[PATCH] Fix arm-netbsd build error
Kamil Rytarowski
n54@gmx.com
Wed Feb 12 17:17:00 GMT 2020
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
>>>>>
>>>
>
>
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