From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>,
<martin.lau@kernel.org>
Cc: <andrii@kernel.org>, <kernel-team@meta.com>
Subject: [PATCH v5 bpf-next 15/23] bpf: unify 32-bit and 64-bit is_branch_taken logic
Date: Fri, 27 Oct 2023 11:13:38 -0700 [thread overview]
Message-ID: <20231027181346.4019398-16-andrii@kernel.org> (raw)
In-Reply-To: <20231027181346.4019398-1-andrii@kernel.org>
Combine 32-bit and 64-bit is_branch_taken logic for SCALAR_VALUE
registers. It makes it easier to see parallels between two domains
(32-bit and 64-bit), and makes subsequent refactoring more
straightforward.
No functional changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/bpf/verifier.c | 154 ++++++++++--------------------------------
1 file changed, 36 insertions(+), 118 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index fedd6d0e76e5..b911d1111fad 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -14185,166 +14185,86 @@ static u64 reg_const_value(struct bpf_reg_state *reg, bool subreg32)
/*
* <reg1> <op> <reg2>, currently assuming reg2 is a constant
*/
-static int is_branch32_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2, u8 opcode)
+static int is_scalar_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2,
+ u8 opcode, bool is_jmp32)
{
- struct tnum subreg = tnum_subreg(reg1->var_off);
- u32 val = (u32)tnum_subreg(reg2->var_off).value;
- s32 sval = (s32)val;
+ struct tnum t1 = is_jmp32 ? tnum_subreg(reg1->var_off) : reg1->var_off;
+ u64 umin1 = is_jmp32 ? (u64)reg1->u32_min_value : reg1->umin_value;
+ u64 umax1 = is_jmp32 ? (u64)reg1->u32_max_value : reg1->umax_value;
+ s64 smin1 = is_jmp32 ? (s64)reg1->s32_min_value : reg1->smin_value;
+ s64 smax1 = is_jmp32 ? (s64)reg1->s32_max_value : reg1->smax_value;
+ u64 val = is_jmp32 ? (u32)tnum_subreg(reg2->var_off).value : reg2->var_off.value;
+ s64 sval = is_jmp32 ? (s32)val : (s64)val;
switch (opcode) {
case BPF_JEQ:
- if (tnum_is_const(subreg))
- return !!tnum_equals_const(subreg, val);
- else if (val < reg1->u32_min_value || val > reg1->u32_max_value)
+ if (tnum_is_const(t1))
+ return !!tnum_equals_const(t1, val);
+ else if (val < umin1 || val > umax1)
return 0;
- else if (sval < reg1->s32_min_value || sval > reg1->s32_max_value)
+ else if (sval < smin1 || sval > smax1)
return 0;
break;
case BPF_JNE:
- if (tnum_is_const(subreg))
- return !tnum_equals_const(subreg, val);
- else if (val < reg1->u32_min_value || val > reg1->u32_max_value)
+ if (tnum_is_const(t1))
+ return !tnum_equals_const(t1, val);
+ else if (val < umin1 || val > umax1)
return 1;
- else if (sval < reg1->s32_min_value || sval > reg1->s32_max_value)
+ else if (sval < smin1 || sval > smax1)
return 1;
break;
case BPF_JSET:
- if ((~subreg.mask & subreg.value) & val)
+ if ((~t1.mask & t1.value) & val)
return 1;
- if (!((subreg.mask | subreg.value) & val))
+ if (!((t1.mask | t1.value) & val))
return 0;
break;
case BPF_JGT:
- if (reg1->u32_min_value > val)
+ if (umin1 > val )
return 1;
- else if (reg1->u32_max_value <= val)
+ else if (umax1 <= val)
return 0;
break;
case BPF_JSGT:
- if (reg1->s32_min_value > sval)
+ if (smin1 > sval)
return 1;
- else if (reg1->s32_max_value <= sval)
+ else if (smax1 <= sval)
return 0;
break;
case BPF_JLT:
- if (reg1->u32_max_value < val)
+ if (umax1 < val)
return 1;
- else if (reg1->u32_min_value >= val)
+ else if (umin1 >= val)
return 0;
break;
case BPF_JSLT:
- if (reg1->s32_max_value < sval)
+ if (smax1 < sval)
return 1;
- else if (reg1->s32_min_value >= sval)
+ else if (smin1 >= sval)
return 0;
break;
case BPF_JGE:
- if (reg1->u32_min_value >= val)
+ if (umin1 >= val)
return 1;
- else if (reg1->u32_max_value < val)
+ else if (umax1 < val)
return 0;
break;
case BPF_JSGE:
- if (reg1->s32_min_value >= sval)
+ if (smin1 >= sval)
return 1;
- else if (reg1->s32_max_value < sval)
+ else if (smax1 < sval)
return 0;
break;
case BPF_JLE:
- if (reg1->u32_max_value <= val)
+ if (umax1 <= val)
return 1;
- else if (reg1->u32_min_value > val)
+ else if (umin1 > val)
return 0;
break;
case BPF_JSLE:
- if (reg1->s32_max_value <= sval)
+ if (smax1 <= sval)
return 1;
- else if (reg1->s32_min_value > sval)
- return 0;
- break;
- }
-
- return -1;
-}
-
-
-/*
- * <reg1> <op> <reg2>, currently assuming reg2 is a constant
- */
-static int is_branch64_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2, u8 opcode)
-{
- u64 val = reg2->var_off.value;
- s64 sval = (s64)val;
-
- switch (opcode) {
- case BPF_JEQ:
- if (tnum_is_const(reg1->var_off))
- return !!tnum_equals_const(reg1->var_off, val);
- else if (val < reg1->umin_value || val > reg1->umax_value)
- return 0;
- else if (sval < reg1->smin_value || sval > reg1->smax_value)
- return 0;
- break;
- case BPF_JNE:
- if (tnum_is_const(reg1->var_off))
- return !tnum_equals_const(reg1->var_off, val);
- else if (val < reg1->umin_value || val > reg1->umax_value)
- return 1;
- else if (sval < reg1->smin_value || sval > reg1->smax_value)
- return 1;
- break;
- case BPF_JSET:
- if ((~reg1->var_off.mask & reg1->var_off.value) & val)
- return 1;
- if (!((reg1->var_off.mask | reg1->var_off.value) & val))
- return 0;
- break;
- case BPF_JGT:
- if (reg1->umin_value > val)
- return 1;
- else if (reg1->umax_value <= val)
- return 0;
- break;
- case BPF_JSGT:
- if (reg1->smin_value > sval)
- return 1;
- else if (reg1->smax_value <= sval)
- return 0;
- break;
- case BPF_JLT:
- if (reg1->umax_value < val)
- return 1;
- else if (reg1->umin_value >= val)
- return 0;
- break;
- case BPF_JSLT:
- if (reg1->smax_value < sval)
- return 1;
- else if (reg1->smin_value >= sval)
- return 0;
- break;
- case BPF_JGE:
- if (reg1->umin_value >= val)
- return 1;
- else if (reg1->umax_value < val)
- return 0;
- break;
- case BPF_JSGE:
- if (reg1->smin_value >= sval)
- return 1;
- else if (reg1->smax_value < sval)
- return 0;
- break;
- case BPF_JLE:
- if (reg1->umax_value <= val)
- return 1;
- else if (reg1->umin_value > val)
- return 0;
- break;
- case BPF_JSLE:
- if (reg1->smax_value <= sval)
- return 1;
- else if (reg1->smin_value > sval)
+ else if (smin1 > sval)
return 0;
break;
}
@@ -14458,9 +14378,7 @@ static int is_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg
}
}
- if (is_jmp32)
- return is_branch32_taken(reg1, reg2, opcode);
- return is_branch64_taken(reg1, reg2, opcode);
+ return is_scalar_branch_taken(reg1, reg2, opcode, is_jmp32);
}
/* Adjusts the register min/max values in the case that the dst_reg is the
--
2.34.1
next prev parent reply other threads:[~2023-10-27 18:17 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-27 18:13 [PATCH v5 bpf-next 00/23] BPF register bounds logic and testing improvements Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 01/23] selftests/bpf: fix RELEASE=1 build for tc_opts Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 02/23] selftests/bpf: satisfy compiler by having explicit return in btf test Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 03/23] bpf: derive smin/smax from umin/max bounds Andrii Nakryiko
2023-10-31 15:37 ` Eduard Zingerman
2023-10-31 17:30 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 04/23] bpf: derive smin32/smax32 from umin32/umax32 bounds Andrii Nakryiko
2023-10-31 15:37 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 05/23] bpf: derive subreg bounds from full bounds when upper 32 bits are constant Andrii Nakryiko
2023-10-31 15:37 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 06/23] bpf: add special smin32/smax32 derivation from 64-bit bounds Andrii Nakryiko
2023-10-31 15:37 ` Eduard Zingerman
2023-10-31 17:39 ` Andrii Nakryiko
2023-10-31 18:41 ` Alexei Starovoitov
2023-10-31 18:49 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 07/23] bpf: improve deduction of 64-bit bounds from 32-bit bounds Andrii Nakryiko
2023-10-31 15:37 ` Eduard Zingerman
2023-10-31 20:26 ` Alexei Starovoitov
2023-10-31 20:33 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 08/23] bpf: try harder to deduce register bounds from different numeric domains Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 09/23] bpf: drop knowledge-losing __reg_combine_{32,64}_into_{64,32} logic Andrii Nakryiko
2023-10-31 15:38 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 10/23] selftests/bpf: BPF register range bounds tester Andrii Nakryiko
2023-11-08 22:08 ` Eduard Zingerman
2023-11-08 23:23 ` Andrii Nakryiko
2023-11-09 0:30 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 11/23] bpf: rename is_branch_taken reg arguments to prepare for the second one Andrii Nakryiko
2023-10-30 19:39 ` Alexei Starovoitov
2023-10-31 5:19 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 12/23] bpf: generalize is_branch_taken() to work with two registers Andrii Nakryiko
2023-10-31 15:38 ` Eduard Zingerman
2023-10-31 17:41 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 13/23] bpf: move is_branch_taken() down Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 14/23] bpf: generalize is_branch_taken to handle all conditional jumps in one place Andrii Nakryiko
2023-10-31 15:38 ` Eduard Zingerman
2023-10-27 18:13 ` Andrii Nakryiko [this message]
2023-10-30 19:52 ` [PATCH v5 bpf-next 15/23] bpf: unify 32-bit and 64-bit is_branch_taken logic Alexei Starovoitov
2023-10-31 5:28 ` Andrii Nakryiko
2023-10-31 17:35 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 16/23] bpf: prepare reg_set_min_max for second set of registers Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 17/23] bpf: generalize reg_set_min_max() to handle two sets of two registers Andrii Nakryiko
2023-10-31 2:02 ` Alexei Starovoitov
2023-10-31 6:03 ` Andrii Nakryiko
2023-10-31 16:23 ` Alexei Starovoitov
2023-10-31 17:50 ` Andrii Nakryiko
2023-10-31 17:56 ` Andrii Nakryiko
2023-10-31 18:04 ` Alexei Starovoitov
2023-10-31 18:06 ` Andrii Nakryiko
2023-10-31 18:14 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 18/23] bpf: generalize reg_set_min_max() to handle non-const register comparisons Andrii Nakryiko
2023-10-31 23:25 ` Eduard Zingerman
2023-11-01 16:35 ` Andrii Nakryiko
2023-11-01 17:12 ` Eduard Zingerman
2023-10-27 18:13 ` [PATCH v5 bpf-next 19/23] bpf: generalize is_scalar_branch_taken() logic Andrii Nakryiko
2023-10-31 2:12 ` Alexei Starovoitov
2023-10-31 6:12 ` Andrii Nakryiko
2023-10-31 16:34 ` Alexei Starovoitov
2023-10-31 18:01 ` Andrii Nakryiko
2023-10-31 20:53 ` Andrii Nakryiko
2023-10-31 20:55 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 20/23] bpf: enhance BPF_JEQ/BPF_JNE is_branch_taken logic Andrii Nakryiko
2023-10-31 2:20 ` Alexei Starovoitov
2023-10-31 6:16 ` Andrii Nakryiko
2023-10-31 16:36 ` Alexei Starovoitov
2023-10-31 18:04 ` Andrii Nakryiko
2023-10-31 18:06 ` Alexei Starovoitov
2023-10-27 18:13 ` [PATCH v5 bpf-next 21/23] selftests/bpf: adjust OP_EQ/OP_NE handling to use subranges for branch taken Andrii Nakryiko
2023-11-08 18:22 ` Eduard Zingerman
2023-11-08 19:59 ` Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 22/23] selftests/bpf: add range x range test to reg_bounds Andrii Nakryiko
2023-10-27 18:13 ` [PATCH v5 bpf-next 23/23] selftests/bpf: add iter test requiring range x range logic Andrii Nakryiko
2023-10-30 17:55 ` [PATCH v5 bpf-next 00/23] BPF register bounds logic and testing improvements Alexei Starovoitov
2023-10-31 5:19 ` Andrii Nakryiko
2023-11-01 12:37 ` Paul Chaignon
2023-11-01 17:13 ` Andrii Nakryiko
2023-11-07 6:37 ` Harishankar Vishwanathan
2023-11-07 16:38 ` Paul Chaignon
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