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https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
bpf: unify 32-bit and 64-bit is_branch_taken logic
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. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231102033759.2541186-16-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
b74c2a842b
commit
4d345887d2
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@ -14204,166 +14204,86 @@ static u64 reg_const_value(struct bpf_reg_state *reg, bool subreg32)
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/*
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* <reg1> <op> <reg2>, currently assuming reg2 is a constant
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*/
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static int is_branch32_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2, u8 opcode)
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static int is_scalar_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2,
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u8 opcode, bool is_jmp32)
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{
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struct tnum subreg = tnum_subreg(reg1->var_off);
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u32 val = (u32)tnum_subreg(reg2->var_off).value;
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s32 sval = (s32)val;
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struct tnum t1 = is_jmp32 ? tnum_subreg(reg1->var_off) : reg1->var_off;
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u64 umin1 = is_jmp32 ? (u64)reg1->u32_min_value : reg1->umin_value;
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u64 umax1 = is_jmp32 ? (u64)reg1->u32_max_value : reg1->umax_value;
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s64 smin1 = is_jmp32 ? (s64)reg1->s32_min_value : reg1->smin_value;
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s64 smax1 = is_jmp32 ? (s64)reg1->s32_max_value : reg1->smax_value;
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u64 uval = is_jmp32 ? (u32)tnum_subreg(reg2->var_off).value : reg2->var_off.value;
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s64 sval = is_jmp32 ? (s32)uval : (s64)uval;
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switch (opcode) {
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case BPF_JEQ:
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if (tnum_is_const(subreg))
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return !!tnum_equals_const(subreg, val);
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else if (val < reg1->u32_min_value || val > reg1->u32_max_value)
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if (tnum_is_const(t1))
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return !!tnum_equals_const(t1, uval);
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else if (uval < umin1 || uval > umax1)
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return 0;
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else if (sval < reg1->s32_min_value || sval > reg1->s32_max_value)
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else if (sval < smin1 || sval > smax1)
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return 0;
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break;
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case BPF_JNE:
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if (tnum_is_const(subreg))
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return !tnum_equals_const(subreg, val);
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else if (val < reg1->u32_min_value || val > reg1->u32_max_value)
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if (tnum_is_const(t1))
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return !tnum_equals_const(t1, uval);
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else if (uval < umin1 || uval > umax1)
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return 1;
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else if (sval < reg1->s32_min_value || sval > reg1->s32_max_value)
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else if (sval < smin1 || sval > smax1)
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return 1;
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break;
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case BPF_JSET:
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if ((~subreg.mask & subreg.value) & val)
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if ((~t1.mask & t1.value) & uval)
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return 1;
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if (!((subreg.mask | subreg.value) & val))
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if (!((t1.mask | t1.value) & uval))
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return 0;
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break;
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case BPF_JGT:
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if (reg1->u32_min_value > val)
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if (umin1 > uval )
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return 1;
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else if (reg1->u32_max_value <= val)
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else if (umax1 <= uval)
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return 0;
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break;
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case BPF_JSGT:
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if (reg1->s32_min_value > sval)
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if (smin1 > sval)
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return 1;
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else if (reg1->s32_max_value <= sval)
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else if (smax1 <= sval)
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return 0;
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break;
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case BPF_JLT:
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if (reg1->u32_max_value < val)
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if (umax1 < uval)
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return 1;
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else if (reg1->u32_min_value >= val)
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else if (umin1 >= uval)
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return 0;
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break;
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case BPF_JSLT:
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if (reg1->s32_max_value < sval)
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if (smax1 < sval)
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return 1;
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else if (reg1->s32_min_value >= sval)
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else if (smin1 >= sval)
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return 0;
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break;
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case BPF_JGE:
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if (reg1->u32_min_value >= val)
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if (umin1 >= uval)
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return 1;
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else if (reg1->u32_max_value < val)
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else if (umax1 < uval)
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return 0;
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break;
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case BPF_JSGE:
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if (reg1->s32_min_value >= sval)
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if (smin1 >= sval)
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return 1;
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else if (reg1->s32_max_value < sval)
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else if (smax1 < sval)
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return 0;
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break;
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case BPF_JLE:
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if (reg1->u32_max_value <= val)
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if (umax1 <= uval)
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return 1;
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else if (reg1->u32_min_value > val)
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else if (umin1 > uval)
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return 0;
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break;
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case BPF_JSLE:
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if (reg1->s32_max_value <= sval)
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if (smax1 <= sval)
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return 1;
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else if (reg1->s32_min_value > sval)
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return 0;
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break;
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}
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return -1;
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}
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/*
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* <reg1> <op> <reg2>, currently assuming reg2 is a constant
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*/
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static int is_branch64_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg2, u8 opcode)
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{
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u64 val = reg2->var_off.value;
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s64 sval = (s64)val;
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switch (opcode) {
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case BPF_JEQ:
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if (tnum_is_const(reg1->var_off))
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return !!tnum_equals_const(reg1->var_off, val);
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else if (val < reg1->umin_value || val > reg1->umax_value)
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return 0;
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else if (sval < reg1->smin_value || sval > reg1->smax_value)
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return 0;
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break;
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case BPF_JNE:
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if (tnum_is_const(reg1->var_off))
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return !tnum_equals_const(reg1->var_off, val);
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else if (val < reg1->umin_value || val > reg1->umax_value)
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return 1;
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else if (sval < reg1->smin_value || sval > reg1->smax_value)
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return 1;
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break;
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case BPF_JSET:
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if ((~reg1->var_off.mask & reg1->var_off.value) & val)
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return 1;
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if (!((reg1->var_off.mask | reg1->var_off.value) & val))
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return 0;
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break;
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case BPF_JGT:
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if (reg1->umin_value > val)
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return 1;
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else if (reg1->umax_value <= val)
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return 0;
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break;
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case BPF_JSGT:
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if (reg1->smin_value > sval)
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return 1;
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else if (reg1->smax_value <= sval)
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return 0;
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break;
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case BPF_JLT:
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if (reg1->umax_value < val)
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return 1;
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else if (reg1->umin_value >= val)
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return 0;
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break;
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case BPF_JSLT:
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if (reg1->smax_value < sval)
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return 1;
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else if (reg1->smin_value >= sval)
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return 0;
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break;
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case BPF_JGE:
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if (reg1->umin_value >= val)
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return 1;
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else if (reg1->umax_value < val)
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return 0;
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break;
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case BPF_JSGE:
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if (reg1->smin_value >= sval)
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return 1;
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else if (reg1->smax_value < sval)
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return 0;
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break;
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case BPF_JLE:
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if (reg1->umax_value <= val)
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return 1;
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else if (reg1->umin_value > val)
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return 0;
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break;
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case BPF_JSLE:
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if (reg1->smax_value <= sval)
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return 1;
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else if (reg1->smin_value > sval)
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else if (smin1 > sval)
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return 0;
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break;
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}
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@ -14477,9 +14397,7 @@ static int is_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg
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}
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}
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if (is_jmp32)
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return is_branch32_taken(reg1, reg2, opcode);
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return is_branch64_taken(reg1, reg2, opcode);
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return is_scalar_branch_taken(reg1, reg2, opcode, is_jmp32);
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}
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/* Adjusts the register min/max values in the case that the dst_reg is the
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@ -14489,15 +14407,15 @@ static int is_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg
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*/
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static void reg_set_min_max(struct bpf_reg_state *true_reg,
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struct bpf_reg_state *false_reg,
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u64 val, u32 val32,
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u64 uval, u32 uval32,
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u8 opcode, bool is_jmp32)
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{
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struct tnum false_32off = tnum_subreg(false_reg->var_off);
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struct tnum false_64off = false_reg->var_off;
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struct tnum true_32off = tnum_subreg(true_reg->var_off);
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struct tnum true_64off = true_reg->var_off;
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s64 sval = (s64)val;
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s32 sval32 = (s32)val32;
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s64 sval = (s64)uval;
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s32 sval32 = (s32)uval32;
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/* If the dst_reg is a pointer, we can't learn anything about its
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* variable offset from the compare (unless src_reg were a pointer into
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@ -14520,49 +14438,49 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
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*/
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case BPF_JEQ:
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if (is_jmp32) {
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__mark_reg32_known(true_reg, val32);
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__mark_reg32_known(true_reg, uval32);
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true_32off = tnum_subreg(true_reg->var_off);
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} else {
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___mark_reg_known(true_reg, val);
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___mark_reg_known(true_reg, uval);
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true_64off = true_reg->var_off;
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}
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break;
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case BPF_JNE:
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if (is_jmp32) {
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__mark_reg32_known(false_reg, val32);
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__mark_reg32_known(false_reg, uval32);
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false_32off = tnum_subreg(false_reg->var_off);
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} else {
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___mark_reg_known(false_reg, val);
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___mark_reg_known(false_reg, uval);
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false_64off = false_reg->var_off;
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}
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break;
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case BPF_JSET:
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if (is_jmp32) {
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false_32off = tnum_and(false_32off, tnum_const(~val32));
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if (is_power_of_2(val32))
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false_32off = tnum_and(false_32off, tnum_const(~uval32));
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if (is_power_of_2(uval32))
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true_32off = tnum_or(true_32off,
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tnum_const(val32));
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tnum_const(uval32));
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} else {
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false_64off = tnum_and(false_64off, tnum_const(~val));
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if (is_power_of_2(val))
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false_64off = tnum_and(false_64off, tnum_const(~uval));
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if (is_power_of_2(uval))
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true_64off = tnum_or(true_64off,
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tnum_const(val));
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tnum_const(uval));
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}
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break;
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case BPF_JGE:
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case BPF_JGT:
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{
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if (is_jmp32) {
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u32 false_umax = opcode == BPF_JGT ? val32 : val32 - 1;
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u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
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u32 false_umax = opcode == BPF_JGT ? uval32 : uval32 - 1;
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u32 true_umin = opcode == BPF_JGT ? uval32 + 1 : uval32;
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false_reg->u32_max_value = min(false_reg->u32_max_value,
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false_umax);
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true_reg->u32_min_value = max(true_reg->u32_min_value,
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true_umin);
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} else {
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u64 false_umax = opcode == BPF_JGT ? val : val - 1;
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u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
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u64 false_umax = opcode == BPF_JGT ? uval : uval - 1;
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u64 true_umin = opcode == BPF_JGT ? uval + 1 : uval;
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false_reg->umax_value = min(false_reg->umax_value, false_umax);
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true_reg->umin_value = max(true_reg->umin_value, true_umin);
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@ -14591,16 +14509,16 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
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case BPF_JLT:
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{
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if (is_jmp32) {
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u32 false_umin = opcode == BPF_JLT ? val32 : val32 + 1;
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u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
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u32 false_umin = opcode == BPF_JLT ? uval32 : uval32 + 1;
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u32 true_umax = opcode == BPF_JLT ? uval32 - 1 : uval32;
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false_reg->u32_min_value = max(false_reg->u32_min_value,
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false_umin);
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true_reg->u32_max_value = min(true_reg->u32_max_value,
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true_umax);
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} else {
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u64 false_umin = opcode == BPF_JLT ? val : val + 1;
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u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
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u64 false_umin = opcode == BPF_JLT ? uval : uval + 1;
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u64 true_umax = opcode == BPF_JLT ? uval - 1 : uval;
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false_reg->umin_value = max(false_reg->umin_value, false_umin);
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true_reg->umax_value = min(true_reg->umax_value, true_umax);
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@ -14649,7 +14567,7 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
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*/
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static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
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struct bpf_reg_state *false_reg,
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u64 val, u32 val32,
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u64 uval, u32 uval32,
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u8 opcode, bool is_jmp32)
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{
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opcode = flip_opcode(opcode);
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@ -14657,7 +14575,7 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
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* BPF_JA, can't get here.
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*/
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if (opcode)
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reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
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reg_set_min_max(true_reg, false_reg, uval, uval32, opcode, is_jmp32);
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}
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/* Regs are known to be equal, so intersect their min/max/var_off */
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