Re: [PATCH v4 3/7] arm64/Kconfig: add LSUI Kconfig

Hi Mark,

On Mon, Jul 21, 2025 at 09:36:14AM +0100, Yeoreum Yun wrote:

quoted

Since Armv9.6, FEAT_LSUI supplies the load/store instructions for
previleged level to access to access user memory without clearing
PSTATE.PAN bit.
It's enough to add CONFIG_AS_HAS_LSUI only because the code for LUSI uses

Nit: s/LUSI/LSUI/

quoted

indiviual `.arch_extension` entries.

Nit: s/indiviual/individual/

Sorry. I'll change it...

quoted

Signed-off-by: Yeoreum Yun <redacted>
---
 arch/arm64/Kconfig | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 393d71124f5d..c0beb44ed5b8 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -2238,6 +2238,15 @@ config ARM64_GCS

 endmenu # "v9.4 architectural features"

+config AS_HAS_LSUI
+	def_bool $(as-instr,.arch_extension lsui)
+	help
+	 Unprivileged Load Store is an extension to introduce unprivileged
+	 variants of load and store instructions so that clearing PSTATE.PAN
+	 is never required in privileged mode.
+	 This feature is available with clang version 20 and later and not yet
+	 supported by gcc.

I don't think we need to describe the feature in detail for the AS_HAS_*
config symbol; I think all we need to say is:

	Supported by LLVM 20 and later, not yet supported by GNU AS.

Okay. I'll change it.

Otherwise this looks fine.

Thanks!

[...]

--
Sincerely,
Yeoreum Yun