From: Nicholas Piggin <npiggin@gmail.com>
To: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>,
libc-alpha@sourceware.org, libc-dev@lists.llvm.org,
linux-api@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Michael Ellerman <mpe@ellerman.id.au>,
Matheus Castanho <msc@linux.ibm.com>,
musl@lists.openwall.com
Subject: Re: Linux powerpc new system call instruction and ABI
Date: Thu, 20 May 2021 15:12:03 +1000 [thread overview]
Message-ID: <1621487263.hkgxyf500s.astroid@bobo.none> (raw)
In-Reply-To: <20210520030611.GB27081@altlinux.org>
Excerpts from Dmitry V. Levin's message of May 20, 2021 1:06 pm:
> On Thu, May 20, 2021 at 12:40:36PM +1000, Nicholas Piggin wrote:
> [...]
>> > Looks like struct pt_regs.trap already contains the information that could
>> > be used to tell 'sc' from 'scv': if (pt_regs.trap & ~0xf) == 0x3000, then
>> > it's scv. Is my reading of arch/powerpc/include/asm/ptrace.h correct?
>>
>> Hmm, I think it is. Certainly in the kernel regs struct it is, I had in
>> my mind that we put it to 0xc00 when populating the user struct for
>> compatibility, but it seems not. So I guess this would work.
>
> OK, can we state that (pt_regs.trap & ~0xf) == 0x3000 is a part of the scv
> ABI, so it's not going to change and could be relied upon by userspace?
> Could this be documented in Documentation/powerpc/syscall64-abi.rst,
> please?
Yeah I think we can do that. The kernel doesn't care what is put in the
userspace pt_regs.trap too much so if this is your preferred approach
then I will document it in the ABI.
Thanks,
Nick
WARNING: multiple messages have this Message-ID (diff)
From: Nicholas Piggin <npiggin@gmail.com>
To: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: libc-alpha@sourceware.org, Matheus Castanho <msc@linux.ibm.com>,
musl@lists.openwall.com, linux-api@vger.kernel.org,
libc-dev@lists.llvm.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: Linux powerpc new system call instruction and ABI
Date: Thu, 20 May 2021 15:12:03 +1000 [thread overview]
Message-ID: <1621487263.hkgxyf500s.astroid@bobo.none> (raw)
In-Reply-To: <20210520030611.GB27081@altlinux.org>
Excerpts from Dmitry V. Levin's message of May 20, 2021 1:06 pm:
> On Thu, May 20, 2021 at 12:40:36PM +1000, Nicholas Piggin wrote:
> [...]
>> > Looks like struct pt_regs.trap already contains the information that could
>> > be used to tell 'sc' from 'scv': if (pt_regs.trap & ~0xf) == 0x3000, then
>> > it's scv. Is my reading of arch/powerpc/include/asm/ptrace.h correct?
>>
>> Hmm, I think it is. Certainly in the kernel regs struct it is, I had in
>> my mind that we put it to 0xc00 when populating the user struct for
>> compatibility, but it seems not. So I guess this would work.
>
> OK, can we state that (pt_regs.trap & ~0xf) == 0x3000 is a part of the scv
> ABI, so it's not going to change and could be relied upon by userspace?
> Could this be documented in Documentation/powerpc/syscall64-abi.rst,
> please?
Yeah I think we can do that. The kernel doesn't care what is put in the
userspace pt_regs.trap too much so if this is your preferred approach
then I will document it in the ABI.
Thanks,
Nick
next prev parent reply other threads:[~2021-05-20 5:12 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 8:12 Linux powerpc new system call instruction and ABI Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-06-11 8:12 ` [PATCH 1/2] powerpc/64s/exception: treat NIA below __end_interrupts as soft-masked Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-07-24 13:25 ` Michael Ellerman
2020-07-24 13:25 ` Michael Ellerman
2020-06-11 8:12 ` [PATCH 2/2] powerpc/64s: system call support for scv/rfscv instructions Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-07-23 6:47 ` Michael Ellerman
2020-07-23 16:48 ` Christophe Leroy
2020-07-23 16:48 ` Christophe Leroy
2020-07-24 10:45 ` Michael Ellerman
2020-07-24 10:45 ` Michael Ellerman
2020-06-11 21:02 ` Linux powerpc new system call instruction and ABI Segher Boessenkool
2020-06-11 21:02 ` Segher Boessenkool
2020-06-14 9:26 ` Nicholas Piggin
2020-06-14 9:26 ` Nicholas Piggin
2021-05-18 23:13 ` Dmitry V. Levin
2021-05-18 23:13 ` Dmitry V. Levin
2021-05-19 2:50 ` Nicholas Piggin
2021-05-19 2:50 ` Nicholas Piggin
2021-05-19 5:01 ` Nicholas Piggin
2021-05-19 5:01 ` Nicholas Piggin
2021-05-21 19:40 ` Matheus Castanho
2021-05-21 19:40 ` Matheus Castanho
2021-05-21 19:52 ` Florian Weimer
2021-05-21 19:52 ` Florian Weimer
2021-05-21 20:00 ` Matheus Castanho
2021-05-21 20:00 ` Matheus Castanho
2021-05-21 20:52 ` Dmitry V. Levin
2021-05-21 20:52 ` Dmitry V. Levin
2021-05-24 12:11 ` Matheus Castanho
2021-05-24 12:11 ` Matheus Castanho
2021-05-24 20:33 ` Matheus Castanho
2021-05-24 20:33 ` Matheus Castanho
2021-05-19 10:24 ` Dmitry V. Levin
2021-05-19 10:24 ` Dmitry V. Levin
2021-05-19 10:59 ` Nicholas Piggin
2021-05-19 10:59 ` Nicholas Piggin
2021-05-19 12:39 ` Tulio Magno Quites Machado Filho
2021-05-19 12:39 ` Tulio Magno Quites Machado Filho
2021-05-19 13:26 ` Dmitry V. Levin
2021-05-19 13:26 ` Dmitry V. Levin
2021-05-19 22:51 ` Nicholas Piggin
2021-05-19 22:51 ` Nicholas Piggin
2021-05-19 23:27 ` Dmitry V. Levin
2021-05-19 23:27 ` Dmitry V. Levin
2021-05-20 2:40 ` Nicholas Piggin
2021-05-20 2:40 ` Nicholas Piggin
2021-05-20 3:06 ` Dmitry V. Levin
2021-05-20 3:06 ` Dmitry V. Levin
2021-05-20 5:12 ` Nicholas Piggin [this message]
2021-05-20 5:12 ` Nicholas Piggin
2021-05-19 7:33 ` Joakim Tjernlund
2021-05-19 7:33 ` Joakim Tjernlund
2021-05-19 7:55 ` Nicholas Piggin
2021-05-19 7:55 ` Nicholas Piggin
2021-05-19 8:08 ` Joakim Tjernlund
2021-05-19 8:08 ` Joakim Tjernlund
2021-05-19 8:42 ` Nicholas Piggin
2021-05-19 8:42 ` Nicholas Piggin
2021-05-19 11:12 ` Nicholas Piggin
2021-05-19 11:12 ` Nicholas Piggin
2021-05-19 14:38 ` Segher Boessenkool
2021-05-19 14:38 ` Segher Boessenkool
2021-05-19 15:06 ` Joakim Tjernlund
2021-05-19 15:06 ` Joakim Tjernlund
2021-05-19 15:22 ` Segher Boessenkool
2021-05-19 15:22 ` Segher Boessenkool
2021-05-19 15:36 ` [musl] " Rich Felker
2021-05-19 15:36 ` Rich Felker
2021-05-19 18:09 ` Joakim Tjernlund
2021-05-19 18:09 ` Joakim Tjernlund
2021-05-19 23:48 ` [musl] " Rich Felker
2021-05-19 23:48 ` Rich Felker
2021-05-20 1:06 ` Dmitry V. Levin
2021-05-20 1:06 ` Dmitry V. Levin
2021-05-20 2:45 ` Nicholas Piggin
2021-05-20 2:45 ` Nicholas Piggin
2021-05-20 2:59 ` Dmitry V. Levin
2021-05-20 2:59 ` Dmitry V. Levin
2021-05-20 7:20 ` Nicholas Piggin
2021-05-20 7:20 ` Nicholas Piggin
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