[PATCH v2 3/3] riscv: add PREEMPT_LAZY support
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2024-10-10 12:25:48
Also in:
linux-riscv, lkml
Subsystem:
risc-v architecture, the rest · Maintainers:
Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
From: Jisheng Zhang <jszhang@kernel.org>
riscv has switched to GENERIC_ENTRY, so adding PREEMPT_LAZY is as simple
as adding TIF_NEED_RESCHED_LAZY related definitions and enabling
ARCH_HAS_PREEMPT_LAZY.
[bigeasy: Replace old PREEMPT_AUTO bits with new PREEMPT_LAZY ]
Cc: Paul Walmsley <redacted>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1…v2:
- shuffle TIF bits around to make RESCHED next to RESCHED_LAZY.
Compiles & boots.
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/thread_info.h | 10 ++++++----
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 62545946ecf43..3516c58480612 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig@@ -39,6 +39,7 @@ config RISCV select ARCH_HAS_MMIOWB select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PMEM_API + select ARCH_HAS_PREEMPT_LAZY select ARCH_HAS_PREPARE_SYNC_CORE_CMD select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU select ARCH_HAS_PTE_SPECIAL
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 9c10fb180f438..f5916a70879a8 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h@@ -107,9 +107,10 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); * - pending work-to-be-done flags are in lowest half-word * - other flags in upper half-word(s) */ -#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ -#define TIF_SIGPENDING 2 /* signal pending */ -#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ +#define TIF_NEED_RESCHED 0 /* rescheduling necessary */ +#define TIF_NEED_RESCHED_LAZY 1 /* Lazy rescheduling needed */ +#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ +#define TIF_SIGPENDING 3 /* signal pending */ #define TIF_RESTORE_SIGMASK 4 /* restore signal mask in do_signal() */ #define TIF_MEMDIE 5 /* is terminating due to OOM killer */ #define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */
@@ -117,9 +118,10 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); #define TIF_32BIT 11 /* compat-mode 32bit process */ #define TIF_RISCV_V_DEFER_RESTORE 12 /* restore Vector before returing to user */ +#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) +#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) -#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) #define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_RISCV_V_DEFER_RESTORE (1 << TIF_RISCV_V_DEFER_RESTORE)
--
2.45.2