linux/arch/s390/kernel/process.c
Linus Torvalds 42859eea96 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull generic execve() changes from Al Viro:
 "This introduces the generic kernel_thread() and kernel_execve()
  functions, and switches x86, arm, alpha, um and s390 over to them."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
  s390: convert to generic kernel_execve()
  s390: switch to generic kernel_thread()
  s390: fold kernel_thread_helper() into ret_from_fork()
  s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
  um: switch to generic kernel_thread()
  x86, um/x86: switch to generic sys_execve and kernel_execve
  x86: split ret_from_fork
  alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  alpha: switch to generic kernel_thread()
  alpha: switch to generic sys_execve()
  arm: get rid of execve wrapper, switch to generic execve() implementation
  arm: optimized current_pt_regs()
  arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
  generic sys_execve()
  generic kernel_execve()
  new helper: current_pt_regs()
  preparation for generic kernel_thread()
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  ...
2012-10-10 12:02:25 +09:00

322 lines
8.4 KiB
C

/*
* This file handles the architecture dependent parts of process handling.
*
* Copyright IBM Corp. 1999, 2009
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
* Hartmut Penner <hp@de.ibm.com>,
* Denis Joseph Barrow,
*/
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/elfcore.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/tick.h>
#include <linux/personality.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/kprobes.h>
#include <linux/random.h>
#include <linux/module.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/vtimer.h>
#include <asm/exec.h>
#include <asm/irq.h>
#include <asm/nmi.h>
#include <asm/smp.h>
#include <asm/switch_to.h>
#include <asm/runtime_instr.h>
#include "entry.h"
asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
/*
* Return saved PC of a blocked thread. used in kernel/sched.
* resume in entry.S does not create a new stack frame, it
* just stores the registers %r6-%r15 to the frame given by
* schedule. We want to return the address of the caller of
* schedule, so we have to walk the backchain one time to
* find the frame schedule() store its return address.
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
struct stack_frame *sf, *low, *high;
if (!tsk || !task_stack_page(tsk))
return 0;
low = task_stack_page(tsk);
high = (struct stack_frame *) task_pt_regs(tsk);
sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
return sf->gprs[8];
}
/*
* The idle loop on a S390...
*/
static void default_idle(void)
{
if (cpu_is_offline(smp_processor_id()))
cpu_die();
local_irq_disable();
if (need_resched()) {
local_irq_enable();
return;
}
local_mcck_disable();
if (test_thread_flag(TIF_MCCK_PENDING)) {
local_mcck_enable();
local_irq_enable();
return;
}
/* Halt the cpu and keep track of cpu time accounting. */
vtime_stop_cpu();
}
void cpu_idle(void)
{
for (;;) {
tick_nohz_idle_enter();
rcu_idle_enter();
while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))
default_idle();
rcu_idle_exit();
tick_nohz_idle_exit();
if (test_thread_flag(TIF_MCCK_PENDING))
s390_handle_mcck();
schedule_preempt_disabled();
}
}
extern void __kprobes kernel_thread_starter(void);
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
exit_thread_runtime_instr();
}
void flush_thread(void)
{
}
void release_thread(struct task_struct *dead_task)
{
}
int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
unsigned long arg,
struct task_struct *p, struct pt_regs *regs)
{
struct thread_info *ti;
struct fake_frame
{
struct stack_frame sf;
struct pt_regs childregs;
} *frame;
frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
p->thread.ksp = (unsigned long) frame;
/* Save access registers to new thread structure. */
save_access_regs(&p->thread.acrs[0]);
/* start new process with ar4 pointing to the correct address space */
p->thread.mm_segment = get_fs();
/* Don't copy debug registers */
memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
clear_tsk_thread_flag(p, TIF_PER_TRAP);
/* Initialize per thread user and system timer values */
ti = task_thread_info(p);
ti->user_timer = 0;
ti->system_timer = 0;
frame->sf.back_chain = 0;
/* new return point is ret_from_fork */
frame->sf.gprs[8] = (unsigned long) ret_from_fork;
/* fake return stack for resume(), don't go back to schedule */
frame->sf.gprs[9] = (unsigned long) frame;
/* Store access registers to kernel stack of new process. */
if (unlikely(!regs)) {
/* 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 = PSW_ADDR_AMODE |
(unsigned long) kernel_thread_starter;
frame->childregs.gprs[9] = new_stackp; /* function */
frame->childregs.gprs[10] = arg;
frame->childregs.gprs[11] = (unsigned long) do_exit;
frame->childregs.orig_gpr2 = -1;
return 0;
}
frame->childregs = *regs;
frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
frame->childregs.gprs[15] = new_stackp;
/* Don't copy runtime instrumentation info */
p->thread.ri_cb = NULL;
p->thread.ri_signum = 0;
frame->childregs.psw.mask &= ~PSW_MASK_RI;
#ifndef CONFIG_64BIT
/*
* save fprs to current->thread.fp_regs to merge them with
* the emulated registers and then copy the result to the child.
*/
save_fp_regs(&current->thread.fp_regs);
memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
sizeof(s390_fp_regs));
/* Set a new TLS ? */
if (clone_flags & CLONE_SETTLS)
p->thread.acrs[0] = regs->gprs[6];
#else /* CONFIG_64BIT */
/* Save the fpu registers to new thread structure. */
save_fp_regs(&p->thread.fp_regs);
/* Set a new TLS ? */
if (clone_flags & CLONE_SETTLS) {
if (is_compat_task()) {
p->thread.acrs[0] = (unsigned int) regs->gprs[6];
} else {
p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
p->thread.acrs[1] = (unsigned int) regs->gprs[6];
}
}
#endif /* CONFIG_64BIT */
return 0;
}
SYSCALL_DEFINE0(fork)
{
struct pt_regs *regs = task_pt_regs(current);
return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
}
SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,
int __user *, parent_tidptr, int __user *, child_tidptr)
{
struct pt_regs *regs = task_pt_regs(current);
if (!newsp)
newsp = regs->gprs[15];
return do_fork(clone_flags, newsp, regs, 0,
parent_tidptr, child_tidptr);
}
/*
* This is trivial, and on the face of it looks like it
* could equally well be done in user mode.
*
* Not so, for quite unobvious reasons - register pressure.
* In user mode vfork() cannot have a stack frame, and if
* done by calling the "clone()" system call directly, you
* do not have enough call-clobbered registers to hold all
* the information you need.
*/
SYSCALL_DEFINE0(vfork)
{
struct pt_regs *regs = task_pt_regs(current);
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
regs->gprs[15], regs, 0, NULL, NULL);
}
asmlinkage void execve_tail(void)
{
current->thread.fp_regs.fpc = 0;
if (MACHINE_HAS_IEEE)
asm volatile("sfpc %0,%0" : : "d" (0));
}
/*
* fill in the FPU structure for a core dump.
*/
int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
{
#ifndef CONFIG_64BIT
/*
* save fprs to current->thread.fp_regs to merge them with
* the emulated registers and then copy the result to the dump.
*/
save_fp_regs(&current->thread.fp_regs);
memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
#else /* CONFIG_64BIT */
save_fp_regs(fpregs);
#endif /* CONFIG_64BIT */
return 1;
}
EXPORT_SYMBOL(dump_fpu);
unsigned long get_wchan(struct task_struct *p)
{
struct stack_frame *sf, *low, *high;
unsigned long return_address;
int count;
if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
return 0;
low = task_stack_page(p);
high = (struct stack_frame *) task_pt_regs(p);
sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
for (count = 0; count < 16; count++) {
sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
return_address = sf->gprs[8] & PSW_ADDR_INSN;
if (!in_sched_functions(return_address))
return return_address;
}
return 0;
}
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
sp -= get_random_int() & ~PAGE_MASK;
return sp & ~0xf;
}
static inline unsigned long brk_rnd(void)
{
/* 8MB for 32bit, 1GB for 64bit */
if (is_32bit_task())
return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
else
return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
if (ret < mm->brk)
return mm->brk;
return ret;
}
unsigned long randomize_et_dyn(unsigned long base)
{
unsigned long ret = PAGE_ALIGN(base + brk_rnd());
if (!(current->flags & PF_RANDOMIZE))
return base;
if (ret < base)
return base;
return ret;
}