From: Puranjay Mohan <puranjay12@gmail.com>
To: andrii@kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
bpf@vger.kernel.org, memxor@gmail.com
Cc: Puranjay Mohan <puranjay12@gmail.com>
Subject: [PATCH bpf-next v3 1/2] libbpf: refactor parse_usdt_arg() to re-use code
Date: Tue, 7 Mar 2023 12:04:39 +0000 [thread overview]
Message-ID: <20230307120440.25941-2-puranjay12@gmail.com> (raw)
In-Reply-To: <20230307120440.25941-1-puranjay12@gmail.com>
The parse_usdt_arg() function is defined differently for each
architecture but the last part of the function is repeated
verbatim for each architecture.
Refactor parse_usdt_arg() to fill the arg_sz and then do the repeated
post-processing in parse_usdt_spec().
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
tools/lib/bpf/usdt.c | 123 +++++++++++++++----------------------------
1 file changed, 42 insertions(+), 81 deletions(-)
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 75b411fc2c77..293b7a37f8a1 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -1141,11 +1141,13 @@ static int parse_usdt_note(Elf *elf, const char *path, GElf_Nhdr *nhdr,
return 0;
}
-static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg);
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz);
static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie)
{
+ struct usdt_arg_spec *arg;
const char *s;
+ int arg_sz;
int len;
spec->usdt_cookie = usdt_cookie;
@@ -1159,10 +1161,25 @@ static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note,
return -E2BIG;
}
- len = parse_usdt_arg(s, spec->arg_cnt, &spec->args[spec->arg_cnt]);
+ arg = &spec->args[spec->arg_cnt];
+ len = parse_usdt_arg(s, spec->arg_cnt, arg, &arg_sz);
if (len < 0)
return len;
+ 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",
+ spec->arg_cnt, s, arg_sz);
+ return -EINVAL;
+ }
+
s += len;
spec->arg_cnt++;
}
@@ -1219,13 +1236,13 @@ static int calc_pt_regs_off(const char *reg_name)
return -ENOENT;
}
-static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
char reg_name[16];
- int arg_sz, len, reg_off;
+ int len, reg_off;
long off;
- if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n", &arg_sz, &off, reg_name, &len) == 3) {
+ if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n", arg_sz, &off, reg_name, &len) == 3) {
/* Memory dereference case, e.g., -4@-20(%rbp) */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = off;
@@ -1233,7 +1250,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
if (reg_off < 0)
return reg_off;
arg->reg_off = reg_off;
- } else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", &arg_sz, reg_name, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", arg_sz, reg_name, &len) == 2) {
/* Memory dereference case without offset, e.g., 8@(%rsp) */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = 0;
@@ -1241,7 +1258,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
if (reg_off < 0)
return reg_off;
arg->reg_off = reg_off;
- } else if (sscanf(arg_str, " %d @ %%%15s %n", &arg_sz, reg_name, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ %%%15s %n", arg_sz, reg_name, &len) == 2) {
/* Register read case, e.g., -4@%eax */
arg->arg_type = USDT_ARG_REG;
arg->val_off = 0;
@@ -1250,7 +1267,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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) {
+ } else if (sscanf(arg_str, " %d @ $%ld %n", arg_sz, &off, &len) == 2) {
/* Constant value case, e.g., 4@$71 */
arg->arg_type = USDT_ARG_CONST;
arg->val_off = off;
@@ -1260,20 +1277,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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;
}
@@ -1281,13 +1284,13 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
/* Do not support __s390__ for now, since user_pt_regs is broken with -m31. */
-static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
unsigned int reg;
- int arg_sz, len;
+ int len;
long off;
- if (sscanf(arg_str, " %d @ %ld ( %%r%u ) %n", &arg_sz, &off, ®, &len) == 3) {
+ if (sscanf(arg_str, " %d @ %ld ( %%r%u ) %n", arg_sz, &off, ®, &len) == 3) {
/* Memory dereference case, e.g., -2@-28(%r15) */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = off;
@@ -1296,7 +1299,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
return -EINVAL;
}
arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
- } else if (sscanf(arg_str, " %d @ %%r%u %n", &arg_sz, ®, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ %%r%u %n", arg_sz, ®, &len) == 2) {
/* Register read case, e.g., -8@%r0 */
arg->arg_type = USDT_ARG_REG;
arg->val_off = 0;
@@ -1305,7 +1308,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
return -EINVAL;
}
arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
- } else if (sscanf(arg_str, " %d @ %ld %n", &arg_sz, &off, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ %ld %n", arg_sz, &off, &len) == 2) {
/* Constant value case, e.g., 4@71 */
arg->arg_type = USDT_ARG_CONST;
arg->val_off = off;
@@ -1315,20 +1318,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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;
}
@@ -1348,13 +1337,13 @@ static int calc_pt_regs_off(const char *reg_name)
return -ENOENT;
}
-static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
char reg_name[16];
- int arg_sz, len, reg_off;
+ int len, reg_off;
long off;
- if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", &arg_sz, reg_name, &off, &len) == 3) {
+ if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", arg_sz, reg_name, &off, &len) == 3) {
/* Memory dereference case, e.g., -4@[sp, 96] */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = off;
@@ -1362,7 +1351,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
if (reg_off < 0)
return reg_off;
arg->reg_off = reg_off;
- } else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", &arg_sz, reg_name, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", arg_sz, reg_name, &len) == 2) {
/* Memory dereference case, e.g., -4@[sp] */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = 0;
@@ -1370,12 +1359,12 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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) {
+ } 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 @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {
/* Register read case, e.g., -8@x4 */
arg->arg_type = USDT_ARG_REG;
arg->val_off = 0;
@@ -1388,20 +1377,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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;
}
@@ -1456,13 +1431,13 @@ static int calc_pt_regs_off(const char *reg_name)
return -ENOENT;
}
-static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
char reg_name[16];
- int arg_sz, len, reg_off;
+ int len, reg_off;
long off;
- if (sscanf(arg_str, " %d @ %ld ( %15[a-z0-9] ) %n", &arg_sz, &off, reg_name, &len) == 3) {
+ if (sscanf(arg_str, " %d @ %ld ( %15[a-z0-9] ) %n", arg_sz, &off, reg_name, &len) == 3) {
/* Memory dereference case, e.g., -8@-88(s0) */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = off;
@@ -1470,12 +1445,12 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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) {
+ } 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 @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {
+ } else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {
/* Register read case, e.g., -8@a1 */
arg->arg_type = USDT_ARG_REG;
arg->val_off = 0;
@@ -1488,26 +1463,12 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
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)
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
pr_warn("usdt: libbpf doesn't support USDTs on current architecture\n");
return -ENOTSUP;
--
2.39.1
next prev parent reply other threads:[~2023-03-07 12:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 12:04 [PATCH bpf-next v3 0/2] libbpf: usdt arm arg parsing support Puranjay Mohan
2023-03-07 12:04 ` Puranjay Mohan [this message]
2023-03-07 12:04 ` [PATCH bpf-next v3 2/2] " Puranjay Mohan
2023-03-07 23:41 ` Andrii Nakryiko
2023-03-08 5:01 ` Puranjay Mohan
2023-03-08 17:15 ` Andrii Nakryiko
2023-03-08 18:36 ` Puranjay Mohan
2023-03-07 23:40 ` [PATCH bpf-next v3 0/2] " patchwork-bot+netdevbpf
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