BMC/Intel-BMC/linux.git/arch/mips/kernel/genex.S, branch dev-4.10

MIPS: IRQ Stack: Fix erroneous jal to plat_irq_dispatch

2017-04-18T04:59:35+00:00

commit c25f8064c1d5731a2ce5664def890140dcdd3e5c upstream. Commit dda45f701c9d ("MIPS: Switch to the irq_stack in interrupts") changed both the normal and vectored interrupt handlers. Unfortunately the vectored version, "except_vec_vi_handler", was incorrectly modified to unconditionally jal to plat_irq_dispatch, rather than doing a jalr to the vectored handler that has been set up. This is ok for many platforms which set the vectored handler to plat_irq_dispatch anyway, but will cause problems with platforms that use other handlers. Fixes: dda45f701c9d ("MIPS: Switch to the irq_stack in interrupts") Signed-off-by: Matt Redfearn Cc: Ralf Baechle Cc: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15110/ Signed-off-by: James Hogan Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman

MIPS: Switch to the irq_stack in interrupts

2017-04-18T04:59:35+00:00

commit dda45f701c9d7ad4ac0bb446e3a96f6df9a468d9 upstream. When enterring interrupt context via handle_int or except_vec_vi, switch to the irq_stack of the current CPU if it is not already in use. The current stack pointer is masked with the thread size and compared to the base or the irq stack. If it does not match then the stack pointer is set to the top of that stack, otherwise this is a nested irq being handled on the irq stack so the stack pointer should be left as it was. The in-use stack pointer is placed in the callee saved register s1. It will be saved to the stack when plat_irq_dispatch is invoked and can be restored once control returns here. Signed-off-by: Matt Redfearn Acked-by: Jason A. Donenfeld Cc: Thomas Gleixner Cc: James Hogan Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14743/ Signed-off-by: Ralf Baechle Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman

MIPS: Check TLB before handle_ri_rdhwr() for Loongson-3

2017-04-12T10:42:08+00:00

commit 5a34133167dce36666ea054e30a561b7f4413b7f upstream. Loongson-3's micro TLB (ITLB) is not strictly a subset of JTLB. That means: when a JTLB entry is replaced by hardware, there may be an old valid entry exists in ITLB. So, a TLB miss exception may occur while handle_ri_rdhwr() is running because it try to access EPC's content. However, handle_ri_rdhwr() doesn't clear EXL, which makes a TLB Refill exception be treated as a TLB Invalid exception and tlbp may fail. In this case, if FTLB (which is usually set-associative instead of set- associative) is enabled, a tlbp failure will cause an invalid tlbwi, which will hang the whole system. This patch rename handle_ri_rdhwr_vivt to handle_ri_rdhwr_tlbp and use it for Loongson-3. It try to solve the same problem described as below, but more straightforwards. https://patchwork.linux-mips.org/patch/12591/ I think Loongson-2 has the same problem, but it has no FTLB, so we just keep it as is. Signed-off-by: Huacai Chen Cc: Rui Wang Cc: John Crispin Cc: Steven J . Hill Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: Huacai Chen Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15753/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman

MIPS: Fix BUILD_ROLLBACK_PROLOGUE for microMIPS

2016-09-29T16:59:49+00:00

When the kernel is built for microMIPS, branches targets need to be known to be microMIPS code in order to result in bit 0 of the PC being set. The branch target in the BUILD_ROLLBACK_PROLOGUE macro was simply the end of the macro, which may be pointing at padding rather than at code. This results in recent enough GNU linkers complaining like so: mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x3e3c: Unsupported branch between ISA modes. mips-img-linux-gnu-ld: final link failed: Bad value Makefile:936: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 Fix this by changing the branch target to be the start of the appropriate handler, skipping over any padding. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14019/ Signed-off-by: Ralf Baechle

MIPS: genex: Indent delay slots & clean whitespace

2016-05-13T12:02:20+00:00

Various branches and jumps in noreorder parts of genex.S don't have their delay slot instructions indented conventionally with the extra space. Fix these, as well as various other inconsistent whitespace problems in this file, such as spaces used after some opcodes instead of a tab. Signed-off-by: James Hogan Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13196/ Signed-off-by: Ralf Baechle

MIPS: Support extended ASIDs

2016-05-13T12:02:20+00:00

Add support for extended ASIDs as determined by the Config4.AE bit. Since the only supported CPUs known to implement this are Netlogic XLP and MIPS I6400, select this variable ASID support based upon CONFIG_CPU_XLP and CONFIG_CPU_MIPSR6. Signed-off-by: Paul Burton Signed-off-by: James Hogan Cc: Jayachandran C. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13211/ Signed-off-by: Ralf Baechle

MIPS: Add & use CP0_EntryHi ASID definitions

2016-05-13T12:02:18+00:00

Add definitions for the ASID field in CP0_EntryHi (along with the soon to be used ASIDX field), and use them in a few previously hardcoded cases. Signed-off-by: James Hogan Cc: Manuel Lauss Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13205/ Signed-off-by: Ralf Baechle

MIPS: Fix LLVM build issue.

2015-08-18T09:40:20+00:00

Matthew Fortune reports: The genex.S file appears to mix the case of a macro between its definition and use. A cut down example of this is below. The macro __build_clear_none has lower case 'build' but ends up being instantiated with upper case BUILD. Can this be fixed on master. It has been picked up by the LLVM integrated assembler which is currently case sensitive. We are likely to fix the assembler as well but the code is currently inconsistent in the kernel. .macro __build_clear_none .endm .macro __BUILD_HANDLER exception handler clear verbose ext .align 5 .globl handle_\exception; .align 2; .type handle_\exception, @function; .ent handle_\exception, 0; handle_\exception: .frame $29, 184, $29 .set noat .globl handle_\exception\ext; .type handle_\exception\ext, @function; handle_\exception\ext: __BUILD_clear_\clear .endm .macro BUILD_HANDLER exception handler clear verbose __BUILD_HANDLER \exception \handler \clear \verbose _int .endm BUILD_HANDLER ftlb ftlb none silent Signed-off-by: Ralf Baechle Reported-by: Matthew Fortune

MIPS: Clear [MSA]FPE CSR.Cause after notify_die()

2015-03-27T21:25:06+00:00

When handling floating point exceptions (FPEs) and MSA FPEs the Cause bits of the appropriate control and status register (FCSR for FPEs and MSACSR for MSA FPEs) are read and cleared before enabling interrupts, presumably so that it doesn't have to go through the pain of restoring those bits if the process is pre-empted, since writing those bits would cause another immediate exception while still in the kernel. The bits aren't normally ever restored again, since userland never expects to see them set. However for virtualisation it is necessary for the kernel to be able to restore these Cause bits, as the guest may have been interrupted in an FP exception handler but before it could read the Cause bits. This can be done by registering a die notifier, to get notified of the exception when such a value is restored, and if the PC was at the instruction which is used to restore the guest state, the handler can step over it and continue execution. The Cause bits can then remain set without causing further exceptions. For this to work safely a few changes are made: - __build_clear_fpe and __build_clear_msa_fpe no longer clear the Cause bits, and now return from exception level with interrupts disabled instead of enabled. - do_fpe() now clears the Cause bits and enables interrupts after notify_die() is called, so that the notifier can chose to return from exception without this happening. - do_msa_fpe() acts similarly, but now actually makes use of the second argument (msacsr) and calls notify_die() with the new DIE_MSAFP, allowing die notifiers to be informed of MSA FPEs too. Signed-off-by: James Hogan Acked-by: Ralf Baechle Cc: Paul Burton Cc: Paolo Bonzini Cc: Gleb Natapov Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

MIPS: clear MSACSR cause bits when handling MSA FP exception

2015-03-27T18:42:45+00:00

Much like for traditional scalar FP exceptions, the cause bits in the MSACSR register need to be cleared following an MSA FP exception. Without doing so the exception will simply be raised again whenever the kernel restores MSACSR from a tasks saved context, leading to undesirable spurious exceptions. Clear the cause bits from the handle_msa_fpe function, mirroring the way handle_fpe clears the cause bits in FCSR. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9164/ Signed-off-by: Ralf Baechle