From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 7/8] powerpc: copy_thread don't set _TIF_RESTOREALL
Date: Wed, 1 Feb 2023 02:55:33 +1000 [thread overview]
Message-ID: <20230131165534.601490-8-npiggin@gmail.com> (raw)
In-Reply-To: <20230131165534.601490-1-npiggin@gmail.com>
In the kernel user thread path, don't set _TIF_RESTOREALL because the
thread is required to call kernel_execve() before it returns, which will
set _TIF_RESTOREALL if necessary via start_thread().
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/interrupt_64.S | 5 +++++
arch/powerpc/kernel/process.c | 2 --
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index 90370b89905b..f53012254fca 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -748,6 +748,11 @@ _GLOBAL(ret_from_kernel_user_thread)
#endif
bctrl
li r3,0
+ /*
+ * It does not matter whether this returns via the scv or sc path
+ * because it returns as execve() and therefore has no calling ABI
+ * (i.e., it sets registers according to the exec()ed entry point).
+ */
b .Lsyscall_exit
_GLOBAL(start_kernel_thread)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 53215cdb19dd..e67597fd998f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1746,7 +1746,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
extern void start_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
- struct thread_info *ti = task_thread_info(p);
#ifdef CONFIG_HAVE_HW_BREAKPOINT
int i;
#endif
@@ -1786,7 +1785,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
#ifdef CONFIG_PPC64
childregs->softe = IRQS_ENABLED;
#endif
- ti->flags |= _TIF_RESTOREALL;
f = ret_from_kernel_user_thread;
} else {
struct pt_regs *regs = current_pt_regs();
--
2.37.2
next prev parent reply other threads:[~2023-01-31 17:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-31 16:55 [PATCH 0/8] powerpc: improve copy_thread Nicholas Piggin
2023-01-31 16:55 ` [PATCH 1/8] powerpc: copy_thread remove unused pkey code Nicholas Piggin
2023-01-31 16:55 ` [PATCH 2/8] powerpc: copy_thread make ret_from_fork register setup consistent Nicholas Piggin
2023-01-31 16:55 ` [PATCH 3/8] powerpc: use switch frame for ret_from_kernel_thread parameters Nicholas Piggin
2023-01-31 16:55 ` [PATCH 4/8] powerpc/64: ret_from_fork avoid restoring regs twice Nicholas Piggin
2023-01-31 16:55 ` [PATCH 5/8] powerpc: copy_thread differentiate kthreads and user mode threads Nicholas Piggin
2023-01-31 16:55 ` [PATCH 6/8] powerpc: differentiate kthread from user kernel thread start Nicholas Piggin
2023-01-31 16:55 ` Nicholas Piggin [this message]
2023-01-31 16:55 ` [PATCH 8/8] powerpc: copy_thread don't set ppr in user interrupt frame regs Nicholas Piggin
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