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    Subject[PATCH v3 1/6] x86/mm: sparse warning fix for early_memremap
    Date
    From: Dave Young <dyoung@redhat.com>

    There's a lot of sparse warnings for code like below:
    void *a = early_memremap(phys_addr, size);

    early_memremap intend to map kernel memory with ioremap facility, the return
    pointer should be a kernel ram pointer instead of iomem one.

    For making the function clearer and supressing sparse warnings this patch
    do below two things:
    1. cast to (__force void *) for the return value of early_memremap
    2. add early_memunmap function and pass (__force void __iomem *) to iounmap

    >From Boris:
    > Ingo told me yesterday, it makes sense too. I'd guess we can try it.
    > FWIW, all callers of early_memremap use the memory they get remapped as
    > normal memory so we should be safe.

    Signed-off-by: Dave Young <dyoung@redhat.com>
    Signed-off-by: Mark Salter <msalter@redhat.com>
    ---
    arch/x86/include/asm/io.h | 3 ++-
    arch/x86/mm/ioremap.c | 10 +++++++---
    2 files changed, 9 insertions(+), 4 deletions(-)

    diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
    index 34f69cb..1db414f 100644
    --- a/arch/x86/include/asm/io.h
    +++ b/arch/x86/include/asm/io.h
    @@ -325,9 +325,10 @@ extern void early_ioremap_init(void);
    extern void early_ioremap_reset(void);
    extern void __iomem *early_ioremap(resource_size_t phys_addr,
    unsigned long size);
    -extern void __iomem *early_memremap(resource_size_t phys_addr,
    +extern void *early_memremap(resource_size_t phys_addr,
    unsigned long size);
    extern void early_iounmap(void __iomem *addr, unsigned long size);
    +extern void early_memunmap(void *addr, unsigned long size);
    extern void fixup_early_ioremap(void);
    extern bool is_early_ioremap_ptep(pte_t *ptep);

    diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
    index 799580c..bbb4504 100644
    --- a/arch/x86/mm/ioremap.c
    +++ b/arch/x86/mm/ioremap.c
    @@ -562,10 +562,9 @@ early_ioremap(resource_size_t phys_addr, unsigned long size)
    }

    /* Remap memory */
    -void __init __iomem *
    -early_memremap(resource_size_t phys_addr, unsigned long size)
    +void __init *early_memremap(resource_size_t phys_addr, unsigned long size)
    {
    - return __early_ioremap(phys_addr, size, PAGE_KERNEL);
    + return (__force void *)__early_ioremap(phys_addr, size, PAGE_KERNEL);
    }

    void __init early_iounmap(void __iomem *addr, unsigned long size)
    @@ -620,3 +619,8 @@ void __init early_iounmap(void __iomem *addr, unsigned long size)
    }
    prev_map[slot] = NULL;
    }
    +
    +void __init early_memunmap(void *addr, unsigned long size)
    +{
    + early_iounmap((__force void __iomem *)addr, size);
    +}
    --
    1.8.3.1


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