linux-kernel - [PATCH v2] ARM: Implement ARCH_HAS_CC_CAN

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Message-Id: <20260206-cc-can-link-arm-v2-1-290cbf369fb6@linutronix.de>
Date: Fri, 06 Feb 2026 14:02:38 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Russell King <linux@...linux.org.uk>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Arnd Bergmann <arnd@...db.de>, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH v2] ARM: Implement ARCH_HAS_CC_CAN_LINK

The generic CC_CAN_LINK detection does not handle different byte orders.
This may lead to userprogs which are not actually runnable on the target
kernel.

Use architecture-specific logic supporting byte orders instead.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
Changes in v2:
- Handle BE8 vs BE32 platforms
- Link to v1: https://lore.kernel.org/r/20260109-cc-can-link-arm-v1-1-b748e2aaa6a6@linutronix.de
---
 arch/arm/Kconfig | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fa83c040ee2d..d5cb85d82dad 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -6,6 +6,7 @@ config ARM
 	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE if HAVE_KRETPROBES && FRAME_POINTER && !ARM_UNWIND
 	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_CACHE_LINE_SIZE if OF
+	select ARCH_HAS_CC_CAN_LINK
 	select ARCH_HAS_CPU_CACHE_ALIASING
 	select ARCH_HAS_CPU_FINALIZE_INIT if MMU
 	select ARCH_HAS_CURRENT_STACK_POINTER
@@ -1715,6 +1716,18 @@ config KERNEL_MODE_NEON
 
 endmenu
 
+config ARCH_CC_CAN_LINK
+	bool
+	default $(cc_can_link_user,-mlittle-endian) if CPU_LITTLE_ENDIAN
+	default $(cc_can_link_user,-mbig-endian -mbe8) if CPU_ENDIAN_BE8
+	default $(cc_can_link_user,-mbig-endian -mbe32) if CPU_ENDIAN_BE32
+
+config ARCH_USERFLAGS
+	string
+	default "-mlittle-endian" if CPU_LITTLE_ENDIAN
+	default "-mbig-endian -mbe8" if CPU_ENDIAN_BE8
+	default "-mbig-endian -mbe32" if CPU_ENDIAN_BE32
+
 menu "Power management options"
 
 source "kernel/power/Kconfig"

---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20260102-cc-can-link-arm-4eecfad2a0e4

Best regards,
-- 
Thomas Weißschuh <thomas.weissschuh@...utronix.de>