| // SPDX-License-Identifier: GPL-2.0 |
| |
| #include <linux/bpf.h> |
| #include <bpf/bpf_helpers.h> |
| #include "bpf_misc.h" |
| |
| /* Check that precision marks propagate through scalar IDs. |
| * Registers r{0,1,2} have the same scalar ID at the moment when r0 is |
| * marked to be precise, this mark is immediately propagated to r{1,2}. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("frame0: regs=r0,r1,r2 stack= before 4: (bf) r3 = r10") |
| __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") |
| __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_same_state(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == r2.id */ |
| "r1 = r0;" |
| "r2 = r0;" |
| /* force r0 to be precise, this immediately marks r1 and r2 as |
| * precise as well because of shared IDs |
| */ |
| "r3 = r10;" |
| "r3 += r0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Same as precision_same_state, but mark propagates through state / |
| * parent state boundary. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("frame0: last_idx 6 first_idx 5 subseq_idx -1") |
| __msg("frame0: regs=r0,r1,r2 stack= before 5: (bf) r3 = r10") |
| __msg("frame0: parent state regs=r0,r1,r2 stack=:") |
| __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0") |
| __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") |
| __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __msg("frame0: parent state regs=r0 stack=:") |
| __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_cross_state(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == r2.id */ |
| "r1 = r0;" |
| "r2 = r0;" |
| /* force checkpoint */ |
| "goto +0;" |
| /* force r0 to be precise, this immediately marks r1 and r2 as |
| * precise as well because of shared IDs |
| */ |
| "r3 = r10;" |
| "r3 += r0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Same as precision_same_state, but break one of the |
| * links, note that r1 is absent from regs=... in __msg below. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("frame0: regs=r0,r2 stack= before 5: (bf) r3 = r10") |
| __msg("frame0: regs=r0,r2 stack= before 4: (b7) r1 = 0") |
| __msg("frame0: regs=r0,r2 stack= before 3: (bf) r2 = r0") |
| __msg("frame0: regs=r0 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_same_state_broken_link(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == r2.id */ |
| "r1 = r0;" |
| "r2 = r0;" |
| /* break link for r1, this is the only line that differs |
| * compared to the previous test |
| */ |
| "r1 = 0;" |
| /* force r0 to be precise, this immediately marks r1 and r2 as |
| * precise as well because of shared IDs |
| */ |
| "r3 = r10;" |
| "r3 += r0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Same as precision_same_state_broken_link, but with state / |
| * parent state boundary. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("frame0: regs=r0,r2 stack= before 6: (bf) r3 = r10") |
| __msg("frame0: regs=r0,r2 stack= before 5: (b7) r1 = 0") |
| __msg("frame0: parent state regs=r0,r2 stack=:") |
| __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0") |
| __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") |
| __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __msg("frame0: parent state regs=r0 stack=:") |
| __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_cross_state_broken_link(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == r2.id */ |
| "r1 = r0;" |
| "r2 = r0;" |
| /* force checkpoint, although link between r1 and r{0,2} is |
| * broken by the next statement current precision tracking |
| * algorithm can't react to it and propagates mark for r1 to |
| * the parent state. |
| */ |
| "goto +0;" |
| /* break link for r1, this is the only line that differs |
| * compared to precision_cross_state() |
| */ |
| "r1 = 0;" |
| /* force r0 to be precise, this immediately marks r1 and r2 as |
| * precise as well because of shared IDs |
| */ |
| "r3 = r10;" |
| "r3 += r0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Check that precision marks propagate through scalar IDs. |
| * Use the same scalar ID in multiple stack frames, check that |
| * precision information is propagated up the call stack. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("11: (0f) r2 += r1") |
| /* Current state */ |
| __msg("frame2: last_idx 11 first_idx 10 subseq_idx -1") |
| __msg("frame2: regs=r1 stack= before 10: (bf) r2 = r10") |
| __msg("frame2: parent state regs=r1 stack=") |
| /* frame1.r{6,7} are marked because mark_precise_scalar_ids() |
| * looks for all registers with frame2.r1.id in the current state |
| */ |
| __msg("frame1: parent state regs=r6,r7 stack=") |
| __msg("frame0: parent state regs=r6 stack=") |
| /* Parent state */ |
| __msg("frame2: last_idx 8 first_idx 8 subseq_idx 10") |
| __msg("frame2: regs=r1 stack= before 8: (85) call pc+1") |
| /* frame1.r1 is marked because of backtracking of call instruction */ |
| __msg("frame1: parent state regs=r1,r6,r7 stack=") |
| __msg("frame0: parent state regs=r6 stack=") |
| /* Parent state */ |
| __msg("frame1: last_idx 7 first_idx 6 subseq_idx 8") |
| __msg("frame1: regs=r1,r6,r7 stack= before 7: (bf) r7 = r1") |
| __msg("frame1: regs=r1,r6 stack= before 6: (bf) r6 = r1") |
| __msg("frame1: parent state regs=r1 stack=") |
| __msg("frame0: parent state regs=r6 stack=") |
| /* Parent state */ |
| __msg("frame1: last_idx 4 first_idx 4 subseq_idx 6") |
| __msg("frame1: regs=r1 stack= before 4: (85) call pc+1") |
| __msg("frame0: parent state regs=r1,r6 stack=") |
| /* Parent state */ |
| __msg("frame0: last_idx 3 first_idx 1 subseq_idx 4") |
| __msg("frame0: regs=r0,r1,r6 stack= before 3: (bf) r6 = r0") |
| __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_many_frames(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == r6.id */ |
| "r1 = r0;" |
| "r6 = r0;" |
| "call precision_many_frames__foo;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| static __naked __noinline __used |
| void precision_many_frames__foo(void) |
| { |
| asm volatile ( |
| /* conflate one of the register numbers (r6) with outer frame, |
| * to verify that those are tracked independently |
| */ |
| "r6 = r1;" |
| "r7 = r1;" |
| "call precision_many_frames__bar;" |
| "exit" |
| ::: __clobber_all); |
| } |
| |
| static __naked __noinline __used |
| void precision_many_frames__bar(void) |
| { |
| asm volatile ( |
| /* force r1 to be precise, this immediately marks: |
| * - bar frame r1 |
| * - foo frame r{1,6,7} |
| * - main frame r{1,6} |
| */ |
| "r2 = r10;" |
| "r2 += r1;" |
| "r0 = 0;" |
| "exit;" |
| ::: __clobber_all); |
| } |
| |
| /* Check that scalars with the same IDs are marked precise on stack as |
| * well as in registers. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| /* foo frame */ |
| __msg("frame1: regs=r1 stack=-8,-16 before 9: (bf) r2 = r10") |
| __msg("frame1: regs=r1 stack=-8,-16 before 8: (7b) *(u64 *)(r10 -16) = r1") |
| __msg("frame1: regs=r1 stack=-8 before 7: (7b) *(u64 *)(r10 -8) = r1") |
| __msg("frame1: regs=r1 stack= before 4: (85) call pc+2") |
| /* main frame */ |
| __msg("frame0: regs=r0,r1 stack=-8 before 3: (7b) *(u64 *)(r10 -8) = r1") |
| __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") |
| __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_stack(void) |
| { |
| asm volatile ( |
| /* r0 = random number up to 0xff */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* tie r0.id == r1.id == fp[-8].id */ |
| "r1 = r0;" |
| "*(u64*)(r10 - 8) = r1;" |
| "call precision_stack__foo;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| static __naked __noinline __used |
| void precision_stack__foo(void) |
| { |
| asm volatile ( |
| /* conflate one of the register numbers (r6) with outer frame, |
| * to verify that those are tracked independently |
| */ |
| "*(u64*)(r10 - 8) = r1;" |
| "*(u64*)(r10 - 16) = r1;" |
| /* force r1 to be precise, this immediately marks: |
| * - foo frame r1,fp{-8,-16} |
| * - main frame r1,fp{-8} |
| */ |
| "r2 = r10;" |
| "r2 += r1;" |
| "exit" |
| ::: __clobber_all); |
| } |
| |
| /* Use two separate scalar IDs to check that these are propagated |
| * independently. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| /* r{6,7} */ |
| __msg("11: (0f) r3 += r7") |
| __msg("frame0: regs=r6,r7 stack= before 10: (bf) r3 = r10") |
| /* ... skip some insns ... */ |
| __msg("frame0: regs=r6,r7 stack= before 3: (bf) r7 = r0") |
| __msg("frame0: regs=r0,r6 stack= before 2: (bf) r6 = r0") |
| /* r{8,9} */ |
| __msg("12: (0f) r3 += r9") |
| __msg("frame0: regs=r8,r9 stack= before 11: (0f) r3 += r7") |
| /* ... skip some insns ... */ |
| __msg("frame0: regs=r8,r9 stack= before 7: (bf) r9 = r0") |
| __msg("frame0: regs=r0,r8 stack= before 6: (bf) r8 = r0") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void precision_two_ids(void) |
| { |
| asm volatile ( |
| /* r6 = random number up to 0xff |
| * r6.id == r7.id |
| */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| "r6 = r0;" |
| "r7 = r0;" |
| /* same, but for r{8,9} */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| "r8 = r0;" |
| "r9 = r0;" |
| /* clear r0 id */ |
| "r0 = 0;" |
| /* force checkpoint */ |
| "goto +0;" |
| "r3 = r10;" |
| /* force r7 to be precise, this also marks r6 */ |
| "r3 += r7;" |
| /* force r9 to be precise, this also marks r8 */ |
| "r3 += r9;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Verify that check_ids() is used by regsafe() for scalars. |
| * |
| * r9 = ... some pointer with range X ... |
| * r6 = ... unbound scalar ID=a ... |
| * r7 = ... unbound scalar ID=b ... |
| * if (r6 > r7) goto +1 |
| * r7 = r6 |
| * if (r7 > X) goto exit |
| * r9 += r6 |
| * ... access memory using r9 ... |
| * |
| * The memory access is safe only if r7 is bounded, |
| * which is true for one branch and not true for another. |
| */ |
| SEC("socket") |
| __failure __msg("register with unbounded min value") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void check_ids_in_regsafe(void) |
| { |
| asm volatile ( |
| /* Bump allocated stack */ |
| "r1 = 0;" |
| "*(u64*)(r10 - 8) = r1;" |
| /* r9 = pointer to stack */ |
| "r9 = r10;" |
| "r9 += -8;" |
| /* r7 = ktime_get_ns() */ |
| "call %[bpf_ktime_get_ns];" |
| "r7 = r0;" |
| /* r6 = ktime_get_ns() */ |
| "call %[bpf_ktime_get_ns];" |
| "r6 = r0;" |
| /* if r6 > r7 is an unpredictable jump */ |
| "if r6 > r7 goto l1_%=;" |
| "r7 = r6;" |
| "l1_%=:" |
| /* if r7 > 4 ...; transfers range to r6 on one execution path |
| * but does not transfer on another |
| */ |
| "if r7 > 4 goto l2_%=;" |
| /* Access memory at r9[r6], r6 is not always bounded */ |
| "r9 += r6;" |
| "r0 = *(u8*)(r9 + 0);" |
| "l2_%=:" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Similar to check_ids_in_regsafe. |
| * The l0 could be reached in two states: |
| * |
| * (1) r6{.id=A}, r7{.id=A}, r8{.id=B} |
| * (2) r6{.id=B}, r7{.id=A}, r8{.id=B} |
| * |
| * Where (2) is not safe, as "r7 > 4" check won't propagate range for it. |
| * This example would be considered safe without changes to |
| * mark_chain_precision() to track scalar values with equal IDs. |
| */ |
| SEC("socket") |
| __failure __msg("register with unbounded min value") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void check_ids_in_regsafe_2(void) |
| { |
| asm volatile ( |
| /* Bump allocated stack */ |
| "r1 = 0;" |
| "*(u64*)(r10 - 8) = r1;" |
| /* r9 = pointer to stack */ |
| "r9 = r10;" |
| "r9 += -8;" |
| /* r8 = ktime_get_ns() */ |
| "call %[bpf_ktime_get_ns];" |
| "r8 = r0;" |
| /* r7 = ktime_get_ns() */ |
| "call %[bpf_ktime_get_ns];" |
| "r7 = r0;" |
| /* r6 = ktime_get_ns() */ |
| "call %[bpf_ktime_get_ns];" |
| "r6 = r0;" |
| /* scratch .id from r0 */ |
| "r0 = 0;" |
| /* if r6 > r7 is an unpredictable jump */ |
| "if r6 > r7 goto l1_%=;" |
| /* tie r6 and r7 .id */ |
| "r6 = r7;" |
| "l0_%=:" |
| /* if r7 > 4 exit(0) */ |
| "if r7 > 4 goto l2_%=;" |
| /* Access memory at r9[r6] */ |
| "r9 += r6;" |
| "r0 = *(u8*)(r9 + 0);" |
| "l2_%=:" |
| "r0 = 0;" |
| "exit;" |
| "l1_%=:" |
| /* tie r6 and r8 .id */ |
| "r6 = r8;" |
| "goto l0_%=;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Check that scalar IDs *are not* generated on register to register |
| * assignments if source register is a constant. |
| * |
| * If such IDs *are* generated the 'l1' below would be reached in |
| * two states: |
| * |
| * (1) r1{.id=A}, r2{.id=A} |
| * (2) r1{.id=C}, r2{.id=C} |
| * |
| * Thus forcing 'if r1 == r2' verification twice. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("11: (1d) if r3 == r4 goto pc+0") |
| __msg("frame 0: propagating r3,r4") |
| __msg("11: safe") |
| __msg("processed 15 insns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void no_scalar_id_for_const(void) |
| { |
| asm volatile ( |
| "call %[bpf_ktime_get_ns];" |
| /* unpredictable jump */ |
| "if r0 > 7 goto l0_%=;" |
| /* possibly generate same scalar ids for r3 and r4 */ |
| "r1 = 0;" |
| "r1 = r1;" |
| "r3 = r1;" |
| "r4 = r1;" |
| "goto l1_%=;" |
| "l0_%=:" |
| /* possibly generate different scalar ids for r3 and r4 */ |
| "r1 = 0;" |
| "r2 = 0;" |
| "r3 = r1;" |
| "r4 = r2;" |
| "l1_%=:" |
| /* predictable jump, marks r3 and r4 precise */ |
| "if r3 == r4 goto +0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Same as no_scalar_id_for_const() but for 32-bit values */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("11: (1e) if w3 == w4 goto pc+0") |
| __msg("frame 0: propagating r3,r4") |
| __msg("11: safe") |
| __msg("processed 15 insns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void no_scalar_id_for_const32(void) |
| { |
| asm volatile ( |
| "call %[bpf_ktime_get_ns];" |
| /* unpredictable jump */ |
| "if r0 > 7 goto l0_%=;" |
| /* possibly generate same scalar ids for r3 and r4 */ |
| "w1 = 0;" |
| "w1 = w1;" |
| "w3 = w1;" |
| "w4 = w1;" |
| "goto l1_%=;" |
| "l0_%=:" |
| /* possibly generate different scalar ids for r3 and r4 */ |
| "w1 = 0;" |
| "w2 = 0;" |
| "w3 = w1;" |
| "w4 = w2;" |
| "l1_%=:" |
| /* predictable jump, marks r1 and r2 precise */ |
| "if w3 == w4 goto +0;" |
| "r0 = 0;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Check that unique scalar IDs are ignored when new verifier state is |
| * compared to cached verifier state. For this test: |
| * - cached state has no id on r1 |
| * - new state has a unique id on r1 |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("6: (25) if r6 > 0x7 goto pc+1") |
| __msg("7: (57) r1 &= 255") |
| __msg("8: (bf) r2 = r10") |
| __msg("from 6 to 8: safe") |
| __msg("processed 12 insns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void ignore_unique_scalar_ids_cur(void) |
| { |
| asm volatile ( |
| "call %[bpf_ktime_get_ns];" |
| "r6 = r0;" |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* r1.id == r0.id */ |
| "r1 = r0;" |
| /* make r1.id unique */ |
| "r0 = 0;" |
| "if r6 > 7 goto l0_%=;" |
| /* clear r1 id, but keep the range compatible */ |
| "r1 &= 0xff;" |
| "l0_%=:" |
| /* get here in two states: |
| * - first: r1 has no id (cached state) |
| * - second: r1 has a unique id (should be considered equivalent) |
| */ |
| "r2 = r10;" |
| "r2 += r1;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Check that unique scalar IDs are ignored when new verifier state is |
| * compared to cached verifier state. For this test: |
| * - cached state has a unique id on r1 |
| * - new state has no id on r1 |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| __msg("6: (25) if r6 > 0x7 goto pc+1") |
| __msg("7: (05) goto pc+1") |
| __msg("9: (bf) r2 = r10") |
| __msg("9: safe") |
| __msg("processed 13 insns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void ignore_unique_scalar_ids_old(void) |
| { |
| asm volatile ( |
| "call %[bpf_ktime_get_ns];" |
| "r6 = r0;" |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| /* r1.id == r0.id */ |
| "r1 = r0;" |
| /* make r1.id unique */ |
| "r0 = 0;" |
| "if r6 > 7 goto l1_%=;" |
| "goto l0_%=;" |
| "l1_%=:" |
| /* clear r1 id, but keep the range compatible */ |
| "r1 &= 0xff;" |
| "l0_%=:" |
| /* get here in two states: |
| * - first: r1 has a unique id (cached state) |
| * - second: r1 has no id (should be considered equivalent) |
| */ |
| "r2 = r10;" |
| "r2 += r1;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| /* Check that two different scalar IDs in a verified state can't be |
| * mapped to the same scalar ID in current state. |
| */ |
| SEC("socket") |
| __success __log_level(2) |
| /* The exit instruction should be reachable from two states, |
| * use two matches and "processed .. insns" to ensure this. |
| */ |
| __msg("13: (95) exit") |
| __msg("13: (95) exit") |
| __msg("processed 18 insns") |
| __flag(BPF_F_TEST_STATE_FREQ) |
| __naked void two_old_ids_one_cur_id(void) |
| { |
| asm volatile ( |
| /* Give unique scalar IDs to r{6,7} */ |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| "r6 = r0;" |
| "call %[bpf_ktime_get_ns];" |
| "r0 &= 0xff;" |
| "r7 = r0;" |
| "r0 = 0;" |
| /* Maybe make r{6,7} IDs identical */ |
| "if r6 > r7 goto l0_%=;" |
| "goto l1_%=;" |
| "l0_%=:" |
| "r6 = r7;" |
| "l1_%=:" |
| /* Mark r{6,7} precise. |
| * Get here in two states: |
| * - first: r6{.id=A}, r7{.id=B} (cached state) |
| * - second: r6{.id=A}, r7{.id=A} |
| * Currently we don't want to consider such states equivalent. |
| * Thus "exit;" would be verified twice. |
| */ |
| "r2 = r10;" |
| "r2 += r6;" |
| "r2 += r7;" |
| "exit;" |
| : |
| : __imm(bpf_ktime_get_ns) |
| : __clobber_all); |
| } |
| |
| char _license[] SEC("license") = "GPL"; |
