[PATCH] ARM: kvm: round HYP section to page size instead of log2 upper bound

[Will Deacon]

On Fri, Mar 27, 2015 at 10:18:01AM +0000, Ard Biesheuvel wrote:
> Older binutils do not support expressions involving the values of
> external symbols so just round up the HYP region to the page size.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

Thanks Ard. I managed to reproduce the failures in -next, and this solves
the problem for me (the only toolchain that chokes seems to be the one on
kernel.org, unfortunately).

I'll push an updated branch after a bit more testing. Let's not touch this
file ever again :)

Will

> ---
>  arch/arm/kernel/vmlinux.lds.S | 31 +------------------------------
>  arch/arm/kvm/init.S           |  3 ---
>  2 files changed, 1 insertion(+), 33 deletions(-)
> 
> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
> index 808398ec024e..f2db429ea75d 100644
> --- a/arch/arm/kernel/vmlinux.lds.S
> +++ b/arch/arm/kernel/vmlinux.lds.S
> @@ -12,26 +12,6 @@
>  #include <asm/pgtable.h>
>  #endif
>  
> -/*
> - * Poor man's version of LOG2CEIL(), which is
> - * not available in binutils before v2.24.
> - */
> -#define LOG2_ROUNDUP(size) (		\
> -	__LOG2_ROUNDUP(size,  2)	\
> -	__LOG2_ROUNDUP(size,  3)	\
> -	__LOG2_ROUNDUP(size,  4)	\
> -	__LOG2_ROUNDUP(size,  5)	\
> -	__LOG2_ROUNDUP(size,  6)	\
> -	__LOG2_ROUNDUP(size,  7)	\
> -	__LOG2_ROUNDUP(size,  8)	\
> -	__LOG2_ROUNDUP(size,  9)	\
> -	__LOG2_ROUNDUP(size, 10)	\
> -	__LOG2_ROUNDUP(size, 11)	\
> -	12)
> -
> -#define __LOG2_ROUNDUP(size, order)	\
> -	(size) <= (1 << order) ? order :
> -
>  #define PROC_INFO							\
>  	. = ALIGN(4);							\
>  	VMLINUX_SYMBOL(__proc_info_begin) = .;				\
> @@ -43,20 +23,11 @@
>  	VMLINUX_SYMBOL(__idmap_text_start) = .;				\
>  	*(.idmap.text)							\
>  	VMLINUX_SYMBOL(__idmap_text_end) = .;				\
> -	. = ALIGN(1 << LOG2_ROUNDUP(__hyp_idmap_size));			\
> +	. = ALIGN(PAGE_SIZE);						\
>  	VMLINUX_SYMBOL(__hyp_idmap_text_start) = .;			\
>  	*(.hyp.idmap.text)						\
>  	VMLINUX_SYMBOL(__hyp_idmap_text_end) = .;
>  
> -/*
> - * If the HYP idmap .text section is populated, it needs to be positioned
> - * such that it will not cross a page boundary in the final output image.
> - * So align it to the section size rounded up to the next power of 2.
> - * If __hyp_idmap_size is undefined, the section will be empty so define
> - * it as 0 in that case.
> - */
> -PROVIDE(__hyp_idmap_size = 0);
> -
>  #ifdef CONFIG_HOTPLUG_CPU
>  #define ARM_CPU_DISCARD(x)
>  #define ARM_CPU_KEEP(x)		x
> diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
> index 11fb1d56f449..3988e72d16ff 100644
> --- a/arch/arm/kvm/init.S
> +++ b/arch/arm/kvm/init.S
> @@ -157,6 +157,3 @@ target:	@ We're now in the trampoline code, switch page tables
>  __kvm_hyp_init_end:
>  
>  	.popsection
> -
> -	.global	__hyp_idmap_size
> -	.set	__hyp_idmap_size, __kvm_hyp_init_end - __kvm_hyp_init
> -- 
> 1.8.3.2
>