diff options
| author | Christoffer Dall <cdall@cs.columbia.edu> | 2011-05-11 14:20:24 +0200 |
|---|---|---|
| committer | Christoffer Dall <cdall@cs.columbia.edu> | 2011-05-11 14:20:24 +0200 |
| commit | d489b9de2299863e19895cd49b81e308f6e63ef9 (patch) | |
| tree | 9ec397ee8ae42f271f29b6f3d3a1a9afa500fac5 | |
| parent | 366e6705e3c57ae49a2912a8016a308ffc1840c3 (diff) | |
Use monitor stack to avoid caller-save
Use callee-save by implementing a small stack space in the monitor
instead.
| -rw-r--r-- | monitor.S | 37 |
1 files changed, 25 insertions, 12 deletions
@@ -24,6 +24,9 @@ @ Secure Monitor Call @ 1: + ldr sp, =_monitor_stack + push {r11, r12} + cmp r7, #0xffffffff beq _non_sec @@ -33,20 +36,22 @@ 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, r13, c2 - lsr r13, r13, #16 - and r13, r13, #0xff - cmp r13, #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 r13, _hyp_funcs - add r13, r13, r12, lsl #2 - ldr pc, [r13] + adr r11, _hyp_funcs + add r11, r11, r12, lsl #2 + ldr pc, [r11] @ @ Jump table for the SMC hypervisor API calls @@ -58,11 +63,12 @@ _hyp_funcs: @ Switch to non-secure mode @ _non_sec: - mrc p15, 0, r0, c1, c1, 0 @ Secure configuration register - bic r0, r0, #0x07f - ldr r13, =0x131 - orr r0, r0, r13 - mcr p15, 0, r0, c1, c1, 0 + 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 @ @@ -70,4 +76,11 @@ _non_sec: @ _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: |