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Subject[PATCH v3 3/3] perf/sdt/powerpc: Add argument support
Date
SDT marker argument is in N@OP format. Here OP is arch dependent
component. Add powerpc logic to parse OP and convert it to uprobe
compatible format.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
tools/perf/arch/powerpc/util/perf_regs.c | 111 +++++++++++++++++++++++++++++++
1 file changed, 111 insertions(+)

diff --git a/tools/perf/arch/powerpc/util/perf_regs.c b/tools/perf/arch/powerpc/util/perf_regs.c
index a3c3e1c..390ff93 100644
--- a/tools/perf/arch/powerpc/util/perf_regs.c
+++ b/tools/perf/arch/powerpc/util/perf_regs.c
@@ -1,5 +1,10 @@
+#include <string.h>
+#include <regex.h>
+
#include "../../perf.h"
+#include "../../util/util.h"
#include "../../util/perf_regs.h"
+#include "../../util/debug.h"

const struct sample_reg sample_reg_masks[] = {
SMPL_REG(r0, PERF_REG_POWERPC_R0),
@@ -47,3 +52,109 @@ const struct sample_reg sample_reg_masks[] = {
SMPL_REG(dsisr, PERF_REG_POWERPC_DSISR),
SMPL_REG_END
};
+
+/* REG or %rREG */
+#define SDT_OP_REGEX1 "^(%r)?([1-2]?[0-9]|3[0-1])$"
+
+/* -NUM(REG) or NUM(REG) or -NUM(%rREG) or NUM(%rREG) */
+#define SDT_OP_REGEX2 "^(\\-)?([0-9]+)\\((%r)?([1-2]?[0-9]|3[0-1])\\)$"
+
+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;
+
+ ret = regcomp(&sdt_op_regex2, SDT_OP_REGEX2, REG_EXTENDED);
+ if (ret)
+ goto free_regex1;
+
+ initialized = 1;
+ return 0;
+
+free_regex1:
+ regfree(&sdt_op_regex1);
+error:
+ pr_debug4("Regex compilation error.\n");
+ return ret;
+}
+
+/*
+ * Parse OP and convert it into uprobe format, which is, +/-NUM(%gprREG).
+ * Possible variants of OP are:
+ * Format Example
+ * -------------------------
+ * NUM(REG) 48(18)
+ * -NUM(REG) -48(18)
+ * NUM(%rREG) 48(%r18)
+ * -NUM(%rREG) -48(%r18)
+ * REG 18
+ * %rREG %r18
+ * iNUM i0
+ * i-NUM i-1
+ *
+ * SDT marker arguments on Powerpc uses %rREG form with -mregnames flag
+ * and REG form with -mno-regnames. Here REG is general purpose register,
+ * which is in 0 to 31 range.
+ */
+int arch_sdt_arg_parse_op(char *old_op, char **new_op)
+{
+ int ret, new_len;
+ regmatch_t rm[5];
+ char prefix;
+
+ /* Constant argument. Uprobe does not support it */
+ if (old_op[0] == 'i') {
+ pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
+ return SDT_ARG_SKIP;
+ }
+
+ ret = sdt_init_op_regex();
+ if (ret < 0)
+ return ret;
+
+ if (!regexec(&sdt_op_regex1, old_op, 3, rm, 0)) {
+ /* REG or %rREG --> %gprREG */
+
+ new_len = 5; /* % g p r NULL */
+ new_len += (int)(rm[2].rm_eo - rm[2].rm_so);
+
+ *new_op = zalloc(new_len);
+ if (!*new_op)
+ return -ENOMEM;
+
+ scnprintf(*new_op, new_len, "%%gpr%.*s",
+ (int)(rm[2].rm_eo - rm[2].rm_so), old_op + rm[2].rm_so);
+ } else if (!regexec(&sdt_op_regex2, old_op, 5, rm, 0)) {
+ /*
+ * -NUM(REG) or NUM(REG) or -NUM(%rREG) or NUM(%rREG) -->
+ * +/-NUM(%gprREG)
+ */
+ prefix = (rm[1].rm_so == -1) ? '+' : '-';
+
+ new_len = 8; /* +/- ( % g p r ) NULL */
+ new_len += (int)(rm[2].rm_eo - rm[2].rm_so);
+ new_len += (int)(rm[4].rm_eo - rm[4].rm_so);
+
+ *new_op = zalloc(new_len);
+ if (!*new_op)
+ return -ENOMEM;
+
+ scnprintf(*new_op, new_len, "%c%.*s(%%gpr%.*s)", prefix,
+ (int)(rm[2].rm_eo - rm[2].rm_so), old_op + rm[2].rm_so,
+ (int)(rm[4].rm_eo - rm[4].rm_so), old_op + rm[4].rm_so);
+ } else {
+ pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
+ return SDT_ARG_SKIP;
+ }
+
+ return SDT_ARG_VALID;
+}
--
2.9.3
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