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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>
This commit is contained in:
Eric W. Biederman 2022-04-12 10:18:48 -05:00
parent 36cb0e1cda
commit 5bd2e97c86
28 changed files with 95 additions and 116 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/alpha/kernel/process.c
View File

@ -237,7 +237,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
extern void ret_from_fork(void);
extern void ret_from_kernel_thread(void);
@ -251,13 +250,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
childti->pcb.ksp = (unsigned long) childstack;
childti->pcb.flags = 1; /* set FEN, clear everything else */
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
memset(childstack, 0,
sizeof(struct switch_stack) + sizeof(struct pt_regs));
childstack->r26 = (unsigned long) ret_from_kernel_thread;
childstack->r9 = usp; /* function */
childstack->r10 = kthread_arg;
childstack->r9 = (unsigned long) args->fn;
childstack->r10 = (unsigned long) args->fn_arg;
childregs->hae = alpha_mv.hae_cache;
childti->pcb.usp = 0;
return 0;

7
arch/arc/kernel/process.c
View File

@ -166,7 +166,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
struct pt_regs *c_regs; /* child's pt_regs */
unsigned long *childksp; /* to unwind out of __switch_to() */
@ -193,11 +192,11 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
childksp[0] = 0; /* fp */
childksp[1] = (unsigned long)ret_from_fork; /* blink */
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(c_regs, 0, sizeof(struct pt_regs));
c_callee->r13 = kthread_arg;
c_callee->r14 = usp; /* function */
c_callee->r13 = (unsigned long)args->fn_arg;
c_callee->r14 = (unsigned long)args->fn;
return 0;
}

7
arch/arm/kernel/process.c
View File

@ -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;

7
arch/arm64/kernel/process.c
View File

@ -320,7 +320,6 @@ 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 pt_regs *childregs = task_pt_regs(p);
@ -337,7 +336,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
ptrauth_thread_init_kernel(p);
if (likely(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) {
if (likely(!args->fn)) {
*childregs = *current_pt_regs();
childregs->regs[0] = 0;
@ -371,8 +370,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
memset(childregs, 0, sizeof(struct pt_regs));
childregs->pstate = PSR_MODE_EL1h | PSR_IL_BIT;
p->thread.cpu_context.x19 = stack_start;
p->thread.cpu_context.x20 = stk_sz;
p->thread.cpu_context.x19 = (unsigned long)args->fn;
p->thread.cpu_context.x20 = (unsigned long)args->fn_arg;
}
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
p->thread.cpu_context.sp = (unsigned long)childregs;

7
arch/csky/kernel/process.c
View File

@ -34,7 +34,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
struct switch_stack *childstack;
struct pt_regs *childregs = task_pt_regs(p);
@ -49,11 +48,11 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
/* setup thread.sp for switch_to !!! */
p->thread.sp = (unsigned long)childstack;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(childregs, 0, sizeof(struct pt_regs));
childstack->r15 = (unsigned long) ret_from_kernel_thread;
childstack->r10 = kthread_arg;
childstack->r9 = usp;
childstack->r10 = (unsigned long) args->fn_arg;
childstack->r9 = (unsigned long) args->fn;
childregs->sr = mfcr("psr");
} else {
*childregs = *(current_pt_regs());

7
arch/h8300/kernel/process.c
View File

@ -108,16 +108,15 @@ void flush_thread(void)
int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long usp = args->stack;
unsigned long topstk = args->stack_size;
struct pt_regs *childregs;
childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(childregs, 0, sizeof(struct pt_regs));
childregs->retpc = (unsigned long) ret_from_kernel_thread;
childregs->er4 = topstk; /* arg */
childregs->er5 = usp; /* fn */
childregs->er4 = (unsigned long) args->fn_arg;
childregs->er5 = (unsigned long) args->fn;
} else {
*childregs = *current_pt_regs();
childregs->er0 = 0;

7
arch/hexagon/kernel/process.c
View File

@ -54,7 +54,6 @@ 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 hexagon_switch_stack *ss;
@ -76,11 +75,11 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
sizeof(*ss));
ss->lr = (unsigned long)ret_from_fork;
p->thread.switch_sp = ss;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(childregs, 0, sizeof(struct pt_regs));
/* r24 <- fn, r25 <- arg */
ss->r24 = usp;
ss->r25 = arg;
ss->r24 = (unsigned long)args->fn;
ss->r25 = (unsigned long)args->fn_arg;
pt_set_kmode(childregs);
return 0;
}

6
arch/ia64/kernel/process.c
View File

@ -341,14 +341,14 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
ia64_drop_fpu(p); /* don't pick up stale state from a CPU's fph */
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
if (unlikely(args->idle)) {
/* fork_idle() called us */
return 0;
}
memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
child_stack->r4 = user_stack_base; /* payload */
child_stack->r5 = user_stack_size; /* argument */
child_stack->r4 = (unsigned long) args->fn;
child_stack->r5 = (unsigned long) args->fn_arg;
/*
* Preserve PSR bits, except for bits 32-34 and 37-45,
* which we can't read.

7
arch/m68k/kernel/process.c
View File

@ -142,7 +142,6 @@ 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 fork_frame {
struct switch_stack sw;
@ -160,12 +159,12 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
*/
p->thread.fc = USER_DATA;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
memset(frame, 0, sizeof(struct fork_frame));
frame->regs.sr = PS_S;
frame->sw.a3 = usp; /* function */
frame->sw.d7 = arg;
frame->sw.a3 = (unsigned long)args->fn;
frame->sw.d7 = (unsigned long)args->fn_arg;
frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
p->thread.usp = 0;
return 0;

7
arch/microblaze/kernel/process.c
View File

@ -56,19 +56,18 @@ 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 pt_regs *childregs = task_pt_regs(p);
struct thread_info *ti = task_thread_info(p);
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* if we're creating a new kernel thread then just zeroing all
* the registers. That's OK for a brand new thread.*/
memset(childregs, 0, sizeof(struct pt_regs));
memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
ti->cpu_context.r1 = (unsigned long)childregs;
ti->cpu_context.r20 = (unsigned long)usp; /* fn */
ti->cpu_context.r19 = (unsigned long)arg;
ti->cpu_context.r20 = (unsigned long)args->fn;
ti->cpu_context.r19 = (unsigned long)args->fn_arg;
childregs->pt_mode = 1;
local_save_flags(childregs->msr);
ti->cpu_context.msr = childregs->msr & ~MSR_IE;

7
arch/mips/kernel/process.c
View File

@ -109,7 +109,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs, *regs = current_pt_regs();
@ -122,12 +121,12 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
/* Put the stack after the struct pt_regs. */
childksp = (unsigned long) childregs;
p->thread.cp0_status = (read_c0_status() & ~(ST0_CU2|ST0_CU1)) | ST0_KERNEL_CUMASK;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
unsigned long status = p->thread.cp0_status;
memset(childregs, 0, sizeof(struct pt_regs));
p->thread.reg16 = usp; /* fn */
p->thread.reg17 = kthread_arg;
p->thread.reg16 = (unsigned long)args->fn;
p->thread.reg17 = (unsigned long)args->fn_arg;
p->thread.reg29 = childksp;
p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
#if defined(CONFIG_CPU_R3000)

7
arch/nios2/kernel/process.c
View File

@ -104,7 +104,6 @@ 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 pt_regs *childregs = task_pt_regs(p);
struct pt_regs *regs;
@ -112,12 +111,12 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
struct switch_stack *childstack =
((struct switch_stack *)childregs) - 1;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(childstack, 0,
sizeof(struct switch_stack) + sizeof(struct pt_regs));
childstack->r16 = usp; /* fn */
childstack->r17 = arg;
childstack->r16 = (unsigned long) args->fn;
childstack->r17 = (unsigned long) args->fn_arg;
childstack->ra = (unsigned long) ret_from_kernel_thread;
childregs->estatus = STATUS_PIE;
childregs->sp = (unsigned long) childstack;

7
arch/openrisc/kernel/process.c
View File

@ -156,7 +156,6 @@ 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 pt_regs *userregs;
struct pt_regs *kregs;
@ -175,10 +174,10 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *)sp;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(kregs, 0, sizeof(struct pt_regs));
kregs->gpr[20] = usp; /* fn, kernel thread */
kregs->gpr[22] = arg;
kregs->gpr[20] = (unsigned long)args->fn;
kregs->gpr[22] = (unsigned long)args->fn_arg;
} else {
*userregs = *current_pt_regs();

11
arch/parisc/kernel/process.c
View File

@ -210,7 +210,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
struct pt_regs *cregs = &(p->thread.regs);
void *stack = task_stack_page(p);
@ -221,7 +220,7 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
extern void * const ret_from_kernel_thread;
extern void * const child_return;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
memset(cregs, 0, sizeof(struct pt_regs));
if (args->idle) /* idle thread */
@ -236,12 +235,12 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
* ret_from_kernel_thread.
*/
#ifdef CONFIG_64BIT
cregs->gr[27] = ((unsigned long *)usp)[3];
cregs->gr[26] = ((unsigned long *)usp)[2];
cregs->gr[27] = ((unsigned long *)args->fn)[3];
cregs->gr[26] = ((unsigned long *)args->fn)[2];
#else
cregs->gr[26] = usp;
cregs->gr[26] = (unsigned long) args->fn;
#endif
cregs->gr[25] = kthread_arg;
cregs->gr[25] = (unsigned long) args->fn_arg;
} else {
/* user thread */
/* usp must be word aligned. This also prevents users from

9
arch/powerpc/kernel/process.c
View File

@ -1720,7 +1720,6 @@ 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 kthread_arg = args->stack_size;
unsigned long tls = args->tls;
struct pt_regs *childregs, *kregs;
extern void ret_from_fork(void);
@ -1738,18 +1737,18 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
if (usp)
childregs->gpr[14] = ppc_function_entry((void *)usp);
if (args->fn)
childregs->gpr[14] = ppc_function_entry((void *)args->fn);
#ifdef CONFIG_PPC64
clear_tsk_thread_flag(p, TIF_32BIT);
childregs->softe = IRQS_ENABLED;
#endif
childregs->gpr[15] = kthread_arg;
childregs->gpr[15] = (unsigned long)args->fn_arg;
p->thread.regs = NULL; /* no user register state */
ti->flags |= _TIF_RESTOREALL;
f = ret_from_kernel_thread;

7
arch/riscv/kernel/process.c
View File

@ -124,12 +124,11 @@ 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 pt_regs *childregs = task_pt_regs(p);
/* p->thread holds context to be restored by __switch_to() */
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* Kernel thread */
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gp = gp_in_global;
@ -137,8 +136,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
childregs->status = SR_PP | SR_PIE;
p->thread.ra = (unsigned long)ret_from_kernel_thread;
p->thread.s[0] = usp; /* fn */
p->thread.s[1] = arg;
p->thread.s[0] = (unsigned long)args->fn;
p->thread.s[1] = (unsigned long)args->fn_arg;
} else {
*childregs = *(current_pt_regs());
if (usp) /* User fork */

7
arch/s390/kernel/process.c
View File

@ -98,7 +98,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long new_stackp = args->stack;
unsigned long arg = args->stack_size;
unsigned long tls = args->tls;
struct fake_frame
{
@ -133,15 +132,15 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
frame->sf.gprs[9] = (unsigned long)frame;
/* Store access registers to kernel stack of new process. */
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
/* kernel thread */
memset(&frame->childregs, 0, sizeof(struct pt_regs));
frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
frame->childregs.psw.addr =
(unsigned long)__ret_from_fork;
frame->childregs.gprs[9] = new_stackp; /* function */
frame->childregs.gprs[10] = arg;
frame->childregs.gprs[9] = (unsigned long)args->fn;
frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
frame->childregs.orig_gpr2 = -1;
frame->childregs.last_break = 1;
return 0;

7
arch/sh/kernel/process_32.c
View File

@ -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;

7
arch/sparc/kernel/process_32.c
View File

@ -263,7 +263,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long sp = 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, *regs = current_pt_regs();
@ -299,13 +298,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
ti->ksp = (unsigned long) new_stack;
p->thread.kregs = childregs;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
extern int nwindows;
unsigned long psr;
memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
childregs->u_regs[UREG_G1] = sp; /* function */
childregs->u_regs[UREG_G2] = arg;
childregs->u_regs[UREG_G1] = (unsigned long) args->fn;
childregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
psr = childregs->psr = get_psr();
ti->kpsr = psr | PSR_PIL;
ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);

7
arch/sparc/kernel/process_64.c
View File

@ -568,7 +568,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long arg = args->stack_size;
unsigned long tls = args->tls;
struct thread_info *t = task_thread_info(p);
struct pt_regs *regs = current_pt_regs();
@ -587,12 +586,12 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
sizeof(struct sparc_stackf));
t->fpsaved[0] = 0;
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (unlikely(args->fn)) {
memset(child_trap_frame, 0, child_stack_sz);
__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
(current_pt_regs()->tstate + 1) & TSTATE_CWP;
t->kregs->u_regs[UREG_G1] = sp; /* function */
t->kregs->u_regs[UREG_G2] = arg;
t->kregs->u_regs[UREG_G1] = (unsigned long) args->fn;
t->kregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
return 0;
}

10
arch/um/kernel/process.c
View File

@ -158,15 +158,13 @@ int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long arg = args->stack_size;
unsigned long tls = args->tls;
void (*handler)(void);
int kthread = current->flags & (PF_KTHREAD | PF_IO_WORKER);
int ret = 0;
p->thread = (struct thread_struct) INIT_THREAD;
if (!kthread) {
if (!args->fn) {
memcpy(&p->thread.regs.regs, current_pt_regs(),
sizeof(p->thread.regs.regs));
PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
@ -178,14 +176,14 @@ int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
arch_copy_thread(&current->thread.arch, &p->thread.arch);
} else {
get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
p->thread.request.u.thread.proc = (int (*)(void *))sp;
p->thread.request.u.thread.arg = (void *)arg;
p->thread.request.u.thread.proc = args->fn;
p->thread.request.u.thread.arg = args->fn_arg;
handler = new_thread_handler;
}
new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
if (!kthread) {
if (!args->fn) {
clear_flushed_tls(p);
/*

2
arch/x86/include/asm/fpu/sched.h
View File

@ -11,7 +11,7 @@
extern void save_fpregs_to_fpstate(struct fpu *fpu);
extern void fpu__drop(struct fpu *fpu);
extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags);
extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal);
extern void fpu_flush_thread(void);
/*

8
arch/x86/include/asm/switch_to.h
View File

@ -78,13 +78,13 @@ static inline void update_task_stack(struct task_struct *task)
}
static inline void kthread_frame_init(struct inactive_task_frame *frame,
unsigned long fun, unsigned long arg)
int (*fun)(void *), void *arg)
{
frame->bx = fun;
frame->bx = (unsigned long)fun;
#ifdef CONFIG_X86_32
frame->di = arg;
frame->di = (unsigned long)arg;
#else
frame->r12 = arg;
frame->r12 = (unsigned long)arg;
#endif
}

4
arch/x86/kernel/fpu/core.c
View File

@ -556,7 +556,7 @@ static inline void fpu_inherit_perms(struct fpu *dst_fpu)
}
/* Clone current's FPU state on fork */
int fpu_clone(struct task_struct *dst, unsigned long clone_flags)
int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal)
{
struct fpu *src_fpu = &current->thread.fpu;
struct fpu *dst_fpu = &dst->thread.fpu;
@ -579,7 +579,7 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags)
* No FPU state inheritance for kernel threads and IO
* worker threads.
*/
if (dst->flags & (PF_KTHREAD | PF_IO_WORKER)) {
if (minimal) {
/* Clear out the minimal state */
memcpy(&dst_fpu->fpstate->regs, &init_fpstate.regs,
init_fpstate_copy_size());

13
arch/x86/kernel/process.c
View File

@ -134,7 +134,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long arg = args->stack_size;
unsigned long tls = args->tls;
struct inactive_task_frame *frame;
struct fork_frame *fork_frame;
@ -172,13 +171,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
frame->flags = X86_EFLAGS_FIXED;
#endif
fpu_clone(p, clone_flags);
fpu_clone(p, clone_flags, args->fn);
/* Kernel thread ? */
if (unlikely(p->flags & PF_KTHREAD)) {
p->thread.pkru = pkru_get_init_value();
memset(childregs, 0, sizeof(struct pt_regs));
kthread_frame_init(frame, sp, arg);
kthread_frame_init(frame, args->fn, args->fn_arg);
return 0;
}
@ -198,10 +197,10 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
task_user_gs(p) = get_user_gs(current_pt_regs());
#endif
if (unlikely(p->flags & PF_IO_WORKER)) {
if (unlikely(args->fn)) {
/*
* An IO thread is a user space thread, but it doesn't
* return to ret_after_fork().
* A user space thread, but it doesn't return to
* ret_after_fork().
*
* In order to indicate that to tools like gdb,
* we reset the stack and instruction pointers.
@ -211,7 +210,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
*/
childregs->sp = 0;
childregs->ip = 0;
kthread_frame_init(frame, sp, arg);
kthread_frame_init(frame, args->fn, args->fn_arg);
return 0;
}

11
arch/xtensa/kernel/process.c
View File

@ -205,7 +205,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long usp_thread_fn = args->stack;
unsigned long thread_fn_arg = args->stack_size;
unsigned long tls = args->tls;
struct pt_regs *childregs = task_pt_regs(p);
@ -226,7 +225,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
#error Unsupported Xtensa ABI
#endif
if (!(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
if (!args->fn) {
struct pt_regs *regs = current_pt_regs();
unsigned long usp = usp_thread_fn ?
usp_thread_fn : regs->areg[1];
@ -278,15 +277,15 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
* Window underflow will load registers from the
* spill slots on the stack on return from _switch_to.
*/
SPILL_SLOT(childregs, 2) = usp_thread_fn;
SPILL_SLOT(childregs, 3) = thread_fn_arg;
SPILL_SLOT(childregs, 2) = (unsigned long)args->fn;
SPILL_SLOT(childregs, 3) = (unsigned long)args->fn_arg;
#elif defined(__XTENSA_CALL0_ABI__)
/*
* a12 = thread_fn, a13 = thread_fn arg.
* _switch_to epilogue will load registers from the stack.
*/
((unsigned long *)p->thread.sp)[0] = usp_thread_fn;
((unsigned long *)p->thread.sp)[1] = thread_fn_arg;
((unsigned long *)p->thread.sp)[0] = (unsigned long)args->fn;
((unsigned long *)p->thread.sp)[1] = (unsigned long)args->fn_arg;
#else
#error Unsupported Xtensa ABI
#endif

2
include/linux/sched/task.h
View File

@ -34,6 +34,8 @@ struct kernel_clone_args {
int io_thread;
int kthread;
int idle;
int (*fn)(void *);
void *fn_arg;
struct cgroup *cgrp;
struct css_set *cset;
};

16
kernel/fork.c
View File

@ -2555,8 +2555,8 @@ struct task_struct * __init fork_idle(int cpu)
struct task_struct *task;
struct kernel_clone_args args = {
.flags = CLONE_VM,
.stack = (unsigned long)&idle_dummy,
.stack_size = (unsigned long)NULL,
.fn = &idle_dummy,
.fn_arg = NULL,
.kthread = 1,
.idle = 1,
};
@ -2589,8 +2589,8 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.stack = (unsigned long)fn,
.stack_size = (unsigned long)arg,
.fn = fn,
.fn_arg = arg,
.io_thread = 1,
};
@ -2694,8 +2694,8 @@ pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.stack = (unsigned long)fn,
.stack_size = (unsigned long)arg,
.fn = fn,
.fn_arg = arg,
.kthread = 1,
};
@ -2711,8 +2711,8 @@ pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags)
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.stack = (unsigned long)fn,
.stack_size = (unsigned long)arg,
.fn = fn,
.fn_arg = arg,
};
return kernel_clone(&args);