From: "Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>
To: Kamil Rytarowski <n54@gmx.com>
Cc: Alan Hayward <Alan.Hayward@arm.com>,
gdb-patches <gdb-patches@sourceware.org>, nd <nd@arm.com>
Subject: Re: [PATCH] Fix arm-netbsd build error
Date: Wed, 12 Feb 2020 23:28:00 -0000 [thread overview]
Message-ID: <CAPTJ0XEEFdO-AyWZRakZLBFwVDhWir2xffoh_c_BSKCd3k--Uw@mail.gmail.com> (raw)
In-Reply-To: <96a09009-a9c9-aad2-5a83-e08f7e8dcb68@gmx.com>
Thanks, Kamil!
Please forgive the stupid question, but is SIMD in this context the
same as IWMMXT?
Christian
On Wed, Feb 12, 2020 at 11:16 AM Kamil Rytarowski <n54@gmx.com> wrote:
>
> On 12.02.2020 18:09, Kamil Rytarowski wrote:
> > On 12.02.2020 17:28, Christian Biesinger wrote:
> >> On Wed, Feb 12, 2020 at 7:29 AM Alan Hayward <Alan.Hayward@arm.com> wrote:
> >>>
> >>>
> >>>
> >>>> On 11 Feb 2020, at 23:34, Christian Biesinger via gdb-patches <gdb-patches@sourceware.org> wrote:
> >>>>
> >>>> On Tue, Feb 11, 2020 at 4:55 PM Christian Biesinger
> >>>> <cbiesinger@google.com> wrote:
> >>>>>
> >>>>> 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.
> >>>>>
> >>>>> Tested by compiling on arm-netbsd on qemu. For actually testing, there
> >>>>> seems to be something missing as "info registers" only shows FPA
> >>>>> registers and no VFP ones. I am still investigating why this is;
> >>>>> please let me know if you know. However, I think this is still good
> >>>>> to check in as-is.
> >>>>
> >>>> Hm... this is perhaps because arm_netbsd_nat_target does not implement
> >>>> read_description; if it returned arm_read_description
> >>>> (ARM_FP_TYPE_VFPV2) this may work?
> >>>>
> >>>
> >>> Yes, looks like netbsd isn’t using any target description functionality.
> >>>
> >>> I suspect the code is getting into arm_gdbarch_init() with a null tdesc,
> >>> and then using the AUTO setting. But that’s just a guess.
> >>>
> >>> Implementing read_description as you suggest should help. However,
> >>> read_description should probably do HWCAP checking similar to the
> >>> arm_linux_nat_target and arm_fbsd_nat_target versions.
> >>>
> >>> Without that, I’d worry that your patch below might start writing off the
> >>> end of the regcache that had been allocated for a fewer number of registers.
> >>
> >> Hm... well, I've probably spent entirely too much time on this
> >> already, but just in case there's an easy fix -- Kamil, does NetBSD
> >> provide an API similar to Linux's HWCAP API that would let me check
> >> which VFP version the current CPU is using? It seems AUXV does not
> >> contain HWCAP data on NetBSD, unlike Linux/FreeBSD, though I may be
> >> missing something.
> >>
> >> (Compare arm_fbsd_read_description_auxv /
> >> arm_linux_nat_target::read_description)
> >>
> >> Christian
> >>
> >
> > Thank you for your work.
> >
> > HWCAP in auxv is not supported (although there is a stub for it).
> >
> > Here is a complete algorithm to detect FPU on ARM 32-bit.
> >
> > http://netbsd.org/~kamil/arm-fpu.c
> >
>
> Here is another example with SIMD:
>
> http://cvsweb.netbsd.org/bsdweb.cgi/xsrc/external/mit/pixman/dist/pixman/pixman-arm.c.diff?r1=1.1&r2=1.2&f=h
>
> >>>
> >>>>>
> >>>>> 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.
> >>>>> (fetch_elfcore_registers): Update.
> >>>>> ---
> >>>>> gdb/arm-nbsd-nat.c | 80 ++++++++++++++++++++--------------------------
> >>>>> 1 file changed, 34 insertions(+), 46 deletions(-)
> >>>>>
> >>>>> diff --git a/gdb/arm-nbsd-nat.c b/gdb/arm-nbsd-nat.c
> >>>>> index 11afc289c3..8027f54dfe 100644
> >>>>> --- a/gdb/arm-nbsd-nat.c
> >>>>> +++ b/gdb/arm-nbsd-nat.c
> >>>>> @@ -65,15 +65,13 @@ 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;
> >>>>> -
> >>>>> - 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 = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++)
> >>>>> + regcache->raw_supply (regno, (char *) &vfp.vfp_regs[regno - ARM_D0_REGNUM]);
> >>>>>
> >>>>> - regcache->raw_supply (ARM_FPS_REGNUM, (char *) &fparegset->fpr_fpsr);
> >>>>> + regcache->raw_supply (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> >>>>> }
> >>>>>
> >>>>> static void
> >>>>> @@ -147,10 +145,10 @@ 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 +156,15 @@ fetch_fp_register (struct regcache *regcache, int regno)
> >>>>> return;
> >>>>> }
> >>>>>
> >>>>> - switch (regno)
> >>>>> + if (regno == ARM_FPSCR_REGNUM)
> >>>>> + regcache->raw_supply (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> >>>>> + else if (regno >= ARM_D0_REGNUM && regno <= ARM_D31_REGNUM)
> >>>>> {
> >>>>> - 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 +183,7 @@ fetch_fp_regs (struct regcache *regcache)
> >>>>> return;
> >>>>> }
> >>>>>
> >>>>> - arm_supply_fparegset (regcache, &inferior_fp_registers);
> >>>>> + arm_supply_vfpregset (regcache, &inferior_fp_registers);
> >>>>> }
> >>>>>
> >>>>> void
> >>>>> @@ -327,10 +322,9 @@ 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 +332,15 @@ store_fp_register (const struct regcache *regcache, int regno)
> >>>>> return;
> >>>>> }
> >>>>>
> >>>>> - switch (regno)
> >>>>> + if (regno == ARM_FPSCR_REGNUM)
> >>>>> + regcache->raw_collect (ARM_FPSCR_REGNUM, (char *) &vfp.vfp_fpscr);
> >>>>> + else if (regno >= ARM_D0_REGNUM && regno <= ARM_D31_REGNUM)
> >>>>> {
> >>>>> - 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 +352,17 @@ 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 fpreg fpregs;
> >>>>>
> >>>>> -
> >>>>> - for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
> >>>>> + for (int regno = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++)
> >>>>> regcache->raw_collect
> >>>>> - (regno, (char *) &inferior_fp_registers.fpr[regno - ARM_F0_REGNUM]);
> >>>>> + (regno, (char *) &fpregs.fpr_vfp.vfp_regs[regno - ARM_D0_REGNUM]);
> >>>>>
> >>>>> - 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"));
> >>>>> @@ -427,7 +415,7 @@ fetch_elfcore_registers (struct regcache *regcache,
> >>>>> /* 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);
> >>>>> + arm_supply_vfpregset (regcache, &fparegset);
> >>>>> }
> >>>>> break;
> >>>>>
> >>>>> --
> >>>>> 2.25.0.225.g125e21ebc7-goog
> >>>>>
> >>>
> >
> >
>
>
next prev parent reply other threads:[~2020-02-12 23:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200211225503.32992-1-cbiesinger@google.com>
2020-02-11 23:35 ` Christian Biesinger via gdb-patches
2020-02-12 13:30 ` Alan Hayward
2020-02-12 16:29 ` Christian Biesinger via gdb-patches
2020-02-12 17:10 ` Kamil Rytarowski
2020-02-12 17:17 ` Kamil Rytarowski
2020-02-12 23:28 ` Christian Biesinger via gdb-patches [this message]
2020-02-12 23:43 ` Christian Biesinger via gdb-patches
2020-02-13 0:01 ` Kamil Rytarowski
2020-02-28 13:18 ` [PATCH v2] Fix arm-netbsd build error: convert from FPA to VFP Christian Biesinger via gdb-patches
2020-02-28 14:35 ` Alan Hayward
2020-02-28 19:19 ` [PATCH v3] " Christian Biesinger via gdb-patches
[not found] ` <ECBA936B-BF56-4F49-9C57-35E0F29D560E@arm.com>
2020-03-02 17:29 ` Christian Biesinger via gdb-patches
2020-03-02 17:32 ` Kamil Rytarowski
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