp2, arm64_ssbd_callback_required, \tmp1
+	cbz	\tmp2,	.L__asm_ssbd_skip\@
+	ldr	\tmp2, [tsk, #TSK_TI_FLAGS]
+	tbnz	\tmp2, #TIF_SSBD, .L__asm_ssbd_skip\@
+	mov	w0, #ARM_SMCCC_ARCH_WORKAROUND_2
+	mov	w1, #\state
+alternative_cb	ARM64_ALWAYS_SYSTEM, smccc_patch_fw_mitigation_conduit
+	nop					// Patched to SMC/HVC #0
+alternative_cb_end
+.L__asm_ssbd_skip\@:
+	.endm
+
+	/* Check for MTE asynchronous tag check faults */
+	.macro check_mte_async_tcf, tmp, ti_flags, thread_sctlr
+#ifdef CONFIG_ARM64_MTE
+	.arch_extension lse
+alternative_if_not ARM64_MTE
+	b	1f
+alternative_else_nop_endif
+	/*
+	 * Asynchronous tag check faults are only possible in ASYNC (2) or
+	 * ASYM (3) modes. In each of these modes bit 1 of SCTLR_EL1.TCF0 is
+	 * set, so skip the check if it is unset.
+	 */
+	tbz	\thread_sctlr, #(SCTLR_EL1_TCF0_SHIFT + 1), 1f
+	mrs_s	\tmp, SYS_TFSRE0_EL1
+	tbz	\tmp, #SYS_TFSR_EL1_TF0_SHIFT, 1f
+	/* Asynchronous TCF occurred for TTBR0 access, set the TI flag */
+	mov	\tmp, #_TIF_MTE_ASYNC_FAULT
+	add	\ti_flags, tsk, #TSK_TI_FLAGS
+	stset	\tmp, [\ti_flags]
+1:
+#endif
+	.endm
+
+	/* Clear the MTE asynchronous tag check faults */
+	.macro clear_mte_async_tcf thread_sctlr
+#ifdef CONFIG_ARM64_MTE
+alternative_if ARM64_MTE
+	/* See comment in check_mte_async_tcf above. */
+	tbz	\thread_sctlr, #(SCTLR_EL1_TCF0_SHIFT + 1), 1f
+	dsb	ish
+	msr_s	SYS_TFSRE0_EL1, xzr
+1:
+alternative_else_nop_endif
+#endif
+	.endm
+
+	.macro mte_set_gcr, mte_ctrl, tmp
+#ifdef CONFIG_ARM64_MTE
+	ubfx	\tmp, \mte_ctrl, #MTE_CTRL_GCR_USER_EXCL_SHIFT, #16
+	orr	\tmp, \tmp, #SYS_GCR_EL1_RRND
+	msr_s	SYS_GCR_EL1, \tmp
+#endif
+	.endm
+
+	.macro mte_set_kernel_gcr, tmp, tmp2
+#ifdef CONFIG_KASAN_HW_TAGS
+alternative_cb	ARM64_ALWAYS_SYSTEM, kasan_hw_tags_enable
+	b	1f
+alternative_cb_end
+	mov	\tmp, KERNEL_GCR_EL1
+	msr_s	SYS_GCR_EL1, \tmp
+1:
+#endif
+	.endm
+
+	.macro mte_set_user_gcr, tsk, tmp, tmp2
+#ifdef CONFIG_KASAN_HW_TAGS
+alternative_cb	ARM64_ALWAYS_SYSTEM, kasan_hw_tags_enable
+	b	1f
+alternative_cb_end
+	ldr	\tmp, [\tsk, #THREAD_MTE_CTRL]
+
+	mte_set_gcr \tmp, \tmp2
+1:
+#endif
+	.endm
+
+	.macro	kernel_entry, el, regsize = 64
+	.if	\regsize == 32
+	mov	w0, w0				// zero upper 32 bits of x0
+	.endif
+	stp	x0, x1, [sp, #16 * 0]
+	stp	x2, x3, [sp, #16 * 1]
+	stp	x4, x5, [sp, #16 * 2]
+	stp	x6, x7, [sp, #16 * 3]
+	stp	x8, x9, [sp, #16 * 4]
+	stp	x10, x11, [sp, #16 * 5]
+	stp	x12, x13, [sp, #16 * 6]
+	stp	x14, x15, [sp, #16 * 7]
+	stp	x16, x17, [sp, #16 * 8]
+	stp	x18, x19, [sp, #16 * 9]
+	stp	x20, x21, [sp, #16 * 10]
+	stp	x22, x23, [sp, #16 * 11]
+	stp	x24, x25, [sp, #16 * 12]
+	stp	x26, x27, [sp, #16 * 13]
+	stp	x28, x29, [sp, #16 * 14]
+
+	.if	\el == 0
+	clear_gp_regs
+	mrs	x21, sp_el0
+	ldr_this_cpu	tsk, __entry_task, x20
+	msr	sp_el0, tsk
+
+	/*
+	 * Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions
+	 * when scheduling.
+	 */
+	ldr	x19, [tsk, #TSK_TI_FLAGS]
+	disable_step_tsk x19, x20
+
+	/* Check for asynchronous tag check faults in user space */
+	ldr	x0, [tsk, THREAD_SCTLR_USER]
+	check_mte_async_tcf x22, x23, x0
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+alternative_if ARM64_HAS_ADDRESS_AUTH
+	/*
+	 * Enable IA for in-kernel PAC if the task had it disabled. Although
+	 * this could be implemented with an unconditional MRS which would avoid
+	 * a load, this was measured to be slower on Cortex-A75 and Cortex-A76.
+	 *
+	 * Install the kernel IA key only if IA was enabled in the task. If IA
+	 * was disabled on kernel exit then we would have left the kernel IA
+	 * installed so there is no need to install it again.
+	 */
+	tbz	x0, SCTLR_ELx_ENIA_SHIFT, 1f
+	__ptrauth_keys_install_kernel_nosync tsk, x20, x22, x23
+	b	2f
+1:
+	mrs	x0, sctlr_el1
+	orr	x0, x0, SCTLR_ELx_ENIA
+	msr	sctlr_el1, x0
+2:
+alternative_else_nop_endif
+#endif
+
+	apply_ssbd 1, x22, x23
+
+	mte_set_kernel_gcr x22, x23
+
+	/*
+	 * Any non-self-synchronizing system register updates required for
+	 * kernel entry should be placed before this point.
+	 */
+alternative_if ARM64_MTE
+	isb
+	b	1f
+alternative_else_nop_endif
+alternative_if ARM64_HAS_ADDRESS_AUTH
+	isb
+alternative_else_nop_endif
+1:
+
+	scs_load_current
+	.else
+	add	x21, sp, #PT_REGS_SIZE
+	get_current_task tsk
+	.endif /* \el == 0 */
+	mrs	x22, elr_el1
+	mrs	x23, spsr_el1
+	stp	lr, x21, [sp, #S_LR]
+
+	/*
+	 * For exceptions from EL0, create a final frame record.
+	 * For exceptions from EL1, create a synthetic frame record so the
+	 * interrupted code shows up in the backtrace.
+	 */
+	.if \el == 0
+	stp	xzr, xzr, [sp, #S_STACKFRAME]
+	.else
+	stp	x29, x22, [sp, #S_STACKFRAME]
+	.endif
+	add	x29, sp, #S_STACKFRAME
+
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+alternative_if_not ARM64_HAS_PAN
+	bl	__swpan_entry_el\el
+alternative_else_nop_endif
+#endif
+
+	stp	x22, x23, [sp, #S_PC]
+
+	/* Not in a syscall by default (el0_svc overwrites for real syscall) */
+	.if	\el == 0
+	mov	w21, #NO_SYSCALL
+	str	w21, [sp, #S_SYSCALLNO]
+	.endif
+
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+	/* Save pmr */
+alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+	mrs_s	x20, SYS_ICC_PMR_EL1
+	str	x20, [sp, #S_PMR_SAVE]
+	mov	x20, #GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET
+	msr_s	SYS_ICC_PMR_EL1, x20
+alternative_else_nop_endif
+#endif
+
+	/*
+	 * Registers that may be useful after this macro is invoked:
+	 *
+	 * x20 - ICC_PMR_EL1
+	 * x21 - aborted SP
+	 * x22 - aborted PC
+	 * x23 - aborted PSTATE
+	*/
+	.endm
+
+	.macro	kernel_exit, el
+	.if	\el != 0
+	disable_daif
+	.endif
+
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+	/* Restore pmr */
+alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+	ldr	x20, [sp, #S_PMR_SAVE]
+	msr_s	SYS_ICC_PMR_EL1, x20
+	mrs_s	x21, SYS_ICC_CTLR_EL1
+	tbz	x21, #6, .L__skip_pmr_sync\@	// Check for ICC_CTLR_EL1.PMHE
+	dsb	sy				// Ensure priority change is seen by redistributor
+.L__skip_pmr_sync\@:
+alternative_else_nop_endif
+#endif
+
+	ldp	x21, x22, [sp, #S_PC]		// load ELR, SPSR
+
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+alternative_if_not ARM64_HAS_PAN
+	bl	__swpan_exit_el\el
+alternative_else_nop_endif
+#endif
+
+	.if	\el == 0
+	ldr	x23, [sp, #S_SP]		// load return stack pointer
+	msr	sp_el0, x23
+	tst	x22, #PSR_MODE32_BIT		// native task?
+	b.eq	3f
+
+#ifdef CONFIG_ARM64_ERRATUM_845719
+alternative_if ARM64_WORKAROUND_845719
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+	mrs	x29, contextidr_el1
+	msr	contextidr_el1, x29
+#else
+	msr contextidr_el1, xzr
+#endif
+alternative_else_nop_endif
+#endif
+3:
+	scs_save tsk
+
+	/* Ignore asynchronous tag check faults in the uaccess routines */
+	ldr	x0, [tsk, THREAD_SCTLR_USER]
+	clear_mte_async_tcf x0
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+alternative_if ARM64_HAS_ADDRESS_AUTH
+	/*
+	 * IA was enabled for in-kernel PAC. Disable it now if needed, or
+	 * alternatively install the user's IA. All other per-task keys and
+	 * SCTLR bits were updated on task switch.
+	 *
+	 * No kernel C function calls after this.
+	 */
+	tbz	x0, SCTLR_ELx_ENIA_SHIFT, 1f
+	__ptrauth_keys_install_user tsk, x0, x1, x2
+	b	2f
+1:
+	mrs	x0, sctlr_el1
+	bic	x0, x0, SCTLR_ELx_ENIA
+	msr	sctlr_el1, x0
+2:
+alternative_else_nop_endif
+#endif
+
+	mte_set_user_gcr tsk, x0, x1
+
+	apply_ssbd 0, x0, x1
+	.endif
+
+	msr	elr_el1, x21			// set up the return data
+	msr	spsr_el1, x22
+	ldp	x0, x1, [sp, #16 * 0]
+	ldp	x2, x3, [sp, #16 * 1]
+	ldp	x4, x5, [sp, #16 * 2]
+	ldp	x6, x7, [sp, #16 * 3]
+	ldp	x8, x9, [sp, #16 * 4]
+	ldp	x10, x11, [sp, #16 * 5]
+	ldp	x12, x13, [sp, #16 * 6]
+	ldp	x14, x15, [sp, #16 * 7]
+	ldp	x16, x17, [sp, #16 * 8]
+	ldp	x18, x19, [sp, #16 * 9]
+	ldp	x20, x21, [sp, #16 * 10]
+	ldp	x22, x23, [sp, #16 * 11]
+	ldp	x24, x25, [sp, #16 * 12]
+	ldp	x26, x27, [sp, #16 * 13]
+	ldp	x28, x29, [sp, #16 * 14]
+
+	.if	\el == 0
+alternative_if ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
+	tlbi	vale1, xzr
+	dsb	nsh
+alternative_else_nop_endif
+alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
+	ldr	lr, [sp, #S_LR]
+	add	sp, sp, #PT_REGS_SIZE		// restore sp
+	eret
+alternative_else_nop_endif
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+	bne	4f
+	msr	far_el1, x29
+	tramp_alias	x30, tramp_exit_native, x29
+	br	x30
+4:
+	tramp_alias	x30, tramp_exit_compat, x29
+	br	x30
+#endif
+	.else
+	ldr	lr, [sp, #S_LR]
+	add	sp, sp, #PT_REGS_SIZE		// restore sp
+
+	/* Ensure any device/NC reads complete */
+	alternative_insn nop, "dmb sy", ARM64_WORKAROUND_1508412
+
+	eret
+	.endif
+	sb
+	.endm
+
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+	/*
+	 * Set the TTBR0 PAN bit in SPSR. When the exception is taken from
+	 * EL0, there is no need to check the state of TTBR0_EL1 since
+	 * accesses are always enabled.
+	 * Note that the meaning of this bit differs from the ARMv8.1 PAN
+	 * feature as all TTBR0_EL1 accesses are disabled, not just those to
+	 * user mappings.
+	 */
+SYM_CODE_START_LOCAL(__swpan_entry_el1)
+	mrs	x21, ttbr0_el1
+	tst	x21, #TTBR_ASID_MASK		// Check for the reserved ASID
+	orr	x23, x23, #PSR_PAN_BIT		// Set the emulated PAN in the saved SPSR
+	b.eq	1f				// TTBR0 access already disabled
+	and	x23, x23, #~PSR_PAN_BIT		// Clear the emulated PAN in the saved SPSR
+SYM_INNER_LABEL(__swpan_entry_el0, SYM_L_LOCAL)
+	__uaccess_ttbr0_disable x21
+1:	ret
+SYM_CODE_END(__swpan_entry_el1)
+
+	/*
+	 * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR
+	 * PAN bit checking.
+	 */
+SYM_CODE_START_LOCAL(__swpan_exit_el1)
+	tbnz	x22, #22, 1f			// Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set
+	__uaccess_ttbr0_enable x0, x1
+1:	and	x22, x22, #~PSR_PAN_BIT		// ARMv8.0 CPUs do not understand this bit
+	ret
+SYM_CODE_END(__swpan_exit_el1)
+
+SYM_CODE_START_LOCAL(__swpan_exit_el0)
+	__uaccess_ttbr0_enable x0, x1
+	/*
+	 * Enable errata workarounds only if returning to user. The only
+	 * workaround currently required for TTBR0_EL1 changes are for the
+	 * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache
+	 * corruption).
+	 */
+	b	post_ttbr_update_workaround
+SYM_CODE_END(__swpan_exit_el0)
+#endif
+
+/* GPRs used by entry code */
+tsk	.req	x28		// current thread_info
+
+	.text
+
+/*
+ * Exception vectors.
+ */
+	.pushsection ".entry.text", "ax"
+
+	.align	11
+SYM_CODE_START(vectors)
+	kernel_ventry	1, t, 64, sync		// Synchronous EL1t
+	kernel_ventry	1, t, 64, irq		// IRQ EL1t
+	kernel_ventry	1, t, 64, fiq		// FIQ EL1t
+	kernel_ventry	1, t, 64, error		// Error EL1t
+
+	kernel_ventry	1, h, 64, sync		// Synchronous EL1h
+	kernel_ventry	1, h, 64, irq		// IRQ EL1h
+	kernel_ventry	1, h, 64, fiq		// FIQ EL1h
+	kernel_ventry	1, h, 64, error		// Error EL1h
+
+	kernel_ventry	0, t, 64, sync		// Synchronous 64-bit EL0
+	kernel_ventry	0, t, 64, irq		// IRQ 64-bit EL0
+	kernel_ventry	0, t, 64, fiq		// FIQ 64-bit EL0
+	kernel_ventry	0, t, 64, error		// Error 64-bit EL0
+
+	kernel_ventry	0, t, 32, sync		// Synchronous 32-bit EL0
+	kernel_ventry	0, t, 32, irq		// IRQ 32-bit EL0
+	kernel_ventry	0, t, 32, fiq		// FIQ 32-bit EL0
+	kernel_ventry	0, t, 32, error		// Error 32-bit EL0
+SYM_CODE_END(vectors)
+
+#ifdef CONFIG_VMAP_STACK
+SYM_CODE_START_LOCAL(__bad_stack)
+	/*
+	 * We detected an overflow in kernel_ventry, which switched to the
+	 * overflow stack. Stash the exception regs, and head to our overflow
+	 * handler.
+	 */
+
+	/* Restore the original x0 value */
+	mrs	x0, tpidrro_el0
+
+	/*
+	 * Store the original GPRs to the new stack. The orginal SP (minus
+	 * PT_REGS_SIZE) was stashed in tpidr_el0 by kernel_ventry.
+	 */
+	sub	sp, sp, #PT_REGS_SIZE
+	kernel_entry 1
+	mrs	x0, tpidr_el0
+	add	x0, x0, #PT_REGS_SIZE
+	str	x0, [sp, #S_SP]
+
+	/* Stash the regs for handle_bad_stack */
+	mov	x0, sp
+
+	/* Time to die */
+	bl	handle_bad_stack
+	ASM_BUG()
+SYM_CODE_END(__bad_stack)
+#endif /* CONFIG_VMAP_STACK */
+
+
+	.macro entry_handler el:req, ht:req, regsize:req, label:req
+SYM_CODE_START_LOCAL(el\el\ht\()_\regsize\()_\label)
+	kernel_entry \el, \regsize
+	mov	x0, sp
+	bl	el\el\ht\()_\regsize\()_\label\()_handler
+	.if \el == 0
+	b	ret_to_user
+	.else
+	b	ret_to_kernel
+	.endif
+SYM_CODE_END(el\el\ht\()_\regsize\()_\label)
+	.endm
+
+/*
+ * Early exception handlers
+ */
+	entry_handler	1, t, 64, sync
+	entry_handler	1, t, 64, irq
+	entry_handler	1, t, 64, fiq
+	entry_handler	1, t, 64, error
+
+	entry_handler	1, h, 64, sync
+	entry_handler	1, h, 64, irq
+	entry_handler	1, h, 64, fiq
+	entry_handler	1, h, 64, error
+
+	entry_handler	0, t, 64, sync
+	entry_handler	0, t, 64, irq
+	entry_handler	0, t, 64, fiq
+	entry_handler	0, t, 64, error
+
+	entry_handler	0, t, 32, sync
+	entry_handler	0, t, 32, irq
+	entry_handler	0, t, 32, fiq
+	entry_handler	0, t, 32, error
+
+SYM_CODE_START_LOCAL(ret_to_kernel)
+	kernel_exit 1
+SYM_CODE_END(ret_to_kernel)
+
+SYM_CODE_START_LOCAL(ret_to_user)
+	ldr	x19, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
+	enable_step_tsk x19, x2
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+	bl	stackleak_erase_on_task_stack
+#endif
+	kernel_exit 0
+SYM_CODE_END(ret_to_user)
+
+	.popsection				// .entry.text
+
+	// Move from tramp_pg_dir to swapper_pg_dir
+	.macro tramp_map_kernel, tmp
+	mrs	\tmp, ttbr1_el1
+	add	\tmp, \tmp, #TRAMP_SWAPPER_OFFSET
+	bic	\tmp, \tmp, #USER_ASID_FLAG
+	msr	ttbr1_el1, \tmp
+#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
+alternative_if ARM64_WORKAROUND_QCOM_FALKOR_E1003
+	/* ASID already in \tmp[63:48] */
+	movk	\tmp, #:abs_g2_nc:(TRAMP_VALIAS >> 12)
+	movk	\tmp, #:abs_g1_nc:(TRAMP_VALIAS >> 12)
+	/* 2MB boundary containing the vectors, so we nobble the walk cache */
+	movk	\tmp, #:abs_g0_nc:((TRAMP_VALIAS & ~(SZ_2M - 1)) >> 12)
+	isb
+	tlbi	vae1, \tmp
+	dsb	nsh
+alternative_else_nop_endif
+#endif /* CONFIG_QCOM_FALKOR_ERRATUM_1003 */
+	.endm
+
+	// Move from swapper_pg_dir to tramp_pg_dir
+	.macro tramp_unmap_kernel, tmp
+	mrs	\tmp, ttbr1_el1
+	sub	\tmp, \tmp, #TRAMP_SWAPPER_OFFSET
+	orr	\tmp, \tmp, #USER_ASID_FLAG
+	msr	ttbr1_el1, \tmp
+	/*
+	 * We avoid running the post_ttbr_update_workaround here because
+	 * it's only needed by Cavium ThunderX, which requires KPTI to be
+	 * disabled.
+	 */
+	.endm
+
+	.macro		tramp_data_read_var	dst, var
+#ifdef CONFIG_RELOCATABLE
+	ldr		\dst, .L__tramp_data_\var
+	.ifndef		.L__tramp_data_\var
+	.pushsection	".entry.tramp.rodata", "a", %progbits
+	.align		3
+.L__tramp_data_\var:
+	.quad		\var
+	.popsection
+	.endif
+#else
+	/*
+	 * As !RELOCATABLE implies !RANDOMIZE_BASE the address is always a
+	 * compile time constant (and hence not secret and not worth hiding).
+	 *
+	 * As statically allocated kernel code and data always live in the top
+	 * 47 bits of the address space we can sign-extend bit 47 and avoid an
+	 * instruction to load the upper 16 bits (which must be 0xFFFF).
+	 */
+	movz		\dst, :abs_g2_s:\var
+	movk		\dst, :abs_g1_nc:\var
+	movk		\dst, :abs_g0_nc:\var
+#endif
+	.endm
+
+#define BHB_MITIGATION_NONE	0
+#define BHB_MITIGATION_LOOP	1
+#define BHB_MITIGATION_FW	2
+#define BHB_MITIGATION_INSN	3
+
+	.macro tramp_ventry, vector_start, regsize, kpti, bhb
+	.align	7
+1:
+	.if	\regsize == 64
+	msr	tpidrro_el0, x30	// Restored in kernel_ventry
+	.endif
+
+	.if	\bhb == BHB_MITIGATION_LOOP
+	/*
+	 * This sequence must appear before the first indirect branch. i.e. the
+	 * ret out of tramp_ventry. It appears here because x30 is free.
+	 */
+	__mitigate_spectre_bhb_loop	x30
+	.endif // \bhb == BHB_MITIGATION_LOOP
+
+	.if	\bhb == BHB_MITIGATION_INSN
+	clearbhb
+	isb
+	.endif // \bhb == BHB_MITIGATION_INSN
+
+	.if	\kpti == 1
+	/*
+	 * Defend against branch aliasing attacks by pushing a dummy
+	 * entry onto the return stack and using a RET instruction to
+	 * enter the full-fat kernel vectors.
+	 */
+	bl	2f
+	b	.
+2:
+	tramp_map_kernel	x30
+alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003
+	tramp_data_read_var	x30, vectors
+alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM
+	prfm	plil1strm, [x30, #(1b - \vector_start)]
+alternative_else_nop_endif
+
+	msr	vbar_el1, x30
+	isb
+	.else
+	adr_l	x30, vectors
+	.endif // \kpti == 1
+
+	.if	\bhb == BHB_MITIGATION_FW
+	/*
+	 * The firmware sequence must appear before the first indirect branch.
+	 * i.e. the ret out of tramp_ventry. But it also needs the stack to be
+	 * mapped to save/restore the registers the SMC clobbers.
+	 */
+	__mitigate_spectre_bhb_fw
+	.endif // \bhb == BHB_MITIGATION_FW
+
+	add	x30, x30, #(1b - \vector_start + 4)
+	ret
+.org 1b + 128	// Did we overflow the ventry slot?
+	.endm
+
+	.macro tramp_exit, regsize = 64
+	tramp_data_read_var	x30, this_cpu_vector
+	get_this_cpu_offset x29
+	ldr	x30, [x30, x29]
+
+	msr	vbar_el1, x30
+	ldr	lr, [sp, #S_LR]
+	tramp_unmap_kernel	x29
+	.if	\regsize == 64
+	mrs	x29, far_el1
+	.endif
+	add	sp, sp, #PT_REGS_SIZE		// restore sp
+	eret
+	sb
+	.endm
+
+	.macro	generate_tramp_vector,	kpti, bhb
+.Lvector_start\@:
+	.space	0x400
+
+	.rept	4
+	tramp_ventry	.Lvector_start\@, 64, \kpti, \bhb
+	.endr
+	.rept	4
+	tramp_ventry	.Lvector_start\@, 32, \kpti, \bhb
+	.endr
+	.endm
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+/*
+ * Exception vectors trampoline.
+ * The order must match __bp_harden_el1_vectors and the
+ * arm64_bp_harden_el1_vectors enum.
+ */
+	.pushsection ".entry.tramp.text", "ax"
+	.align	11
+SYM_CODE_START_NOALIGN(tramp_vectors)
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+	generate_tramp_vector	kpti=1, bhb=BHB_MITIGATION_LOOP
+	generate_tramp_vector	kpti=1, bhb=BHB_MITIGATION_FW
+	generate_tramp_vector	kpti=1, bhb=BHB_MITIGATION_INSN
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+	generate_tramp_vector	kpti=1, bhb=BHB_MITIGATION_NONE
+SYM_CODE_END(tramp_vectors)
+
+SYM_CODE_START(tramp_exit_native)
+	tramp_exit
+SYM_CODE_END(tramp_exit_native)
+
+SYM_CODE_START(tramp_exit_compat)
+	tramp_exit	32
+SYM_CODE_END(tramp_exit_compat)
+	.popsection				// .entry.tramp.text
+#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
+
+/*
+ * Exception vectors for spectre mitigations on entry from EL1 when
+ * kpti is not in use.
+ */
+	.macro generate_el1_vector, bhb
+.Lvector_start\@:
+	kernel_ventry	1, t, 64, sync		// Synchronous EL1t
+	kernel_ventry	1, t, 64, irq		// IRQ EL1t
+	kernel_ventry	1, t, 64, fiq		// FIQ EL1h
+	kernel_ventry	1, t, 64, error		// Error EL1t
+
+	kernel_ventry	1, h, 64, sync		// Synchronous EL1h
+	kernel_ventry	1, h, 64, irq		// IRQ EL1h
+	kernel_ventry	1, h, 64, fiq		// FIQ EL1h
+	kernel_ventry	1, h, 64, error		// Error EL1h
+
+	.rept	4
+	tramp_ventry	.Lvector_start\@, 64, 0, \bhb
+	.endr
+	.rept 4
+	tramp_ventry	.Lvector_start\@, 32, 0, \bhb
+	.endr
+	.endm
+
+/* The order must match tramp_vecs and the arm64_bp_harden_el1_vectors enum. */
+	.pushsection ".entry.text", "ax"
+	.align	11
+SYM_CODE_START(__bp_harden_el1_vectors)
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+	generate_el1_vector	bhb=BHB_MITIGATION_LOOP
+	generate_el1_vector	bhb=BHB_MITIGATION_FW
+	generate_el1_vector	bhb=BHB_MITIGATION_INSN
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+SYM_CODE_END(__bp_harden_el1_vectors)
+	.popsection
+
+
+/*
+ * Register switch for AArch64. The callee-saved registers need to be saved
+ * and restored. On entry:
+ *   x0 = previous task_struct (must be preserved across the switch)
+ *   x1 = next task_struct
+ * Previous and next are guaranteed not to be the same.
+ *
+ */
+SYM_FUNC_START(cpu_switch_to)
+	mov	x10, #THREAD_CPU_CONTEXT
+	add	x8, x0, x10
+	mov	x9, sp
+	stp	x19, x20, [x8], #16		// store callee-saved registers
+	stp	x21, x22, [x8], #16
+	stp	x23, x24, [x8], #16
+	stp	x25, x26, [x8], #16
+	stp	x27, x28, [x8], #16
+	stp	x29, x9, [x8], #16
+	str	lr, [x8]
+	add	x8, x1, x10
+	ldp	x19, x20, [x8], #16		// restore callee-saved registers
+	ldp	x21, x22, [x8], #16
+	ldp	x23, x24, [x8], #16
+	ldp	x25, x26, [x8], #16
+	ldp	x27, x28, [x8], #16
+	ldp	x29, x9, [x8], #16
+	ldr	lr, [x8]
+	mov	sp, x9
+	msr	sp_el0, x1
+	ptrauth_keys_install_kernel x1, x8, x9, x10
+	scs_save x0
+	scs_load_current
+	ret
+SYM_FUNC_END(cpu_switch_to)
+NOKPROBE(cpu_switch_to)
+
+/*
+ * This is how we return from a fork.
+ */
+SYM_CODE_START(ret_from_fork)
+	bl	schedule_tail
+	cbz	x19, 1f				// not a kernel thread
+	mov	x0, x20
+	blr	x19
+1:	get_current_task tsk
+	mov	x0, sp
+	bl	asm_exit_to_user_mode
+	b	ret_to_user
+SYM_CODE_END(ret_from_fork)
+NOKPROBE(ret_from_fork)
+
+/*
+ * void call_on_irq_stack(struct pt_regs *regs,
+ * 		          void (*func)(struct pt_regs *));
+ *
+ * Calls func(regs) using this CPU's irq stack and shadow irq stack.
+ */
+SYM_FUNC_START(call_on_irq_stack)
+#ifdef CONFIG_SHADOW_CALL_STACK
+	get_current_task x16
+	scs_save x16
+	ldr_this_cpu scs_sp, irq_shadow_call_stack_ptr, x17
+#endif
+
+	/* Create a frame record to save our LR and SP (implicit in FP) */
+	stp	x29, x30, [sp, #-16]!
+	mov	x29, sp
+
+	ldr_this_cpu x16, irq_stack_ptr, x17
+
+	/* Move to the new stack and call the function there */
+	add	sp, x16, #IRQ_STACK_SIZE
+	blr	x1
+
+	/*
+	 * Restore the SP from the FP, and restore the FP and LR from the frame
+	 * record.
+	 */
+	mov	sp, x29
+	ldp	x29, x30, [sp], #16
+	scs_load_current
+	ret
+SYM_FUNC_END(call_on_irq_stack)
+NOKPROBE(call_on_irq_stack)
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+
+#include <asm/sdei.h>
+#include <uapi/linux/arm_sdei.h>
+
+.macro sdei_handler_exit exit_mode
+	/* On success, this call never returns... */
+	cmp	\exit_mode, #SDEI_EXIT_SMC
+	b.ne	99f
+	smc	#0
+	b	.
+99:	hvc	#0
+	b	.
+.endm
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+/*
+ * The regular SDEI entry point may have been unmapped along with the rest of
+ * the kernel. This trampoline restores the kernel mapping to make the x1 memory
+ * argument accessible.
+ *
+ * This clobbers x4, __sdei_handler() will restore this from firmware's
+ * copy.
+ */
+.pushsection ".entry.tramp.text", "ax"
+SYM_CODE_START(__sdei_asm_entry_trampoline)
+	mrs	x4, ttbr1_el1
+	tbz	x4, #USER_ASID_BIT, 1f
+
+	tramp_map_kernel tmp=x4
+	isb
+	mov	x4, xzr
+
+	/*
+	 * Remember whether to unmap the kernel on exit.
+	 */
+1:	str	x4, [x1, #(SDEI_EVENT_INTREGS + S_SDEI_TTBR1)]
+	tramp_data_read_var     x4, __sdei_asm_handler
+	br	x4
+SYM_CODE_END(__sdei_asm_entry_trampoline)
+NOKPROBE(__sdei_asm_entry_trampoline)
+
+/*
+ * Make the exit call and restore the original ttbr1_el1
+ *
+ * x0 & x1: setup for the exit API call
+ * x2: exit_mode
+ * x4: struct sdei_registered_event argument from registration time.
+ */
+SYM_CODE_START(__sdei_asm_exit_trampoline)
+	ldr	x4, [x4, #(SDEI_EVENT_INTREGS + S_SDEI_TTBR1)]
+	cbnz	x4, 1f
+
+	tramp_unmap_kernel	tmp=x4
+
+1:	sdei_handler_exit exit_mode=x2
+SYM_CODE_END(__sdei_asm_exit_trampoline)
+NOKPROBE(__sdei_asm_exit_trampoline)
+.popsection		// .entry.tramp.text
+#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
+
+/*
+ * Software Delegated Exception entry point.
+ *
+ * x0: Event number
+ * x1: struct sdei_registered_event argument from registration time.
+ * x2: interrupted PC
+ * x3: interrupted PSTATE
+ * x4: maybe clobbered by the trampoline
+ *
+ * Firmware has preserved x0->x17 for us, we must save/restore the rest to
+ * follow SMC-CC. We save (or retrieve) all the registers as the handler may
+ * want them.
+ */
+SYM_CODE_START(__sdei_asm_handler)
+	stp     x2, x3, [x1, #SDEI_EVENT_INTREGS + S_PC]
+	stp     x4, x5, [x1, #SDEI_EVENT_INTREGS + 16 * 2]
+	stp     x6, x7, [x1, #SDEI_EVENT_INTREGS + 16 * 3]
+	stp     x8, x9, [x1, #SDEI_EVENT_INTREGS + 16 * 4]
+	stp     x10, x11, [x1, #SDEI_EVENT_INTREGS + 16 * 5]
+	stp     x12, x13, [x1, #SDEI_EVENT_INTREGS + 16 * 6]
+	stp     x14, x15, [x1, #SDEI_EVENT_INTREGS + 16 * 7]
+	stp     x16, x17, [x1, #SDEI_EVENT_INTREGS + 16 * 8]
+	stp     x18, x19, [x1, #SDEI_EVENT_INTREGS + 16 * 9]
+	stp     x20, x21, [x1, #SDEI_EVENT_INTREGS + 16 * 10]
+	stp     x22, x23, [x1, #SDEI_EVENT_INTREGS + 16 * 11]
+	stp     x24, x25, [x1, #SDEI_EVENT_INTREGS + 16 * 12]
+	stp     x26, x27, [x1, #SDEI_EVENT_INTREGS + 16 * 13]
+	stp     x28, x29, [x1, #SDEI_EVENT_INTREGS + 16 * 14]
+	mov	x4, sp
+	stp     lr, x4, [x1, #SDEI_EVENT_INTREGS + S_LR]
+
+	mov	x19, x1
+
+	/* Store the registered-event for crash_smp_send_stop() */
+	ldrb	w4, [x19, #SDEI_EVENT_PRIORITY]
+	cbnz	w4, 1f
+	adr_this_cpu dst=x5, sym=sdei_active_normal_event, tmp=x6
+	b	2f
+1:	adr_this_cpu dst=x5, sym=sdei_active_critical_event, tmp=x6
+2:	str	x19, [x5]
+
+#ifdef CONFIG_VMAP_STACK
+	/*
+	 * entry.S may have been using sp as a scratch register, find whether
+	 * this is a normal or critical event and switch to the appropriate
+	 * stack for this CPU.
+	 */
+	cbnz	w4, 1f
+	ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6
+	b	2f
+1:	ldr_this_cpu dst=x5, sym=sdei_stack_critical_ptr, tmp=x6
+2:	mov	x6, #SDEI_STACK_SIZE
+	add	x5, x5, x6
+	mov	sp, x5
+#endif
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+	/* Use a separate shadow call stack for normal and critical events */
+	cbnz	w4, 3f
+	ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal_ptr, tmp=x6
+	b	4f
+3:	ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical_ptr, tmp=x6
+4:
+#endif
+
+	/*
+	 * We may have interrupted userspace, or a guest, or exit-from or
+	 * return-to either of these. We can't trust sp_el0, restore it.
+	 */
+	mrs	x28, sp_el0
+	ldr_this_cpu	dst=x0, sym=__entry_task, tmp=x1
+	msr	sp_el0, x0
+
+	/* If we interrupted the kernel point to the previous stack/frame. */
+	and     x0, x3, #0xc
+	mrs     x1, CurrentEL
+	cmp     x0, x1
+	csel	x29, x29, xzr, eq	// fp, or zero
+	csel	x4, x2, xzr, eq		// elr, or zero
+
+	stp	x29, x4, [sp, #-16]!
+	mov	x29, sp
+
+	add	x0, x19, #SDEI_EVENT_INTREGS
+	mov	x1, x19
+	bl	__sdei_handler
+
+	msr	sp_el0, x28
+	/* restore regs >x17 that we clobbered */
+	mov	x4, x19         // keep x4 for __sdei_asm_exit_trampoline
+	ldp	x28, x29, [x4, #SDEI_EVENT_INTREGS + 16 * 14]
+	ldp	x18, x19, [x4, #SDEI_EVENT_INTREGS + 16 * 9]
+	ldp	lr, x1, [x4, #SDEI_EVENT_INTREGS + S_LR]
+	mov	sp, x1
+
+	mov	x1, x0			// address to complete_and_resume
+	/* x0 = (x0 <= SDEI_EV_FAILED) ?
+	 * EVENT_COMPLETE:EVENT_COMPLETE_AND_RESUME
+	 */
+	cmp	x0, #SDEI_EV_FAILED
+	mov_q	x2, SDEI_1_0_FN_SDEI_EVENT_COMPLETE
+	mov_q	x3, SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME
+	csel	x0, x2, x3, ls
+
+	ldr_l	x2, sdei_exit_mode
+
+	/* Clear the registered-event seen by crash_smp_send_stop() */
+	ldrb	w3, [x4, #SDEI_EVENT_PRIORITY]
+	cbnz	w3, 1f
+	adr_this_cpu dst=x5, sym=sdei_active_normal_event, tmp=x6
+	b	2f
+1:	adr_this_cpu dst=x5, sym=sdei_active_critical_event, tmp=x6
+2:	str	xzr, [x5]
+
+alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
+	sdei_handler_exit exit_mode=x2
+alternative_else_nop_endif
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+	tramp_alias	dst=x5, sym=__sdei_asm_exit_trampoline, tmp=x3
+	br	x5
+#endif
+SYM_CODE_END(__sdei_asm_handler)
+NOKPROBE(__sdei_asm_handler)
+
+SYM_CODE_START(__sdei_handler_abort)
+	mov_q	x0, SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME
+	adr	x1, 1f
+	ldr_l	x2, sdei_exit_mode
+	sdei_handler_exit exit_mode=x2
+	// exit the handler and jump to the next instruction.
+	// Exit will stomp x0-x17, PSTATE, ELR_ELx, and SPSR_ELx.
+1:	ret
+SYM_CODE_END(__sdei_handler_abort)
+NOKPROBE(__sdei_handler_abort)
+#endif /* CONFIG_ARM_SDE_INTERFACE */