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[ARM] Set bit 4 on section mappings correctly depending on CPU

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On some CPUs, bit 4 of section mappings means "update the
cache when written to".  On others, this bit is required to
be one, and others it's required to be zero.  Finally, on
ARMv6 and above, setting it turns on "no execute" and prevents
speculative prefetches.

With all these combinations, no one value fits all CPUs, so we
have to pick a value depending on the CPU type, and the area
we're mapping.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
2006-06-29 18:24:21 +01:00
committed by Russell King
parent 326764a85b
commit 8799ee9f49
20 changed files with 147 additions and 22 deletions
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5
arch/arm/kernel/head.S
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@@ -221,7 +221,7 @@ __create_page_tables:
teq r0, r6
bne 1b
ldr r7, [r10, #PROCINFO_MMUFLAGS] @ mmuflags
ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
/*
* Create identity mapping for first MB of kernel to
@@ -272,8 +272,7 @@ __create_page_tables:
#endif
#ifdef CONFIG_DEBUG_LL
bic r7, r7, #0x0c @ turn off cacheable
@ and bufferable bits
ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
/*
* Map in IO space for serial debugging.
* This allows debug messages to be output