From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Thu, 7 Apr 2022 23:44:11 +0200
Subject: libbpf: Add s390-specific USDT arg spec parsing logic
Patch-mainline: v5.19-rc1
Git-commit: bd022685bd441056365e9a44a6bf940f45054250
References: jsc#PED-1377
The logic is superficially similar to that of x86, but the small
differences (no need for register table and dynamic allocation of
register names, no $ sign before constants) make maintaining a common
implementation too burdensome. Therefore simply add a s390x-specific
version of parse_usdt_arg().
Note that while bcc supports index registers, this patch does not. This
should not be a problem in most cases, since s390 uses a default value
"nor" for STAP_SDT_ARG_CONSTRAINT.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220407214411.257260-4-iii@linux.ibm.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/lib/bpf/usdt.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -1269,6 +1269,61 @@ static int parse_usdt_arg(const char *ar
return len;
}
+#elif defined(__s390x__)
+
+/* 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)
+{
+ unsigned int reg;
+ int arg_sz, len;
+ long off;
+
+ 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;
+ if (reg > 15) {
+ pr_warn("usdt: unrecognized register '%%r%u'\n", reg);
+ return -EINVAL;
+ }
+ arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
+ } 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;
+ if (reg > 15) {
+ pr_warn("usdt: unrecognized register '%%r%u'\n", reg);
+ return -EINVAL;
+ }
+ arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
+ } 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;
+ arg->reg_off = 0;
+ } 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)