Re: [PATCH v1 2/2] LoongArch: mm: Expand modules virtual address space to 2GB

[Mike Rapoport]

Hi,

On Fri, Jul 17, 2026 at 03:57:15PM +0800, Tiezhu Yang wrote:
> Frequent "execmem: unable to allocate memory" warnings are observed
> during kernel module loading when updating the latest kernel.
> 
> This is because the modules virtual address region on LoongArch is
> tightly constrained to 256MB, while ARM64 and RISC-V are natively
> configured with a spacious 2GB region.

The constraint follows architecture ability to address kernel instructions
and data from modules code.

I don't know what are loongarch requirements, but I remember that arm64
added a layer of relocation support to allow 2G module address space.

> Expand the modules virtual address space to 2GB for LoongArch to
> eliminate these allocation bottlenecks.
> 
> This change only applies to 64-bit kernels (CONFIG_64BIT), 32-bit
> kernels (CONFIG_32BIT) are entirely unaffected since they do not
> define separate module address regions.
> 
> With this patch, there are no "execmem: unable to allocate memory"
> warnings anymore for 64-bit kernels.
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
>  arch/loongarch/include/asm/pgtable.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
> index 223528c04d73..e5952ecd6a73 100644
> --- a/arch/loongarch/include/asm/pgtable.h
> +++ b/arch/loongarch/include/asm/pgtable.h
> @@ -96,7 +96,7 @@ struct vm_area_struct;
>  #ifdef CONFIG_64BIT
>  
>  #define MODULES_VADDR	(vm_map_base + PCI_IOSIZE + (2 * PAGE_SIZE))
> -#define MODULES_END	(MODULES_VADDR + SZ_256M)
> +#define MODULES_END	(MODULES_VADDR + SZ_2G)
>  
>  #ifdef CONFIG_KFENCE
>  #define KFENCE_AREA_SIZE	(((CONFIG_KFENCE_NUM_OBJECTS + 1) * 2 + 2) * PAGE_SIZE)
> -- 
> 2.42.0
> 

-- 
Sincerely yours,
Mike.