Commit 4c5f21d4 authored by Emil Tsalapatis's avatar Emil Tsalapatis Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add tests for non-arena/arena operations 



Add a selftest that ensures instructions with arena source and
non-arena destination registers are accepted by the verifier.

Signed-off-by: default avatarEmil Tsalapatis <emil@etsalapatis.com>
Acked-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20260412174546.18684-3-emil@etsalapatis.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ac61bffe

tools/testing/selftests/bpf/progs/verifier_arena.c

+130 −0
Original line number Diff line number Diff line
@@ -477,4 +477,134 @@ int arena_kfuncs_under_bpf_lock(void *ctx) 


	return 0;

}



#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)



/*

 * Test that scalar += PTR_TO_ARENA correctly upgrades the

 * destination register to a PTR_TO_ARENA.

 */

SEC("syscall")

__success __retval(0)

int scalar_add_arena_ptr(void *ctx)

{

	int __arena *scalar, *arena_ptr;



	volatile char __arena *base = arena_base(&arena);



	asm volatile (

		"%[arena_ptr] = 8192;"

		"%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"

		"%[scalar] = 12;"

		"%[scalar] += %[arena_ptr];"

		: [scalar] "=r"(scalar),

		  [arena_ptr] "=&r"(arena_ptr)

		: "r"(base)

		:

	);

	return 0;

}



/*

 * Tests that PTR_TO_ARENA + PTR_TO_ARENA is allowed.

 */

SEC("syscall")

__success __retval(0)

int arena_ptr_add_arena_ptr(void *ctx)

{

	int __arena *arena_ptr2, *arena_ptr1;



	/* Needed for the verifier to link the arena to the subprog. */

	volatile char __arena *base = arena_base(&arena);



	asm volatile (

		"%[arena_ptr1] = 8192;"

		"%[arena_ptr1] = addr_space_cast(%[arena_ptr1], 0x0, 0x1);"

		"%[arena_ptr2] = 4096;"

		"%[arena_ptr2] = addr_space_cast(%[arena_ptr2], 0x0, 0x1);"

		"%[arena_ptr2] += %[arena_ptr1];"

		: [arena_ptr2] "=r"(arena_ptr2),

		  [arena_ptr1] "=&r"(arena_ptr1)

		: "r"(base)

		:

	);

	return 0;

}



SEC("syscall")

__success __retval(0)

int scalar_xor_arena_ptr(void *ctx)

{

	int __arena *scalar, *arena_ptr;



	volatile char __arena *base = arena_base(&arena);



	asm volatile (

		"%[arena_ptr] = 8192;"

		"%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"

		"%[scalar] = 12;"

		"%[scalar] ^= %[arena_ptr];"

		: [scalar] "=r"(scalar),

		  [arena_ptr] "=&r"(arena_ptr)

		: "r"(base)

		:

	);

	return 0;

}



/*

 * Tests that PTR_TO_ARENA and non-arena pointers can be added.

 */

SEC("syscall")

__success __retval(0)

int arena_ptr_add_to_non_arena_ptr(void *ctx)

{

	register int __arena *arena_ptr asm("r3");

	register void *dst asm("r4");



	volatile char __arena *base = arena_base(&arena);



	asm volatile (

		"%[arena_ptr] = 8192;"

		"%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"

		"%[dst] = %[ctx];"

		"%[dst] += %[arena_ptr];"

		: [arena_ptr] "=&r"(arena_ptr),

		  [dst] "=&r"(dst)

		: [ctx] "r"(ctx), "r"(base)

		:

	);



	(void)ctx;



	return 0;

}



SEC("syscall")

__success __retval(0)

int non_arena_ptr_add_to_arena_ptr(void *ctx)

{

	register int __arena *arena_ptr asm("r3");

	register void *src asm("r4");



	volatile char __arena *base = arena_base(&arena);



	asm volatile (

		"%[arena_ptr] = 8192;"

		"%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"

		"%[src] = %[ctx];"

		"%[arena_ptr] += %[src];"

		: [arena_ptr] "=&r"(arena_ptr),

		  [src] "=&r"(src)

		: [ctx] "r"(ctx), "r"(base)

		:

	);



	(void)ctx;



	return 0;

}



#endif



char _license[] SEC("license") = "GPL";