[PATCH v3] powerpc: fix compile error on 64K pages on 40x, 44x

[PATCH v3] powerpc: fix compile error on 64K pages on 40x, 44x

[Christian Lamparter]

The mmu context on the 40x, 44x does not define pte_frag
entry. This causes gcc abort the compilation due to:

setup-common.c: In function ‘setup_arch’:
setup-common.c:908: error: ‘mm_context_t’ has no ‘pte_frag’

This patch fixes the issue by removing the pte_frag
initialization in setup-common.c.

This is possible, because the compiler will do the
initialization, since the mm_context is a sub struct of
init_mm. init_mm is declared in mm_types.h as external linkage.
according to C99 6.2.4.3:
"An object whose identifier is declared with external linkage
[...] has static storage duration."

C99 defines in 6.7.8.10 that: "
If an object that has static storage duration is not
initialized explicitly, then:
- if it has pointer type, it is initialized to a null pointer
[...]
"

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 arch/powerpc/kernel/setup-common.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 0ac741fae90e..2e3bc16d02b2 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -904,9 +904,6 @@ void __init setup_arch(char **cmdline_p)
 #endif
 #endif
 
-#ifdef CONFIG_PPC_64K_PAGES
-	init_mm.context.pte_frag = NULL;
-#endif
 #ifdef CONFIG_SPAPR_TCE_IOMMU
 	mm_iommu_init(&init_mm);
 #endif
-- 
2.14.2

Re: [PATCH v3] powerpc: fix compile error on 64K pages on 40x, 44x

[Christophe LEROY]

Le 01/10/2017 à 16:33, Christian Lamparter a écrit :
> The mmu context on the 40x, 44x does not define pte_frag
> entry. This causes gcc abort the compilation due to:
> 
> setup-common.c: In function ‘setup_arch’:
> setup-common.c:908: error: ‘mm_context_t’ has no ‘pte_frag’
> 
> This patch fixes the issue by removing the pte_frag
> initialization in setup-common.c.
> 
> This is possible, because the compiler will do the
> initialization, since the mm_context is a sub struct of
> init_mm. init_mm is declared in mm_types.h as external linkage.
> according to C99 6.2.4.3:
> "An object whose identifier is declared with external linkage
> [...] has static storage duration."
> 
> C99 defines in 6.7.8.10 that: "
> If an object that has static storage duration is not
> initialized explicitly, then:
> - if it has pointer type, it is initialized to a null pointer
> [...]
> "
> 
> Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>

> ---
>   arch/powerpc/kernel/setup-common.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index 0ac741fae90e..2e3bc16d02b2 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -904,9 +904,6 @@ void __init setup_arch(char **cmdline_p)
>   #endif
>   #endif
>   
> -#ifdef CONFIG_PPC_64K_PAGES
> -	init_mm.context.pte_frag = NULL;
> -#endif
>   #ifdef CONFIG_SPAPR_TCE_IOMMU
>   	mm_iommu_init(&init_mm);
>   #endif
> 

Re: [v3] powerpc: fix compile error on 64K pages on 40x, 44x

[Michael Ellerman]

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On Sun, 2017-10-01 at 14:33:03 UTC, Christian Lamparter wrote:
> The mmu context on the 40x, 44x does not define pte_frag
> entry. This causes gcc abort the compilation due to:
> 
> setup-common.c: In function ‘setup_arch’:
> setup-common.c:908: error: ‘mm_context_t’ has no ‘pte_frag’
> 
> This patch fixes the issue by removing the pte_frag
> initialization in setup-common.c.
> 
> This is possible, because the compiler will do the
> initialization, since the mm_context is a sub struct of
> init_mm. init_mm is declared in mm_types.h as external linkage.
> according to C99 6.2.4.3:
> "An object whose identifier is declared with external linkage
> [...] has static storage duration."
> 
> C99 defines in 6.7.8.10 that: "
> If an object that has static storage duration is not
> initialized explicitly, then:
> - if it has pointer type, it is initialized to a null pointer
> [...]
> "
> 
> Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/070e004912fed099263408bf2ff1bb

cheers