From 8bf82b340e59cdc7d6cac49762104d48cebd2283 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Mon, 7 Dec 2020 15:09:28 +0000 Subject: [PATCH] arm: Let the GDB stub write to SP, LR and GP registers This can be handy if gdb's stack unwinder fails, for example because of a bug in kgdb's trap frame unwinder. PR: 251463 Submitted by: Dmitry Salychev MFC after: 1 week --- sys/arm/arm/gdb_machdep.c | 18 ++++++++++++++++-- sys/arm/include/gdb_machdep.h | 2 ++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/sys/arm/arm/gdb_machdep.c b/sys/arm/arm/gdb_machdep.c index e4adbd80669..d4289297255 100644 --- a/sys/arm/arm/gdb_machdep.c +++ b/sys/arm/arm/gdb_machdep.c @@ -97,11 +97,25 @@ gdb_cpu_getreg(int regnum, size_t *regsz) void gdb_cpu_setreg(int regnum, void *val) { + if (kdb_thread != curthread) + return; switch (regnum) { case GDB_REG_PC: - if (kdb_thread == curthread) - kdb_frame->tf_pc = *(register_t *)val; + kdb_frame->tf_pc = *(register_t *)val; + break; + case GDB_REG_SP: + kdb_frame->tf_svc_sp = *(register_t *)val; + break; + case GDB_REG_LR: + kdb_frame->tf_svc_lr = *(register_t *)val; + break; + default: + /* Write to the general purpose registers r0-r12. */ + if (regnum >= 0 && regnum <= 12) { + *(&kdb_frame->tf_r0 + regnum) = *(register_t *)val; + } + break; } } diff --git a/sys/arm/include/gdb_machdep.h b/sys/arm/include/gdb_machdep.h index 79c74cdd0e1..017025253bd 100644 --- a/sys/arm/include/gdb_machdep.h +++ b/sys/arm/include/gdb_machdep.h @@ -33,6 +33,8 @@ #define GDB_BUFSZ 400 #define GDB_NREGS 26 +#define GDB_REG_SP 13 +#define GDB_REG_LR 14 #define GDB_REG_PC 15 static __inline size_t -- 2.45.0