[RFT v3 4/4] coresight: Document for CoreSight trace disassembler
From: Leo Yan <hidden>
Date: 2018-05-28 08:46:15
Also in:
linux-doc, lkml
Subsystem:
documentation, the rest, tracing · Maintainers:
Jonathan Corbet, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
This commit documents CoreSight trace disassembler usage and gives example for it. Signed-off-by: Leo Yan <redacted> --- Documentation/trace/coresight.txt | 52 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+)
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 6f0120c..b8f2359 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.txt@@ -381,3 +381,55 @@ sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tuto $ taskset -c 2 ./sort_autofdo Bubble sorting array of 30000 elements 5806 ms + + +Tracing data disassembler +------------------------- + +'perf script' supports to use script to parse tracing packet and rely on +'objdump' for disassembled lines, this can convert tracing data to readable +program execution flow for easily reviewing tracing data. + +The CoreSight trace disassembler is located in the folder: +tools/perf/scripts/python/arm-cs-trace-disasm.py. This script support below +options: + + -d, --objdump: Set path to objdump executable, this option is + mandatory. + -k, --vmlinux: Set path to vmlinux file. + -v, --verbose: Enable debugging log, after enable this option the + script dumps every event data. + +Below is one example for using python script to dump CoreSight trace +disassembler: + + $ perf script -s arm-cs-trace-disasm.py -i perf.data \ + -F cpu,event,ip,addr,sym -- -d objdump -k ./vmlinux > cs-disasm.log + +Below is one example for the disassembler log: + +ARM CoreSight Trace Data Assembler Dump + ffff000008a5f2dc <etm4_enable_hw+0x344>: + ffff000008a5f2dc: 340000a0 cbz w0, ffff000008a5f2f0 <etm4_enable_hw+0x358> + ffff000008a5f2f0 <etm4_enable_hw+0x358>: + ffff000008a5f2f0: f9400260 ldr x0, [x19] + ffff000008a5f2f4: d5033f9f dsb sy + ffff000008a5f2f8: 913ec000 add x0, x0, #0xfb0 + ffff000008a5f2fc: b900001f str wzr, [x0] + ffff000008a5f300: f9400bf3 ldr x19, [sp, #16] + ffff000008a5f304: a8c27bfd ldp x29, x30, [sp], #32 + ffff000008a5f308: d65f03c0 ret + ffff000008a5fa18 <etm4_enable+0x1b0>: + ffff000008a5fa18: 14000025 b ffff000008a5faac <etm4_enable+0x244> + ffff000008a5faac <etm4_enable+0x244>: + ffff000008a5faac: b9406261 ldr w1, [x19, #96] + ffff000008a5fab0: 52800015 mov w21, #0x0 // #0 + ffff000008a5fab4: f901ca61 str x1, [x19, #912] + ffff000008a5fab8: 2a1503e0 mov w0, w21 + ffff000008a5fabc: 3940e261 ldrb w1, [x19, #56] + ffff000008a5fac0: f901ce61 str x1, [x19, #920] + ffff000008a5fac4: a94153f3 ldp x19, x20, [sp, #16] + ffff000008a5fac8: a9425bf5 ldp x21, x22, [sp, #32] + ffff000008a5facc: a94363f7 ldp x23, x24, [sp, #48] + ffff000008a5fad0: a8c47bfd ldp x29, x30, [sp], #64 + ffff000008a5fad4: d65f03c0 ret
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2.7.4