diff options
Diffstat (limited to 'arch/arm/cpu/armv7/nonsec_virt.S')
| -rw-r--r-- | arch/arm/cpu/armv7/nonsec_virt.S | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/nonsec_virt.S b/arch/arm/cpu/armv7/nonsec_virt.S new file mode 100644 index 000000000..358348ffa --- /dev/null +++ b/arch/arm/cpu/armv7/nonsec_virt.S @@ -0,0 +1,208 @@ +/* + * code for switching cores into non-secure state and into HYP mode + * + * Copyright (c) 2013 Andre Przywara <andre.przywara@linaro.org> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <config.h> +#include <linux/linkage.h> +#include <asm/gic.h> +#include <asm/armv7.h> + +.arch_extension sec +.arch_extension virt + +/* the vector table for secure state and HYP mode */ +_monitor_vectors: + .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. + */ + .align 5 +_secure_monitor: + 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 + +#ifdef CONFIG_ARMV7_VIRT + 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 +#endif + + mcr p15, 0, r1, c1, c1, 0 @ write SCR (with NS bit set) + +#ifdef CONFIG_ARMV7_VIRT + mrceq p15, 0, r0, c12, c0, 1 @ get MVBAR value + mcreq p15, 4, r0, c12, c0, 0 @ write HVBAR +#endif + + movs pc, lr @ return to non-secure SVC + +_hyp_trap: + 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. + */ +ENTRY(_smp_pen) + 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 +#ifdef CONFIG_ARMV7_VIRT + bl _switch_to_hyp +#endif + + 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 +ENDPROC(_smp_pen) + +/* + * 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. + */ +ENTRY(_nonsec_init) +#ifdef CONFIG_ARM_GIC_BASE_ADDRESS + ldr r2, =CONFIG_ARM_GIC_BASE_ADDRESS +#else + mrc p15, 4, r2, c15, c0, 0 @ read CBAR + bfc r2, #0, #15 @ clear reserved bits +#endif + 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 + ldr r1, =MIDR_PRIMARY_PART_MASK + and r0, r0, r1 @ mask out variant and revision + + ldr r1, =MIDR_CORTEX_A7_R0P0 & MIDR_PRIMARY_PART_MASK + cmp r0, r1 @ check for Cortex-A7 + + ldr r1, =MIDR_CORTEX_A15_R0P0 & MIDR_PRIMARY_PART_MASK + 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. + */ +#ifdef CONFIG_SYS_CLK_FREQ + mrc p15, 0, r0, c0, c1, 1 @ read ID_PFR1 + and r0, r0, #CPUID_ARM_GENTIMER_MASK @ mask arch timer bits + cmp r0, #(1 << CPUID_ARM_GENTIMER_SHIFT) + ldreq r1, =CONFIG_SYS_CLK_FREQ + mcreq p15, 0, r1, c14, c0, 0 @ write CNTFRQ +#endif + + 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 + + isb + 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 +ENDPROC(_nonsec_init) + +#ifdef CONFIG_SMP_PEN_ADDR +/* void __weak smp_waitloop(unsigned previous_address); */ +ENTRY(smp_waitloop) + wfi + 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 +ENDPROC(smp_waitloop) +.weak smp_waitloop +#endif + +ENTRY(_switch_to_hyp) + mov r0, lr + mov r1, sp @ save SVC copy of LR and SP + isb + 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 +ENDPROC(_switch_to_hyp) |