| Message ID | 20210416202404.3443623-17-andrii@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | BPF static linker: support externs | expand |
On 4/16/21 1:24 PM, Andrii Nakryiko wrote: > Add selftest validating various aspects of statically linking global > variables: > - correct resolution of extern variables across .bss, .data, and .rodata > sections; > - correct handling of weak definitions; > - correct de-duplication of repeating special externs (.kconfig, .ksyms). > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Ack with a minor nit below. Acked-by: Yonghong Song <yhs@fb.com> > --- > tools/testing/selftests/bpf/Makefile | 3 +- > .../selftests/bpf/prog_tests/linked_vars.c | 43 +++++++++++++++ > .../selftests/bpf/progs/linked_vars1.c | 54 ++++++++++++++++++ > .../selftests/bpf/progs/linked_vars2.c | 55 +++++++++++++++++++ > 4 files changed, 154 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_vars.c > create mode 100644 tools/testing/selftests/bpf/progs/linked_vars1.c > create mode 100644 tools/testing/selftests/bpf/progs/linked_vars2.c > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > index 427ccfec1a6a..d8f176b55c01 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -308,10 +308,11 @@ endef > > SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c > > -LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h > +LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h linked_vars.skel.h > > test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o > linked_funcs.skel.h-deps := linked_funcs1.o linked_funcs2.o > +linked_vars.skel.h-deps := linked_vars1.o linked_vars2.o > > LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) > > diff --git a/tools/testing/selftests/bpf/prog_tests/linked_vars.c b/tools/testing/selftests/bpf/prog_tests/linked_vars.c > new file mode 100644 > index 000000000000..f3d6ba31ef99 > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/linked_vars.c > @@ -0,0 +1,43 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2021 Facebook */ > + > +#include <test_progs.h> > +#include <sys/syscall.h> > +#include "linked_vars.skel.h" > + > +void test_linked_vars(void) > +{ > + int err; > + struct linked_vars *skel; > + > + skel = linked_vars__open(); > + if (!ASSERT_OK_PTR(skel, "skel_open")) > + return; > + > + skel->bss->input_bss1 = 1000; > + skel->bss->input_bss2 = 2000; > + skel->bss->input_bss_weak = 3000; > + > + err = linked_vars__load(skel); > + if (!ASSERT_OK(err, "skel_load")) > + goto cleanup; > + > + err = linked_vars__attach(skel); > + if (!ASSERT_OK(err, "skel_attach")) > + goto cleanup; > + > + /* trigger */ > + syscall(SYS_getpgid); > + > + ASSERT_EQ(skel->bss->output_bss1, 1000 + 2000 + 3000, "output_bss1"); > + ASSERT_EQ(skel->bss->output_bss2, 1000 + 2000 + 3000, "output_bss2"); > + /* 10 comes from "winner" input_data_weak in first obj file */ > + ASSERT_EQ(skel->bss->output_data1, 1 + 2 + 10, "output_bss1"); > + ASSERT_EQ(skel->bss->output_data2, 1 + 2 + 10, "output_bss2"); > + /* 10 comes from "winner" input_rodata_weak in first obj file */ 10 => 100 here. > + ASSERT_EQ(skel->bss->output_rodata1, 11 + 22 + 100, "output_weak1"); > + ASSERT_EQ(skel->bss->output_rodata2, 11 + 22 + 100, "output_weak2"); > + > +cleanup: > + linked_vars__destroy(skel); > +} > diff --git a/tools/testing/selftests/bpf/progs/linked_vars1.c b/tools/testing/selftests/bpf/progs/linked_vars1.c > new file mode 100644 > index 000000000000..bc96eff9b8c1 > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/linked_vars1.c > @@ -0,0 +1,54 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2021 Facebook */ > + > +#include "vmlinux.h" > +#include <bpf/bpf_helpers.h> > +#include <bpf/bpf_tracing.h> > + > +extern int LINUX_KERNEL_VERSION __kconfig; > +/* this weak extern will be strict due to the other file's strong extern */ > +extern bool CONFIG_BPF_SYSCALL __kconfig __weak; > +extern const void bpf_link_fops __ksym __weak; > + > +int input_bss1 = 0; > +int input_data1 = 1; > +const volatile int input_rodata1 = 11; > + > +int input_bss_weak __weak = 0; > +/* these two definitions should win */ > +int input_data_weak __weak = 10; > +const volatile int input_rodata_weak __weak = 100; > + [...]
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 427ccfec1a6a..d8f176b55c01 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -308,10 +308,11 @@ endef SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c -LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h +LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h linked_vars.skel.h test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o linked_funcs.skel.h-deps := linked_funcs1.o linked_funcs2.o +linked_vars.skel.h-deps := linked_vars1.o linked_vars2.o LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_vars.c b/tools/testing/selftests/bpf/prog_tests/linked_vars.c new file mode 100644 index 000000000000..f3d6ba31ef99 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/linked_vars.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include <test_progs.h> +#include <sys/syscall.h> +#include "linked_vars.skel.h" + +void test_linked_vars(void) +{ + int err; + struct linked_vars *skel; + + skel = linked_vars__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->input_bss1 = 1000; + skel->bss->input_bss2 = 2000; + skel->bss->input_bss_weak = 3000; + + err = linked_vars__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + err = linked_vars__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* trigger */ + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->output_bss1, 1000 + 2000 + 3000, "output_bss1"); + ASSERT_EQ(skel->bss->output_bss2, 1000 + 2000 + 3000, "output_bss2"); + /* 10 comes from "winner" input_data_weak in first obj file */ + ASSERT_EQ(skel->bss->output_data1, 1 + 2 + 10, "output_bss1"); + ASSERT_EQ(skel->bss->output_data2, 1 + 2 + 10, "output_bss2"); + /* 10 comes from "winner" input_rodata_weak in first obj file */ + ASSERT_EQ(skel->bss->output_rodata1, 11 + 22 + 100, "output_weak1"); + ASSERT_EQ(skel->bss->output_rodata2, 11 + 22 + 100, "output_weak2"); + +cleanup: + linked_vars__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/linked_vars1.c b/tools/testing/selftests/bpf/progs/linked_vars1.c new file mode 100644 index 000000000000..bc96eff9b8c1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_vars1.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +extern int LINUX_KERNEL_VERSION __kconfig; +/* this weak extern will be strict due to the other file's strong extern */ +extern bool CONFIG_BPF_SYSCALL __kconfig __weak; +extern const void bpf_link_fops __ksym __weak; + +int input_bss1 = 0; +int input_data1 = 1; +const volatile int input_rodata1 = 11; + +int input_bss_weak __weak = 0; +/* these two definitions should win */ +int input_data_weak __weak = 10; +const volatile int input_rodata_weak __weak = 100; + +extern int input_bss2; +extern int input_data2; +extern const int input_rodata2; + +int output_bss1 = 0; +int output_data1 = 0; +int output_rodata1 = 0; + +long output_sink1 = 0; + +static __noinline int get_bss_res(void) +{ + /* just make sure all the relocations work against .text as well */ + return input_bss1 + input_bss2 + input_bss_weak; +} + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler1) +{ + output_bss1 = get_bss_res(); + output_data1 = input_data1 + input_data2 + input_data_weak; + output_rodata1 = input_rodata1 + input_rodata2 + input_rodata_weak; + + /* make sure we actually use above special externs, otherwise compiler + * will optimize them out + */ + output_sink1 = LINUX_KERNEL_VERSION + + CONFIG_BPF_SYSCALL + + (long)&bpf_link_fops; + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_vars2.c b/tools/testing/selftests/bpf/progs/linked_vars2.c new file mode 100644 index 000000000000..946c0ce4f505 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_vars2.c @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +extern int LINUX_KERNEL_VERSION __kconfig; +/* when an extern is defined as both strong and weak, resulting symbol will be strong */ +extern bool CONFIG_BPF_SYSCALL __kconfig; +extern const void __start_BTF __ksym; + +int input_bss2 = 0; +int input_data2 = 2; +const volatile int input_rodata2 = 22; + +int input_bss_weak __weak = 0; +/* these two weak variables should lose */ +int input_data_weak __weak = 20; +const volatile int input_rodata_weak __weak = 200; + +extern int input_bss1; +extern int input_data1; +extern const int input_rodata1; + +int output_bss2 = 0; +int output_data2 = 0; +int output_rodata2 = 0; + +int output_sink2 = 0; + +static __noinline int get_data_res(void) +{ + /* just make sure all the relocations work against .text as well */ + return input_data1 + input_data2 + input_data_weak; +} + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler2) +{ + output_bss2 = input_bss1 + input_bss2 + input_bss_weak; + output_data2 = get_data_res(); + output_rodata2 = input_rodata1 + input_rodata2 + input_rodata_weak; + + /* make sure we actually use above special externs, otherwise compiler + * will optimize them out + */ + output_sink2 = LINUX_KERNEL_VERSION + + CONFIG_BPF_SYSCALL + + (long)&__start_BTF; + + return 0; +} + +char LICENSE[] SEC("license") = "GPL";
Add selftest validating various aspects of statically linking global variables: - correct resolution of extern variables across .bss, .data, and .rodata sections; - correct handling of weak definitions; - correct de-duplication of repeating special externs (.kconfig, .ksyms). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/linked_vars.c | 43 +++++++++++++++ .../selftests/bpf/progs/linked_vars1.c | 54 ++++++++++++++++++ .../selftests/bpf/progs/linked_vars2.c | 55 +++++++++++++++++++ 4 files changed, 154 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_vars.c create mode 100644 tools/testing/selftests/bpf/progs/linked_vars1.c create mode 100644 tools/testing/selftests/bpf/progs/linked_vars2.c