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2022-05-07ARM: PXA: fix multi-cpu build of xsc3Arnd Bergmann
On a kernel that includes both ARMv4 and XScale support, the copypage function fails to build with invalid instructions. Since these are only called on an actual XScale processor, annotate the assembly with the correct .arch directive. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-12ARM: 8811/1: always list both ldrd/strd registers explicitlyNicolas Pitre
The ldrd and strd instructions work on a pair of consecutive registers. It is possible to specify either the first register in the pair, or both registers explicitly. Let's always do the later to make things clearer. Signed-off-by: Nicolas Pitre <nico@linaro.org> Suggested-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-11-08ARM: 8805/2: remove unneeded naked function usageNicolas Pitre
The naked attribute is known to confuse some old gcc versions when function arguments aren't explicitly listed as inline assembly operands despite the gcc documentation. That resulted in commit 9a40ac86152c ("ARM: 6164/1: Add kto and kfrom to input operands list."). Yet that commit has problems of its own by having assembly operand constraints completely wrong. If the generated code has been OK since then, it is due to luck rather than correctness. So this patch also provides proper assembly operand constraints, and removes two instances of redundant register usages in the implementation while at it. Inspection of the generated code with this patch doesn't show any obvious quality degradation either, so not relying on __naked at all will make the code less fragile, and avoid some issues with clang. The only remaining __naked instances (excluding the kprobes test cases) are exynos_pm_power_up_setup(), tc2_pm_power_up_setup() and cci_enable_port_for_self(. But in the first two cases, only the function address is used by the compiler with no chance of inlining it by mistake, and the third case is called from assembly code only. And the fact that no stack is available when the corresponding code is executed does warrant the __naked usage in those cases. Signed-off-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Stefan Agner <stefan@agner.ch> Tested-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2012-03-20arm: remove the second argument of k[un]map_atomic()Cong Wang
Signed-off-by: Cong Wang <amwang@redhat.com>
2010-06-08ARM: 6164/1: Add kto and kfrom to input operands list.Khem Raj
When functions incoming parameters are not in input operands list gcc 4.5 does not load the parameters into registers before calling this function but the inline assembly assumes valid addresses inside this function. This breaks the code because r0 and r1 are invalid when execution enters v4wb_copy_user_page () Also the constant needs to be used as third input operand so account for that as well. Tested on qemu arm. CC: <stable@kernel.org> Signed-off-by: Khem Raj <raj.khem@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-10-05ARM: Flush user mapping on VIVT processors when copying a pageRussell King
Steven Walter <stevenrwalter@gmail.com> writes: > I've been tracking down an instance of userspace data corruption, > and I believe I have found a window during fork where data can be > lost. The corruption is occurring on an ARMv5 system with VIVT > caches. Here's the scenario in question. Thread A is forking, > Thread B is running in userspace: > > Thread A: flush_cache_mm() (dup_mmap) > Thread B: writes to a page in the above mm > Thread A: pte_wrprotect() the above page (copy_one_pte) > Thread B: writes to the same page again > > During thread B's second write, he'll take a fault and enter the > do_wp_page() case. We'll end up calling copy_page(), which notably > uses the kernel virtual addresses for the old and new pages. This > means that the new page does not necessarily have the data from the > first write. Now there are two conflicting copies of the same > cache-line in dcache. If the userspace cache-line flushes before > the kernel cache-line, we lose the changes made during the first > write. do_wp_page does call flush_dcache_page on the newly-copied > page, but there's still a window where the CPU could flush the > userspace cache-line before then. Resolve this by flushing the user mapping before copying the page on processors with a writeback VIVT cache. Note: this does have a performance impact, and so needs further consideration before being merged - can we optimize out some of the cache flushes if, eg, we know that the page isn't yet mapped? Thread: <e06498070903061426o5875ad13hc6328aa0d3f08ed7@mail.gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-10-05ARM: Pass VMA to copy_user_highpage() implementationsRussell King
Our copy_user_highpage() implementations may require cache maintainence. Ensure that implementations have all necessary details to perform this maintainence. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-03-12[ARM] 5421/1: ftrace: fix crash due to tracing of __naked functionsUwe Kleine-König
This is a fix for the following crash observed in 2.6.29-rc3: http://lkml.org/lkml/2009/1/29/150 On ARM it doesn't make sense to trace a naked function because then mcount is called without stack and frame pointer being set up and there is no chance to restore the lr register to the value before mcount was called. Reported-by: Matthias Kaehlcke <matthias@kaehlcke.net> Tested-by: Matthias Kaehlcke <matthias@kaehlcke.net> Cc: Abhishek Sagar <sagar.abhishek@gmail.com> Cc: Steven Rostedt <rostedt@home.goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-28[ARM] fix a couple clear_user_highpage assembly constraintsNicolas Pitre
In all cases the kaddr is assigned an input register even though it is modified in the assembly code. Let's assign a new variable to the modified value and mark those inline asm with volatile otherwise they get optimized away because the output variable is otherwise not used. Also fix a few conversion errors in copypage-feroceon.c and copypage-v4mc.c. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27[ARM] clearpage: provide our own clear_user_highpage()Russell King
For similar reasons as copy_user_page(), we want to avoid the additional kmap_atomic if it's unnecessary. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27[ARM] copypage: provide our own copy_user_highpage()Russell King
We used to override the copy_user_page() function. However, this is not only inefficient, it also causes additional complexity for highmem support, since we convert from a struct page to a kernel direct mapped address and back to a struct page again. Moreover, with highmem support, we end up pointlessly setting up kmap entries for pages which we're going to remap. So, push the kmapping down into the copypage implementation files where it's required. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-27[ARM] copypage: convert assembly files to CRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>