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

Message ID 20230616085038.4121892-2-rppt@kernel.org (mailing list archive)
State Not Applicable
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Series mm: jit/text allocator | expand

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Commit Message

Mike Rapoport June 16, 2023, 8:50 a.m. UTC 
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>
---
 arch/nios2/include/asm/pgtable.h |  5 ++++-
 arch/nios2/kernel/module.c       | 19 ++++---------------
 2 files changed, 8 insertions(+), 16 deletions(-)

Comments

Edgecombe, Rick P June 16, 2023, 4 p.m. UTC | #1 
On Fri, 2023-06-16 at 11:50 +0300, Mike Rapoport wrote:
>  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 *s

I wonder if the (size == 0) check is really needed, but
__vmalloc_node_range() will WARN on this case where the old code won't.
Song Liu June 16, 2023, 6:14 p.m. UTC | #2 
On Fri, Jun 16, 2023 at 1:51 AM Mike Rapoport <rppt@kernel.org> wrote:
>
> 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/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
>
Mike Rapoport June 17, 2023, 5:52 a.m. UTC | #3 
On Fri, Jun 16, 2023 at 04:00:19PM +0000, Edgecombe, Rick P wrote:
> On Fri, 2023-06-16 at 11:50 +0300, Mike Rapoport wrote:
> >  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 *s
> 
> I wonder if the (size == 0) check is really needed, but
> __vmalloc_node_range() will WARN on this case where the old code won't.

module_alloc() should not be called with zero size, so a warning there
would be appropriate.
Besides, no other module_alloc() had this check.
diff mbox series

Patch

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,