diff options
-rw-r--r-- | arch/x86/net/Makefile | 2 | ||||
-rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 5 | ||||
-rw-r--r-- | arch/x86/net/bpf_timed_may_goto.S | 44 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c | 58 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_may_goto_1.c | 34 |
5 files changed, 130 insertions, 13 deletions
diff --git a/arch/x86/net/Makefile b/arch/x86/net/Makefile index 383c87300b0d..dddbefc0f439 100644 --- a/arch/x86/net/Makefile +++ b/arch/x86/net/Makefile @@ -6,5 +6,5 @@ ifeq ($(CONFIG_X86_32),y) obj-$(CONFIG_BPF_JIT) += bpf_jit_comp32.o else - obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o + obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o bpf_timed_may_goto.o endif diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index a43fc5af973d..f3e9ef6b5329 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -3791,3 +3791,8 @@ u64 bpf_arch_uaddress_limit(void) { return 0; } + +bool bpf_jit_supports_timed_may_goto(void) +{ + return true; +} diff --git a/arch/x86/net/bpf_timed_may_goto.S b/arch/x86/net/bpf_timed_may_goto.S new file mode 100644 index 000000000000..20de4a14dc4c --- /dev/null +++ b/arch/x86/net/bpf_timed_may_goto.S @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include <linux/export.h> +#include <linux/linkage.h> +#include <asm/nospec-branch.h> + + .code64 + .section .text, "ax" + +SYM_FUNC_START(arch_bpf_timed_may_goto) + ANNOTATE_NOENDBR + + /* Save r0-r5. */ + pushq %rax + pushq %rdi + pushq %rsi + pushq %rdx + pushq %rcx + pushq %r8 + + /* + * r10 passes us stack depth, load the pointer to count and timestamp as + * first argument to the call below. + */ + leaq (%rbp, %r10, 1), %rdi + + /* Emit call depth accounting for call below. */ + CALL_DEPTH_ACCOUNT + call bpf_check_timed_may_goto + + /* BPF_REG_AX=r10 will be stored into count, so move return value to it. */ + movq %rax, %r10 + + /* Restore r5-r0. */ + popq %r8 + popq %rcx + popq %rdx + popq %rsi + popq %rdi + popq %rax + + RET +SYM_FUNC_END(arch_bpf_timed_may_goto) diff --git a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c index 5094c288cfd7..a9be6ae49454 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c +++ b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c @@ -620,23 +620,61 @@ __naked void helper_call_does_not_prevent_bpf_fastcall(void) SEC("raw_tp") __arch_x86_64 +__log_level(4) __msg("stack depth 24") +/* may_goto counter at -24 */ +__xlated("0: *(u64 *)(r10 -24) =") +/* may_goto timestamp at -16 */ +__xlated("1: *(u64 *)(r10 -16) =") +__xlated("2: r1 = 1") +__xlated("...") +__xlated("4: r0 = &(void __percpu *)(r0)") +__xlated("...") +/* may_goto expansion starts */ +__xlated("6: r11 = *(u64 *)(r10 -24)") +__xlated("7: if r11 == 0x0 goto pc+6") +__xlated("8: r11 -= 1") +__xlated("9: if r11 != 0x0 goto pc+2") +__xlated("10: r11 = -24") +__xlated("11: call unknown") +__xlated("12: *(u64 *)(r10 -24) = r11") +/* may_goto expansion ends */ +__xlated("13: *(u64 *)(r10 -8) = r1") +__xlated("14: exit") +__success +__naked void may_goto_interaction_x86_64(void) +{ + asm volatile ( + "r1 = 1;" + "*(u64 *)(r10 - 16) = r1;" + "call %[bpf_get_smp_processor_id];" + "r1 = *(u64 *)(r10 - 16);" + ".8byte %[may_goto];" + /* just touch some stack at -8 */ + "*(u64 *)(r10 - 8) = r1;" + "exit;" + : + : __imm(bpf_get_smp_processor_id), + __imm_insn(may_goto, BPF_RAW_INSN(BPF_JMP | BPF_JCOND, 0, 0, +1 /* offset */, 0)) + : __clobber_all); +} + +SEC("raw_tp") +__arch_arm64 __log_level(4) __msg("stack depth 16") /* may_goto counter at -16 */ __xlated("0: *(u64 *)(r10 -16) =") __xlated("1: r1 = 1") -__xlated("...") -__xlated("3: r0 = &(void __percpu *)(r0)") -__xlated("...") +__xlated("2: call bpf_get_smp_processor_id") /* may_goto expansion starts */ -__xlated("5: r11 = *(u64 *)(r10 -16)") -__xlated("6: if r11 == 0x0 goto pc+3") -__xlated("7: r11 -= 1") -__xlated("8: *(u64 *)(r10 -16) = r11") +__xlated("3: r11 = *(u64 *)(r10 -16)") +__xlated("4: if r11 == 0x0 goto pc+3") +__xlated("5: r11 -= 1") +__xlated("6: *(u64 *)(r10 -16) = r11") /* may_goto expansion ends */ -__xlated("9: *(u64 *)(r10 -8) = r1") -__xlated("10: exit") +__xlated("7: *(u64 *)(r10 -8) = r1") +__xlated("8: exit") __success -__naked void may_goto_interaction(void) +__naked void may_goto_interaction_arm64(void) { asm volatile ( "r1 = 1;" diff --git a/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c b/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c index e81097c96fe2..3966d827f288 100644 --- a/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c +++ b/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c @@ -69,8 +69,38 @@ __naked void may_goto_batch_1(void) } SEC("raw_tp") -__description("may_goto batch with offsets 2/0") +__description("may_goto batch with offsets 2/0 - x86_64") __arch_x86_64 +__xlated("0: *(u64 *)(r10 -16) = 65535") +__xlated("1: *(u64 *)(r10 -8) = 0") +__xlated("2: r11 = *(u64 *)(r10 -16)") +__xlated("3: if r11 == 0x0 goto pc+6") +__xlated("4: r11 -= 1") +__xlated("5: if r11 != 0x0 goto pc+2") +__xlated("6: r11 = -16") +__xlated("7: call unknown") +__xlated("8: *(u64 *)(r10 -16) = r11") +__xlated("9: r0 = 1") +__xlated("10: r0 = 2") +__xlated("11: exit") +__success +__naked void may_goto_batch_2_x86_64(void) +{ + asm volatile ( + ".8byte %[may_goto1];" + ".8byte %[may_goto3];" + "r0 = 1;" + "r0 = 2;" + "exit;" + : + : __imm_insn(may_goto1, BPF_RAW_INSN(BPF_JMP | BPF_JCOND, 0, 0, 2 /* offset */, 0)), + __imm_insn(may_goto3, BPF_RAW_INSN(BPF_JMP | BPF_JCOND, 0, 0, 0 /* offset */, 0)) + : __clobber_all); +} + +SEC("raw_tp") +__description("may_goto batch with offsets 2/0 - arm64") +__arch_arm64 __xlated("0: *(u64 *)(r10 -8) = 8388608") __xlated("1: r11 = *(u64 *)(r10 -8)") __xlated("2: if r11 == 0x0 goto pc+3") @@ -80,7 +110,7 @@ __xlated("5: r0 = 1") __xlated("6: r0 = 2") __xlated("7: exit") __success -__naked void may_goto_batch_2(void) +__naked void may_goto_batch_2_arm64(void) { asm volatile ( ".8byte %[may_goto1];" |