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  1. 10 Feb, 2021 2 commits
    • Andrei Matei's avatar
      selftest/bpf: Adjust expected verifier errors · a680cb3d
      Andrei Matei authored 
      The verifier errors around stack accesses have changed slightly in the
previous commit (generally for the better).
Signed-off-by: default avatarAndrei Matei <andreimatei1@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-3-andreimatei1@gmail.com
      a680cb3d
    • Andrei Matei's avatar
      bpf: Allow variable-offset stack access · 01f810ac
      Andrei Matei authored 
      Before this patch, variable offset access to the stack was dissalowed
for regular instructions, but was allowed for "indirect" accesses (i.e.
helpers). This patch removes the restriction, allowing reading and
writing to the stack through stack pointers with variable offsets. This
makes stack-allocated buffers more usable in programs, and brings stack
pointers closer to other types of pointers.

The motivation is being able to use stack-allocated buffers for data
manipulation. When the stack size limit is sufficient, allocating
buffers on the stack is simpler than per-cpu arrays, or other
alternatives.

In unpriviledged programs, variable-offset reads and writes are
disallowed (they were already disallowed for the indirect access case)
because the speculative execution checking code doesn't support them.
Additionally, when writing through a variable-offset stack pointer, if
any pointers are in the accessible range, there's possilibities of later
leaking pointers because the write cannot be tracked precisely.

Writes with variable offset mark the whole range as initialized, even
though we don't know which stack slots are actually written. This is in
order to not reject future reads to these slots. Note that this doesn't
affect writes done through helpers; like before, helpers need the whole
stack range to be initialized to begin with.
All the stack slots are in range are considered scalars after the write;
variable-offset register spills are not tracked.

For reads, all the stack slots in the variable range needs to be
initialized (but see above about what writes do), otherwise the read is
rejected. All register spilled in stack slots that might be read are
marked as having been read, however reads through such pointers don't do
register filling; the target register will always be either a scalar or
a constant zero.
Signed-off-by: default avatarAndrei Matei <andreimatei1@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-2-andreimatei1@gmail.com
      01f810ac
  3. 09 Feb, 2021 8 commits
  5. 08 Feb, 2021 1 commit
  7. 05 Feb, 2021 7 commits
  9. 04 Feb, 2021 3 commits
  11. 03 Feb, 2021 4 commits
  13. 02 Feb, 2021 1 commit
    • Tiezhu Yang's avatar
      samples/bpf: Add include dir for MIPS Loongson64 to fix build errors · 058107ab
      Tiezhu Yang authored 
      There exists many build errors when make M=samples/bpf on the Loongson
platform. This issue is MIPS related, x86 compiles just fine.

Here are some errors:

  CLANG-bpf  samples/bpf/sockex2_kern.o
In file included from samples/bpf/sockex2_kern.c:2:
In file included from ./include/uapi/linux/in.h:24:
In file included from ./include/linux/socket.h:8:
In file included from ./include/linux/uio.h:8:
In file included from ./include/linux/kernel.h:11:
In file included from ./include/linux/bitops.h:32:
In file included from ./arch/mips/include/asm/bitops.h:19:
In file included from ./arch/mips/include/asm/barrier.h:11:
./arch/mips/include/asm/addrspace.h:13:10: fatal error: 'spaces.h' file not found
         ^~~~~~~~~~
1 error generated.

  CLANG-bpf  samples/bpf/sockex2_kern.o
In file included from samples/bpf/sockex2_kern.c:2:
In file included from ./include/uapi/linux/in.h:24:
In file included from ./include/linux/socket.h:8:
In file included from ./include/linux/uio.h:8:
In file included from ./include/linux/kernel.h:11:
In file included from ./include/linux/bitops.h:32:
In file included from ./arch/mips/include/asm/bitops.h:22:
In file included from ./arch/mips/include/asm/cpu-features.h:13:
In file included from ./arch/mips/include/asm/cpu-info.h:15:
In file included from ./include/linux/cache.h:6:
./arch/mips/include/asm/cache.h:12:10: fatal error: 'kmalloc.h' file not found
         ^~~~~~~~~~~
1 error generated.

  CLANG-bpf  samples/bpf/sockex2_kern.o
In file included from samples/bpf/sockex2_kern.c:2:
In file included from ./include/uapi/linux/in.h:24:
In file included from ./include/linux/socket.h:8:
In file included from ./include/linux/uio.h:8:
In file included from ./include/linux/kernel.h:11:
In file included from ./include/linux/bitops.h:32:
In file included from ./arch/mips/include/asm/bitops.h:22:
./arch/mips/include/asm/cpu-features.h:15:10: fatal error: 'cpu-feature-overrides.h' file not found
         ^~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

$ find arch/mips/include/asm -name spaces.h | sort
arch/mips/include/asm/mach-ar7/spaces.h
...
arch/mips/include/asm/mach-generic/spaces.h
...
arch/mips/include/asm/mach-loongson64/spaces.h
...
arch/mips/include/asm/mach-tx49xx/spaces.h

$ find arch/mips/include/asm -name kmalloc.h | sort
arch/mips/include/asm/mach-generic/kmalloc.h
arch/mips/include/asm/mach-ip32/kmalloc.h
arch/mips/include/asm/mach-tx49xx/kmalloc.h

$ find arch/mips/include/asm -name cpu-feature-overrides.h | sort
arch/mips/include/asm/mach-ath25/cpu-feature-overrides.h
...
arch/mips/include/asm/mach-generic/cpu-feature-overrides.h
...
arch/mips/include/asm/mach-loongson64/cpu-feature-overrides.h
...
arch/mips/include/asm/mach-tx49xx/cpu-feature-overrides.h

In the arch/mips/Makefile, there exists the following board-dependent
options:

include arch/mips/Kbuild.platforms
cflags-y += -I$(srctree)/arch/mips/include/asm/mach-generic

So we can do the similar things in samples/bpf/Makefile, just add
platform specific and generic include dir for MIPS Loongson64 to
fix the build errors.
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1611669925-25315-1-git-send-email-yangtiezhu@loongson.cn
      058107ab
  15. 29 Jan, 2021 6 commits
  17. 28 Jan, 2021 2 commits
  19. 27 Jan, 2021 2 commits
  21. 26 Jan, 2021 1 commit
  23. 25 Jan, 2021 3 commits
    • Tiezhu Yang's avatar
      samples/bpf: Set flag __SANE_USERSPACE_TYPES__ for MIPS to fix build warnings · 190d1c92
      Tiezhu Yang authored 
      There exists many build warnings when make M=samples/bpf on the Loongson
platform, this issue is MIPS related, x86 compiles just fine.

Here are some warnings:

  CC  samples/bpf/ibumad_user.o
samples/bpf/ibumad_user.c: In function ‘dump_counts’:
samples/bpf/ibumad_user.c:46:24: warning: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘__u64’ {aka ‘long unsigned int’} [-Wformat=]
    printf("0x%02x : %llu\n", key, value);
                     ~~~^          ~~~~~
                     %lu
  CC  samples/bpf/offwaketime_user.o
samples/bpf/offwaketime_user.c: In function ‘print_ksym’:
samples/bpf/offwaketime_user.c:34:17: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘__u64’ {aka ‘long unsigned int’} [-Wformat=]
   printf("%s/%llx;", sym->name, addr);
              ~~~^               ~~~~
              %lx
samples/bpf/offwaketime_user.c: In function ‘print_stack’:
samples/bpf/offwaketime_user.c:68:17: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘__u64’ {aka ‘long unsigned int’} [-Wformat=]
  printf(";%s %lld\n", key->waker, count);
              ~~~^                 ~~~~~
              %ld

MIPS needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
'int-ll64.h' in arch/mips/include/uapi/asm/types.h, then it can avoid
build warnings when printing __u64 with %llu, %llx or %lld.

The header tools/include/linux/types.h defines __SANE_USERSPACE_TYPES__,
it seems that we can include <linux/types.h> in the source files which
have build warnings, but it has no effect due to actually it includes
usr/include/linux/types.h instead of tools/include/linux/types.h, the
problem is that "usr/include" is preferred first than "tools/include"
in samples/bpf/Makefile, that sounds like a ugly hack to -Itools/include
before -Iusr/include.

So define __SANE_USERSPACE_TYPES__ for MIPS in samples/bpf/Makefile
is proper, if add "TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__" in
samples/bpf/Makefile, it appears the following error:

Auto-detecting system features:
...                        libelf: [ on  ]
...                          zlib: [ on  ]
...                           bpf: [ OFF ]

BPF API too old
make[3]: *** [Makefile:293: bpfdep] Error 1
make[2]: *** [Makefile:156: all] Error 2

With #ifndef __SANE_USERSPACE_TYPES__  in tools/include/linux/types.h,
the above error has gone and this ifndef change does not hurt other
compilations.
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/1611551146-14052-1-git-send-email-yangtiezhu@loongson.cn
      190d1c92
    • Florian Lehner's avatar
      tools, headers: Sync struct bpf_perf_event_data · 726bf76f
      Florian Lehner authored 
      Update struct bpf_perf_event_data with the addr field to match the
tools headers with the kernel headers.
Signed-off-by: default avatarFlorian Lehner <dev@der-flo.net>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210123185221.23946-1-dev@der-flo.net
      726bf76f
    • Björn Töpel's avatar
      selftests/bpf: Avoid useless void *-casts · 095af986
      Björn Töpel authored 
      There is no need to cast to void * when the argument is void *. Avoid
cluttering of code.
Signed-off-by: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210122154725.22140-13-bjorn.topel@gmail.com
      095af986
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