From: Conor Dooley <conor@kernel.org>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Anup Patel <anup@brainfault.org>,
Atish Patra <atishp@atishpatra.org>,
Heiko Stuebner <heiko@sntech.de>,
Conor Dooley <conor.dooley@microchip.com>,
Andrew Jones <ajones@ventanamicro.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, kvm-riscv@lists.infradead.org
Subject: Re: [PATCH v4 09/13] riscv: switch to relative alternative entries
Date: Wed, 18 Jan 2023 22:11:04 +0000 [thread overview]
Message-ID: <Y8hueOxeSzF6MT2+@spud> (raw)
In-Reply-To: <20230115154953.831-10-jszhang@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 1603 bytes --]
On Sun, Jan 15, 2023 at 11:49:49PM +0800, Jisheng Zhang wrote:
> Instead of using absolute addresses for both the old instrucions and
> the alternative instructions, use offsets relative to the alt_entry
> values. So this not only cuts the size of the alternative entry, but
> also meets the prerequisite for patching alternatives in the vDSO,
> since absolute alternative entries are subject to dynamic relocation,
> which is incompatible with the vDSO building.
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> +/* add the relative offset to the address of the offset to get the absolute address */
> +#define __ALT_PTR(a, f) ((void *)&(a)->f + (a)->f)
> +#define ALT_OLD_PTR(a) __ALT_PTR(a, old_offset)
> +#define ALT_ALT_PTR(a) __ALT_PTR(a, alt_offset)
LGTM, thanks for doing that! Certainly makes things more understandable.
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> + oldptr = ALT_OLD_PTR(alt);
> + altptr = ALT_ALT_PTR(alt);
> if (!__riscv_isa_extension_available(NULL, alt->errata_id))
> continue;
>
One minor nit, the oldptr/altptr assignments could go down here, below
the if/continue, right? Obviously don't respin for that though!
> - patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
> - riscv_alternative_fix_offsets(alt->old_ptr, alt->alt_len,
> - alt->old_ptr - alt->alt_ptr);
> + patch_text_nosync(oldptr, altptr, alt->alt_len);
> + riscv_alternative_fix_offsets(oldptr, alt->alt_len, oldptr - altptr);
> }
> }
> #endif
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
next prev parent reply other threads:[~2023-01-18 22:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-15 15:49 [PATCH v4 00/13] riscv: improve boot time isa extensions handling Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 01/13] riscv: fix jal offsets in patched alternatives Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 02/13] riscv: move riscv_noncoherent_supported() out of ZICBOM probe Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 03/13] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 04/13] riscv: hwcap: make ISA extension ids can be used in asm Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 05/13] riscv: cpufeature: extend riscv_cpufeature_patch_func to all ISA extensions Jisheng Zhang
2023-01-18 22:28 ` Conor Dooley
2023-01-15 15:49 ` [PATCH v4 06/13] riscv: introduce riscv_has_extension_[un]likely() Jisheng Zhang
2023-01-15 16:29 ` Conor Dooley
2023-01-18 22:18 ` Conor Dooley
2023-01-15 15:49 ` [PATCH v4 07/13] riscv: fpu: switch has_fpu() to riscv_has_extension_likely() Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 08/13] riscv: module: move find_section to module.h Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 09/13] riscv: switch to relative alternative entries Jisheng Zhang
2023-01-18 22:11 ` Conor Dooley [this message]
2023-01-20 18:34 ` Andrew Jones
2023-01-26 7:09 ` Andrew Jones
2023-01-28 16:43 ` Jisheng Zhang
2023-01-26 19:33 ` Conor Dooley
2023-01-15 15:49 ` [PATCH v4 10/13] riscv: alternative: patch alternatives in the vDSO Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 11/13] riscv: cpu_relax: switch to riscv_has_extension_likely() Jisheng Zhang
2023-01-15 15:49 ` [PATCH v4 12/13] riscv: KVM: Switch has_svinval() to riscv_has_extension_unlikely() Jisheng Zhang
2023-01-27 3:51 ` Anup Patel
2023-01-15 15:49 ` [PATCH v4 13/13] riscv: remove riscv_isa_ext_keys[] array and related usage Jisheng Zhang
2023-01-25 3:50 ` [PATCH v4 00/13] riscv: improve boot time isa extensions handling patchwork-bot+linux-riscv
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=Y8hueOxeSzF6MT2+@spud \
--to=conor@kernel.org \
--cc=ajones@ventanamicro.com \
--cc=anup@brainfault.org \
--cc=aou@eecs.berkeley.edu \
--cc=atishp@atishpatra.org \
--cc=conor.dooley@microchip.com \
--cc=heiko@sntech.de \
--cc=jszhang@kernel.org \
--cc=kvm-riscv@lists.infradead.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.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).