1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (c) 2012 Linaro Limited.
4 */
5
6#include <linux/init.h>
7#include <linux/irqchip/arm-gic-v3.h>
8#include <linux/linkage.h>
9#include <asm/assembler.h>
10#include <asm/virt.h>
11
12.arch armv7-a
13
14#ifndef ZIMAGE
15/*
16 * For the kernel proper, we need to find out the CPU boot mode long after
17 * boot, so we need to store it in a writable variable.
18 *
19 * This is not in .bss, because we set it sufficiently early that the boot-time
20 * zeroing of .bss would clobber it.
21 */
22.data
23 .align 2
24ENTRY(__boot_cpu_mode)
25 .long 0
26.text
27
28 /*
29 * Save the primary CPU boot mode. Requires 2 scratch registers.
30 */
31 .macro store_primary_cpu_mode reg1, reg2
32 mrs \reg1, cpsr
33 and \reg1, \reg1, #MODE_MASK
34 str_l \reg1, __boot_cpu_mode, \reg2
35 .endm
36
37 /*
38 * Compare the current mode with the one saved on the primary CPU.
39 * If they don't match, record that fact. The Z bit indicates
40 * if there's a match or not.
41 * Requires 2 additional scratch registers.
42 */
43 .macro compare_cpu_mode_with_primary mode, reg1, reg2
44 adr_l \reg2, __boot_cpu_mode
45 ldr \reg1, [\reg2]
46 cmp \mode, \reg1 @ matches primary CPU boot mode?
47 orrne \reg1, \reg1, #BOOT_CPU_MODE_MISMATCH
48 strne \reg1, [\reg2] @ record what happened and give up
49 .endm
50
51#else /* ZIMAGE */
52
53 .macro store_primary_cpu_mode reg1:req, reg2:req
54 .endm
55
56/*
57 * The zImage loader only runs on one CPU, so we don't bother with mult-CPU
58 * consistency checking:
59 */
60 .macro compare_cpu_mode_with_primary mode, reg1, reg2
61 cmp \mode, \mode
62 .endm
63
64#endif /* ZIMAGE */
65
66/*
67 * Hypervisor stub installation functions.
68 *
69 * These must be called with the MMU and D-cache off.
70 * They are not ABI compliant and are only intended to be called from the kernel
71 * entry points in head.S.
72 */
73@ Call this from the primary CPU
74ENTRY(__hyp_stub_install)
75 store_primary_cpu_mode r4, r5
76ENDPROC(__hyp_stub_install)
77
78 @ fall through...
79
80@ Secondary CPUs should call here
81ENTRY(__hyp_stub_install_secondary)
82 mrs r4, cpsr
83 and r4, r4, #MODE_MASK
84
85 /*
86 * If the secondary has booted with a different mode, give up
87 * immediately.
88 */
89 compare_cpu_mode_with_primary r4, r5, r6
90 retne lr
91
92 /*
93 * Once we have given up on one CPU, we do not try to install the
94 * stub hypervisor on the remaining ones: because the saved boot mode
95 * is modified, it can't compare equal to the CPSR mode field any
96 * more.
97 *
98 * Otherwise...
99 */
100
101 cmp r4, #HYP_MODE
102 retne lr @ give up if the CPU is not in HYP mode
103
104/*
105 * Configure HSCTLR to set correct exception endianness/instruction set
106 * state etc.
107 * Turn off all traps
108 * Eventually, CPU-specific code might be needed -- assume not for now
109 *
110 * This code relies on the "eret" instruction to synchronize the
111 * various coprocessor accesses. This is done when we switch to SVC
112 * (see safe_svcmode_maskall).
113 */
114 @ Now install the hypervisor stub:
115 W(adr) r7, __hyp_stub_vectors
116 mcr p15, 4, r7, c12, c0, 0 @ set hypervisor vector base (HVBAR)
117
118 @ Disable all traps, so we don't get any nasty surprise
119 mov r7, #0
120 mcr p15, 4, r7, c1, c1, 0 @ HCR
121 mcr p15, 4, r7, c1, c1, 2 @ HCPTR
122 mcr p15, 4, r7, c1, c1, 3 @ HSTR
123
124THUMB( orr r7, #(1 << 30) ) @ HSCTLR.TE
125ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
126 mcr p15, 4, r7, c1, c0, 0 @ HSCTLR
127
128 mrc p15, 4, r7, c1, c1, 1 @ HDCR
129 and r7, #0x1f @ Preserve HPMN
130 mcr p15, 4, r7, c1, c1, 1 @ HDCR
131
132 @ Make sure NS-SVC is initialised appropriately
133 mrc p15, 0, r7, c1, c0, 0 @ SCTLR
134 orr r7, #(1 << 5) @ CP15 barriers enabled
135 bic r7, #(3 << 7) @ Clear SED/ITD for v8 (RES0 for v7)
136 bic r7, #(3 << 19) @ WXN and UWXN disabled
137 mcr p15, 0, r7, c1, c0, 0 @ SCTLR
138
139 mrc p15, 0, r7, c0, c0, 0 @ MIDR
140 mcr p15, 4, r7, c0, c0, 0 @ VPIDR
141
142 mrc p15, 0, r7, c0, c0, 5 @ MPIDR
143 mcr p15, 4, r7, c0, c0, 5 @ VMPIDR
144
145#if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
146 @ make CNTP_* and CNTPCT accessible from PL1
147 mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
148 ubfx r7, r7, #16, #4
149 teq r7, #0
150 beq 1f
151 mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL
152 orr r7, r7, #3 @ PL1PCEN | PL1PCTEN
153 mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
154 mov r7, #0
155 mcrr p15, 4, r7, r7, c14 @ CNTVOFF
156
157 @ Disable virtual timer in case it was counting
158 mrc p15, 0, r7, c14, c3, 1 @ CNTV_CTL
159 bic r7, #1 @ Clear ENABLE
160 mcr p15, 0, r7, c14, c3, 1 @ CNTV_CTL
1611:
162#endif
163
164#ifdef CONFIG_ARM_GIC_V3
165 @ Check whether GICv3 system registers are available
166 mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
167 ubfx r7, r7, #28, #4
168 teq r7, #0
169 beq 2f
170
171 @ Enable system register accesses
172 mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
173 orr r7, r7, #(ICC_SRE_EL2_ENABLE | ICC_SRE_EL2_SRE)
174 mcr p15, 4, r7, c12, c9, 5 @ ICC_HSRE
175 isb
176
177 @ SRE bit could be forced to 0 by firmware.
178 @ Check whether it sticks before accessing any other sysreg
179 mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
180 tst r7, #ICC_SRE_EL2_SRE
181 beq 2f
182 mov r7, #0
183 mcr p15, 4, r7, c12, c11, 0 @ ICH_HCR
1842:
185#endif
186
187 bx lr @ The boot CPU mode is left in r4.
188ENDPROC(__hyp_stub_install_secondary)
189
190__hyp_stub_do_trap:
191#ifdef ZIMAGE
192 teq r0, #HVC_SET_VECTORS
193 bne 1f
194 /* Only the ZIMAGE stubs can change the HYP vectors */
195 mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
196 b __hyp_stub_exit
197#endif
198
1991: teq r0, #HVC_SOFT_RESTART
200 bne 2f
201 bx r1
202
2032: ldr r0, =HVC_STUB_ERR
204 __ERET
205
206__hyp_stub_exit:
207 mov r0, #0
208 __ERET
209ENDPROC(__hyp_stub_do_trap)
210
211/*
212 * __hyp_set_vectors is only used when ZIMAGE must bounce between HYP
213 * and SVC. For the kernel itself, the vectors are set once and for
214 * all by the stubs.
215 */
216ENTRY(__hyp_set_vectors)
217 mov r1, r0
218 mov r0, #HVC_SET_VECTORS
219 __HVC(0)
220 ret lr
221ENDPROC(__hyp_set_vectors)
222
223ENTRY(__hyp_soft_restart)
224 mov r1, r0
225 mov r0, #HVC_SOFT_RESTART
226 __HVC(0)
227 ret lr
228ENDPROC(__hyp_soft_restart)
229
230.align 5
231ENTRY(__hyp_stub_vectors)
232__hyp_stub_reset: W(b) .
233__hyp_stub_und: W(b) .
234__hyp_stub_svc: W(b) .
235__hyp_stub_pabort: W(b) .
236__hyp_stub_dabort: W(b) .
237__hyp_stub_trap: W(b) __hyp_stub_do_trap
238__hyp_stub_irq: W(b) .
239__hyp_stub_fiq: W(b) .
240ENDPROC(__hyp_stub_vectors)
241
242

source code of linux/arch/arm/kernel/hyp-stub.S