Minimize casts to pointers #1870

Job	Run time
Check docs	40s
Check	54s
Build	1m 48s
Clippy	1m 20s
Format	22s
Run Hermit for Rust (x86_64 + kvm)	4m 3s
Run (x86_64, rusty_demo, none, dev)	4m 3s
Test	1m 36s
Run (x86_64, rusty_demo, none, release)	3m 12s
Run (x86_64, httpd, virtio-net-pci, dev)	2m 58s
Run (x86_64, httpd, virtio-net-pci, release)	2m 56s
Run (x86_64, httpd, rtl8139, dev)	2m 56s
Run (x86_64, httpd, rtl8139, release)	2m 58s
Run (x86_64, testudp, virtio-net-pci, dev)	2m 35s
Run (x86_64, testudp, virtio-net-pci, release)	2m 51s
Run (x86_64, testudp, rtl8139, dev)	3m 42s
Run (x86_64, testudp, rtl8139, release)	2m 44s
Run (x86_64, hello_world, none, dev)	2m 28s
Run (x86_64, hello_world, none, release)	2m 36s
Run (aarch64, rusty_demo, none, dev)	4m 20s
Run (aarch64, rusty_demo, none, release)	3m 20s
Run (aarch64, httpd, virtio-net-pci, dev)	3m 24s
Run (aarch64, httpd, virtio-net-pci, release)	3m 46s
Run (aarch64, testudp, virtio-net-pci, dev)	3m 14s
Run (aarch64, testudp, virtio-net-pci, release)	3m 14s
	1h 8m 0s

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