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2021-05-25MIPS: Fix kernel hang under FUNCTION_GRAPH_TRACER and PREEMPT_TRACERTiezhu Yang
When update the latest mainline kernel with the following three configs, the kernel hangs during startup: (1) CONFIG_FUNCTION_GRAPH_TRACER=y (2) CONFIG_PREEMPT_TRACER=y (3) CONFIG_FTRACE_STARTUP_TEST=y When update the latest mainline kernel with the above two configs (1) and (2), the kernel starts normally, but it still hangs when execute the following command: echo "function_graph" > /sys/kernel/debug/tracing/current_tracer Without CONFIG_PREEMPT_TRACER=y, the above two kinds of kernel hangs disappeared, so it seems that CONFIG_PREEMPT_TRACER has some influences with function_graph tracer at the first glance. I use ejtag to find out the epc address is related with preempt_enable() in the file arch/mips/lib/mips-atomic.c, because function tracing can trace the preempt_{enable,disable} calls that are traced, replace them with preempt_{enable,disable}_notrace to prevent function tracing from going into an infinite loop, and then it can fix the kernel hang issue. By the way, it seems that this commit is a complement and improvement of commit f93a1a00f2bd ("MIPS: Fix crash that occurs when function tracing is enabled"). Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-01-23MIPS: Make DIEI support as a config optionJiaxun Yang
DI(Disable Interrupt) and EI(Enable Interrupt) instructions is required by MIPSR2/MIPSR6, however, it appears to be buggy on some processors such as Loongson-3A1000. Thus we make it as a config option to allow disable it at compile time with CPU_MIPSR2 selected. Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Paul Burton <paulburton@kernel.org> Cc: linux-mips@vger.kernel.org Cc: chenhc@lemote.com Cc: paul.burton@mips.com Cc: linux-kernel@vger.kernel.org
2016-01-22MIPS: Cleanup the unused __arch_local_irq_restore() functionHuacai Chen
In history, __arch_local_irq_restore() is only used by SMTC. However, SMTC support has been removed since 3.16, this patch remove the unused function. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12159/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-17MIPS: asm: irqflags: Add MIPS R6 related definitionsMarkos Chandras
Add the MIPS R6 related definitions to the IRQ related macros Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2014-11-24MIPS: lib: mips-atomic.c: Remove obsolete ifdeferyMarkos Chandras
Having #ifdefs just to guard comments is not really helpful so drop them. Moreover, the code wasn't really reached anyway since there is a #ifndef CONFIG_CPU_MIPSR2 on the top of the file. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8513/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-05-24MIPS: MT: Remove SMTC supportRalf Baechle
Nobody is maintaining SMTC anymore and there also seems to be no userbase. Which is a pity - the SMTC technology primarily developed by Kevin D. Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT ASE's power and elegance. Based on Markos Chandras <Markos.Chandras@imgtec.com> patch https://patchwork.linux-mips.org/patch/6719/ which while very similar did no longer apply cleanly when I tried to merge it plus some additional post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to merge once upon a time. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-04-11MIPS: Get rid of the use of .macro in C code.Ralf Baechle
It fails with LTO and probably has always been a fragile. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-23MIPS: Fix crash that occurs when function tracing is enabledAl Cooper
A recent patch changed some irq routines from inlines to functions. These routines are called by the tracer code. Now that they're functions, if they are compiled for function tracing they will call the tracer and crash the system due to infinite recursion. The fix disables tracing in these functions by using "notrace" in the function definition. Signed-off-by: Al Cooper <alcooperx@gmail.com> Reviewed-by: David Daney <david.daney@cavium.com> Pathchwork: https://patchwork.linux-mips.org/patch/4564/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-09MIPS: Make irqflags.h functions preempt-safe for non-mipsr2 cpusJim Quinlan
For non MIPSr2 processors, such as the BMIPS 5000, calls to arch_local_irq_disable() and others may be preempted, and in doing so a stale value may be restored to c0_status. This fix disables preemption for such processors prior to the call and enables it after the call. Those functions that needed this fix have been "outlined" to mips-atomic.c, as they are no longer good candidates for inlining. This bug was observed in a BMIPS 5000, occuring once every few hours in a continuous reboot test. It was traced to the write_lock_irq() function which was being invoked in release_task() in exit.c. By placing a number of "nops" inbetween the mfc0/mtc0 pair in arch_local_irq_disable(), which is called by write_lock_irq(), we were able to greatly increase the occurance of this bug. Similarly, the application of this commit silenced the bug. Signed-off-by: Jim Quinlan <jim2101024@gmail.com> Cc: linux-mips@linux-mips.org Cc: David Daney <ddaney.cavm@gmail.com> Cc: Kevin Cernekee cernekee@gmail.com Cc: Jim Quinlan <jim2101024@gmail.com> Patchwork: https://patchwork.linux-mips.org/patch/4321/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>