Re: [PATCH v2 01/12] nios2: define virtual address space for modules

[Song Liu]

On Fri, Jun 16, 2023 at 1:51 AM Mike Rapoport <rppt@xxxxxxxxxx> wrote:
>
> From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
>
> nios2 uses kmalloc() to implement module_alloc() because CALL26/PCREL26
> cannot reach all of vmalloc address space.
>
> Define module space as 32MiB below the kernel base and switch nios2 to
> use vmalloc for module allocations.
>
> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> Acked-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>

Acked-by: Song Liu <song@xxxxxxxxxx>


> ---
>  arch/nios2/include/asm/pgtable.h |  5 ++++-
>  arch/nios2/kernel/module.c       | 19 ++++---------------
>  2 files changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
> index 0f5c2564e9f5..0073b289c6a4 100644
> --- a/arch/nios2/include/asm/pgtable.h
> +++ b/arch/nios2/include/asm/pgtable.h
> @@ -25,7 +25,10 @@
>  #include <asm-generic/pgtable-nopmd.h>
>
>  #define VMALLOC_START          CONFIG_NIOS2_KERNEL_MMU_REGION_BASE
> -#define VMALLOC_END            (CONFIG_NIOS2_KERNEL_REGION_BASE - 1)
> +#define VMALLOC_END            (CONFIG_NIOS2_KERNEL_REGION_BASE - SZ_32M - 1)
> +
> +#define MODULES_VADDR          (CONFIG_NIOS2_KERNEL_REGION_BASE - SZ_32M)
> +#define MODULES_END            (CONFIG_NIOS2_KERNEL_REGION_BASE - 1)
>
>  struct mm_struct;
>
> diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
> index 76e0a42d6e36..9c97b7513853 100644
> --- a/arch/nios2/kernel/module.c
> +++ b/arch/nios2/kernel/module.c
> @@ -21,23 +21,12 @@
>
>  #include <asm/cacheflush.h>
>
> -/*
> - * Modules should NOT be allocated with kmalloc for (obvious) reasons.
> - * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
> - * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
> - * addresses in 0xc0000000)
> - */
>  void *module_alloc(unsigned long size)
>  {
> -       if (size == 0)
> -               return NULL;
> -       return kmalloc(size, GFP_KERNEL);
> -}
> -
> -/* Free memory returned from module_alloc */
> -void module_memfree(void *module_region)
> -{
> -       kfree(module_region);
> +       return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
> +                                   GFP_KERNEL, PAGE_KERNEL_EXEC,
> +                                   VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> +                                   __builtin_return_address(0));
>  }
>
>  int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
> --
> 2.35.1
>