kernel/linux.git/arch/mips/include/asm/irq.h, branch linux-4.4.y

MIPS: Fix minimum alignment requirement of IRQ stack

2017-10-21T15:09:01+00:00

commit 5fdc66e046206306bf61ff2d626bfa52ca087f7b upstream. Commit db8466c581cc ("MIPS: IRQ Stack: Unwind IRQ stack onto task stack") erroneously set the initial stack pointer of the IRQ stack to a value with a 4 byte alignment. The MIPS32 ABI requires that the minimum stack alignment is 8 byte, and the MIPS64 ABIs(n32/n64) require 16 byte minimum alignment. Fix IRQ_STACK_START such that it leaves space for the dummy stack frame (containing interrupted task kernel stack pointer) while also meeting minimum alignment requirements. Fixes: db8466c581cc ("MIPS: IRQ Stack: Unwind IRQ stack onto task stack") Reported-by: Darius Ivanauskas Signed-off-by: Matt Redfearn Cc: Chris Metcalf Cc: Petr Mladek Cc: Aaron Tomlin Cc: Jason A. Donenfeld Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16760/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman

MIPS: IRQ Stack: Unwind IRQ stack onto task stack

2017-10-08T08:14:19+00:00

[ Upstream commit db8466c581cca1a08b505f1319c3ecd246f16fa8 ] When the separate IRQ stack was introduced, stack unwinding only proceeded as far as the top of the IRQ stack, leading to kernel backtraces being less useful, lacking the trace of what was interrupted. Fix this by providing a means for the kernel to unwind the IRQ stack onto the interrupted task stack. The processor state is saved to the kernel task stack on interrupt. The IRQ_STACK_START macro reserves an unsigned long at the top of the IRQ stack where the interrupted task stack pointer can be saved. After the active stack is switched to the IRQ stack, save the interrupted tasks stack pointer to the reserved location. Fix the stack unwinding code to look for the frame being the top of the IRQ stack and if so get the next frame from the saved location. The existing test does not work with the separate stack since the ra is no longer pointed at ret_from_{irq,exception}. The test to stop unwinding the stack 32 bytes from the top of a stack must be modified to allow unwinding to continue up to the location of the saved task stack pointer when on the IRQ stack. The low / high marks of the stack are set depending on whether the sp is on an irq stack or not. Signed-off-by: Matt Redfearn Cc: Paolo Bonzini Cc: Marcin Nowakowski Cc: Masanari Iida Cc: Chris Metcalf Cc: James Hogan Cc: Paul Burton Cc: Ingo Molnar Cc: Jason A. Donenfeld Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15788/ Signed-off-by: Ralf Baechle Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

MIPS: Introduce irq_stack

2017-04-18T05:14:35+00:00

commit fe8bd18ffea5327344d4ec2bf11f47951212abd0 upstream. Allocate a per-cpu irq stack for use within interrupt handlers. Also add a utility function on_irq_stack to determine if a given stack pointer is within the irq stack for that cpu. Signed-off-by: Matt Redfearn Acked-by: Jason A. Donenfeld Cc: Thomas Gleixner Cc: Paolo Bonzini Cc: Chris Metcalf Cc: Petr Mladek Cc: James Hogan Cc: Paul Burton Cc: Aaron Tomlin Cc: Andrew Morton Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14740/ Signed-off-by: Ralf Baechle Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman

MIPS: Remove "weak" from get_c0_fdc_int() declaration

2015-09-03T10:07:38+00:00

Weak header file declarations are error-prone because they make every definition weak, and the linker chooses one based on link order (see 10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node decl")). The most elegant solution is to have a weak default implementation and allow a strong function to override it. Then we don't have to test whether a definition is present, and if there are ever multiple strong definitions, we get a link error instead of calling a random definition. Add a weak get_c0_fdc_int() definition with the default code and remove the weak annotation from the declaration. Signed-off-by: Bjorn Helgaas Reviewed-by: James Hogan Cc: Andrew Bresticker Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/10687/ Signed-off-by: Ralf Baechle

MIPS: Read CPU IRQ line that FDC to routed to

2015-03-31T10:04:12+00:00

Read the CPU IRQ line reportedly used for the Fast Debug Channel (FDC) interrupt from the IntCtl register and store it in cp0_fdc_irq where platform implementations of the new weak platform function get_c0_fdc_int() can refer to it. [ralf@linux-mips.org: Fixed conflict.] Signed-off-by: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: James Hogan Patchwork: https://patchwork.linux-mips.org/patch/9140/ Signed-off-by: Ralf Baechle

MIPS: Add arch_trigger_all_cpu_backtrace() function

2014-11-24T06:44:49+00:00

Currently, arch_trigger_all_cpu_backtrace() is defined in only x86 and sparc which have an NMI. But in case of softlockup, it could be possible to dump backtrace of all cpus. and this could be helpful for debugging. for example, if system has 2 cpus. CPU 0 CPU 1 acquire read_lock() try to do write_lock() ,,, missing read_unlock() In this case, softlockup will occur becasuse CPU 0 does not call read_unlock(). And dump_stack() print only backtrace for "CPU 0". If CPU1's backtrace is printed it's very helpful. [ralf@linux-mips.org: Fixed whitespace and formatting issues.] Signed-off-by: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/8200/

MIPS: Add common plat_irq_dispatch declaration

2014-08-19T11:30:45+00:00

Add common declaration to get rid of following sparse warning: "symbol 'plat_irq_dispatch' was not declared. Should it be static?" Signed-off-by: Sergey Ryazanov Cc: Linux MIPS Patchwork: https://patchwork.linux-mips.org/patch/7539/ Signed-off-by: Ralf Baechle

MIPS: MT: Remove SMTC support

2014-05-23T22:07:01+00:00

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 is an ingenious demonstration for the MT ASE's power and elegance. Based on Markos Chandras 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

MIPS: Whitespace cleanup.

2013-02-01T09:00:22+00:00

Having received another series of whitespace patches I decided to do this once and for all rather than dealing with this kind of patches trickling in forever. Signed-off-by: Ralf Baechle

MIPS: Provide a symbol for the legacy performance counter interrupt.

2012-07-06T21:56:00+00:00

Based on https://patchwork.linux-mips.org/patch/3576 - but this really deserves its own patchset and the symbol should also be used :) Signed-off-by: Ralf Baechle