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[PATCH] ARM: 2656/1: Access permission bits are wrong for kernel XIP sections on ARMv6

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Patch from George G. Davis

This patch is required for kernel XIP support on ARMv6 machines.  It ensures that the access permission bits for kernel XIP section descriptors are APX=1 and AP[1:0]=01, which is Kernel read-only/User no access permissions.  Prior to this change, kernel XIP section descriptor access permissions were set to Kernel no access/User no access on ARMv6 machines and the kernel would therefore hang upon entry to userspace when set_fs(USER_DS) was executed.

Signed-off-by: Steve Longerbeam
Signed-off-by: George G. Davis
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
George G. Davis 2005-04-29 22:08:35 +01:00 committed by Russell King
parent 05f9869bf2
commit ca315159df
1 changed files with 3 additions and 2 deletions
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5
arch/arm/mm/mm-armv.c
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@ -411,9 +411,10 @@ static void __init build_mem_type_table(void)
mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
/*
* Mark cache clean areas read only from SVC mode
* and no access from userspace.
* Mark cache clean areas and XIP ROM read only
* from SVC mode and no access from userspace.
*/
mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
}