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* code for switching cores into non-secure state and into HYP mode
* Copyright (c) 2013 Andre Przywara <>
* SPDX-License-Identifier: GPL-2.0+
#include <config.h>
#include <linux/linkage.h>
#include <asm/gic.h>
#include <asm/armv7.h>
.arch_extension sec
.arch_extension virt
.align 5
/* the vector table for secure state and HYP mode */
.word 0 /* reset */
.word 0 /* undef */
adr pc, _secure_monitor
.word 0
.word 0
adr pc, _hyp_trap
.word 0
.word 0
* secure monitor handler
* U-boot calls this "software interrupt" in start.S
* This is executed on a "smc" instruction, we use a "smc #0" to switch
* to non-secure state.
* We use only r0 and r1 here, due to constraints in the caller.
mrc p15, 0, r1, c1, c1, 0 @ read SCR
bic r1, r1, #0x4e @ clear IRQ, FIQ, EA, nET bits
orr r1, r1, #0x31 @ enable NS, AW, FW bits
mrc p15, 0, r0, c0, c1, 1 @ read ID_PFR1
and r0, r0, #CPUID_ARM_VIRT_MASK @ mask virtualization bits
cmp r0, #(1 << CPUID_ARM_VIRT_SHIFT)
orreq r1, r1, #0x100 @ allow HVC instruction
mcr p15, 0, r1, c1, c1, 0 @ write SCR (with NS bit set)
mrceq p15, 0, r0, c12, c0, 1 @ get MVBAR value
mcreq p15, 4, r0, c12, c0, 0 @ write HVBAR
movs pc, lr @ return to non-secure SVC
mrs lr, elr_hyp @ for older asm: .byte 0x00, 0xe3, 0x0e, 0xe1
mov pc, lr @ do no switch modes, but
@ return to caller
* Secondary CPUs start here and call the code for the core specific parts
* of the non-secure and HYP mode transition. The GIC distributor specific
* code has already been executed by a C function before.
* Then they go back to wfi and wait to be woken up by the kernel again.
mrs r0, cpsr
orr r0, r0, #0xc0
msr cpsr, r0 @ disable interrupts
ldr r1, =_start
mcr p15, 0, r1, c12, c0, 0 @ set VBAR
bl _nonsec_init
mov r12, r0 @ save GICC address
bl _switch_to_hyp
ldr r1, [r12, #GICC_IAR] @ acknowledge IPI
str r1, [r12, #GICC_EOIR] @ signal end of interrupt
adr r0, _smp_pen @ do not use this address again
b smp_waitloop @ wait for IPIs, board specific
* Switch a core to non-secure state.
* 1. initialize the GIC per-core interface
* 2. allow coprocessor access in non-secure modes
* 3. switch the cpu mode (by calling "smc #0")
* Called from smp_pen by secondary cores and directly by the BSP.
* Do not assume that the stack is available and only use registers
* r0-r3 and r12.
* PERIPHBASE is used to get the GIC address. This could be 40 bits long,
* though, but we check this in C before calling this function.
mrc p15, 4, r2, c15, c0, 0 @ read CBAR
bfc r2, #0, #15 @ clear reserved bits
add r3, r2, #GIC_DIST_OFFSET @ GIC dist i/f offset
mvn r1, #0 @ all bits to 1
str r1, [r3, #GICD_IGROUPRn] @ allow private interrupts
mrc p15, 0, r0, c0, c0, 0 @ read MIDR
and r0, r0, r1 @ mask out variant and revision
cmp r0, r1 @ check for Cortex-A7
cmpne r0, r1 @ check for Cortex-A15
movne r1, #GIC_CPU_OFFSET_A9 @ GIC CPU offset for A9
moveq r1, #GIC_CPU_OFFSET_A15 @ GIC CPU offset for A15/A7
add r3, r2, r1 @ r3 = GIC CPU i/f addr
mov r1, #1 @ set GICC_CTLR[enable]
str r1, [r3, #GICC_CTLR] @ and clear all other bits
mov r1, #0xff
str r1, [r3, #GICC_PMR] @ set priority mask register
movw r1, #0x3fff
movt r1, #0x0006
mcr p15, 0, r1, c1, c1, 2 @ NSACR = all copros to non-sec
/* The CNTFRQ register of the generic timer needs to be
* programmed in secure state. Some primary bootloaders / firmware
* omit this, so if the frequency is provided in the configuration,
* we do this here instead.
* But first check if we have the generic timer.
mrc p15, 0, r0, c0, c1, 1 @ read ID_PFR1
and r0, r0, #CPUID_ARM_GENTIMER_MASK @ mask arch timer bits
mcreq p15, 0, r1, c14, c0, 0 @ write CNTFRQ
adr r1, _monitor_vectors
mcr p15, 0, r1, c12, c0, 1 @ set MVBAR to secure vectors
mrc p15, 0, ip, c12, c0, 0 @ save secure copy of VBAR
smc #0 @ call into MONITOR mode
mcr p15, 0, ip, c12, c0, 0 @ write non-secure copy of VBAR
mov r1, #1
str r1, [r3, #GICC_CTLR] @ enable non-secure CPU i/f
add r2, r2, #GIC_DIST_OFFSET
str r1, [r2, #GICD_CTLR] @ allow private interrupts
mov r0, r3 @ return GICC address
bx lr
/* void __weak smp_waitloop(unsigned previous_address); */
ldr r1, =CONFIG_SMP_PEN_ADDR @ load start address
ldr r1, [r1]
cmp r0, r1 @ make sure we dont execute this code
beq smp_waitloop @ again (due to a spurious wakeup)
mov pc, r1
.weak smp_waitloop
mov r0, lr
mov r1, sp @ save SVC copy of LR and SP
hvc #0 @ for older asm: .byte 0x70, 0x00, 0x40, 0xe1
mov sp, r1
mov lr, r0 @ restore SVC copy of LR and SP
bx lr