linux-kernel - [PATCH 48/52] perf annotate: Parse x86 segment register location

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Date:   Thu,  9 Nov 2023 16:00:07 -0800
From:   Namhyung Kim <namhyung@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Stephane Eranian <eranian@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-trace-devel@...r.kernel.org, linux-toolchains@...r.kernel.org
Subject: [PATCH 48/52] perf annotate: Parse x86 segment register location

Add a segment field in the struct annotated_insn_loc and save it for the
segment based addressing like %gs:0x28.  For simplicity it now handles
%gs register only.

Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 tools/perf/util/annotate.c | 21 +++++++++++++++++++--
 tools/perf/util/annotate.h | 13 +++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 33fd032bf463..a9075af10d24 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -3561,6 +3561,12 @@ static int extract_reg_offset(struct arch *arch, const char *str,
 	 * %gs:0x18(%rbx).  In that case it should skip the part.
 	 */
 	if (*str == arch->objdump.register_char) {
+		if (arch__is(arch, "x86")) {
+			/* FIXME: Handle other segment registers */
+			if (!strncmp(str, "%gs:", 4))
+				op_loc->segment = INSN_SEG_X86_GS;
+		}
+
 		while (*str && !isdigit(*str) &&
 		       *str != arch->objdump.memory_ref_char)
 			str++;
@@ -3657,8 +3663,19 @@ int annotate_get_insn_location(struct arch *arch, struct disasm_line *dl,
 			op_loc->multi_regs = multi_regs;
 			extract_reg_offset(arch, insn_str, op_loc);
 		} else {
-			char *s = strdup(insn_str);
+			char *s;
+
+			if (arch__is(arch, "x86")) {
+				/* FIXME: Handle other segment registers */
+				if (!strncmp(insn_str, "%gs:", 4)) {
+					op_loc->segment = INSN_SEG_X86_GS;
+					op_loc->offset = strtol(insn_str + 4,
+								NULL, 0);
+					continue;
+				}
+			}
 
+			s = strdup(insn_str);
 			if (s) {
 				op_loc->reg1 = get_dwarf_regnum(s, 0);
 				free(s);
@@ -3874,7 +3891,7 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
 			.op = op_loc,
 		};
 
-		if (!op_loc->mem_ref)
+		if (!op_loc->mem_ref && op_loc->segment == INSN_SEG_NONE)
 			continue;
 
 		/* Recalculate IP because of LOCK prefix or insn fusion */
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 13c9b6a30b15..21a0947ed5e9 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -452,6 +452,7 @@ int annotate_check_args(struct annotation_options *args);
  * @reg1: First register in the operand
  * @reg2: Second register in the operand
  * @offset: Memory access offset in the operand
+ * @segment: Segment selector register
  * @mem_ref: Whether the operand accesses memory
  * @multi_regs: Whether the second register is used
  */
@@ -459,6 +460,7 @@ struct annotated_op_loc {
 	int reg1;
 	int reg2;
 	int offset;
+	u8 segment;
 	bool mem_ref;
 	bool multi_regs;
 };
@@ -470,6 +472,17 @@ enum annotated_insn_ops {
 	INSN_OP_MAX,
 };
 
+enum annotated_x86_segment {
+	INSN_SEG_NONE = 0,
+
+	INSN_SEG_X86_CS,
+	INSN_SEG_X86_DS,
+	INSN_SEG_X86_ES,
+	INSN_SEG_X86_FS,
+	INSN_SEG_X86_GS,
+	INSN_SEG_X86_SS,
+};
+
 /**
  * struct annotated_insn_loc - Location info of instruction
  * @ops: Array of location info for source and target operands
-- 
2.42.0.869.gea05f2083d-goog