From: guoren@kernel.org
To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com,
tglx@linutronix.de, peterz@infradead.org, luto@kernel.org,
conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org,
lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org,
apatel@ventanamicro.com, atishp@atishpatra.org,
mark.rutland@arm.com, ben@decadent.org.uk, bjorn@kernel.org,
miguel.ojeda.sandonis@gmail.com
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org,
"Björn Töpel" <bjorn@rivosinc.com>
Subject: [PATCH -next V16 6/7] riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork
Date: Sat, 4 Feb 2023 02:02:12 -0500 [thread overview]
Message-ID: <20230204070213.753369-7-guoren@kernel.org> (raw)
In-Reply-To: <20230204070213.753369-1-guoren@kernel.org>
From: Jisheng Zhang <jszhang@kernel.org>
The ret_from_kernel_thread() behaves similarly with ret_from_fork(),
the only difference is whether call the fn(arg) or not, this can be
achieved by testing fn is NULL or not, I.E s0 is 0 or not. Many
architectures have done the same thing, it makes entry.S more clean.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/kernel/entry.S | 12 +++---------
arch/riscv/kernel/process.c | 5 ++---
2 files changed, 5 insertions(+), 12 deletions(-)
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index bc322f92ba34..5ccef259498d 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -132,7 +132,6 @@ SYM_CODE_END(handle_exception)
* caller list:
* - handle_exception
* - ret_from_fork
- * - ret_from_kernel_thread
*/
SYM_CODE_START_NOALIGN(ret_from_exception)
REG_L s0, PT_STATUS(sp)
@@ -334,20 +333,15 @@ SYM_CODE_END(handle_kernel_stack_overflow)
SYM_CODE_START(ret_from_fork)
call schedule_tail
- move a0, sp /* pt_regs */
- la ra, ret_from_exception
- tail syscall_exit_to_user_mode
-SYM_CODE_END(ret_from_fork)
-
-SYM_CODE_START(ret_from_kernel_thread)
- call schedule_tail
+ beqz s0, 1f /* not from kernel thread */
/* Call fn(arg) */
move a0, s1
jalr s0
+1:
move a0, sp /* pt_regs */
la ra, ret_from_exception
tail syscall_exit_to_user_mode
-SYM_CODE_END(ret_from_kernel_thread)
+SYM_CODE_END(ret_from_fork)
/*
* Integer register context switch
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 8955f2432c2d..46806d5d10fa 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -34,7 +34,6 @@ EXPORT_SYMBOL(__stack_chk_guard);
#endif
extern asmlinkage void ret_from_fork(void);
-extern asmlinkage void ret_from_kernel_thread(void);
void arch_cpu_idle(void)
{
@@ -174,7 +173,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
/* Supervisor/Machine, irqs on: */
childregs->status = SR_PP | SR_PIE;
- p->thread.ra = (unsigned long)ret_from_kernel_thread;
p->thread.s[0] = (unsigned long)args->fn;
p->thread.s[1] = (unsigned long)args->fn_arg;
} else {
@@ -184,8 +182,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
if (clone_flags & CLONE_SETTLS)
childregs->tp = tls;
childregs->a0 = 0; /* Return value of fork() */
- p->thread.ra = (unsigned long)ret_from_fork;
+ p->thread.s[0] = 0;
}
+ p->thread.ra = (unsigned long)ret_from_fork;
p->thread.sp = (unsigned long)childregs; /* kernel sp */
return 0;
}
--
2.36.1
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next prev parent reply other threads:[~2023-02-04 7:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-04 7:02 [PATCH -next V16 0/7] riscv: Add GENERIC_ENTRY support guoren
2023-02-04 7:02 ` [PATCH -next V16 1/7] compiler_types.h: Add __noinstr_section() for noinstr guoren
2023-02-04 7:02 ` [PATCH -next V16 2/7] riscv: ptrace: Remove duplicate operation guoren
2023-02-04 7:02 ` [PATCH -next V16 3/7] riscv: entry: Add noinstr to prevent instrumentation inserted guoren
2023-02-04 7:02 ` [PATCH -next V16 4/7] riscv: entry: Convert to generic entry guoren
2023-02-05 10:43 ` Conor Dooley
2023-02-05 13:56 ` Guo Ren
2023-02-05 14:04 ` Conor Dooley
2023-02-10 15:22 ` Conor Dooley
2023-02-04 7:02 ` [PATCH -next V16 5/7] riscv: entry: Remove extra level wrappers of trace_hardirqs_{on,off} guoren
2023-02-04 7:02 ` guoren [this message]
2023-02-04 7:02 ` [PATCH -next V16 7/7] riscv: entry: Consolidate general regs saving/restoring guoren
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