bpf: prepare reg_set_min_max for second set of registers

Similarly to is_branch_taken()-related refactorings, start preparing
reg_set_min_max() to handle more generic case of two non-const
registers. Start with renaming arguments to accommodate later addition
of second register as an input argument.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231102033759.2541186-17-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c77cca5..40ed261 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -14405,25 +14405,25 @@ static int is_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg
  * simply doing a BPF_K check.
  * In JEQ/JNE cases we also adjust the var_off values.
  */
-static void reg_set_min_max(struct bpf_reg_state *true_reg,
-                           struct bpf_reg_state *false_reg,
+static void reg_set_min_max(struct bpf_reg_state *true_reg1,
+                           struct bpf_reg_state *false_reg1,
                            u64 uval, u32 uval32,
                            u8 opcode, bool is_jmp32)
 {
-       struct tnum false_32off = tnum_subreg(false_reg->var_off);
-       struct tnum false_64off = false_reg->var_off;
-       struct tnum true_32off = tnum_subreg(true_reg->var_off);
-       struct tnum true_64off = true_reg->var_off;
+       struct tnum false_32off = tnum_subreg(false_reg1->var_off);
+       struct tnum false_64off = false_reg1->var_off;
+       struct tnum true_32off = tnum_subreg(true_reg1->var_off);
+       struct tnum true_64off = true_reg1->var_off;
        s64 sval = (s64)uval;
        s32 sval32 = (s32)uval32;
 
        /* If the dst_reg is a pointer, we can't learn anything about its
         * variable offset from the compare (unless src_reg were a pointer into
         * the same object, but we don't bother with that.
-        * Since false_reg and true_reg have the same type by construction, we
+        * Since false_reg1 and true_reg1 have the same type by construction, we
         * only need to check one of them for pointerness.
         */
-       if (__is_pointer_value(false, false_reg))
+       if (__is_pointer_value(false, false_reg1))
                return;
 
        switch (opcode) {
@@ -14438,20 +14438,20 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
         */
        case BPF_JEQ:
                if (is_jmp32) {
-                       __mark_reg32_known(true_reg, uval32);
-                       true_32off = tnum_subreg(true_reg->var_off);
+                       __mark_reg32_known(true_reg1, uval32);
+                       true_32off = tnum_subreg(true_reg1->var_off);
                } else {
-                       ___mark_reg_known(true_reg, uval);
-                       true_64off = true_reg->var_off;
+                       ___mark_reg_known(true_reg1, uval);
+                       true_64off = true_reg1->var_off;
                }
                break;
        case BPF_JNE:
                if (is_jmp32) {
-                       __mark_reg32_known(false_reg, uval32);
-                       false_32off = tnum_subreg(false_reg->var_off);
+                       __mark_reg32_known(false_reg1, uval32);
+                       false_32off = tnum_subreg(false_reg1->var_off);
                } else {
-                       ___mark_reg_known(false_reg, uval);
-                       false_64off = false_reg->var_off;
+                       ___mark_reg_known(false_reg1, uval);
+                       false_64off = false_reg1->var_off;
                }
                break;
        case BPF_JSET:
@@ -14474,16 +14474,16 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
                        u32 false_umax = opcode == BPF_JGT ? uval32  : uval32 - 1;
                        u32 true_umin = opcode == BPF_JGT ? uval32 + 1 : uval32;
 
-                       false_reg->u32_max_value = min(false_reg->u32_max_value,
+                       false_reg1->u32_max_value = min(false_reg1->u32_max_value,
                                                       false_umax);
-                       true_reg->u32_min_value = max(true_reg->u32_min_value,
+                       true_reg1->u32_min_value = max(true_reg1->u32_min_value,
                                                      true_umin);
                } else {
                        u64 false_umax = opcode == BPF_JGT ? uval    : uval - 1;
                        u64 true_umin = opcode == BPF_JGT ? uval + 1 : uval;
 
-                       false_reg->umax_value = min(false_reg->umax_value, false_umax);
-                       true_reg->umin_value = max(true_reg->umin_value, true_umin);
+                       false_reg1->umax_value = min(false_reg1->umax_value, false_umax);
+                       true_reg1->umin_value = max(true_reg1->umin_value, true_umin);
                }
                break;
        }
@@ -14494,14 +14494,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
                        s32 false_smax = opcode == BPF_JSGT ? sval32    : sval32 - 1;
                        s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
 
-                       false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
-                       true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
+                       false_reg1->s32_max_value = min(false_reg1->s32_max_value, false_smax);
+                       true_reg1->s32_min_value = max(true_reg1->s32_min_value, true_smin);
                } else {
                        s64 false_smax = opcode == BPF_JSGT ? sval    : sval - 1;
                        s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
 
-                       false_reg->smax_value = min(false_reg->smax_value, false_smax);
-                       true_reg->smin_value = max(true_reg->smin_value, true_smin);
+                       false_reg1->smax_value = min(false_reg1->smax_value, false_smax);
+                       true_reg1->smin_value = max(true_reg1->smin_value, true_smin);
                }
                break;
        }
@@ -14512,16 +14512,16 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
                        u32 false_umin = opcode == BPF_JLT ? uval32  : uval32 + 1;
                        u32 true_umax = opcode == BPF_JLT ? uval32 - 1 : uval32;
 
-                       false_reg->u32_min_value = max(false_reg->u32_min_value,
+                       false_reg1->u32_min_value = max(false_reg1->u32_min_value,
                                                       false_umin);
-                       true_reg->u32_max_value = min(true_reg->u32_max_value,
+                       true_reg1->u32_max_value = min(true_reg1->u32_max_value,
                                                      true_umax);
                } else {
                        u64 false_umin = opcode == BPF_JLT ? uval    : uval + 1;
                        u64 true_umax = opcode == BPF_JLT ? uval - 1 : uval;
 
-                       false_reg->umin_value = max(false_reg->umin_value, false_umin);
-                       true_reg->umax_value = min(true_reg->umax_value, true_umax);
+                       false_reg1->umin_value = max(false_reg1->umin_value, false_umin);
+                       true_reg1->umax_value = min(true_reg1->umax_value, true_umax);
                }
                break;
        }
@@ -14532,14 +14532,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
                        s32 false_smin = opcode == BPF_JSLT ? sval32    : sval32 + 1;
                        s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
 
-                       false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
-                       true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
+                       false_reg1->s32_min_value = max(false_reg1->s32_min_value, false_smin);
+                       true_reg1->s32_max_value = min(true_reg1->s32_max_value, true_smax);
                } else {
                        s64 false_smin = opcode == BPF_JSLT ? sval    : sval + 1;
                        s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
 
-                       false_reg->smin_value = max(false_reg->smin_value, false_smin);
-                       true_reg->smax_value = min(true_reg->smax_value, true_smax);
+                       false_reg1->smin_value = max(false_reg1->smin_value, false_smin);
+                       true_reg1->smax_value = min(true_reg1->smax_value, true_smax);
                }
                break;
        }
@@ -14548,17 +14548,17 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
        }
 
        if (is_jmp32) {
-               false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
+               false_reg1->var_off = tnum_or(tnum_clear_subreg(false_64off),
                                             tnum_subreg(false_32off));
-               true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
+               true_reg1->var_off = tnum_or(tnum_clear_subreg(true_64off),
                                            tnum_subreg(true_32off));
-               reg_bounds_sync(false_reg);
-               reg_bounds_sync(true_reg);
+               reg_bounds_sync(false_reg1);
+               reg_bounds_sync(true_reg1);
        } else {
-               false_reg->var_off = false_64off;
-               true_reg->var_off = true_64off;
-               reg_bounds_sync(false_reg);
-               reg_bounds_sync(true_reg);
+               false_reg1->var_off = false_64off;
+               true_reg1->var_off = true_64off;
+               reg_bounds_sync(false_reg1);
+               reg_bounds_sync(true_reg1);
        }
 }