Hi Thomas,
Your patch looks good to me. I've tested in my environment and it works.
Please resend it to lkml and let Arnaldo to collect it.
Thank you.
On 2017/8/14 17:47, Thomas Richter wrote:
Perf BPF prologue generator unconditionally fetches 8 bytes for function
parameters, which causes problem on big endian machine. Thomas gives a
detail analysis for this problem:
http://lkml.kernel.org/r/[email protected]
This patch parses the type of each argument and converts data from
memory to expected type.
Now the test runs successfully on 4.13.0-rc5:
[root@s8360046 perf]# ./perf test bpf
38: BPF filter :
38.1: Basic BPF filtering : Ok
38.2: BPF pinning : Ok
38.3: BPF prologue generation : Ok
38.4: BPF relocation checker : Ok
[root@s8360046 perf]#
Signed-off-by: Thomas Richter <[email protected]>
Signed-off-by: Wang Nan <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Thomas Richter <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Li Zefan <[email protected]>
---
tools/perf/util/bpf-prologue.c | 49 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 47 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/bpf-prologue.c b/tools/perf/util/bpf-prologue.c
index 1356220..827f914 100644
--- a/tools/perf/util/bpf-prologue.c
+++ b/tools/perf/util/bpf-prologue.c
@@ -58,6 +58,46 @@ check_pos(struct bpf_insn_pos *pos)
return 0;
}
+/*
+ * Convert type string (u8/u16/u32/u64/s8/s16/s32/s64 ..., see
+ * Documentation/trace/kprobetrace.txt) to size field of BPF_LDX_MEM
+ * instruction (BPF_{B,H,W,DW}).
+ */
+static int
+argtype_to_ldx_size(const char *type)
+{
+ int arg_size = type ? atoi(&type[1]) : 64;
+
+ switch (arg_size) {
+ case 8:
+ return BPF_B;
+ case 16:
+ return BPF_H;
+ case 32:
+ return BPF_W;
+ case 64:
+ default:
+ return BPF_DW;
+ }
+}
+
+static const char *
+insn_sz_to_str(int insn_sz)
+{
+ switch (insn_sz) {
+ case BPF_B:
+ return "BPF_B";
+ case BPF_H:
+ return "BPF_H";
+ case BPF_W:
+ return "BPF_W";
+ case BPF_DW:
+ return "BPF_DW";
+ default:
+ return "UNKNOWN";
+ }
+}
+
/* Give it a shorter name */
#define ins(i, p) append_insn((i), (p))
@@ -258,9 +298,14 @@ gen_prologue_slowpath(struct bpf_insn_pos *pos,
}
/* Final pass: read to registers */
- for (i = 0; i < nargs; i++)
- ins(BPF_LDX_MEM(BPF_DW, BPF_PROLOGUE_START_ARG_REG + i,
+ for (i = 0; i < nargs; i++) {
+ int insn_sz = (args[i].ref) ? argtype_to_ldx_size(args[i].type)
: BPF_DW;
+
+ pr_debug("prologue: load arg %d, insn_sz is %s\n",
+ i, insn_sz_to_str(insn_sz));
+ ins(BPF_LDX_MEM(insn_sz, BPF_PROLOGUE_START_ARG_REG + i,
BPF_REG_FP, -BPF_REG_SIZE * (i + 1)), pos);
+ }
ins(BPF_JMP_IMM(BPF_JA, BPF_REG_0, 0, JMP_TO_SUCCESS_CODE), pos);
