From c5febea0956fd3874e8fb59c6f84d68f128d68f8 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 8 Apr 2022 18:07:50 -0500 Subject: fork: Pass struct kernel_clone_args into copy_thread With io_uring we have started supporting tasks that are for most purposes user space tasks that exclusively run code in kernel mode. The kernel task that exec's init and tasks that exec user mode helpers are also user mode tasks that just run kernel code until they call kernel execve. Pass kernel_clone_args into copy_thread so these oddball tasks can be supported more cleanly and easily. v2: Fix spelling of kenrel_clone_args on h8300 Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" --- arch/arm/kernel/process.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 0617af11377f..8e13b426dd26 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -238,9 +238,12 @@ void release_thread(struct task_struct *dead_task) asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); -int copy_thread(unsigned long clone_flags, unsigned long stack_start, - unsigned long stk_sz, struct task_struct *p, unsigned long tls) +int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) { + unsigned long clone_flags = args->flags; + unsigned long stack_start = args->stack; + unsigned long stk_sz = args->stack_size; + unsigned long tls = args->tls; struct thread_info *thread = task_thread_info(p); struct pt_regs *childregs = task_pt_regs(p); -- cgit From 5bd2e97c868a8a44470950ed01846cab6328e540 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 12 Apr 2022 10:18:48 -0500 Subject: 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" --- arch/arm/kernel/process.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 8e13b426dd26..3d9cace63884 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -242,7 +242,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) { unsigned long clone_flags = args->flags; unsigned long stack_start = args->stack; - unsigned long stk_sz = args->stack_size; unsigned long tls = args->tls; struct thread_info *thread = task_thread_info(p); struct pt_regs *childregs = task_pt_regs(p); @@ -259,15 +258,15 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) thread->cpu_domain = get_domain(); #endif - if (likely(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) { + if (likely(!args->fn)) { *childregs = *current_pt_regs(); childregs->ARM_r0 = 0; if (stack_start) childregs->ARM_sp = stack_start; } else { memset(childregs, 0, sizeof(struct pt_regs)); - thread->cpu_context.r4 = stk_sz; - thread->cpu_context.r5 = stack_start; + thread->cpu_context.r4 = (unsigned long)args->fn_arg; + thread->cpu_context.r5 = (unsigned long)args->fn; childregs->ARM_cpsr = SVC_MODE; } thread->cpu_context.pc = (unsigned long)ret_from_fork; -- cgit