Subject: Re: linux-next: manual merge of the akpm-current tree with the powerpc tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 15 Apr 2021 19:58:14 +1000

Hi all,

On Thu, 15 Apr 2021 19:44:17 +1000 Stephen Rothwell <[email-masked]> wrote:
> 
> Today's linux-next merge of the akpm-current tree got a conflict in:
> 
>   arch/powerpc/kernel/module.c
> 
> between commit:
> 
>   2ec13df16704 ("powerpc/modules: Load modules closer to kernel text")
> 
> from the powerpc tree and commit:
> 
>   4930ba789f8d ("powerpc/64s/radix: enable huge vmalloc mappings")
> 
> from the akpm-current tree.
> 
> I fixed it up (I think - see below) and can carry the fix as
> necessary. This is now fixed as far as linux-next is concerned, but any
> non trivial conflicts should be mentioned to your upstream maintainer
> when your tree is submitted for merging.  You may also want to consider
> cooperating with the maintainer of the conflicting tree to minimise any
> particularly complex conflicts.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc arch/powerpc/kernel/module.c
> index fab84024650c,cdb2d88c54e7..000000000000
> --- a/arch/powerpc/kernel/module.c
> +++ b/arch/powerpc/kernel/module.c
> @@@ -88,29 -88,26 +89,42 @@@ int module_finalize(const Elf_Ehdr *hdr
>   	return 0;
>   }
>   
> - #ifdef MODULES_VADDR
>  -void *module_alloc(unsigned long size)
>  +static __always_inline void *
>  +__module_alloc(unsigned long size, unsigned long start, unsigned long end)
>   {
>  -	unsigned long start = VMALLOC_START;
>  -	unsigned long end = VMALLOC_END;
>  -
>  -#ifdef MODULES_VADDR
>  -	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
>  -	start = MODULES_VADDR;
>  -	end = MODULES_END;
>  -#endif
>  -
> + 	/*
> + 	 * Don't do huge page allocations for modules yet until more testing
> + 	 * is done. STRICT_MODULE_RWX may require extra work to support this
> + 	 * too.
> + 	 */
> + 
>   	return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL,
> - 				    PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> + 				    PAGE_KERNEL_EXEC,
> + 				    VM_NO_HUGE_VMAP | VM_FLUSH_RESET_PERMS,
> + 				    NUMA_NO_NODE,
>   				    __builtin_return_address(0));
>   }
>  +
> ++
>  +void *module_alloc(unsigned long size)
>  +{
> ++	unsigned long start = VMALLOC_START;
> ++	unsigned long end = VMALLOC_END;
>  +	unsigned long limit = (unsigned long)_etext - SZ_32M;
>  +	void *ptr = NULL;
>  +
> ++#ifdef MODULES_VADDR
>  +	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
> ++	start = MODULES_VADDR;
> ++	end = MODULES_END;
>  +
>  +	/* First try within 32M limit from _etext to avoid branch trampolines */
>  +	if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit)
> - 		ptr = __module_alloc(size, limit, MODULES_END);
> ++		ptr = __module_alloc(size, limit, end);
>  +
>  +	if (!ptr)
> - 		ptr = __module_alloc(size, MODULES_VADDR, MODULES_END);
> ++#endif
> ++		ptr = __module_alloc(size, start, end);
>  +
>  +	return ptr;
>  +}
> - #endif

Unfortunately, it also needs this:

From: Stephen Rothwell <[email-masked]>
Date: Thu, 15 Apr 2021 19:53:58 +1000
Subject: [PATCH] merge fix up for powerpc merge fix

Signed-off-by: Stephen Rothwell <[email-masked]>
---
 arch/powerpc/kernel/module.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index d8ab1ad2eb05..c060f99afd4d 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -110,7 +110,9 @@ void *module_alloc(unsigned long size)
 {
 	unsigned long start = VMALLOC_START;
 	unsigned long end = VMALLOC_END;
+#ifdef MODULES_VADDR
 	unsigned long limit = (unsigned long)_etext - SZ_32M;
+#endif
 	void *ptr = NULL;
 
 #ifdef MODULES_VADDR
-- 
2.30.2

-- 
Cheers,
Stephen Rothwell