From: Jisheng Zhang <jszhang@kernel.org>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Subject: [PATCH 2/4] riscv: consolidate ret_from_kernel_thread into ret_from_fork
Date: Mon, 26 Sep 2022 01:53:54 +0800 [thread overview]
Message-ID: <20220925175356.681-3-jszhang@kernel.org> (raw)
In-Reply-To: <20220925175356.681-1-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
acchieved by testing fn is NULL or not, I.E s0 is 0 or not.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/kernel/entry.S | 11 +++--------
arch/riscv/kernel/process.c | 5 ++---
2 files changed, 5 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 2207cf44a3bc..a3e1ed2fa2ac 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -323,20 +323,15 @@ END(handle_kernel_stack_overflow)
ENTRY(ret_from_fork)
call schedule_tail
- move a0, sp /* pt_regs */
- la ra, ret_from_exception
- tail syscall_exit_to_user_mode
-ENDPROC(ret_from_fork)
-
-ENTRY(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
-ENDPROC(ret_from_kernel_thread)
+ENDPROC(ret_from_fork)
#ifdef CONFIG_IRQ_STACKS
ENTRY(call_on_stack)
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index ceb9ebab6558..67e7cd123ceb 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)
{
@@ -172,7 +171,6 @@ 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 {
@@ -182,8 +180,9 @@ 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;
}
--
2.34.1
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next prev parent reply other threads:[~2022-09-25 18:03 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-25 17:53 [PATCH 0/4] riscv: entry: further clean up and VMAP_STACK fix Jisheng Zhang
2022-09-25 17:53 ` [PATCH 1/4] riscv: remove extra level wrappers of trace_hardirqs_{on,off} Jisheng Zhang
2022-09-25 23:18 ` Guo Ren
2022-09-25 17:53 ` Jisheng Zhang [this message]
2022-09-25 23:25 ` [PATCH 2/4] riscv: consolidate ret_from_kernel_thread into ret_from_fork Guo Ren
2022-09-26 16:05 ` Jisheng Zhang
2022-09-26 23:55 ` Guo Ren
2022-09-28 16:40 ` Jisheng Zhang
2022-09-30 11:42 ` Guo Ren
2022-09-25 17:53 ` [PATCH 3/4] riscv: fix race when vmap stack overflow and remove shadow_stack Jisheng Zhang
2022-09-25 23:46 ` Guo Ren
2022-09-27 0:18 ` Jisheng Zhang
2022-09-27 2:00 ` Guo Ren
2022-11-23 17:02 ` Deepak Gupta
2022-09-25 17:53 ` [PATCH 4/4] riscv: entry: consolidate general regs saving into save_gp Jisheng Zhang
2022-09-25 23:29 ` Guo Ren
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