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Re: [Qemu-devel] [PATCH 01/13] target/arm: Add ARM_FEATURE_SWP
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 01/13] target/arm: Add ARM_FEATURE_SWP |
Date: |
Sun, 16 Sep 2018 08:53:01 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 |
On 9/15/18 6:32 PM, Peter Maydell wrote:
> In the current scheme of doing things I'd look for whether
> we could say that some more generic thing implied SWP
> rather than setting it in a lot of initfns (eg v5-but-not-v7VE?),
> but maybe the later patches make that a bad approach
> (haven't looked at the meat of this series).
Perhaps. But indeed this goes back to the main question
posed in the cover letter.
> We want to arrange to have SWP work anyway on linux-user,
> I think, since the kernel will typically trap-and-emulate
> it assuming it was built with CONFIG_SWP_EMULATE. (I don't
> know if those kernels will advertise swp in the hwcaps,
> but I guess not.)
Ah, I did not know about SWP_EMULATE. It appears to be
specific to armv7+ (though we don't support the pre-v4
cpus for which it might otherwise be relevant).
It does appear that HWCAP_SWP is advertised anyway:
mm/proc-v7.S: .long HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB | HWCAP_FAST_MULT
r~
- [Qemu-devel] [RFC PATCH 00/13] target/arm: Derive cpu id regs from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 02/13] target/arm: Derive id_isar0 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 03/13] target/arm: Derive id_isar1 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 05/13] target/arm: Derive id_isar3 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 06/13] target/arm: Derive id_isar4 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 04/13] target/arm: Derive id_isar2 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 08/13] target/arm: Derive id_pfr0 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 07/13] target/arm: Derive id_isar5 and id_isar6 from features, Richard Henderson, 2018/09/15
- [Qemu-devel] [PATCH 09/13] target/arm: Derive id_pfr1 from features, Richard Henderson, 2018/09/15