dbd7eb14e0
The tailcall_3 test program uses bpf_tail_call_static() where the JIT would patch a direct jump. Add a new tailcall_6 test program replicating exactly the same test just ensuring that bpf_tail_call() uses a map index where the verifier cannot make assumptions this time. In other words, this will now cover both on x86-64 JIT, meaning, JIT images with emit_bpf_tail_call_direct() emission as well as JIT images with emit_bpf_tail_call_indirect() emission. # echo 1 > /proc/sys/net/core/bpf_jit_enable # ./test_progs -t tailcalls #136/1 tailcalls/tailcall_1:OK #136/2 tailcalls/tailcall_2:OK #136/3 tailcalls/tailcall_3:OK #136/4 tailcalls/tailcall_4:OK #136/5 tailcalls/tailcall_5:OK #136/6 tailcalls/tailcall_6:OK #136/7 tailcalls/tailcall_bpf2bpf_1:OK #136/8 tailcalls/tailcall_bpf2bpf_2:OK #136/9 tailcalls/tailcall_bpf2bpf_3:OK #136/10 tailcalls/tailcall_bpf2bpf_4:OK #136/11 tailcalls/tailcall_bpf2bpf_5:OK #136 tailcalls:OK Summary: 1/11 PASSED, 0 SKIPPED, 0 FAILED # echo 0 > /proc/sys/net/core/bpf_jit_enable # ./test_progs -t tailcalls #136/1 tailcalls/tailcall_1:OK #136/2 tailcalls/tailcall_2:OK #136/3 tailcalls/tailcall_3:OK #136/4 tailcalls/tailcall_4:OK #136/5 tailcalls/tailcall_5:OK #136/6 tailcalls/tailcall_6:OK [...] For interpreter, the tailcall_1-6 tests are passing as well. The later tailcall_bpf2bpf_* are failing due lack of bpf2bpf + tailcall support in interpreter, so this is expected. Also, manual inspection shows that both loaded programs from tailcall_3 and tailcall_6 test case emit the expected opcodes: * tailcall_3 disasm, emit_bpf_tail_call_direct(): [...] b: push %rax c: push %rbx d: push %r13 f: mov %rdi,%rbx 12: movabs $0xffff8d3f5afb0200,%r13 1c: mov %rbx,%rdi 1f: mov %r13,%rsi 22: xor %edx,%edx _ 24: mov -0x4(%rbp),%eax | limit check 2a: cmp $0x20,%eax | 2d: ja 0x0000000000000046 | 2f: add $0x1,%eax | 32: mov %eax,-0x4(%rbp) |_ 38: nopl 0x0(%rax,%rax,1) 3d: pop %r13 3f: pop %rbx 40: pop %rax 41: jmpq 0xffffffffffffe377 [...] * tailcall_6 disasm, emit_bpf_tail_call_indirect(): [...] 47: movabs $0xffff8d3f59143a00,%rsi 51: mov %edx,%edx 53: cmp %edx,0x24(%rsi) 56: jbe 0x0000000000000093 _ 58: mov -0x4(%rbp),%eax | limit check 5e: cmp $0x20,%eax | 61: ja 0x0000000000000093 | 63: add $0x1,%eax | 66: mov %eax,-0x4(%rbp) |_ 6c: mov 0x110(%rsi,%rdx,8),%rcx 74: test %rcx,%rcx 77: je 0x0000000000000093 79: pop %rax 7a: mov 0x30(%rcx),%rcx 7e: add $0xb,%rcx 82: callq 0x000000000000008e 87: pause 89: lfence 8c: jmp 0x0000000000000087 8e: mov %rcx,(%rsp) 92: retq [...] Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Acked-by: Paul Chaignon <paul@cilium.io> Link: https://lore.kernel.org/bpf/CAM1=_QRyRVCODcXo_Y6qOm1iT163HoiSj8U2pZ8Rj3hzMTT=HQ@mail.gmail.com Link: https://lore.kernel.org/bpf/20210910091900.16119-1-daniel@iogearbox.net
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.