baremetal: working aarch64 svc example adapted from takeharukato

Not yet generalized for usage on multiple files.

README.adoc

@@ -8967,7 +8967,13 @@ less "$(./getvar --arch aarch64 run_dir)/trace.txt"
 Output the trace to stdout instead of a file:
 
 ....
-./run --arch aarch64 --eval 'm5 exit' --emulator gem5 --trace Exec --trace-stdout
+./run \
+  --arch aarch64 \
+  --emulator gem5 \
+  --eval 'm5 exit' \
+  --trace Exec \
+  --trace-stdout \
+;
 ....
 
 This would produce a lot of output however, so you will likely not want that when tracing a Linux kernel boot instructions. But it can be very convenient for smaller traces.
@@ -11201,6 +11207,14 @@ output:
 
 Setup a handler for `svc`, do an `svc`, and observe that the handler got called and returned:
 
+....
+./run --arch aarch64 --baremetal arch/aarch64/svc_asm
+....
+
+Source: link:baremetal/arch/aarch64/svc_asm.S[]
+
+TODO: factor out the above, and make it also work on C:
+
 ....
 ./run --arch aarch64 --baremetal arch/aarch64/svc
 ....
@@ -11261,6 +11275,7 @@ This reset value is defined `UNKNOWN` by <<armarm8>> D10.2.116 "VBAR_EL1, Vector
 
 Bibliography:
 
+* https://github.com/torvalds/linux/blob/v4.20/arch/arm64/kernel/entry.S#L430 this is where the kernel defines the vector table
 * https://github.com/dwelch67/qemu_arm_samples/tree/07162ba087111e0df3f44fd857d1b4e82458a56d/swi01
 * https://github.com/NienfengYao/armv8-bare-metal/blob/572c6f95880e70aa92fe9fed4b8ad7697082a764/vector.S#L168
 * https://stackoverflow.com/questions/51094092/how-to-make-timer-irq-work-on-qemu-machine-virt-cpu-cortex-a57