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riscv: gdb(4) support

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Add the MD portion required for the gdb stub.

Reviewed by:	jhb (earlier version)
Discussed with:	jrtc27
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D33734
This commit is contained in:
Mitchell Horne 2020-09-11 14:02:17 -03:00
parent 479ef15dfd
commit d72e944812
5 changed files with 225 additions and 4 deletions
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1
sys/conf/files.riscv
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@ -46,6 +46,7 @@ riscv/riscv/dump_machdep.c standard
riscv/riscv/elf_machdep.c standard
riscv/riscv/exception.S standard
riscv/riscv/exec_machdep.c standard
riscv/riscv/gdb_machdep.c optional gdb
riscv/riscv/intr_machdep.c standard
riscv/riscv/identcpu.c standard
riscv/riscv/locore.S standard no-obj

2
sys/riscv/conf/GENERIC
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@ -173,7 +173,7 @@ options KDB # Enable kernel debugger support.
options KDB_TRACE # Print a stack trace for a panic.
# For full debugger support use (turn off in stable branch):
options DDB # Support DDB.
# options GDB # Support remote GDB.
options GDB # Support remote GDB.
options DEADLKRES # Enable the deadlock resolver
options INVARIANTS # Enable calls of extra sanity checking
options INVARIANT_SUPPORT # Extra sanity checks of internal structures, required by INVARIANTS

3
sys/riscv/conf/NOTES
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@ -90,9 +90,6 @@ nooptions COMPAT_FREEBSD9
nooptions COMPAT_FREEBSD10
nooptions COMPAT_FREEBSD11
# No support for remote GDB
nooptions GDB
# riscv doesn't support inb/outb, so disable chipset probing which needs it
nooptions PPC_PROBE_CHIPSET

88
sys/riscv/include/gdb_machdep.h Normal file
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@ -0,0 +1,88 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2021 Mitchell Horne <mhorne@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _MACHINE_GDB_MACHDEP_H_
#define _MACHINE_GDB_MACHDEP_H_
#define GDB_BUFSZ 4096
#define GDB_NREGS 33
#define GDB_REG_ZERO 0
#define GDB_REG_RA 1
#define GDB_REG_SP 2
#define GDB_REG_GP 3
#define GDB_REG_TP 4
#define GDB_REG_T0 5
#define GDB_REG_FP 8
#define GDB_REG_S1 9
#define GDB_REG_A0 10
#define GDB_REG_S2 18
#define GDB_REG_T3 28
#define GDB_REG_PC 32
#define GDB_REG_CSR_BASE 65
#define GDB_REG_SSTATUS (GDB_REG_CSR_BASE + 0x100)
#define GDB_REG_SCAUSE (GDB_REG_CSR_BASE + 0x142)
#define GDB_REG_STVAL (GDB_REG_CSR_BASE + 0x143)
_Static_assert(GDB_BUFSZ >= (GDB_NREGS * 8), "buffer fits 'g' regs");
static __inline size_t
gdb_cpu_regsz(int regnum __unused)
{
return (8);
}
static __inline int
gdb_cpu_query(void)
{
return (0);
}
static __inline void *
gdb_begin_write(void)
{
return (NULL);
}
static __inline void
gdb_end_write(void *arg __unused)
{
}
static __inline void
gdb_cpu_stop_reason(int type __unused, int code __unused)
{
}
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
#endif /* !_MACHINE_GDB_MACHDEP_H_ */

135
sys/riscv/riscv/gdb_machdep.c Normal file
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@ -0,0 +1,135 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2021 Mitchell Horne <mhorne@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/signal.h>
#include <machine/frame.h>
#include <machine/gdb_machdep.h>
#include <machine/pcb.h>
#include <machine/riscvreg.h>
#include <gdb/gdb.h>
void *
gdb_cpu_getreg(int regnum, size_t *regsz)
{
*regsz = gdb_cpu_regsz(regnum);
if (kdb_thread == curthread) {
switch (regnum) {
case GDB_REG_RA: return (&kdb_frame->tf_ra);
case GDB_REG_PC: return (&kdb_frame->tf_sepc);
case GDB_REG_SSTATUS: return (&kdb_frame->tf_sstatus);
case GDB_REG_STVAL: return (&kdb_frame->tf_stval);
case GDB_REG_SCAUSE: return (&kdb_frame->tf_scause);
default:
if (regnum >= GDB_REG_A0 && regnum < GDB_REG_S2)
return (&kdb_frame->tf_a[regnum - GDB_REG_A0]);
if (regnum >= GDB_REG_T0 && regnum < GDB_REG_FP)
return (&kdb_frame->tf_t[regnum - GDB_REG_T0]);
if (regnum >= GDB_REG_T3 && regnum < GDB_REG_PC)
return (&kdb_frame->tf_t[regnum - GDB_REG_T3]);
break;
}
}
switch (regnum) {
case GDB_REG_PC: /* FALLTHROUGH */
case GDB_REG_RA: return (&kdb_thrctx->pcb_ra);
case GDB_REG_SP: return (&kdb_thrctx->pcb_sp);
case GDB_REG_GP: return (&kdb_thrctx->pcb_gp);
case GDB_REG_TP: return (&kdb_thrctx->pcb_tp);
case GDB_REG_FP: return (&kdb_thrctx->pcb_s[0]);
case GDB_REG_S1: return (&kdb_thrctx->pcb_s[1]);
default:
if (regnum >= GDB_REG_S2 && regnum < GDB_REG_T3)
return (&kdb_thrctx->pcb_s[regnum - GDB_REG_S2]);
break;
}
return (NULL);
}
void
gdb_cpu_setreg(int regnum, void *val)
{
register_t regval = *(register_t *)val;
/* For curthread, keep the pcb and trapframe in sync. */
if (kdb_thread == curthread) {
switch (regnum) {
case GDB_REG_PC: kdb_frame->tf_sepc = regval; break;
case GDB_REG_RA: kdb_frame->tf_ra = regval; break;
case GDB_REG_SP: kdb_frame->tf_sp = regval; break;
case GDB_REG_GP: kdb_frame->tf_gp = regval; break;
case GDB_REG_TP: kdb_frame->tf_tp = regval; break;
case GDB_REG_FP: kdb_frame->tf_s[0] = regval; break;
case GDB_REG_S1: kdb_frame->tf_s[1] = regval; break;
case GDB_REG_SSTATUS: kdb_frame->tf_sstatus = regval; break;
case GDB_REG_STVAL: kdb_frame->tf_stval = regval; break;
case GDB_REG_SCAUSE: kdb_frame->tf_scause = regval; break;
default:
if (regnum >= GDB_REG_A0 && regnum < GDB_REG_S2)
kdb_frame->tf_a[regnum - GDB_REG_A0] = regval;
if (regnum >= GDB_REG_S2 && regnum < GDB_REG_T3)
kdb_frame->tf_s[regnum - GDB_REG_S2] = regval;
if (regnum >= GDB_REG_T0 && regnum < GDB_REG_FP)
kdb_frame->tf_t[regnum - GDB_REG_T0] = regval;
if (regnum >= GDB_REG_T3 && regnum < GDB_REG_PC)
kdb_frame->tf_t[regnum - GDB_REG_T3] = regval;
break;
}
}
switch (regnum) {
case GDB_REG_PC: /* FALLTHROUGH */
case GDB_REG_RA: kdb_thrctx->pcb_ra = regval; break;
case GDB_REG_SP: kdb_thrctx->pcb_sp = regval; break;
case GDB_REG_GP: kdb_thrctx->pcb_gp = regval; break;
case GDB_REG_TP: kdb_thrctx->pcb_tp = regval; break;
case GDB_REG_FP: kdb_thrctx->pcb_s[0] = regval; break;
case GDB_REG_S1: kdb_thrctx->pcb_s[1] = regval; break;
default:
if (regnum >= GDB_REG_S2 && regnum < GDB_REG_T3)
kdb_thrctx->pcb_s[regnum - GDB_REG_S2] = regval;
break;
}
}
int
gdb_cpu_signal(int type, int code)
{
if (type == SCAUSE_BREAKPOINT)
return (SIGTRAP);
return (SIGEMT);
}