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      1 /* $NetBSD: efi_machdep.c,v 1.14 2023/07/10 07:00:11 rin Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2018 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jared McNeill <jmcneill (at) invisible.ca>.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: efi_machdep.c,v 1.14 2023/07/10 07:00:11 rin Exp $");
     34 
     35 #include <sys/param.h>
     36 
     37 #include <uvm/uvm_extern.h>
     38 
     39 #include <arm/cpufunc.h>
     40 #include <arm/efirt.h>
     41 
     42 #include <arm/arm/efi_runtime.h>
     43 
     44 #include <aarch64/machdep.h>
     45 
     46 static struct {
     47 	struct faultbuf	faultbuf;
     48 	bool		fpu_used;
     49 } arm_efirt_state;
     50 
     51 static bool efi_userva = true;
     52 
     53 void
     54 cpu_efirt_map_range(vaddr_t va, paddr_t pa, size_t sz,
     55     enum cpu_efirt_mem_type type)
     56 {
     57 	int flags = 0;
     58 	int prot = 0;
     59 
     60 	switch (type) {
     61 	case ARM_EFIRT_MEM_CODE:
     62 		/* need write permission because fw devs */
     63 		prot = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
     64 		break;
     65 	case ARM_EFIRT_MEM_DATA:
     66 		prot = VM_PROT_READ | VM_PROT_WRITE;
     67 		break;
     68 	case ARM_EFIRT_MEM_MMIO:
     69 		prot = VM_PROT_READ | VM_PROT_WRITE;
     70 		flags = PMAP_DEV;
     71 		break;
     72 	default:
     73 		panic("%s: unsupported type %d", __func__, type);
     74 	}
     75 
     76 	/* even if TBI is disabled, AARCH64_ADDRTOP_TAG means KVA */
     77 	bool kva = (va & AARCH64_ADDRTOP_TAG) != 0;
     78 	if (kva) {
     79 		if (va < EFI_RUNTIME_VA ||
     80 		    va >= EFI_RUNTIME_VA + EFI_RUNTIME_SIZE) {
     81 			printf("Incorrect EFI mapping address %" PRIxVADDR "\n", va);
     82 		    return;
     83 		}
     84 		efi_userva = false;
     85 	} else {
     86 		if (!efi_userva) {
     87 			printf("Can't mix EFI RT address spaces\n");
     88 			return;
     89 		}
     90 	}
     91 
     92 	while (sz != 0) {
     93 		if (kva) {
     94 			pmap_kenter_pa(va, pa, prot, flags);
     95 		} else {
     96 			pmap_enter(pmap_efirt(), va, pa, prot, flags | PMAP_WIRED);
     97 		}
     98 		va += PAGE_SIZE;
     99 		pa += PAGE_SIZE;
    100 		sz -= PAGE_SIZE;
    101 	}
    102 	if (kva)
    103 		pmap_update(pmap_kernel());
    104 	else
    105 		pmap_update(pmap_efirt());
    106 }
    107 
    108 int
    109 arm_efirt_md_enter(void)
    110 {
    111 	kpreempt_disable();
    112 
    113 	struct lwp * const l = curlwp;
    114 
    115 	/* Save FPU state */
    116 	arm_efirt_state.fpu_used = fpu_used_p(l) != 0;
    117 	if (arm_efirt_state.fpu_used)
    118 		fpu_save(l);
    119 
    120 	/* Enable FP access (AArch64 UEFI calling convention) */
    121 	reg_cpacr_el1_write(CPACR_FPEN_ALL);
    122 	isb();
    123 
    124 	/*
    125 	 * Install custom fault handler. EFI lock is held across calls so
    126 	 * shared faultbuf is safe here.
    127 	 */
    128 	int err = cpu_set_onfault(&arm_efirt_state.faultbuf);
    129 	if (err)
    130 		return err;
    131 
    132 	if (efi_userva) {
    133 		if ((l->l_flag & LW_SYSTEM) == 0) {
    134 			pmap_deactivate(l);
    135 		}
    136 		pmap_activate_efirt();
    137 	}
    138 
    139 	return 0;
    140 }
    141 
    142 void
    143 arm_efirt_md_exit(void)
    144 {
    145 	struct lwp * const l = curlwp;
    146 
    147 	if (efi_userva) {
    148 		pmap_deactivate_efirt();
    149 		if ((l->l_flag & LW_SYSTEM) == 0) {
    150 			pmap_activate(l);
    151 		}
    152 	}
    153 
    154 	/* Disable FP access */
    155 	reg_cpacr_el1_write(CPACR_FPEN_NONE);
    156 	isb();
    157 
    158 	/* Restore FPU state */
    159 	if (arm_efirt_state.fpu_used)
    160 		fpu_load(l);
    161 
    162 	/* Remove custom fault handler */
    163 	cpu_unset_onfault();
    164 
    165 	kpreempt_enable();
    166 }
    167