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From: Richard Henderson <richard.henderson@linaro.org>
To: Song Gao <gaosong@loongson.cn>,
	qemu-devel@nongnu.org, chenhuacai@gmail.com
Cc: peter.maydell@linaro.org, yangxiaojuan@loongson.cn,
	david@redhat.com, bin.meng@windriver.com,
	mark.cave-ayland@ilande.co.uk, aleksandar.rikalo@syrmia.com,
	jcmvbkbc@gmail.com, tsimpson@quicinc.com,
	alistair.francis@wdc.com, edgar.iglesias@gmail.com,
	philmd@redhat.com, atar4qemu@gmail.com, thuth@redhat.com,
	ehabkost@redhat.com, groug@kaod.org, maobibo@loongson.cn,
	mrolnik@gmail.com, shorne@gmail.com, alex.bennee@linaro.org,
	david@gibson.dropbear.id.au, kbastian@mail.uni-paderborn.de,
	crwulff@gmail.com, laurent@vivier.eu, palmer@dabbelt.com,
	pbonzini@redhat.com, aurelien@aurel32.net
Subject: Re: [PATCH v4 17/21] LoongArch Linux User Emulation
Date: Fri, 10 Sep 2021 14:52:28 +0200	[thread overview]
Message-ID: <d6349ca9-2483-2f83-f5cb-f9e1f740a404@linaro.org> (raw)
In-Reply-To: <3e7fd708-fe13-8163-2926-d1baa75e3b10@loongson.cn>

On 9/8/21 11:50 AM, Song Gao wrote:
> 
> Hi Richard,
> 
> On 09/05/2021 06:04 PM, Richard Henderson wrote:
>>> +struct sigframe {
>>> +    uint32_t sf_ass[4];             /* argument save space for o32 */
>>
>> Surely there is no "o32" for loongarch?
>>
> 
> Yes, qemu only support 64bit. but the kernel has 'o32'.  Should we have to be consistent with the kernel?

Yes, you need to be consistent with the kernel.  However... the kernel is not yet 
upstream, and therefore the ABI is (officially) still malleable.

Anyway, this padding was copied from mips o32, and should not have been.  Looking at the 
loongarch gcc sources, REG_PARM_STACK_SPACE is always 0, and thus the 4 words reserved 
here are never used.

I see that gcc/libgcc/config/loongarch/linux-unwind.h builds in knowledge of these unused 
words.  I also see that linux/arch/loongarch/vdso/sigreturn.S does not provide correct 
unwind info.  Certainly the kernel vdso should be fixed, so that code within gcc should 
not be needed.  At which point the ABI for the signal frame is entirely private to the kernel.


r~


  reply	other threads:[~2021-09-10 12:54 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 12:40 [PATCH v4 00/21] Add LoongArch linux-user emulation support Song Gao
2021-09-02 12:40 ` [PATCH v4 01/21] target/loongarch: Add README Song Gao
2021-09-02 12:40 ` [PATCH v4 02/21] target/loongarch: Add core definition Song Gao
2021-09-04  9:44   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 03/21] target/loongarch: Add main translation routines Song Gao
2021-09-04  9:45   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 04/21] target/loongarch: Add fixed point arithmetic instruction translation Song Gao
2021-09-04 11:04   ` Richard Henderson
2021-09-07 12:36     ` Song Gao
2021-09-02 12:40 ` [PATCH v4 05/21] target/loongarch: Add fixed point shift " Song Gao
2021-09-04 11:17   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 06/21] target/loongarch: Add fixed point bit " Song Gao
2021-09-04 12:57   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 07/21] target/loongarch: Add fixed point load/store " Song Gao
2021-09-04 13:03   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 08/21] target/loongarch: Add fixed point atomic " Song Gao
2021-09-04 13:14   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 09/21] target/loongarch: Add fixed point extra " Song Gao
2021-09-05  8:39   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 10/21] target/loongarch: Add floating point arithmetic " Song Gao
2021-09-05  9:08   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 11/21] target/loongarch: Add floating point comparison " Song Gao
2021-09-05  9:24   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 12/21] target/loongarch: Add floating point conversion " Song Gao
2021-09-05  9:29   ` Richard Henderson
2021-09-02 12:40 ` [PATCH v4 13/21] target/loongarch: Add floating point move " Song Gao
2021-09-05  9:38   ` Richard Henderson
2021-09-05  9:45   ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 14/21] target/loongarch: Add floating point load/store " Song Gao
2021-09-05  9:46   ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 15/21] target/loongarch: Add branch " Song Gao
2021-09-05  9:49   ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 16/21] target/loongarch: Add disassembler Song Gao
2021-09-02 12:41 ` [PATCH v4 17/21] LoongArch Linux User Emulation Song Gao
2021-09-05 10:04   ` Richard Henderson
2021-09-08  9:50     ` Song Gao
2021-09-10 12:52       ` Richard Henderson [this message]
2021-09-11  5:58         ` Song Gao
2021-09-12 12:38           ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 18/21] default-configs: Add loongarch linux-user support Song Gao
2021-09-02 12:41 ` [PATCH v4 19/21] target/loongarch: Add target build suport Song Gao
2021-09-05 10:05   ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 20/21] target/loongarch: 'make check-tcg' support Song Gao
2021-09-05 10:06   ` Richard Henderson
2021-09-02 12:41 ` [PATCH v4 21/21] scripts: add loongarch64 binfmt config Song Gao
2021-09-05 10:08   ` Richard Henderson

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