perf sdt powerpc: Add argument support

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.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170328094754.3156-4-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/powerpc/util/perf_regs.c b/tools/perf/arch/powerpc/util/perf_regs.c
index a3c3e1ce6807cefddeaffd1304f353218c8bc835..4268f7762e256dbaf431194785249505d859f1bb 100644 (file)
--- 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;
+}