kernel/git/stable/linux.git/arch/riscv/include, branch linux-5.8.y

RISC-V: Take text_mutex in ftrace_init_nop()

2020-10-01T15:36:24+00:00

[ Upstream commit 66d18dbda8469a944dfec6c49d26d5946efba218 ] Without this we get lockdep failures. They're spurious failures as SMP isn't up when ftrace_init_nop() is called. As far as I can tell the easiest fix is to just take the lock, which also seems like the safest fix. Signed-off-by: Palmer Dabbelt Acked-by: Guo Ren Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin

RISC-V: Upgrade smp_mb__after_spinlock() to iorw,iorw

2020-07-17T16:28:35+00:00

While digging through the recent mmiowb preemption issue it came up that we aren't actually preventing IO from crossing a scheduling boundary. While it's a bit ugly to overload smp_mb__after_spinlock() with this behavior, it's what PowerPC is doing so there's some precedent. Signed-off-by: Palmer Dabbelt

riscv: use 16KB kernel stack on 64-bit

2020-07-14T20:40:04+00:00

With the current 8KB stack size there are frequent overflows in a 64-bit configuration. We may split IRQ stacks off in the future, but this fixes a number of issues right now. Signed-off-by: Andreas Schwab Reviewed-by: Anup Patel [Palmer: mention irqstack in the commit text] Fixes: 7db91e57a0ac ("RISC-V: Task implementation") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt

riscv: Avoid kgdb.h including gdb_xml.h to solve unused-const-variable warning

2020-07-10T03:12:28+00:00

The constant arrays in gdb_xml.h are only used in arch/riscv/kernel/kgdb.c, but other c files may include the gdb_xml.h indirectly via including the kgdb.h. Hence, It will cause many unused-const-variable warnings. This patch makes the kgdb.h not to include the gdb_xml.h to solve this problem. Signed-off-by: Vincent Chen Signed-off-by: Palmer Dabbelt

kgdb: Move the extern declaration kgdb_has_hit_break() to generic kgdb.h

2020-07-10T03:12:19+00:00

Currently, only riscv kgdb.c uses the kgdb_has_hit_break() to identify the kgdb breakpoint. It causes other architectures will encounter the "no previous prototype" warnings if the compile option has W=1. Moving the declaration of extern kgdb_has_hit_break() from risc-v kgdb.h to generic kgdb.h to avoid generating these warnings. Signed-off-by: Vincent Chen Acked-by: Daniel Thompson Signed-off-by: Palmer Dabbelt

riscv/atomic: Fix sign extension for RV64I

2020-06-12T19:07:58+00:00

The argument passed to cmpxchg is not guaranteed to be sign extended, but lr.w sign extends on RV64I. This makes cmpxchg fail on clang built kernels when __old is negative. To fix this, we just cast __old to long which sign extends on RV64I. With this fix, clang built RISC-V kernels now boot. Link: https://github.com/ClangBuiltLinux/linux/issues/867 Signed-off-by: Nathan Huckleberry Signed-off-by: Palmer Dabbelt

Merge tag 'riscv-for-linus-5.8-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2020-06-11T19:55:20+00:00

Pull more RISC-V updates from Palmer Dabbelt: - Kconfig select statements are now sorted alphanumerically - first-level interrupts are now handled via a full irqchip driver - CPU hotplug is fixed - vDSO calls now use the common vDSO infrastructure * tag 'riscv-for-linus-5.8-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: set the permission of vdso_data to read-only riscv: use vDSO common flow to reduce the latency of the time-related functions riscv: fix build warning of missing prototypes RISC-V: Don't mark init section as non-executable RISC-V: Force select RISCV_INTC for CONFIG_RISCV RISC-V: Remove do_IRQ() function clocksource/drivers/timer-riscv: Use per-CPU timer interrupt irqchip: RISC-V per-HART local interrupt controller driver RISC-V: Rename and move plic_find_hart_id() to arch directory RISC-V: self-contained IPI handling routine RISC-V: Sort select statements alphanumerically

riscv: use vDSO common flow to reduce the latency of the time-related functions

2020-06-11T02:47:16+00:00

Even if RISC-V has supported the vDSO feature, the latency of the functions for obtaining the system time is still expensive. It is because these functions still trigger a corresponding system call in the process, which slows down the response time. If we want to remove the system call to reduce the latency, the kernel should have the ability to output the system clock information to userspace. This patch introduces the vDSO common flow to enable the kernel to achieve the above feature and uses "rdtime" instruction to obtain the current time in the user space. Under this condition, the latency cost by the ecall from U-mode to S-mode can be eliminated. After applying this patch, the latency of gettimeofday() measured on the HiFive unleashed board can be reduced by %61. Signed-off-by: Vincent Chen Reviewed-by: Atish Patra Signed-off-by: Palmer Dabbelt

clocksource/drivers/timer-riscv: Use per-CPU timer interrupt

2020-06-10T02:11:22+00:00

Instead of directly calling RISC-V timer interrupt handler from RISC-V local interrupt conntroller driver, this patch implements RISC-V timer interrupt as a per-CPU interrupt using per-CPU APIs of Linux IRQ subsystem. Signed-off-by: Anup Patel Reviewed-by: Atish Patra Reviewed-by: Marc Zyngier Signed-off-by: Palmer Dabbelt

irqchip: RISC-V per-HART local interrupt controller driver

2020-06-10T02:11:21+00:00

The RISC-V per-HART local interrupt controller manages software interrupts, timer interrupts, external interrupts (which are routed via the platform level interrupt controller) and other per-HART local interrupts. We add a driver for the RISC-V local interrupt controller, which eventually replaces the RISC-V architecture code, allowing for a better split between arch code and drivers. The driver is compliant with RISC-V Hart-Level Interrupt Controller DT bindings located at: Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt Co-developed-by: Palmer Dabbelt Signed-off-by: Anup Patel [Palmer: Cleaned up warnings] Signed-off-by: Palmer Dabbelt