Compile and run RISC-V and CHERI-RISC-V programs

This exercise steps you through getting up and running with code compilation and execution for RISC-V and CHERI-RISC-V programs.

The first test program is written in conventional C, and can be compiled to RISC-V or CHERI-RISC-V targets:

1. Compile print-pointer.c with a RISC-V target and a binary name of print-pointer-riscv.

print-pointer.c:

/*
 * SPDX-License-Identifier: BSD-2-Clause-DARPA-SSITH-ECATS-HR0011-18-C-0016
 * Copyright (c) 2020 SRI International
 */
#include <stdio.h>

int
main(void)
{
	printf("size of pointer: %zu\n", sizeof(void *));
	/* XXX: ideally we'd use ptraddr_t below */
	printf("size of address: %zu\n", sizeof(size_t));

	return (0);
}

2. Run the binary.
3. Compile print-pointer.c with a CHERI-RISC-V target and a binary name of print-pointer-cheri.
4. Run the binary: it should print a pointer size of 16 and address size of 8.

The second test program is written in CHERI C:

5. Compile print-capability.c with a CHERI-RISC-V target and a binary name of print-capability.

/*
 * SPDX-License-Identifier: BSD-2-Clause-DARPA-SSITH-ECATS-HR0011-18-C-0016
 * Copyright (c) 2020 SRI International
 */
#include <stdio.h>
#include <cheriintrin.h>

int
main(void)
{
	int i;
	char *c;
	void *cap_to_int = &i;
	void *cap_to_cap = &c;

	printf("cap to int length: %lu\n", cheri_length_get(cap_to_int));
	printf("cap to cap length: %lu\n", cheri_length_get(cap_to_cap));

	return (0);
}

6. Run the binary: note how the length of the capability depends on the size of the type it points to.