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d6c78f1c |
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14-Jan-2024 |
Andy Chiu <andy.chiu@sifive.com> |
riscv: vector: do not pass task_struct into riscv_v_vstate_{save,restore}() riscv_v_vstate_{save,restore}() can operate only on the knowlege of struct __riscv_v_ext_state, and struct pt_regs. Let the caller decides which should be passed into the function. Meanwhile, the kernel-mode Vector is going to introduce another vstate, so this also makes functions potentially able to be reused. Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Link: https://lore.kernel.org/r/20240115055929.4736-8-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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7df56cbc2 |
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14-Jan-2024 |
Andy Chiu <andy.chiu@sifive.com> |
riscv: sched: defer restoring Vector context for user User will use its Vector registers only after the kernel really returns to the userspace. So we can delay restoring Vector registers as long as we are still running in kernel mode. So, add a thread flag to indicates the need of restoring Vector and do the restore at the last arch-specific exit-to-user hook. This save the context restoring cost when we switch over multiple processes that run V in kernel mode. For example, if the kernel performs a context swicth from A->B->C, and returns to C's userspace, then there is no need to restore B's V-register. Besides, this also prevents us from repeatedly restoring V context when executing kernel-mode Vector multiple times. The cost of this is that we must disable preemption and mark vector as busy during vstate_{save,restore}. Because then the V context will not get restored back immediately when a trap-causing context switch happens in the middle of vstate_{save,restore}. Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Link: https://lore.kernel.org/r/20240115055929.4736-5-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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7c832321 |
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04-Oct-2023 |
Clément Léger <cleger@rivosinc.com> |
riscv: add support for misaligned trap handling in S-mode Misalignment trap handling is only supported for M-mode and uses direct accesses to user memory. In S-mode, when handling usermode fault, this requires to use the get_user()/put_user() accessors. Implement load_u8(), store_u8() and get_insn() using these accessors for userspace and direct text access for kernel. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-3-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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f0bddf50 |
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21-Feb-2023 |
Guo Ren <guoren@kernel.org> |
riscv: entry: Convert to generic entry This patch converts riscv to use the generic entry infrastructure from kernel/entry/*. The generic entry makes maintainers' work easier and codes more elegant. Here are the changes: - More clear entry.S with handle_exception and ret_from_exception - Get rid of complex custom signal implementation - Move syscall procedure from assembly to C, which is much more readable. - Connect ret_from_fork & ret_from_kernel_thread to generic entry. - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode - Use the standard preemption code instead of custom Suggested-by: Huacai Chen <chenhuacai@kernel.org> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Yipeng Zou <zouyipeng@huawei.com> Tested-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Ben Hutchings <ben@decadent.org.uk> Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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