Comment 51 for bug 605042

On Tue, Mar 8, 2011 at 10:03 AM, Jeremy Kerr <email address hidden> wrote:
> From: Catalin Marinas <email address hidden>
>
> BugLink: http://launchpad.net/bugs/605042
>
> This is needed because applications using the sys_cacheflush system call
> can pass a memory range which isn't mapped yet even though the
> corresponding vma is valid. The patch also adds unwinding annotations
> for correct backtraces from the coherent_user_range() functions.
>
> Signed-off-by: Catalin Marinas <email address hidden>
> Signed-off-by: Russell King <email address hidden>
>
> cherry-picked from upstream commit 32cfb1b16f2b68d2296536811cadfffe26a06c1b
>
> Signed-off-by: Jeremy Kerr <email address hidden>
>

That's great, it looks like it fixed an very old issue for fsl-imx51 in Lucid.
So I think this patch is for [Lucid] [fsl-imx51] and there is no such
issue in Maverick kernel, right?

-Bryan

> ---
>  arch/arm/mm/cache-v6.S |   20 ++++++++++++++++++--
>  arch/arm/mm/cache-v7.S |   19 +++++++++++++++++--
>  2 files changed, 35 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
> index 8f5c13f..295e25d 100644
> --- a/arch/arm/mm/cache-v6.S
> +++ b/arch/arm/mm/cache-v6.S
> @@ -12,6 +12,7 @@
>  #include <linux/linkage.h>
>  #include <linux/init.h>
>  #include <asm/assembler.h>
> +#include <asm/unwind.h>
>
>  #include "proc-macros.S"
>
> @@ -121,11 +122,13 @@ ENTRY(v6_coherent_kern_range)
>  *     - the Icache does not read data from the write buffer
>  */
>  ENTRY(v6_coherent_user_range)
> -
> + UNWIND(.fnstart               )
>  #ifdef HARVARD_CACHE
>        bic     r0, r0, #CACHE_LINE_SIZE - 1
> -1:     mcr     p15, 0, r0, c7, c10, 1          @ clean D line
> +1:
> + USER( mcr     p15, 0, r0, c7, c10, 1  )       @ clean D line
>        add     r0, r0, #CACHE_LINE_SIZE
> +2:
>        cmp     r0, r1
>        blo     1b
>  #endif
> @@ -143,6 +146,19 @@ ENTRY(v6_coherent_user_range)
>        mov     pc, lr
>
>  /*
> + * Fault handling for the cache operation above. If the virtual address in r0
> + * isn't mapped, just try the next page.
> + */
> +9001:
> +       mov     r0, r0, lsr #12
> +       mov     r0, r0, lsl #12
> +       add     r0, r0, #4096
> +       b       2b
> + UNWIND(.fnend         )
> +ENDPROC(v6_coherent_user_range)
> +ENDPROC(v6_coherent_kern_range)
> +
> +/*
>  *     v6_flush_kern_dcache_page(kaddr)
>  *
>  *     Ensure that the data held in the page kaddr is written back
> diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
> index be93ff0..3290dac 100644
> --- a/arch/arm/mm/cache-v7.S
> +++ b/arch/arm/mm/cache-v7.S
> @@ -13,6 +13,7 @@
>  #include <linux/linkage.h>
>  #include <linux/init.h>
>  #include <asm/assembler.h>
> +#include <asm/unwind.h>
>
>  #include "proc-macros.S"
>
> @@ -147,13 +148,16 @@ ENTRY(v7_coherent_kern_range)
>  *     - the Icache does not read data from the write buffer
>  */
>  ENTRY(v7_coherent_user_range)
> + UNWIND(.fnstart               )
>        dcache_line_size r2, r3
>        sub     r3, r2, #1
>        bic     r0, r0, r3
> -1:     mcr     p15, 0, r0, c7, c11, 1          @ clean D line to the point of unification
> +1:
> + USER( mcr     p15, 0, r0, c7, c11, 1  )       @ clean D line to the point of unification
>        dsb
> -       mcr     p15, 0, r0, c7, c5, 1           @ invalidate I line
> + USER( mcr     p15, 0, r0, c7, c5, 1   )       @ invalidate I line
>        add     r0, r0, r2
> +2:
>        cmp     r0, r1
>        blo     1b
>        mov     r0, #0
> @@ -161,6 +165,17 @@ ENTRY(v7_coherent_user_range)
>        dsb
>        isb
>        mov     pc, lr
> +
> +/*
> + * Fault handling for the cache operation above. If the virtual address in r0
> + * isn't mapped, just try the next page.
> + */
> +9001:
> +       mov     r0, r0, lsr #12
> +       mov     r0, r0, lsl #12
> +       add     r0, r0, #4096
> +       b       2b
> + UNWIND(.fnend         )
>  ENDPROC(v7_coherent_kern_range)
>  ENDPROC(v7_coherent_user_range)
>
>
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