On Fri, 27 Jul 2012, Ian Campbell wrote:
Should this comment be by 'privcmd_call'?
When we add a 5 argument hypercall I suppose we'll see the required push/pop of r4 added to this macro too.
For performance and simplicity I would add a second macro that push/pop r4, only required for hypercalls with more than 4 arguments.
For clarity / documentation purposes it might actually be worthwhile to define all of HYPERCALL{0,1,2,3,4} even if the {0,1,2,3} cases are all just: #define HYPERCALL0(x) HYPERCALL_SIMPLE(x)
I agree
+#define HYPERCALL(hypercall) \ +ENTRY(HYPERVISOR_##hypercall) \
- mov r12, #__HYPERVISOR_##hypercall; \
- xen_hvc; \
- mov pc, lr; \
+ENDPROC(HYPERVISOR_##hypercall)
.text+HYPERCALL(xen_version); +HYPERCALL(console_io); +HYPERCALL(grant_table_op); +HYPERCALL(sched_op); +HYPERCALL(event_channel_op); +HYPERCALL(hvm_op); +HYPERCALL(memory_op); +HYPERCALL(physdev_op);
+ENTRY(privcmd_call)
- stmdb sp!, {r4}
- mov r12, r0
- mov r0, r1
- mov r1, r2
- mov r2, r3
- ldr r3, [sp, #8]
- ldr r4, [sp, #4]
- xen_hvc
- pop {r4}
Why not ldmdb for symmetry?
Yep, I can do that.
Actually it is just ldm or ldmia