diff options
Diffstat (limited to 'monitor.S')
| -rw-r--r-- | monitor.S | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/monitor.S b/monitor.S new file mode 100644 index 0000000..052ab1e --- /dev/null +++ b/monitor.S @@ -0,0 +1,86 @@ +/* + * monitor.S - simple monitor code to switch to NS state before executing kernel + * + * Copyright (C) 2011 Columbia University. All rights reserved. + * Christoffer Dall <cdall@cs.columbia.edu> + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE.txt file. + */ + +#.syntax unified + .section monitor, "x" + + .word 0 + .word 0 + b 1f + .word 0 + .word 0 + .word 0 + .word 0 + .word 0 + + @ + @ Secure Monitor Call + @ +1: + ldr sp, =_monitor_stack + push {r11, r12} + + cmp r7, #0xffffffff + beq _non_sec + + @ Check smc number and VMID + bic r12, r7, #0xf + cmp r12, #0xfffffff0 + movnes pc, lr + and r12, r7, #0xf + cmp r12, #0x0 + popgt {r11, r12} + movgts pc, lr + + @ Check the VMID is 0 + mrrc p15, 6, r12, r11, c2 + lsr r11, r11, #16 + and r11, r11, #0xff + cmp r11, #0 + popne {r11, r12} + movnes pc, lr + + @ Jump to the right function + and r12, r7, #0xf + adr r11, _hyp_funcs + add r11, r11, r12, lsl #2 + ldr pc, [r11] + + @ + @ Jump table for the SMC hypervisor API calls + @ +_hyp_funcs: + .long _write_hvbar + + @ + @ Switch to non-secure mode + @ +_non_sec: + mrc p15, 0, r12, c1, c1, 0 @ Secure configuration register + bic r12, r12, #0x07f + ldr r11, =0x131 + orr r12, r12, r11 + mcr p15, 0, r12, c1, c1, 0 + pop {r11, r12} + movs pc, lr + + @ + @ Read/Write HVBAR + @ +_write_hvbar: + mcr p15, 4, r0, c12, c0, 0 + pop {r11, r12} + movs pc, lr + + .ltorg + + /* A bit of stack space for monitor mode */ + .align 12 +_monitor_stack: |