arm64/kernel/head.S

1 /* SPDX-License-Identifier: GPL-2.0-only */
3  * Low-level CPU initialisation
6  * Copyright (C) 1994-2002 Russell King
7  * Copyright (C) 2003-2012 ARM Ltd.
21 #include <asm/asm-offsets.h>
27 #include <asm/kernel-pgtable.h>
30 #include <asm/pgtable-hwdef.h>
38 #include "efi-header.S"
46  * ---------------------------
49  *   MMU = off, D-cache = off, I-cache = on or off,
52  * Note that the callee-saved registers are used for storing variables
58 	 * DO NOT MODIFY. Image header expected by Linux boot-loaders.
62 	.quad	0				// Image load offset from start of RAM, little-endian
63 	le64sym	_kernel_size_le			// Effective size of kernel image, little-endian
64 	le64sym	_kernel_flags_le		// Informative flags, little-endian
65 	.quad	0				// reserved
66 	.quad	0				// reserved
67 	.quad	0				// reserved
81 	 *  x20        primary_entry() .. __primary_switch()    CPU boot mode
96 	 * If the page tables have been populated with non-cacheable
123 	 * The following calls CPU setup code, see arch/arm64/mm/proc.S for
125 	 * On return, the CPU will be ready for the MMU to be turned on and
187 	 * Initialize CPU registers with task-specific and cpu-specific context.
189 	 * Create a final frame record at task_pt_regs(current)->stackframe, so
221 	adr_l	x8, vectors			// load VBAR_EL1 with virtual
225 	stp	x29, x30, [sp, #-16]!
254  * Starting from EL2 or EL1, configure the CPU to execute at the highest
301 	 * Compliant CPUs advertise their VHE-onlyness with
310 	tbz	x1, #(ID_AA64MMFR4_EL1_E2H0_SHIFT + ID_AA64MMFR4_EL1_E2H0_WIDTH - 1), 1f
403 	adr_l	x5, vectors
428  * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
436 1:	str	w0, [x1]			// Save CPU boot mode
441  * The booting CPU updates the failed status @__early_cpu_boot_status,
445  *  - Corrupts tmp1, tmp2
446  *  - Writes 'status' to __early_cpu_boot_status and makes sure
468  * Checks if the selected granule size is supported by the CPU.
469  * If it isn't, park the CPU
512 	/* Indicate that this CPU can't boot and is stuck in the kernel */