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authorEric W. Biederman <ebiederm@xmission.com>2022-04-12 10:18:48 -0500
committerEric W. Biederman <ebiederm@xmission.com>2022-05-07 09:01:59 -0500
commit5bd2e97c868a8a44470950ed01846cab6328e540 (patch)
tree7919866d9e44b6c98bfe16f6ac436013ce9e75c0 /arch/sh
parent36cb0e1cda645ee645b85a6ce652cb46a16e14e5 (diff)
downloadlinux-5bd2e97c868a8a44470950ed01846cab6328e540.tar.gz
fork: Generalize PF_IO_WORKER handling
Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size".  These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/kernel/process_32.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 6023399b1892..a808843375e7 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -96,7 +96,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
 	unsigned long clone_flags = args->flags;
 	unsigned long usp = args->stack;
-	unsigned long arg = args->stack_size;
 	unsigned long tls = args->tls;
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs;
@@ -117,11 +116,11 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
 	childregs = task_pt_regs(p);
 	p->thread.sp = (unsigned long) childregs;
-	if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
+	if (unlikely(args->fn)) {
 		memset(childregs, 0, sizeof(struct pt_regs));
 		p->thread.pc = (unsigned long) ret_from_kernel_thread;
-		childregs->regs[4] = arg;
-		childregs->regs[5] = usp;
+		childregs->regs[4] = (unsigned long) args->fn_arg;
+		childregs->regs[5] = (unsigned long) args->fn;
 		childregs->sr = SR_MD;
 #if defined(CONFIG_SH_FPU)
 		childregs->sr |= SR_FD;