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author | David Daney <david.daney@cavium.com> | 2017-06-14 01:49:38 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-06-14 21:03:23 +0200 |
commit | 4b7190e8416d9238e995da993a7fb851996654e2 (patch) | |
tree | cd9223768849c8dc218787198acdc37d4ba2dc17 /samples/bpf | |
parent | bpf: Add MIPS support to samples/bpf. (diff) | |
download | linux-4b7190e8416d9238e995da993a7fb851996654e2.tar.xz linux-4b7190e8416d9238e995da993a7fb851996654e2.zip |
samples/bpf: Fix tracex5 to work with MIPS syscalls.
There are two problems:
1) In MIPS the __NR_* macros expand to an expression, this causes the
sections of the object file to be named like:
.
.
.
[ 5] kprobe/(5000 + 1) PROGBITS 0000000000000000 000160 ...
[ 6] kprobe/(5000 + 0) PROGBITS 0000000000000000 000258 ...
[ 7] kprobe/(5000 + 9) PROGBITS 0000000000000000 000348 ...
.
.
.
The fix here is to use the "asm_offsets" trick to evaluate the macros
in the C compiler and generate a header file with a usable form of the
macros.
2) MIPS syscall numbers start at 5000, so we need a bigger map to hold
the sub-programs.
Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf')
-rw-r--r-- | samples/bpf/Makefile | 13 | ||||
-rw-r--r-- | samples/bpf/syscall_nrs.c | 12 | ||||
-rw-r--r-- | samples/bpf/tracex5_kern.c | 11 |
3 files changed, 33 insertions, 3 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 6c7468eb3684..a0561dc762fe 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -160,6 +160,17 @@ clean: $(MAKE) -C ../../ M=$(CURDIR) clean @rm -f *~ +$(obj)/syscall_nrs.s: $(src)/syscall_nrs.c + $(call if_changed_dep,cc_s_c) + +$(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE + $(call filechk,offsets,__SYSCALL_NRS_H__) + +clean-files += syscall_nrs.h + +FORCE: + + # Verify LLVM compiler tools are available and bpf target is supported by llc .PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC) @@ -180,6 +191,8 @@ verify_target_bpf: verify_cmds $(src)/*.c: verify_target_bpf +$(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h + # asm/sysreg.h - inline assembly used by it is incompatible with llvm. # But, there is no easy way to fix it, so just exclude it since it is # useless for BPF samples. diff --git a/samples/bpf/syscall_nrs.c b/samples/bpf/syscall_nrs.c new file mode 100644 index 000000000000..ce2a30b11248 --- /dev/null +++ b/samples/bpf/syscall_nrs.c @@ -0,0 +1,12 @@ +#include <uapi/linux/unistd.h> +#include <linux/kbuild.h> + +#define SYSNR(_NR) DEFINE(SYS ## _NR, _NR) + +void syscall_defines(void) +{ + COMMENT("Linux system call numbers."); + SYSNR(__NR_write); + SYSNR(__NR_read); + SYSNR(__NR_mmap); +} diff --git a/samples/bpf/tracex5_kern.c b/samples/bpf/tracex5_kern.c index 7e4cf74553ff..f57f4e1ea1ec 100644 --- a/samples/bpf/tracex5_kern.c +++ b/samples/bpf/tracex5_kern.c @@ -9,6 +9,7 @@ #include <uapi/linux/bpf.h> #include <uapi/linux/seccomp.h> #include <uapi/linux/unistd.h> +#include "syscall_nrs.h" #include "bpf_helpers.h" #define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F @@ -17,7 +18,11 @@ struct bpf_map_def SEC("maps") progs = { .type = BPF_MAP_TYPE_PROG_ARRAY, .key_size = sizeof(u32), .value_size = sizeof(u32), +#ifdef __mips__ + .max_entries = 6000, /* MIPS n64 syscalls start at 5000 */ +#else .max_entries = 1024, +#endif }; SEC("kprobe/__seccomp_filter") @@ -37,7 +42,7 @@ int bpf_prog1(struct pt_regs *ctx) } /* we jump here when syscall number == __NR_write */ -PROG(__NR_write)(struct pt_regs *ctx) +PROG(SYS__NR_write)(struct pt_regs *ctx) { struct seccomp_data sd; @@ -50,7 +55,7 @@ PROG(__NR_write)(struct pt_regs *ctx) return 0; } -PROG(__NR_read)(struct pt_regs *ctx) +PROG(SYS__NR_read)(struct pt_regs *ctx) { struct seccomp_data sd; @@ -63,7 +68,7 @@ PROG(__NR_read)(struct pt_regs *ctx) return 0; } -PROG(__NR_mmap)(struct pt_regs *ctx) +PROG(SYS__NR_mmap)(struct pt_regs *ctx) { char fmt[] = "mmap\n"; bpf_trace_printk(fmt, sizeof(fmt)); |