On Mon, Feb 08, 2021 at 06:03:08PM +0100, Maciej W. Rozycki wrote: > On Fri, 22 Jan 2021, Arnd Bergmann wrote: > > > From: Arnd Bergmann <a...@arndb.de> > > > > kgdb fails to build when the FPU support is disabled: > > > > arch/mips/kernel/kgdb.c: In function 'dbg_set_reg': > > arch/mips/kernel/kgdb.c:147:35: error: 'struct thread_struct' has no member > > named 'fpu' > > 147 | memcpy((void *)¤t->thread.fpu.fcr31, mem, > > | ^ > > arch/mips/kernel/kgdb.c:155:34: error: 'struct thread_struct' has no member > > named 'fpu' > > 155 | memcpy((void *)¤t->thread.fpu.fpr[fp_reg], mem, > > > > This is only relevant for CONFIG_EXPERT=y, so disallowing it > > in Kconfig is an easier workaround than fixing it properly. > > Wrapping the relevant parts of this file into #ifdef MIPS_FP_SUPPORT > would be as easy though and would qualify as a proper fix given that we > have no XML description support for the MIPS target (so we need to supply > the inexistent registers in the protocol; or maybe we can return NULL in > `dbg_get_reg' to get them padded out in the RSP packet, I haven't checked > if generic KGDB code supports this feature).
Returning NULL should be fine. The generic code will cope OK. The values in the f.p. registers may act a little odd if gdb uses a 'G' packet to set them to non-zero values (since kgdb will cache the values gdb sent it) but the developer operating the debugger will probably figure out what is going on without too much pain. Daniel.
