From c354cfe89c7620562fd2aa9e243b638a7fc7b7af Mon Sep 17 00:00:00 2001 From: Tim Newsome Date: Fri, 9 Jun 2017 10:30:40 -0700 Subject: [PATCH] Update README to use --rbb-port --- README.md | 136 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 91 insertions(+), 45 deletions(-) diff --git a/README.md b/README.md index a5ed802..60c0922 100644 --- a/README.md +++ b/README.md @@ -111,18 +111,83 @@ To end the simulation from the debug prompt, press `-` or: Debugging With Gdb ------------------ -An alternative to interactive debug mode is to attach using gdb. When invoked -with '--gdb-port ' spike will listen on the given TCP port. It's -possible to attach with gdb (that has riscv support compiled in) by entering -`target remote localhost:` in gdb. For example, in one shell run: +An alternative to interactive debug mode is to attach using gdb. Because spike +tries to be like real hardware, you also need OpenOCD to do that. OpenOCD +doesn't currently know about address translation, so it's not possible to +easily debug programs that are run under `pk`. We'll use the following test +program: ``` -spike --gdb-port 9824 pk tests/debug +$ cat rot13.c +char text[] = "Vafgehpgvba frgf jnag gb or serr!"; + +// Don't use the stack, because sp isn't set up. +volatile int wait = 1; + +int main() +{ + while (wait) + ; + + // Doesn't actually go on the stack, because there are lots of GPRs. + int i = 0; + while (text[i]) { + char lower = text[i] | 32; + if (lower >= 'a' && lower <= 'm') + text[i] += 13; + else if (lower > 'm' && lower <= 'z') + text[i] -= 13; + i++; + } + + while (!wait) + ; +} +$ cat spike.lds +OUTPUT_ARCH( "riscv" ) + +SECTIONS +{ + . = 0x10010000; + .text : { *(.text) } + .data : { *(.data) } +} +$ riscv64-unknown-elf-gcc -g -Og -o rot13-64.o -c rot13.c +$ riscv64-unknown-elf-gcc -g -Og -T spike.lds -nostartfiles -o rot13-64 rot13-64.o ``` -Then in a second shell you may do something like: +To debug this program, first run spike telling it to listen for OpenOCD: ``` -tnewsome@compy-vm:~/SiFive/riscv-isa-sim$ $RISCV/bin/riscv64-unknown-elf-gdb tests/debug -GNU gdb (GDB) 7.11.50.20160212-git +$ spike --rbb-port=9824 -m0x10000000:0x20000 rot13-64 +Listening for remote bitbang connection on port 9824. +``` + +In a separate shell run OpenOCD with the appropriate configuration file: +``` +$ cat spike.cfg +interface remote_bitbang +remote_bitbang_host localhost +remote_bitbang_port 9824 + +set _CHIPNAME riscv +jtag newtap $_CHIPNAME cpu -irlen 5 -expected-id 0x10e31913 + +set _TARGETNAME $_CHIPNAME.cpu +target create $_TARGETNAME riscv -chain-position $_TARGETNAME + +gdb_report_data_abort enable + +init +halt +$ openocd -f spike.cfg +Open On-Chip Debugger 0.10.0-dev-00002-gc3b344d (2017-06-08-12:14) +... +riscv.cpu: target state: halted +``` + +In yet another shell, start your gdb debug session: +``` +tnewsome@compy-vm:~/SiFive/spike-test$ riscv64-unknown-elf-gdb rot13-64 +GNU gdb (GDB) 7.12.50.20170505-git Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. @@ -136,45 +201,26 @@ Find the GDB manual and other documentation resources online at: . For help, type "help". Type "apropos word" to search for commands related to "word"... -Reading symbols from tests/debug...done. -(gdb) target remote localhost:9824 -Remote debugging using localhost:9824 -0x00000000000101f0 in main () - at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:20 -20 while (i) -(gdb) p i -$1 = 42 -(gdb) list -15 volatile int i = 42; -16 const char *text = "constant\n"; -17 int threshold = 7; -18 -19 // Wait for the debugger to get us out of this loop. -20 while (i) -21 ; -22 -23 printf("%s", text); -24 for (int y=0; y < 10; y++) { -(gdb) p i=0 +Reading symbols from rot13-64...done. +(gdb) target remote localhost:3333 +Remote debugging using localhost:3333 +0x000000001001000a in main () at rot13.c:8 +8 while (wait) +(gdb) print wait +$1 = 1 +(gdb) print wait=0 $2 = 0 -(gdb) b print_row -Breakpoint 1 at 0x10178: file /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c, line 7. +(gdb) print text +$3 = "Vafgehpgvba frgf jnag gb or serr!" +(gdb) b 23 +Breakpoint 1 at 0x10010064: file rot13.c, line 23. (gdb) c Continuing. -Breakpoint 1, print_row (length=0) - at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:7 -7 for (int x=0; x