Commit 81eff2e3 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

bpf: simplify tnum output if a fully known constant 



Emit tnum representation as just a constant if all bits are known.
Use decimal-vs-hex logic to determine exact format of emitted
constant value, just like it's done for register range values.
For that move tnum_strn() to kernel/bpf/log.c to reuse decimal-vs-hex
determination logic and constants.

Acked-by: default avatarShung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231202175705.885270-12-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 5c19e1d0

kernel/bpf/log.c

+13 −0
Original line number Diff line number Diff line
@@ -539,6 +539,19 @@ static void verbose_snum(struct bpf_verifier_env *env, s64 num) 
		verbose(env, "%#llx", num);

}



int tnum_strn(char *str, size_t size, struct tnum a)

{

	/* print as a constant, if tnum is fully known */

	if (a.mask == 0) {

		if (is_unum_decimal(a.value))

			return snprintf(str, size, "%llu", a.value);

		else

			return snprintf(str, size, "%#llx", a.value);

	}

	return snprintf(str, size, "(%#llx; %#llx)", a.value, a.mask);

}

EXPORT_SYMBOL_GPL(tnum_strn);



static void print_scalar_ranges(struct bpf_verifier_env *env,

				const struct bpf_reg_state *reg,

				const char **sep)

kernel/bpf/tnum.c

+0 −6
Original line number Diff line number Diff line
@@ -172,12 +172,6 @@ bool tnum_in(struct tnum a, struct tnum b) 
	return a.value == b.value;

}



int tnum_strn(char *str, size_t size, struct tnum a)

{

	return snprintf(str, size, "(%#llx; %#llx)", a.value, a.mask);

}

EXPORT_SYMBOL_GPL(tnum_strn);



int tnum_sbin(char *str, size_t size, struct tnum a)

{

	size_t n;

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

+1 −1
Original line number Diff line number Diff line
@@ -411,7 +411,7 @@ l0_%=: r0 = 0; \ 


SEC("tc")

__description("direct packet access: test17 (pruning, alignment)")

__failure __msg("misaligned packet access off 2+(0x0; 0x0)+15+-4 size 4")

__failure __msg("misaligned packet access off 2+0+15+-4 size 4")

__flag(BPF_F_STRICT_ALIGNMENT)

__naked void packet_access_test17_pruning_alignment(void)

{

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

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ __naked void ptr_to_long_half_uninitialized(void) 


SEC("cgroup/sysctl")

__description("ARG_PTR_TO_LONG misaligned")

__failure __msg("misaligned stack access off (0x0; 0x0)+-20+0 size 8")

__failure __msg("misaligned stack access off 0+-20+0 size 8")

__naked void arg_ptr_to_long_misaligned(void)

{

	asm volatile ("					\

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

+2 −2
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ __naked void ptr_to_stack_store_load(void) 


SEC("socket")

__description("PTR_TO_STACK store/load - bad alignment on off")

__failure __msg("misaligned stack access off (0x0; 0x0)+-8+2 size 8")

__failure __msg("misaligned stack access off 0+-8+2 size 8")

__failure_unpriv

__naked void load_bad_alignment_on_off(void)

{
@@ -53,7 +53,7 @@ __naked void load_bad_alignment_on_off(void) 


SEC("socket")

__description("PTR_TO_STACK store/load - bad alignment on reg")

__failure __msg("misaligned stack access off (0x0; 0x0)+-10+8 size 8")

__failure __msg("misaligned stack access off 0+-10+8 size 8")

__failure_unpriv

__naked void load_bad_alignment_on_reg(void)

{