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From:   Song Liu <song@kernel.org>
Date:   Fri, 16 Jun 2023 11:14:31 -0700
Message-ID: <CAPhsuW4nDne7L=Qh142w+dMX2pqM_4k+SZSB=QBJ8ruG_j8dug@mail.gmail.com>
Subject: Re: [PATCH v2 01/12] nios2: define virtual address space for modules
To:     Mike Rapoport <rppt@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Dinh Nguyen <dinguyen@kernel.org>,
        Heiko Carstens <hca@linux.ibm.com>,
        Helge Deller <deller@gmx.de>,
        Huacai Chen <chenhuacai@kernel.org>,
        Kent Overstreet <kent.overstreet@linux.dev>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nadav Amit <nadav.amit@gmail.com>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Puranjay Mohan <puranjay12@gmail.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Russell King <linux@armlinux.org.uk>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Thomas Gleixner <tglx@linutronix.de>,
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On Fri, Jun 16, 2023 at 1:51=E2=80=AFAM Mike Rapoport <rppt@kernel.org> wro=
te:
>
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
>
> 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@linutronix.de>
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> Acked-by: Dinh Nguyen <dinguyen@kernel.org>

Acked-by: Song Liu <song@kernel.org>


> ---
>  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/pg=
table.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 canno=
t reach
> - * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc retur=
ns
> - * addresses in 0xc0000000)
> - */
>  void *module_alloc(unsigned long size)
>  {
> -       if (size =3D=3D 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
>