From: Tong Tiangen <tongtiangen@huawei.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Robin Murphy <robin.murphy@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, <x86@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>,
<linuxppc-dev@lists.ozlabs.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Xie XiuQi <xiexiuqi@huawei.com>, Guohanjun <guohanjun@huawei.com>
Subject: Re: [PATCH -next v5 2/8] arm64: extable: make uaaccess helper use extable type EX_TYPE_UACCESS_ERR_ZERO
Date: Mon, 20 Jun 2022 22:13:41 +0800 [thread overview]
Message-ID: <908f4c14-b9cb-71f8-7a3c-7569f7c89033@huawei.com> (raw)
In-Reply-To: <YrA5f44hySky8v5g@FVFF77S0Q05N>
在 2022/6/20 17:10, Mark Rutland 写道:
> On Mon, Jun 20, 2022 at 10:59:12AM +0800, Tong Tiangen wrote:
>> 在 2022/6/18 20:40, Mark Rutland 写道:
>>> On Sat, Jun 18, 2022 at 04:42:06PM +0800, Tong Tiangen wrote:
>>>>>>> diff --git a/arch/arm64/include/asm/asm-extable.h
>>>>>>> b/arch/arm64/include/asm/asm-extable.h
>>>>>>> index 56ebe183e78b..9c94ac1f082c 100644
>>>>>>> --- a/arch/arm64/include/asm/asm-extable.h
>>>>>>> +++ b/arch/arm64/include/asm/asm-extable.h
>>>>>>> @@ -28,6 +28,14 @@
>>>>>>> __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
>>>>>>> .endm
>>>>>>> +/*
>>>>>>> + * Create an exception table entry for uaccess `insn`, which
>>>>>>> will branch to `fixup`
>>>>>>> + * when an unhandled fault is taken.
>>>>>>> + * ex->data = ~0 means both reg_err and reg_zero is set to wzr(x31).
>>>>>>> + */
>>>>>>> + .macro _asm_extable_uaccess, insn, fixup
>>>>>>> + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_ERR_ZERO, ~0)
>>>>>>> + .endm
>>>>>>
>>>>>> I'm not too keen on using `~0` here, since that also sets other bits
>>>>>> in the
>>>>>> data field, and its somewhat opaque.
>>>>>>
>>>>>> How painful is it to generate the data fields as with the C version
>>>>>> of this
>>>>>> macro, so that we can pass in wzr explciitly for the two sub-fields?
>>>>>>
>>>>>> Other than that, this looks good to me.
>>>>>>
>>>>>> Thanks,
>>>>>> Mark.
>>>>>
>>>>> ok, will fix next version.
>>>>>
>>>>> Thanks,
>>>>> Tong.
>>>>
>>>> I tried to using data filelds as with C version, but here assembly code we
>>>> can not using operator such as << and |, if we use lsl and orr instructions,
>>>> the gpr will be occupied.
>>>>
>>>> So how about using 0x3ff directly here? it means err register and zero
>>>> register both set to x31.
>>>
>>> I had a go at implementing this, and it seems simple enough. Please see:
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/extable/asm-uaccess
>>>
>>
>> I made the following modifications, and the other parts are based on your
>> implementation:
>>
>> arch/arm64/include/asm/asm-extable.h
>> [...]
>> .macro _asm_extable_uaccess, insn, fixup
>> _ASM_EXTABLE_UACCESS(\insn, \fixup)
>> .endm
>> [...]
>
> I also made this same change locally when testing, and building with GCC 11.1.0
> or LLVM 14.0.0 I am not seeing any problem when building, and the result is as
> expected:
>
> | [mark@lakrids:~/src/linux]% usekorg 11.1.0 make ARCH=arm64 CROSS_COMPILE=aarch64-linux- defconfig
> | *** Default configuration is based on 'defconfig'
> | #
> | # No change to .config
> | #
> | [mark@lakrids:~/src/linux]% usekorg 11.1.0 make ARCH=arm64 CROSS_COMPILE=aarch64-linux- -j50 arch/arm64/lib/
> | CALL scripts/atomic/check-atomics.sh
> | CC arch/arm64/kernel/asm-offsets.s
> | CALL scripts/checksyscalls.sh
> | AS arch/arm64/kernel/vdso/note.o
> | AS arch/arm64/kernel/vdso/sigreturn.o
> | LD arch/arm64/kernel/vdso/vdso.so.dbg
> | VDSOSYM include/generated/vdso-offsets.h
> | OBJCOPY arch/arm64/kernel/vdso/vdso.so
> | make[2]: Nothing to be done for 'arch/arm64/lib/'.
> | AS arch/arm64/lib/clear_page.o
> | AS arch/arm64/lib/clear_user.o
> | AS arch/arm64/lib/copy_from_user.o
> | AS arch/arm64/lib/copy_page.o
> | AS arch/arm64/lib/copy_to_user.o
> | CC arch/arm64/lib/csum.o
> | CC arch/arm64/lib/delay.o
> | AS arch/arm64/lib/memchr.o
> | AS arch/arm64/lib/memcmp.o
> | AS arch/arm64/lib/memcpy.o
> | AS arch/arm64/lib/memset.o
> | AS arch/arm64/lib/strchr.o
> | AS arch/arm64/lib/strcmp.o
> | AS arch/arm64/lib/strlen.o
> | AS arch/arm64/lib/strncmp.o
> | AS arch/arm64/lib/strnlen.o
> | AS arch/arm64/lib/strrchr.o
> | AS arch/arm64/lib/tishift.o
> | AS arch/arm64/lib/crc32.o
> | AS arch/arm64/lib/mte.o
> | CC [M] arch/arm64/lib/xor-neon.o
> | AR arch/arm64/lib/built-in.a
> | AR arch/arm64/lib/lib.a
> | [mark@lakrids:~/src/linux]% usekorg 12.1.0 aarch64-linux-objdump -j __ex_table -D arch/arm64/lib/clear_user.o
> |
> | arch/arm64/lib/clear_user.o: file format elf64-littleaarch64
> |
> |
> | Disassembly of section __ex_table:
> |
> | 0000000000000000 <__ex_table>:
> | ...
> | 8: 03ff0003 .inst 0x03ff0003 ; undefined
> | ...
> | 14: 03ff0003 .inst 0x03ff0003 ; undefined
> | ...
> | 20: 03ff0003 .inst 0x03ff0003 ; undefined
> | ...
> | 2c: 03ff0003 .inst 0x03ff0003 ; undefined
> | ...
> | 38: 03ff0003 .inst 0x03ff0003 ; undefined
> | ...
> | 44: 03ff0003 .inst 0x03ff0003 ; undefined
>
>> The following errors are reported during compilation:
>> [...]
>> arch/arm64/lib/clear_user.S:45: Error: invalid operands (*ABS* and *UND*
>> sections) for `<<'
>> [...]
>
> As above, I'm not seeing this.
>
> This suggests that the EX_DATA_REG() macro is going wrong somehow. Assuming the
> operand types correspond to the LHS and RHS of the expression, this would mean
> the GPR number is defined, but the REG value is not, and I can't currently see
> how that can happen.
>
>> "<<" is invalid operands in assembly, is there something wrong with me?
>
> At the moment I can only assume there is a local problem. I'd suspect a typo
> somewhere, but maybe you have a toolchain which behaves differently?
>
> Thanks,
> Mark.
> .
Now I can compile success, both versions 9.4.0 and 11.2.0.
I should have made a mistake. There is no problem using your
implementation. I will send a new version these days.
Thans,
Tong.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-06-20 14:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-28 6:50 [PATCH -next v5 0/8]arm64: add machine check safe support Tong Tiangen
2022-05-28 6:50 ` [PATCH -next v5 1/8] arm64: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support Tong Tiangen
2022-06-17 8:23 ` Mark Rutland
2022-06-18 2:44 ` Tong Tiangen
2022-05-28 6:50 ` [PATCH -next v5 2/8] arm64: extable: make uaaccess helper use extable type EX_TYPE_UACCESS_ERR_ZERO Tong Tiangen
2022-06-17 8:24 ` Mark Rutland
2022-06-18 3:26 ` Tong Tiangen
2022-06-18 8:42 ` Tong Tiangen
2022-06-18 12:40 ` Mark Rutland
2022-06-20 2:59 ` Tong Tiangen
2022-06-20 9:10 ` Mark Rutland
2022-06-20 13:32 ` Tong Tiangen
2022-06-20 14:13 ` Tong Tiangen [this message]
2022-06-20 14:26 ` Mark Rutland
2022-05-28 6:50 ` [PATCH -next v5 3/8] arm64: extable: move _cond_extable to _cond_uaccess_extable Tong Tiangen
2022-06-17 8:31 ` Mark Rutland
2022-05-28 6:50 ` [PATCH -next v5 4/8] arm64: extable: cleanup redundant extable type EX_TYPE_FIXUP Tong Tiangen
2022-06-17 8:43 ` Mark Rutland
2022-05-28 6:50 ` [PATCH -next v5 5/8] Add generic fallback version of copy_mc_to_user() Tong Tiangen
2022-05-28 6:50 ` [PATCH -next v5 6/8] arm64: add support for machine check error safe Tong Tiangen
2022-06-17 8:55 ` Mark Rutland
2022-06-18 9:18 ` Tong Tiangen
2022-06-18 12:52 ` Mark Rutland
2022-06-20 1:53 ` Tong Tiangen
2022-05-28 6:50 ` [PATCH -next v5 7/8] arm64: add uaccess to machine check safe Tong Tiangen
2022-06-17 9:06 ` Mark Rutland
2022-06-18 9:27 ` Tong Tiangen
2022-06-18 11:35 ` Mark Rutland
2022-06-20 2:04 ` Tong Tiangen
2022-05-28 6:50 ` [PATCH -next v5 8/8] arm64: add cow " Tong Tiangen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=908f4c14-b9cb-71f8-7a3c-7569f7c89033@huawei.com \
--to=tongtiangen@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=benh@kernel.crashing.org \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dave.hansen@linux.intel.com \
--cc=guohanjun@huawei.com \
--cc=hpa@zytor.com \
--cc=james.morse@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
--cc=robin.murphy@arm.com \
--cc=tglx@linutronix.de \
--cc=viro@zeniv.linux.org.uk \
--cc=wangkefeng.wang@huawei.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=xiexiuqi@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).