Re: [PATCH v9 04/21] ARM64: allow late use of early_ioremap

[Grant Likely]

On Wed, 25 Feb 2015 16:39:44 +0800
, Hanjun Guo <hanjun.guo@xxxxxxxxxx>
 wrote:
> From: Mark Salter <msalter@xxxxxxxxxx>
> 
> Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
> added a missing call to early_ioremap_reset(). This triggers a BUG if code
> tries using early_ioremap() after the early_ioremap_reset(). This is a
> problem for some ACPI code which needs short-lived temporary mappings
> after paging_init() but before acpi_early_init() in start_kernel(). This
> patch adds definitions for the __late_set_fixmap() and __late_clear_fixmap()
> which avoids the BUG by allowing later use of early_ioremap().
> 
> CC: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
> CC: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> Tested-by: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
> Tested-by: Jon Masters <jcm@xxxxxxxxxx>
> Tested-by: Robert Richter <rrichter@xxxxxxxxxx>
> Acked-by: Robert Richter <rrichter@xxxxxxxxxx>
> Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>

Reviewed-by: Grant Likely <grant.likely@xxxxxxxxxx>

> ---
>  arch/arm64/include/asm/fixmap.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
> index defa0ff9..f196e40 100644
> --- a/arch/arm64/include/asm/fixmap.h
> +++ b/arch/arm64/include/asm/fixmap.h
> @@ -62,6 +62,9 @@ void __init early_fixmap_init(void);
>  
>  #define __early_set_fixmap __set_fixmap
>  
> +#define __late_set_fixmap __set_fixmap
> +#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
> +
>  extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
>  
>  #include <asm-generic/fixmap.h>
> -- 
> 1.9.1
> 

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