.../perf/util/perf-regs-arch/perf_regs_s390.c | 77 +++++++++++++++++++ tools/perf/util/perf_regs.c | 3 + tools/perf/util/perf_regs.h | 1 + 3 files changed, 81 insertions(+)
V4: Add comments from Ian and Sashiko:
Reset variable initialized to zero on error
Rework regular expression and reduce to one case.
V3: Add comments from Ian
Print register expression without leading 'r' (wrong).
V2: Add comments from Sumanth Koirkkar
commit e5e66adfe45a6 ("perf regs: Remove __weak attributive arch_sdt_arg_parse_op() function")
removes arch_sdt_arg_parse_op() functions and reveals missing s390 support.
The following warning is printed:
Unknown ELF machine 22, standard arguments parse will be skipped.
ELF machine 22 is the EM_S390 host. This happens with command
# ./perf record -v -- stress-ng -t 1s --matrix 0
on a z/VM system when the event is not specified.
Add s390 specific __perf_sdt_arg_parse_op_s390() function to support
-architecture calls to arch_sdt_arg_parse_op() for s390.
The warning disappears.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Tested-by: Jan Polensky <japo@linux.ibm.com>
---
.../perf/util/perf-regs-arch/perf_regs_s390.c | 77 +++++++++++++++++++
tools/perf/util/perf_regs.c | 3 +
tools/perf/util/perf_regs.h | 1 +
3 files changed, 81 insertions(+)
diff --git a/tools/perf/util/perf-regs-arch/perf_regs_s390.c b/tools/perf/util/perf-regs-arch/perf_regs_s390.c
index c61df24edf0f..9d34549be477 100644
--- a/tools/perf/util/perf-regs-arch/perf_regs_s390.c
+++ b/tools/perf/util/perf-regs-arch/perf_regs_s390.c
@@ -1,7 +1,13 @@
// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <regex.h>
#include "../perf_regs.h"
#include "../../arch/s390/include/perf_regs.h"
+#include "debug.h"
+
+#include <linux/zalloc.h>
+#include <linux/kernel.h>
uint64_t __perf_reg_mask_s390(bool intr __maybe_unused)
{
@@ -95,3 +101,74 @@ uint64_t __perf_reg_sp_s390(void)
{
return PERF_REG_S390_R15;
}
+
+/* %rXX */
+#define SDT_OP_REGEX1 "^(%r([0-9]|1[0-5]))$"
+/* +-###(%rXX) */
+#define SDT_OP_REGEX2 "^([+-]?[0-9]+\\(%r([0-9]|1[0-5])\\))$"
+static regex_t sdt_op_regex1, sdt_op_regex2;
+
+static int sdt_init_op_regex(void)
+{
+ static int initialized;
+ int ret = 0;
+
+ if (initialized)
+ return 0;
+
+ ret = regcomp(&sdt_op_regex1, SDT_OP_REGEX1, REG_EXTENDED);
+ if (ret)
+ goto error;
+ initialized = 1;
+
+ ret = regcomp(&sdt_op_regex2, SDT_OP_REGEX2, REG_EXTENDED);
+ if (ret)
+ goto free_regex1;
+ initialized = 2;
+
+ return 0;
+
+free_regex1:
+ regfree(&sdt_op_regex1);
+error:
+ pr_debug4("Regex compilation error, initialized %d\n", initialized);
+ initialized = 0;
+ return ret;
+}
+
+/*
+ * Parse OP and convert it into uprobe format, which is, +/-NUM(%gprREG).
+ * Possible variants of OP are:
+ * Format Example
+ * -------------------------
+ * NUM(%rREG) 48(%r1)
+ * -NUM(%rREG) -48(%r1)
+ * %rREG %r1
+ */
+int __perf_sdt_arg_parse_op_s390(char *old_op, char **new_op)
+{
+ int ret, new_len;
+ regmatch_t rm[6];
+
+ *new_op = NULL;
+ ret = sdt_init_op_regex();
+ if (ret)
+ return -EINVAL;
+
+ if (!regexec(&sdt_op_regex1, old_op, ARRAY_SIZE(rm), rm, 0) ||
+ !regexec(&sdt_op_regex2, old_op, ARRAY_SIZE(rm), rm, 0)) {
+ new_len = 1; /* NULL byte */
+ new_len += (int)(rm[1].rm_eo - rm[1].rm_so);
+ *new_op = zalloc(new_len);
+ if (!*new_op)
+ return -ENOMEM;
+
+ scnprintf(*new_op, new_len, "%.*s",
+ (int)(rm[1].rm_eo - rm[1].rm_so), old_op + rm[1].rm_so);
+ } else {
+ pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
+ return SDT_ARG_SKIP;
+ }
+
+ return SDT_ARG_VALID;
+}
diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
index 5b8f34beb24e..f52b0e1f7fc7 100644
--- a/tools/perf/util/perf_regs.c
+++ b/tools/perf/util/perf_regs.c
@@ -23,6 +23,9 @@ int perf_sdt_arg_parse_op(uint16_t e_machine, char *old_op, char **new_op)
case EM_X86_64:
ret = __perf_sdt_arg_parse_op_x86(old_op, new_op);
break;
+ case EM_S390:
+ ret = __perf_sdt_arg_parse_op_s390(old_op, new_op);
+ break;
default:
pr_debug("Unknown ELF machine %d, standard arguments parse will be skipped.\n",
e_machine);
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index 7c04700bf837..573f0d1dfe04 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -62,6 +62,7 @@ uint64_t __perf_reg_mask_s390(bool intr);
const char *__perf_reg_name_s390(int id);
uint64_t __perf_reg_ip_s390(void);
uint64_t __perf_reg_sp_s390(void);
+int __perf_sdt_arg_parse_op_s390(char *old_op, char **new_op);
int __perf_sdt_arg_parse_op_x86(char *old_op, char **new_op);
uint64_t __perf_reg_mask_x86(bool intr);
--
2.53.0On Wed, Mar 18, 2026 at 4:34 AM Thomas Richter <tmricht@linux.ibm.com> wrote:
>
> V4: Add comments from Ian and Sashiko:
> Reset variable initialized to zero on error
> Rework regular expression and reduce to one case.
> V3: Add comments from Ian
> Print register expression without leading 'r' (wrong).
> V2: Add comments from Sumanth Koirkkar
nit: these need to be placed after a line of "---" so that git mailbox
won't include it in the commit message.
> commit e5e66adfe45a6 ("perf regs: Remove __weak attributive arch_sdt_arg_parse_op() function")
> removes arch_sdt_arg_parse_op() functions and reveals missing s390 support.
> The following warning is printed:
>
> Unknown ELF machine 22, standard arguments parse will be skipped.
>
> ELF machine 22 is the EM_S390 host. This happens with command
> # ./perf record -v -- stress-ng -t 1s --matrix 0
> on a z/VM system when the event is not specified.
>
> Add s390 specific __perf_sdt_arg_parse_op_s390() function to support
> -architecture calls to arch_sdt_arg_parse_op() for s390.
> The warning disappears.
>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Tested-by: Jan Polensky <japo@linux.ibm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
> ---
> .../perf/util/perf-regs-arch/perf_regs_s390.c | 77 +++++++++++++++++++
> tools/perf/util/perf_regs.c | 3 +
> tools/perf/util/perf_regs.h | 1 +
> 3 files changed, 81 insertions(+)
>
> diff --git a/tools/perf/util/perf-regs-arch/perf_regs_s390.c b/tools/perf/util/perf-regs-arch/perf_regs_s390.c
> index c61df24edf0f..9d34549be477 100644
> --- a/tools/perf/util/perf-regs-arch/perf_regs_s390.c
> +++ b/tools/perf/util/perf-regs-arch/perf_regs_s390.c
> @@ -1,7 +1,13 @@
> // SPDX-License-Identifier: GPL-2.0
>
> +#include <errno.h>
> +#include <regex.h>
> #include "../perf_regs.h"
> #include "../../arch/s390/include/perf_regs.h"
> +#include "debug.h"
> +
> +#include <linux/zalloc.h>
> +#include <linux/kernel.h>
>
> uint64_t __perf_reg_mask_s390(bool intr __maybe_unused)
> {
> @@ -95,3 +101,74 @@ uint64_t __perf_reg_sp_s390(void)
> {
> return PERF_REG_S390_R15;
> }
> +
> +/* %rXX */
> +#define SDT_OP_REGEX1 "^(%r([0-9]|1[0-5]))$"
> +/* +-###(%rXX) */
> +#define SDT_OP_REGEX2 "^([+-]?[0-9]+\\(%r([0-9]|1[0-5])\\))$"
> +static regex_t sdt_op_regex1, sdt_op_regex2;
> +
> +static int sdt_init_op_regex(void)
> +{
> + static int initialized;
> + int ret = 0;
> +
> + if (initialized)
> + return 0;
> +
> + ret = regcomp(&sdt_op_regex1, SDT_OP_REGEX1, REG_EXTENDED);
> + if (ret)
> + goto error;
> + initialized = 1;
> +
> + ret = regcomp(&sdt_op_regex2, SDT_OP_REGEX2, REG_EXTENDED);
> + if (ret)
> + goto free_regex1;
> + initialized = 2;
> +
> + return 0;
> +
> +free_regex1:
> + regfree(&sdt_op_regex1);
> +error:
> + pr_debug4("Regex compilation error, initialized %d\n", initialized);
> + initialized = 0;
> + return ret;
> +}
> +
> +/*
> + * Parse OP and convert it into uprobe format, which is, +/-NUM(%gprREG).
> + * Possible variants of OP are:
> + * Format Example
> + * -------------------------
> + * NUM(%rREG) 48(%r1)
> + * -NUM(%rREG) -48(%r1)
> + * %rREG %r1
> + */
nit: Sashiko notes this comment may be stale:
https://sashiko.dev/#/patchset/20260318113416.2287472-1-tmricht%40linux.ibm.com
This isn't a bug, but the comment mentions converting the OP into the
+/-NUM(%gprREG) format. Is this a leftover copy-paste from the PowerPC
implementation?
The actual s390 implementation correctly parses and outputs the %rREG format
as shown in the examples.
Thanks,
Ian
> +int __perf_sdt_arg_parse_op_s390(char *old_op, char **new_op)
> +{
> + int ret, new_len;
> + regmatch_t rm[6];
> +
> + *new_op = NULL;
> + ret = sdt_init_op_regex();
> + if (ret)
> + return -EINVAL;
> +
> + if (!regexec(&sdt_op_regex1, old_op, ARRAY_SIZE(rm), rm, 0) ||
> + !regexec(&sdt_op_regex2, old_op, ARRAY_SIZE(rm), rm, 0)) {
> + new_len = 1; /* NULL byte */
> + new_len += (int)(rm[1].rm_eo - rm[1].rm_so);
> + *new_op = zalloc(new_len);
> + if (!*new_op)
> + return -ENOMEM;
> +
> + scnprintf(*new_op, new_len, "%.*s",
> + (int)(rm[1].rm_eo - rm[1].rm_so), old_op + rm[1].rm_so);
> + } else {
> + pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
> + return SDT_ARG_SKIP;
> + }
> +
> + return SDT_ARG_VALID;
> +}
> diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
> index 5b8f34beb24e..f52b0e1f7fc7 100644
> --- a/tools/perf/util/perf_regs.c
> +++ b/tools/perf/util/perf_regs.c
> @@ -23,6 +23,9 @@ int perf_sdt_arg_parse_op(uint16_t e_machine, char *old_op, char **new_op)
> case EM_X86_64:
> ret = __perf_sdt_arg_parse_op_x86(old_op, new_op);
> break;
> + case EM_S390:
> + ret = __perf_sdt_arg_parse_op_s390(old_op, new_op);
> + break;
> default:
> pr_debug("Unknown ELF machine %d, standard arguments parse will be skipped.\n",
> e_machine);
> diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
> index 7c04700bf837..573f0d1dfe04 100644
> --- a/tools/perf/util/perf_regs.h
> +++ b/tools/perf/util/perf_regs.h
> @@ -62,6 +62,7 @@ uint64_t __perf_reg_mask_s390(bool intr);
> const char *__perf_reg_name_s390(int id);
> uint64_t __perf_reg_ip_s390(void);
> uint64_t __perf_reg_sp_s390(void);
> +int __perf_sdt_arg_parse_op_s390(char *old_op, char **new_op);
>
> int __perf_sdt_arg_parse_op_x86(char *old_op, char **new_op);
> uint64_t __perf_reg_mask_x86(bool intr);
> --
> 2.53.0
>
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