[PATCH v2 2/2] ARM: arm11: Add C wrapper for allow_unaligned()

[Marek Vasut]

Rename current assembler implementation of allow_unaligned() to
arm11_arch_cp15_allow_unaligned() and add it into arm11.h header,
then add C wrapper of allow_unaligned().

This fixes misbehavior when linking U-Boot, where the CPU specific
allow_unaligned() implementation was ignored and instead the
__weak allow_unaligned() implementation from lib/efi_loader/efi_setup.c
was used, which led to "data abort" just before booting Linux via tftp,
in efi_dp_from_file() -> path_to_uefi() -> utf16_put() .

The problem is triggerd by c7c0ca37673 ("efi_loader: fix efi_dp_from_file()") .
Adding the wrapper fixes the problem.

Fixes: d47a774680d ("arm: arm11: allow unaligned memory access")
Signed-off-by: Marek Vasut <marex at denx.de>
---
V2: Update Fixes tag and commit message
---
Cc: Fabio Estevam <festevam at denx.de>
Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Cc: Simon Glass <sjg at chromium.org>
Cc: Tom Rini <trini at konsulko.com>
---
 arch/arm/cpu/arm11/cpu.c     |  6 ++++++
 arch/arm/cpu/arm11/sctlr.S   |  6 +++---
 arch/arm/include/asm/arm11.h | 12 ++++++++++++
 3 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 arch/arm/include/asm/arm11.h

diff --git a/arch/arm/cpu/arm11/cpu.c b/arch/arm/cpu/arm11/cpu.c
index ffe35111d58..1e16b89d006 100644
--- a/arch/arm/cpu/arm11/cpu.c
+++ b/arch/arm/cpu/arm11/cpu.c
@@ -20,6 +20,7 @@
 #include <irq_func.h>
 #include <asm/cache.h>
 #include <asm/system.h>
+#include <asm/arm11.h>
 
 static void cache_flush(void);
 
@@ -43,6 +44,11 @@ int cleanup_before_linux (void)
 	return 0;
 }
 
+void allow_unaligned(void)
+{
+	arm11_arch_cp15_allow_unaligned();
+}
+
 static void cache_flush(void)
 {
 	unsigned long i = 0;
diff --git a/arch/arm/cpu/arm11/sctlr.S b/arch/arm/cpu/arm11/sctlr.S
index 74a7fc4a25b..8722f8380c8 100644
--- a/arch/arm/cpu/arm11/sctlr.S
+++ b/arch/arm/cpu/arm11/sctlr.S
@@ -8,7 +8,7 @@
 #include <linux/linkage.h>
 
 /*
- * void allow_unaligned(void) - allow unaligned access
+ * void arm11_arch_cp15_allow_unaligned(void) - allow unaligned access
  *
  * This routine sets the enable unaligned data support flag and clears the
  * aligned flag in the system control register.
@@ -16,10 +16,10 @@
  * data abort or undefined behavior but is handled by the CPU.
  * For details see the "ARM Architecture Reference Manual" for ARMv6.
  */
-ENTRY(allow_unaligned)
+ENTRY(arm11_arch_cp15_allow_unaligned)
 	mrc	p15, 0, r0, c1, c0, 0	@ load system control register
 	orr	r0, r0, #1 << 22	@ set unaligned data support flag
 	bic	r0, r0, #2		@ clear aligned flag
 	mcr	p15, 0, r0, c1, c0, 0	@ write system control register
 	bx	lr			@ return
-ENDPROC(allow_unaligned)
+ENDPROC(arm11_arch_cp15_allow_unaligned)
diff --git a/arch/arm/include/asm/arm11.h b/arch/arm/include/asm/arm11.h
new file mode 100644
index 00000000000..5276f735ef9
--- /dev/null
+++ b/arch/arm/include/asm/arm11.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2023 Marek Vasut <marex at denx.de>
+ */
+#ifndef ARM11_H
+#define ARM11_H
+
+#ifndef __ASSEMBLY__
+void arm11_arch_cp15_allow_unaligned(void);
+#endif /* ! __ASSEMBLY__ */
+
+#endif	/* ARM11_H */
-- 
2.40.1