Commit Graph

15 Commits

Author SHA1 Message Date
Nicolas Pitre c89efa731e ARM: 7836/1: add __get_user_unaligned/__put_user_unaligned
BTRFS is now relying on those since v3.12-rc1.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-09-18 10:58:23 +01:00
Arnd Bergmann 8e7fc18b5e ARM: warnings in arch/arm/include/asm/uaccess.h
On NOMMU ARM, the __addr_ok() and __range_ok() macros do not evaluate
their arguments, which may lead to harmless build warnings in some
code where the variables are not used otherwise. Adding a cast to void
gets rid of the warning and does not make any semantic changes.

Without this patch, building at91x40_defconfig results in:

fs/read_write.c: In function 'rw_copy_check_uvector':
fs/read_write.c:684:9: warning: unused variable 'buf' [-Wunused-variable]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
2012-10-09 20:29:07 +02:00
Will Deacon ad72907acd ARM: 7528/1: uaccess: annotate [__]{get,put}_user functions with might_fault()
The user access functions may generate a fault, resulting in invocation
of a handler that may sleep.

This patch annotates the accessors with might_fault() so that we print a
warning if they are invoked from atomic context and help lockdep keep
track of mmap_sem.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-09-09 17:28:48 +01:00
Russell King 8404663f81 ARM: 7527/1: uaccess: explicitly check __user pointer when !CPU_USE_DOMAINS
The {get,put}_user macros don't perform range checking on the provided
__user address when !CPU_HAS_DOMAINS.

This patch reworks the out-of-line assembly accessors to check the user
address against a specified limit, returning -EFAULT if is is out of
range.

[will: changed get_user register allocation to match put_user]
[rmk: fixed building on older ARM architectures]

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-09-09 17:28:47 +01:00
Will Deacon 8c56cc8be5 ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions
This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-09 17:41:11 +01:00
David Howells 9f97da78bf Disintegrate asm/system.h for ARM
Disintegrate asm/system.h for ARM.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org
2012-03-28 18:30:01 +01:00
Catalin Marinas 4e7682d077 ARM: 7301/1: Rename the T() macro to TUSER() to avoid namespace conflicts
This macro is used to generate unprivileged accesses (LDRT/STRT) to user
space.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-01-25 11:07:40 +00:00
Catalin Marinas 247055aa21 ARM: 6384/1: Remove the domain switching on ARMv6k/v7 CPUs
This patch removes the domain switching functionality via the set_fs and
__switch_to functions on cores that have a TLS register.

Currently, the ioremap and vmalloc areas share the same level 1 page
tables and therefore have the same domain (DOMAIN_KERNEL). When the
kernel domain is modified from Client to Manager (via the __set_fs or in
the __switch_to function), the XN (eXecute Never) bit is overridden and
newer CPUs can speculatively prefetch the ioremap'ed memory.

Linux performs the kernel domain switching to allow user-specific
functions (copy_to/from_user, get/put_user etc.) to access kernel
memory. In order for these functions to work with the kernel domain set
to Client, the patch modifies the LDRT/STRT and related instructions to
the LDR/STR ones.

The user pages access rights are also modified for kernel read-only
access rather than read/write so that the copy-on-write mechanism still
works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register
(CPU_32v6K is defined) since writing the TLS value to the high vectors page
isn't possible.

The user addresses passed to the kernel are checked by the access_ok()
function so that they do not point to the kernel space.

Tested-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-04 15:44:31 +00:00
Russell King 4260415f6a ARM: fix build error in arch/arm/kernel/process.c
/tmp/ccJ3ssZW.s: Assembler messages:
/tmp/ccJ3ssZW.s:1952: Error: can't resolve `.text' {.text section} - `.LFB1077'

This is caused because:

	.section .data
	.section .text
	.section .text
	.previous

does not return us to the .text section, but the .data section; this
makes use of .previous dangerous if the ordering of previous sections
is not known.

Fix up the other users of .previous; .pushsection and .popsection are
a safer pairing to use than .section and .previous.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-04-21 08:45:21 +01:00
Catalin Marinas 8b592783a2 Thumb-2: Implement the unified arch/arm/lib functions
This patch adds the ARM/Thumb-2 unified support for the arch/arm/lib/*
files.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-07-24 12:32:57 +01:00
Nicolas Pitre a1f98849fd [ARM] allow for alternative __copy_to_user/__clear_user implementations
This allows for optional alternative implementations of __copy_to_user
and __clear_user, with a possible runtime fallback to the standard
version when the alternative provides no gain over that standard
version. This is done by making the standard __copy_to_user into a weak
alias for the symbol __copy_to_user_std.  Same thing for __clear_user.

Those two functions are particularly good candidates to have alternative
implementations for, since they rely on the STRT instruction which has
lower performances than STM instructions on some CPU cores such as
the ARM1176 and Marvell Feroceon.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
2009-05-29 22:34:45 -04:00
Russell King 87c52578bd [ARM] Remove linux/sched.h from asm/cacheflush.h and asm/uaccess.h
... and fix those drivers that were incorrectly relying upon
that include.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-29 18:49:55 +00:00
Russell King 59f0cb0fdd [ARM] remove memzero()
As suggested by Andrew Morton, remove memzero() - it's not supported
on other architectures so use of it is a potential build breaking bug.
Since the compiler optimizes memset(x,0,n) to __memzero() perfectly
well, we don't miss out on the underlying benefits of memzero().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27 12:37:59 +00:00
Catalin Marinas 4e6a0c397f [ARM] 5230/1: Replace post-indexed LDRT/STRT in uaccess.h
The post-index immediate value is optional if it is 0 and this patch
removes it. The reason is to allow such instructions to compile to
Thumb-2 where only pre-indexed LDRT/STRT instructions are allowed.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01 12:06:35 +01:00
Russell King 4baa992243 [ARM] move include/asm-arm to arch/arm/include/asm
Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-02 21:32:35 +01:00