[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20220418042222.2464199-1-pulehui@huawei.com>
Date: Mon, 18 Apr 2022 12:22:22 +0800
From: Pu Lehui <pulehui@...wei.com>
To: <bpf@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<netdev@...r.kernel.org>, <linux-riscv@...ts.infradead.org>
CC: <andrii@...nel.org>, <ast@...nel.org>, <daniel@...earbox.net>,
<kafai@...com>, <songliubraving@...com>, <yhs@...com>,
<john.fastabend@...il.com>, <kpsingh@...nel.org>,
<paul.walmsley@...ive.com>, <palmer@...belt.com>,
<aou@...s.berkeley.edu>, <pulehui@...wei.com>
Subject: [PATCH bpf-next] libbpf: Support riscv USDT argument parsing logic
Add riscv-specific USDT argument specification parsing logic.
riscv USDT argument format is shown below:
- Memory dereference case:
"size@off(reg)", e.g. "-8@-88(s0)"
- Constant value case:
"size@val", e.g. "4@5"
- Register read case:
"size@reg", e.g. "-8@a1"
s8 will be marked as poison while it's a reg of riscv, we need
to alias it in advance.
Signed-off-by: Pu Lehui <pulehui@...wei.com>
---
tools/lib/bpf/usdt.c | 107 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 107 insertions(+)
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 934c25301ac1..b8af409cc763 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -10,6 +10,11 @@
#include <linux/ptrace.h>
#include <linux/kernel.h>
+/* s8 will be marked as poison while it's a reg of riscv */
+#if defined(__riscv)
+#define rv_s8 s8
+#endif
+
#include "bpf.h"
#include "libbpf.h"
#include "libbpf_common.h"
@@ -1400,6 +1405,108 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
return len;
}
+#elif defined(__riscv)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+ static struct {
+ const char *name;
+ size_t pt_regs_off;
+ } reg_map[] = {
+ { "ra", offsetof(struct user_regs_struct, ra) },
+ { "sp", offsetof(struct user_regs_struct, sp) },
+ { "gp", offsetof(struct user_regs_struct, gp) },
+ { "tp", offsetof(struct user_regs_struct, tp) },
+ { "t0", offsetof(struct user_regs_struct, t0) },
+ { "t1", offsetof(struct user_regs_struct, t1) },
+ { "t2", offsetof(struct user_regs_struct, t2) },
+ { "s0", offsetof(struct user_regs_struct, s0) },
+ { "s1", offsetof(struct user_regs_struct, s1) },
+ { "a0", offsetof(struct user_regs_struct, a0) },
+ { "a1", offsetof(struct user_regs_struct, a1) },
+ { "a2", offsetof(struct user_regs_struct, a2) },
+ { "a3", offsetof(struct user_regs_struct, a3) },
+ { "a4", offsetof(struct user_regs_struct, a4) },
+ { "a5", offsetof(struct user_regs_struct, a5) },
+ { "a6", offsetof(struct user_regs_struct, a6) },
+ { "a7", offsetof(struct user_regs_struct, a7) },
+ { "s2", offsetof(struct user_regs_struct, s2) },
+ { "s3", offsetof(struct user_regs_struct, s3) },
+ { "s4", offsetof(struct user_regs_struct, s4) },
+ { "s5", offsetof(struct user_regs_struct, s5) },
+ { "s6", offsetof(struct user_regs_struct, s6) },
+ { "s7", offsetof(struct user_regs_struct, s7) },
+ { "s8", offsetof(struct user_regs_struct, rv_s8) },
+ { "s9", offsetof(struct user_regs_struct, s9) },
+ { "s10", offsetof(struct user_regs_struct, s10) },
+ { "s11", offsetof(struct user_regs_struct, s11) },
+ { "t3", offsetof(struct user_regs_struct, t3) },
+ { "t4", offsetof(struct user_regs_struct, t4) },
+ { "t5", offsetof(struct user_regs_struct, t5) },
+ { "t6", offsetof(struct user_regs_struct, t6) },
+ };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(reg_map); i++) {
+ if (strcmp(reg_name, reg_map[i].name) == 0)
+ return reg_map[i].pt_regs_off;
+ }
+
+ pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+ return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+{
+ char *reg_name = NULL;
+ int arg_sz, len, reg_off;
+ long off;
+
+ if (sscanf(arg_str, " %d @ %ld ( %m[a-z0-9] ) %n", &arg_sz, &off, ®_name, &len) == 3) {
+ /* Memory dereference case, e.g., -8@-88(s0) */
+ arg->arg_type = USDT_ARG_REG_DEREF;
+ arg->val_off = off;
+ reg_off = calc_pt_regs_off(reg_name);
+ free(reg_name);
+ if (reg_off < 0)
+ return reg_off;
+ arg->reg_off = reg_off;
+ } else if (sscanf(arg_str, " %d @ %ld %n", &arg_sz, &off, &len) == 2) {
+ /* Constant value case, e.g., 4@5 */
+ arg->arg_type = USDT_ARG_CONST;
+ arg->val_off = off;
+ arg->reg_off = 0;
+ } else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, ®_name, &len) == 2) {
+ /* Register read case, e.g., -8@a1 */
+ arg->arg_type = USDT_ARG_REG;
+ arg->val_off = 0;
+ reg_off = calc_pt_regs_off(reg_name);
+ free(reg_name);
+ if (reg_off < 0)
+ return reg_off;
+ arg->reg_off = reg_off;
+ } else {
+ pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+ return -EINVAL;
+ }
+
+ arg->arg_signed = arg_sz < 0;
+ if (arg_sz < 0)
+ arg_sz = -arg_sz;
+
+ switch (arg_sz) {
+ case 1: case 2: case 4: case 8:
+ arg->arg_bitshift = 64 - arg_sz * 8;
+ break;
+ default:
+ pr_warn("usdt: unsupported arg #%d (spec '%s') size: %d\n",
+ arg_num, arg_str, arg_sz);
+ return -EINVAL;
+ }
+
+ return len;
+}
+
#else
static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
--
2.25.1
Powered by blists - more mailing lists