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2019-05-16RISC-V: Access CSRs using CSR numbersAnup Patel
We should prefer accessing CSRs using their CSR numbers because: 1. It compiles fine with older toolchains. 2. We can use latest CSR names in #define macro names of CSR numbers as-per RISC-V spec. 3. We can access newly added CSRs even if toolchain does not recognize newly addes CSRs by name. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-01-23RISC-V: Add _TIF_NEED_RESCHED check for kernel thread when CONFIG_PREEMPT=yVincent Chen
The cond_resched() can be used to yield the CPU resource if CONFIG_PREEMPT is not defined. Otherwise, cond_resched() is a dummy function. In order to avoid kernel thread occupying entire CPU, when CONFIG_PREEMPT=y, the kernel thread needs to follow the rescheduling mechanism like a user thread. Signed-off-by: Vincent Chen <vincentc@andestech.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-01-07riscv: add audit supportDavid Abdurachmanov
On RISC-V (riscv) audit is supported through generic lib/audit.c. The patch adds required arch specific definitions. Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22RISC-V: SMP cleanup and new featuresPalmer Dabbelt
This patch series now has evolved to contain several related changes. 1. Updated the assorted cleanup series by Palmer. The original cleanup patch series can be found here. http://lists.infradead.org/pipermail/linux-riscv/2018-August/001232.html 2. Implemented decoupling linux logical CPU ids from hart id. Some of the work has been inspired from ARM64. Tested on QEMU & HighFive Unleashed board with/without SMP enabled. 3. Included Anup's cleanup and IPI stat patch. All the patch series have been combined to avoid conflicts as a lot of common code is changed different patch sets. Atish has mostly addressed review comments and fixed checkpatch errors from Palmer's and Anup's series. Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22RISC-V: No need to pass scause as arg to do_IRQ()Anup Patel
The scause is already part of pt_regs so no need to pass scause as separate arg to do_IRQ(). Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22Extract FPU context operations from entry.SAlan Kao
We move __fstate_save and __fstate_restore to a new source file, fpu.S. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-13RISC-V: implement low-level interrupt handlingChristoph Hellwig
Add support for a routine that dispatches exceptions with the interrupt flags set to either the IPI or irqdomain code (and the clock source in the future). Loosely based on the irq-riscv-int.c irqchip driver from the RISC-V tree. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-03-14RISC-V: Move to the new GENERIC_IRQ_MULTI_HANDLER handlerPalmer Dabbelt
The existing mechanism for handling IRQs on RISC-V is pretty ugly: the irq entry code selects the handler via Kconfig dependencies. Use the new generic IRQ handling infastructure, which allows boot time registration of the low level entry handler. This does add an additional load to the interrupt latency, but there's a lot of tuning left to be done there on RISC-V so it's OK for now. Signed-off-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Stafford Horne <shorne@gmail.com> Cc: jonas@southpole.se Cc: catalin.marinas@arm.com Cc: Will Deacon <will.deacon@arm.com> Cc: linux@armlinux.org.uk Cc: stefan.kristiansson@saunalahti.fi Cc: openrisc@lists.librecores.org Cc: linux-riscv@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lkml.kernel.org/r/20180307235731.22627-3-palmer@sifive.com
2018-02-20RISC-V: Enable IRQ during exception handlingzongbox@gmail.com
Interrupt is allowed during exception handling. There are warning messages if the kernel enables the configuration 'CONFIG_DEBUG_ATOMIC_SLEEP=y'. BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:23 in_atomic(): 0, irqs_disabled(): 1, pid: 43, name: ash CPU: 0 PID: 43 Comm: ash Tainted: G W 4.15.0-rc8-00089-g89ffdae-dirty #17 Call Trace: [<000000009abb1587>] walk_stackframe+0x0/0x7a [<00000000d4f3d088>] ___might_sleep+0x102/0x11a [<00000000b1fd792a>] down_read+0x18/0x28 [<000000000289ec01>] do_page_fault+0x86/0x2f6 [<00000000012441f6>] _do_fork+0x1b4/0x1e0 [<00000000f46c3e3b>] ret_from_syscall+0xa/0xe Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Zong Li <zong@andestech.com> Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-30riscv: disable SUM in the exception handlerChristoph Hellwig
The SUM bit is enabled at the beginning of the copy_{to,from}_user and {get,put}_user routines, and cleared before they return. But these user copy helper can be interrupted by exceptions, in which case the SUM bit will remain set, which leads to elevated privileges for the code running in exception context, as that can now access userspace address space unconditionally. This frequently happens when the user copy routines access freshly allocated user memory that hasn't been faulted in, and a pagefault needs to be taken before the user copy routines can continue. Fix this by unconditionally clearing SUM when the exception handler is called - the restore code will automatically restore it based on the saved value. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-07riscv: rename SR_* constants to match the specChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2017-09-26RISC-V: Task implementationPalmer Dabbelt
This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>