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2024-05-30riscv: prevent pt_regs corruption for secondary idle threadsSergey Matyukevich1-2/+1
Top of the kernel thread stack should be reserved for pt_regs. However this is not the case for the idle threads of the secondary boot harts. Their stacks overlap with their pt_regs, so both may get corrupted. Similar issue has been fixed for the primary hart, see c7cdd96eca28 ("riscv: prevent stack corruption by reserving task_pt_regs(p) early"). However that fix was not propagated to the secondary harts. The problem has been noticed in some CPU hotplug tests with V enabled. The function smp_callin stored several registers on stack, corrupting top of pt_regs structure including status field. As a result, kernel attempted to save or restore inexistent V context. Fixes: 9a2451f18663 ("RISC-V: Avoid using per cpu array for ordered booting") Fixes: 2875fe056156 ("RISC-V: Add cpu_ops and modify default booting method") Signed-off-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20240523084327.2013211-1-geomatsi@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-01-04riscv: Remove unused members from struct cpu_operationsSamuel Holland1-11/+0
name is not used anywhere at all. cpu_prepare and cpu_disable do nothing and always return 0 if implemented. Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20231121234736.3489608-3-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-08-11RISC-V: cpu_ops_spinwait.c should include head.hBen Dooks1-0/+2
Running sparse shows cpu_ops_spinwait.c is missing two definitions found in head.h, so include it to stop the following warnings: arch/riscv/kernel/cpu_ops_spinwait.c:15:6: warning: symbol '__cpu_spinwait_stack_pointer' was not declared. Should it be static? arch/riscv/kernel/cpu_ops_spinwait.c:16:6: warning: symbol '__cpu_spinwait_task_pointer' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@sifive.com> Link: https://lore.kernel.org/r/20220713215306.94675-1-ben.dooks@sifive.com Fixes: c78f94f35cf6 ("RISC-V: Use __cpu_up_stack/task_pointer only for spinwait method") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-07-19riscv: spinwait: Fix hartid variable typeSunil V L1-2/+2
The hartid variable is of type int but compared with ULONG_MAX(INVALID_HARTID). This issue is fixed by changing the hartid variable type to unsigned long. Fixes: c78f94f35cf6 ("RISC-V: Use __cpu_up_stack/task_pointer only for spinwait method") Signed-off-by: Sunil V L <sunilvl@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20220527051743.2829940-3-sunilvl@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20RISC-V: Use __cpu_up_stack/task_pointer only for spinwait methodAtish Patra1-1/+26
The __cpu_up_stack/task_pointer array is only used for spinwait method now. The per cpu array based lookup is also fragile for platforms with discontiguous/sparse hartids. The spinwait method is only used for M-mode Linux or older firmwares without SBI HSM extension. For general Linux systems, ordered booting method is preferred anyways to support cpu hotplug and kexec. Make sure that __cpu_up_stack/task_pointer is only used for spinwait method. Take this opportunity to rename it to __cpu_spinwait_stack/task_pointer to emphasize the purpose as well. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2020-03-31RISC-V: Add cpu_ops and modify default booting methodAtish Patra1-0/+43
Currently, all non-booting harts start booting after the booting hart updates the per-hart stack pointer. This is done in a way that, it's difficult to implement any other booting method without breaking the backward compatibility. Define a cpu_ops method that allows to introduce other booting methods in future. Modify the current booting method to be compatible with cpu_ops. Signed-off-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>