[PATCH 1/2] ARM: armv7: Add C wrapper for allow_unaligned()

[Heinrich Schuchardt]

On 7/1/23 15:00, Marek Vasut wrote:
> Rename current assembler implementation of allow_unaligned() to
> v7_arch_cp15_allow_unaligned() and add it into armv7.h header,
> then add C wrapper of allow_unaligned().
>
> This fixes misbehavior when linking U-Boot on ARMv7a i.MX6Q, 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() .
>
> Adding the wrapper fixes the problem.
>
> Fixes: c7c0ca37673 ("efi_loader: fix efi_dp_from_file()")

Hello Marek,

Thank you for investigating this issue.

Looking at
https://lore.kernel.org/u-boot/20230320171335.1368308-1-ilias.apalodimas@linaro.org/
the problem predates c7c0ca37673. So this fixes line seems wrong.

Your series has a fix for armv7 but misses arm11. So we would be better
of with Ilias patch. Somehow Ilias never followed up on my questions and
we lost track.

Could you, please, test Ilias patch.

Best regards

Heinrich

> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Fabio Estevam <festevam at denx.de>
> Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Tom Rini <trini at konsulko.com>
> ---
>   arch/arm/cpu/armv7/cpu.c     | 5 +++++
>   arch/arm/cpu/armv7/sctlr.S   | 6 +++---
>   arch/arm/include/asm/armv7.h | 1 +
>   3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/cpu.c b/arch/arm/cpu/armv7/cpu.c
> index 68807d20997..6259ffa5108 100644
> --- a/arch/arm/cpu/armv7/cpu.c
> +++ b/arch/arm/cpu/armv7/cpu.c
> @@ -83,3 +83,8 @@ int cleanup_before_linux(void)
>   {
>   	return cleanup_before_linux_select(CBL_ALL);
>   }
> +
> +void allow_unaligned(void)
> +{
> +	v7_arch_cp15_allow_unaligned();
> +}
> diff --git a/arch/arm/cpu/armv7/sctlr.S b/arch/arm/cpu/armv7/sctlr.S
> index bd56e41afe1..d44b21498f6 100644
> --- a/arch/arm/cpu/armv7/sctlr.S
> +++ b/arch/arm/cpu/armv7/sctlr.S
> @@ -8,15 +8,15 @@
>   #include <linux/linkage.h>
>
>   /*
> - * void allow_unaligned(void) - allow unaligned access
> + * void v7_arch_cp15_allow_unaligned(void) - allow unaligned access
>    *
>    * This routine clears the aligned flag in the system control register.
>    * After calling this routine unaligned access does no longer lead to a
>    * data abort but is handled by the CPU.
>    */
> -ENTRY(allow_unaligned)
> +ENTRY(v7_arch_cp15_allow_unaligned)
>   	mrc	p15, 0, r0, c1, c0, 0	@ load system control register
>   	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(v7_arch_cp15_allow_unaligned)
> diff --git a/arch/arm/include/asm/armv7.h b/arch/arm/include/asm/armv7.h
> index 2fb824b69e2..c002998ac0b 100644
> --- a/arch/arm/include/asm/armv7.h
> +++ b/arch/arm/include/asm/armv7.h
> @@ -156,6 +156,7 @@ void v7_arch_cp15_set_l2aux_ctrl(u32 l2auxctrl, u32 cpu_midr,
>   				 u32 cpu_rev);
>   void v7_arch_cp15_set_acr(u32 acr, u32 cpu_midr, u32 cpu_rev_comb,
>   			  u32 cpu_variant, u32 cpu_rev);
> +void v7_arch_cp15_allow_unaligned(void);
>   #endif /* ! __ASSEMBLY__ */
>
>   #endif