[PATCH v3] Fix arm-netbsd build error: convert from FPA to VFP
Christian Biesinger via gdb-patches
gdb-patches@sourceware.org
Mon Mar 2 17:29:00 GMT 2020
On Mon, Mar 2, 2020 at 5:42 AM Alan Hayward <Alan.Hayward@arm.com> wrote:
> > On 28 Feb 2020, at 19:19, Christian Biesinger via gdb-patches <gdb-patches@sourceware.org> wrote:
> >
> > Hi Alan,
> >
> > there is already a num_vfp_registers field in tdep, so I thought it easiest
> > to just use that. Does that look good? See below.
> >
>
> That works for the ARM_FP_TYPE_NONE case.
>
> I had to convince myself it works for the aarch32_read_description case.
> And after thinking it through, I’m happy because both have the same size
> FP register banks.
>
> So, ok to push.
Thanks! Pushing now with a minor change in {fetch,store}_fp_register
to not fetch/store ARM_FPSCR_REGNUM if tdep->vfp_register_count == 0.
Christian
> > The floating point register interface has changed to this:
> > https://github.com/NetBSD/src/blob/trunk/sys/arch/arm/include/reg.h
> >
> > It now uses VFP instead of FPA registers. This patch updates
> > arm-nbsd-nat.c accordingly.
> >
> > Also implements read_description so that these registers are correctly
> > printed by "info registers" et al.
> >
> > Tested by compiling & running on arm-netbsd on qemu.
> >
> > gdb/ChangeLog:
> >
> > 2020-02-11 Christian Biesinger <cbiesinger@google.com>
> >
> > * arm-nbsd-nat.c (arm_supply_fparegset): Rename to...
> > (arm_supply_vfpregset): ...this, and update to use VFP registers.
> > (fetch_fp_register): Update.
> > (fetch_fp_regs): Update.
> > (store_fp_register): Update.
> > (store_fp_regs): Update.
> > (arm_netbsd_nat_target::read_description): New function.
> > (fetch_elfcore_registers): Update.
> > ---
> > gdb/arm-nbsd-nat.c | 121 +++++++++++++++++++++++++--------------------
> > 1 file changed, 68 insertions(+), 53 deletions(-)
> >
> > diff --git a/gdb/arm-nbsd-nat.c b/gdb/arm-nbsd-nat.c
> > index 11afc289c3..cee7917db2 100644
> > --- a/gdb/arm-nbsd-nat.c
> > +++ b/gdb/arm-nbsd-nat.c
> > @@ -26,10 +26,12 @@
> > #include "target.h"
> > #include <sys/types.h>
> > #include <sys/ptrace.h>
> > +#include <sys/sysctl.h>
> > #include <machine/reg.h>
> > #include <machine/frame.h>
> >
> > #include "arm-tdep.h"
> > +#include "aarch32-tdep.h"
> > #include "inf-ptrace.h"
> >
> > class arm_netbsd_nat_target final : public inf_ptrace_target
> > @@ -38,6 +40,7 @@ public:
> > /* Add our register access methods. */
> > void fetch_registers (struct regcache *, int) override;
> > void store_registers (struct regcache *, int) override;
> > + const struct target_desc *read_description () override;
> > };
> >
> > static arm_netbsd_nat_target the_arm_netbsd_nat_target;
> > @@ -65,15 +68,17 @@ arm_supply_gregset (struct regcache *regcache, struct reg *gregset)
> > }
> >
> > static void
> > -arm_supply_fparegset (struct regcache *regcache, struct fpreg *fparegset)
> > +arm_supply_vfpregset (struct regcache *regcache, struct fpreg *fpregset)
> > {
> > - int regno;
> > + struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
> > + if (tdep->vfp_register_count == 0)
> > + return;
> >
> > - for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
> > - regcache->raw_supply (regno,
> > - (char *) &fparegset->fpr[regno - ARM_F0_REGNUM]);
> > + struct vfpreg &vfp = fpregset->fpr_vfp;
> > + for (int regno = 0; regno <= tdep->vfp_register_count; regno++)
> > + regcache->raw_supply (regno + ARM_D0_REGNUM, (char *) &vfp.vfp_regs[regno]);
> >
> > - regcache->raw_supply (ARM_FPS_REGNUM, (char *) &fparegset->fpr_fpsr);
> > + regcache->raw_supply (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> > }
> >
> > static void
> > @@ -147,10 +152,10 @@ static void
> > fetch_fp_register (struct regcache *regcache, int regno)
> > {
> > struct fpreg inferior_fp_registers;
> > - int ret;
> > + int ret = ptrace (PT_GETFPREGS, regcache->ptid ().pid (),
> > + (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> >
> > - ret = ptrace (PT_GETFPREGS, regcache->ptid ().pid (),
> > - (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> > + struct vfpreg &vfp = inferior_fp_registers.fpr_vfp;
> >
> > if (ret < 0)
> > {
> > @@ -158,18 +163,17 @@ fetch_fp_register (struct regcache *regcache, int regno)
> > return;
> > }
> >
> > - switch (regno)
> > + struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
> > + if (regno == ARM_FPSCR_REGNUM)
> > + regcache->raw_supply (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> > + else if (regno >= ARM_D0_REGNUM
> > + && regno <= ARM_D0_REGNUM + tdep->vfp_register_count)
> > {
> > - case ARM_FPS_REGNUM:
> > - regcache->raw_supply (ARM_FPS_REGNUM,
> > - (char *) &inferior_fp_registers.fpr_fpsr);
> > - break;
> > -
> > - default:
> > - regcache->raw_supply
> > - (regno, (char *) &inferior_fp_registers.fpr[regno - ARM_F0_REGNUM]);
> > - break;
> > + regcache->raw_supply (regno,
> > + (char *) &vfp.vfp_regs[regno - ARM_D0_REGNUM]);
> > }
> > + else
> > + warning (_("Invalid register number."));
> > }
> >
> > static void
> > @@ -188,7 +192,7 @@ fetch_fp_regs (struct regcache *regcache)
> > return;
> > }
> >
> > - arm_supply_fparegset (regcache, &inferior_fp_registers);
> > + arm_supply_vfpregset (regcache, &inferior_fp_registers);
> > }
> >
> > void
> > @@ -327,10 +331,9 @@ static void
> > store_fp_register (const struct regcache *regcache, int regno)
> > {
> > struct fpreg inferior_fp_registers;
> > - int ret;
> > -
> > - ret = ptrace (PT_GETFPREGS, regcache->ptid ().pid (),
> > - (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> > + int ret = ptrace (PT_GETFPREGS, regcache->ptid ().pid (),
> > + (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> > + struct vfpreg &vfp = inferior_fp_registers.fpr_vfp;
> >
> > if (ret < 0)
> > {
> > @@ -338,18 +341,17 @@ store_fp_register (const struct regcache *regcache, int regno)
> > return;
> > }
> >
> > - switch (regno)
> > + struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
> > + if (regno == ARM_FPSCR_REGNUM)
> > + regcache->raw_collect (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> > + else if (regno >= ARM_D0_REGNUM
> > + && regno <= ARM_D0_REGNUM + tdep->vfp_register_count)
> > {
> > - case ARM_FPS_REGNUM:
> > - regcache->raw_collect (ARM_FPS_REGNUM,
> > - (char *) &inferior_fp_registers.fpr_fpsr);
> > - break;
> > -
> > - default:
> > - regcache->raw_collect
> > - (regno, (char *) &inferior_fp_registers.fpr[regno - ARM_F0_REGNUM]);
> > - break;
> > + regcache->raw_collect (regno,
> > + (char *) &vfp.vfp_regs[regno - ARM_D0_REGNUM]);
> > }
> > + else
> > + warning (_("Invalid register number."));
> >
> > ret = ptrace (PT_SETFPREGS, regcache->ptid ().pid (),
> > (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> > @@ -361,20 +363,20 @@ store_fp_register (const struct regcache *regcache, int regno)
> > static void
> > store_fp_regs (const struct regcache *regcache)
> > {
> > - struct fpreg inferior_fp_registers;
> > - int ret;
> > - int regno;
> > -
> > + struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
> > + if (tdep->vfp_register_count == 0)
> > + return;
> >
> > - for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
> > + struct fpreg fpregs;
> > + for (int regno = 0; regno <= tdep->vfp_register_count; regno++)
> > regcache->raw_collect
> > - (regno, (char *) &inferior_fp_registers.fpr[regno - ARM_F0_REGNUM]);
> > + (regno + ARM_D0_REGNUM, (char *) &fpregs.fpr_vfp.vfp_regs[regno]);
> >
> > - regcache->raw_collect (ARM_FPS_REGNUM,
> > - (char *) &inferior_fp_registers.fpr_fpsr);
> > + regcache->raw_collect (ARM_FPSCR_REGNUM,
> > + (char *) &fpregs.fpr_vfp.vfp_fpscr);
> >
> > - ret = ptrace (PT_SETFPREGS, regcache->ptid ().pid (),
> > - (PTRACE_TYPE_ARG3) &inferior_fp_registers, 0);
> > + int ret = ptrace (PT_SETFPREGS, regcache->ptid ().pid (),
> > + (PTRACE_TYPE_ARG3) &fpregs, 0);
> >
> > if (ret < 0)
> > warning (_("unable to store floating-point registers"));
> > @@ -397,6 +399,23 @@ arm_netbsd_nat_target::store_registers (struct regcache *regcache, int regno)
> > }
> > }
> >
> > +const struct target_desc *
> > +arm_netbsd_nat_target::read_description ()
> > +{
> > + int flag;
> > + size_t len = sizeof (flag);
> > +
> > + if (sysctlbyname("machdep.fpu_present", &flag, &len, NULL, 0) != 0
> > + || !flag)
> > + return arm_read_description (ARM_FP_TYPE_NONE);
> > +
> > + len = sizeof(flag);
> > + if (sysctlbyname("machdep.neon_present", &flag, &len, NULL, 0) == 0 && flag)
> > + return aarch32_read_description ();
> > +
> > + return arm_read_description (ARM_FP_TYPE_VFPV3);
> > +}
> > +
> > static void
> > fetch_elfcore_registers (struct regcache *regcache,
> > gdb_byte *core_reg_sect, unsigned core_reg_size,
> > @@ -420,15 +439,11 @@ fetch_elfcore_registers (struct regcache *regcache,
> > break;
> >
> > case 2:
> > - if (core_reg_size != sizeof (struct fpreg))
> > - warning (_("wrong size of FPA register set in core file"));
> > - else
> > - {
> > - /* The memcpy may be unnecessary, but we can't really be sure
> > - of the alignment of the data in the core file. */
> > - memcpy (&fparegset, core_reg_sect, sizeof (fparegset));
> > - arm_supply_fparegset (regcache, &fparegset);
> > - }
> > + /* cbiesinger/2020-02-12 -- as far as I can tell, ARM/NetBSD does
> > + not write any floating point registers into the core file (tested
> > + with NetBSD 9.1_RC1). When it does, this block will need to read them,
> > + and the arm-netbsd gdbarch will need a core_read_description function
> > + to return the right description for them. */
> > break;
> >
> > default:
> > --
> > 2.25.0.265.gbab2e86ba0-goog
> >
>
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