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path: root/arch/arm/mm/abort-ev6.S
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2015-08-26ARM: entry: provide uaccess assembly macro hooksRussell King
Provide hooks into the kernel entry and exit paths to permit control of userspace visibility to the kernel. The intended use is: - on entry to kernel from user, uaccess_disable will be called to disable userspace visibility - on exit from kernel to user, uaccess_enable will be called to enable userspace visibility - on entry from a kernel exception, uaccess_save_and_disable will be called to save the current userspace visibility setting, and disable access - on exit from a kernel exception, uaccess_restore will be called to restore the userspace visibility as it was before the exception occurred. These hooks allows us to keep userspace visibility disabled for the vast majority of the kernel, except for localised regions where we want to explicitly access userspace. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-08-25ARM: mm: improve do_ldrd_abort macroRussell King
Improve the do_ldrd_abort macro code - firstly, it inefficiently checks for the LDRD encoding by doing a multi-stage test of various bits. This can be simplified by generating a mask, bitmasking the instruction and then comparing the result. Secondly, we want to be able to test the result rather than branching to do_DataAbort, so remove the branch at the end and rename the macro to 'teq_ldrd' to reflect it's new usage. teq_ldrd macro returns 'eq' if the instruction was a LDRD. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-08-27ARM: 8128/1: abort: don't clear the exclusive monitorsMark Rutland
The ARMv6 and ARMv7 early abort handlers clear the exclusive monitors upon entry to the kernel, but this is redundant: - We clear the monitors on every exception return since commit 200b812d0084 ("Clear the exclusive monitor when returning from an exception"), so this is not necessary to ensure the monitors are cleared before returning from a fault handler. - Any dummy STREX will target a temporary scratch area in memory, and may succeed or fail without corrupting useful data. Its status value will not be used. - Any other STREX in the kernel must be preceded by an LDREX, which will initialise the monitors consistently and will not depend on the earlier state of the monitors. Therefore we have no reason to care about the initial state of the exclusive monitors when a data abort is taken, and clearing the monitors prior to exception return (as we already do) is sufficient. This patch removes the redundant clearing of the exclusive monitors from the early abort handlers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-19ARM: asm: Add ARM_BE8() assembly helperBen Dooks
Add ARM_BE8() helper to wrap any code conditional on being compile when CONFIG_ARM_ENDIAN_BE8 is selected and convert existing places where this is to use it. Acked-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
2012-04-23ARM: 7396/1: errata: only handle ARM erratum #326103 on affected coresWill Deacon
Erratum #326103 ("FSR write bit incorrect on a SWP to read-only memory") only affects the ARM 1136 core prior to r1p0. The workaround disassembles the faulting instruction to determine whether it was a read or write access on all v6 cores. An issue has been reported on the ARM 11MPCore whereby loading the faulting instruction may happen in parallel with that page being unmapped, resulting in a deadlock due to the lack of TLB broadcasting in hardware: http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/091561.html This patch limits the workaround so that it is only used on affected cores, which are known to be UP only. Other v6 cores can rely on the FSR to indicate the access type correctly. Cc: stable@vger.kernel.org Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-07-02ARM: entry: data abort: tail-call the main data abort handlerRussell King
Tail-call the main C data abort handler code from the per-CPU helper code. Update the comments in the code wrt the new calling and return register state. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-07-02ARM: entry: data abort: avoid using r2 in abort helpersRussell King
This allows us to pass the pt_regs pointer in to these functions ready for tail-calling the abort handler. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-07-02ARM: entry: data abort: arrange for CPU abort helpers to take pc/psr in r4/r5Russell King
Re-jig the CPU abort helpers to take the PC/PSR in r4/r5 rather than r2/r3. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-06-29ARM: entry: abort-macro: specify registers to be used for macrosRussell King
Require all callers of abort macros to specify the registers to be used. This improves the documentation at the callsites as to which registers are being used by this assembly code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-02ARM: v6k: select clear exclusive code seqences according to V6 variantsRussell King
If CONFIG_CPU_V6 is enabled, then the kernel must support ARMv6 CPUs which don't have the V6K extensions implemented. Always use the dummy store-exclusive method to ensure that the exclusive monitors are cleared. If CONFIG_CPU_V6 is not set, but CONFIG_CPU_32v6K is enabled, then we have the K extensions available on all CPUs we're building support for, so we can use the new clear-exclusive instruction. Acked-by: Tony Lindgren <tony@atomide.com> Tested-by: Sourav Poddar <sourav.poddar@ti.com> Tested-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-30Add core support for ARMv6/v7 big-endianCatalin Marinas
Starting with ARMv6, the CPUs support the BE-8 variant of big-endian (byte-invariant). This patch adds the core support: - setting of the BE-8 mode via the CPSR.E register for both kernel and user threads - big-endian page table walking - REV used to rotate instructions read from memory during fault processing as they are still little-endian format - Kconfig and Makefile support for BE-8. The --be8 option must be passed to the final linking stage to convert the instructions to little-endian Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-04-01[ARM] 5439/1: Do not clear bit 10 of DFSR during abort handling on ARMv6Catalin Marinas
Because of an ARM1136 erratum (326103), the current v6_early_abort function needs to set the correct FSR[11] value which determines whether the data abort was caused by a read or write. For legacy reasons (bit 10 not handled by software), bit 10 was also cleared masking out imprecise aborts on ARMv6 CPUs. This patch removes the clearing of bit 10 of FSR. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-03-03[ARM] 5416/1: Use unused address in v6_early_abortSeth Forshee
The target of the strex instruction to clear the exlusive monitor is currently the top of the stack. If the store succeeeds this corrupts r0 in pt_regs. Use the next stack location instead of the current one to prevent any chance of corrupting an in-use address. Signed-off-by: Seth Forshee <seth.forshee@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-02-22[ARM] CONFIG_CPU_MPCORE -> CONFIG_CPU_32v6KRussell King
CONFIG_CPU_MPCORE has never been a configuration symbol - it should be CONFIG_CPU_32v6K. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-02[ARM] 2943/1: Clear the exclusive monitor in v6_early_abortCatalin Marinas
Patch from Catalin Marinas Data abort caused by ldrex/strex can leave the exclusive monitor in an unpredictable state. It is recommended that a clrex/strex is performed to clear this state. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-04-29[PATCH] ARM: 2655/1: ARM1136 SWP instruction abort handler fixGeorge G. Davis
Patch from George G. Davis As noted in http://www.arm.com/linux/patch-2.6.9-arm1.gz, the "Faulty SWP instruction on 1136 doesn't set bit 11 in DFSR." So the v6_early_abort handler does not report the correct rd/wr direction for the SWP instruction which may result in SEGVS or hangs. In order to work around this problem, this patch merely updates the fix contained in the ARM Ltd. patch to use the macroised abort handler fixups. Signed-off-by: George G. Davis Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!