ia64: switch to generic kernel_thread()/kernel_execve()
Acked-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 3279646..6706004 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -42,6 +42,8 @@
select GENERIC_TIME_VSYSCALL_OLD
select HAVE_MOD_ARCH_SPECIFIC
select MODULES_USE_ELF_RELA
+ select GENERIC_KERNEL_THREAD
+ select GENERIC_KERNEL_EXECVE
default y
help
The Itanium Processor Family is Intel's 64-bit successor to
diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
index 944152a..e0a899a 100644
--- a/arch/ia64/include/asm/processor.h
+++ b/arch/ia64/include/asm/processor.h
@@ -340,22 +340,6 @@
*/
#define release_thread(dead_task)
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE 1: Only a kernel-only process (ie the swapper or direct
- * descendants who haven't done an "execve()") should use this: it
- * will work within a system call from a "real" process, but the
- * process memory space will not be free'd until both the parent and
- * the child have exited.
- *
- * NOTE 2: This MUST NOT be an inlined function. Otherwise, we get
- * into trouble in init/main.c when the child thread returns to
- * do_basic_setup() and the timing is such that free_initmem() has
- * been called already.
- */
-extern pid_t kernel_thread (int (*fn)(void *), void *arg, unsigned long flags);
-
/* Get wait channel for task P. */
extern unsigned long get_wchan (struct task_struct *p);
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 6b0648d..0dea684 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -484,13 +484,6 @@
br.ret.sptk.many rp
END(prefetch_stack)
-GLOBAL_ENTRY(kernel_execve)
- rum psr.ac
- mov r15=__NR_execve // put syscall number in place
- break __BREAK_SYSCALL
- br.ret.sptk.many rp
-END(kernel_execve)
-
/*
* Invoke a system call, but do some tracing before and after the call.
* We MUST preserve the current register frame throughout this routine
@@ -594,6 +587,27 @@
.ret4: br.cond.sptk ia64_leave_kernel
END(ia64_strace_leave_kernel)
+ENTRY(call_payload)
+ .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(0)
+ /* call the kernel_thread payload; fn is in r4, arg - in r5 */
+ alloc loc1=ar.pfs,0,3,1,0
+ mov loc0=rp
+ mov loc2=gp
+ mov out0=r5 // arg
+ ld8 r14 = [r4], 8 // fn.address
+ ;;
+ mov b6 = r14
+ ld8 gp = [r4] // fn.gp
+ ;;
+ br.call.sptk.many rp=b6 // fn(arg)
+.ret12: mov gp=loc2
+ mov rp=loc0
+ mov ar.pfs=loc1
+ /* ... and if it has returned, we are going to userland */
+ cmp.ne pKStk,pUStk=r0,r0
+ br.ret.sptk.many rp
+END(call_payload)
+
GLOBAL_ENTRY(ia64_ret_from_clone)
PT_REGS_UNWIND_INFO(0)
{ /*
@@ -610,6 +624,7 @@
br.call.sptk.many rp=ia64_invoke_schedule_tail
}
.ret8:
+(pKStk) br.call.sptk.many rp=call_payload
adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
;;
ld4 r2=[r2]
diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index 629a250..4738ff7 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -1093,19 +1093,6 @@
END(cycle_to_cputime)
#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
-GLOBAL_ENTRY(start_kernel_thread)
- .prologue
- .save rp, r0 // this is the end of the call-chain
- .body
- alloc r2 = ar.pfs, 0, 0, 2, 0
- mov out0 = r9
- mov out1 = r11;;
- br.call.sptk.many rp = kernel_thread_helper;;
- mov out0 = r8
- br.call.sptk.many rp = sys_exit;;
-1: br.sptk.few 1b // not reached
-END(start_kernel_thread)
-
#ifdef CONFIG_IA64_BRL_EMU
/*
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 6a48775..37686db 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -401,55 +401,15 @@
struct pt_regs *child_ptregs;
int retval = 0;
- stack = ((struct switch_stack *) regs) - 1;
-
child_ptregs = (struct pt_regs *) ((unsigned long) p + IA64_STK_OFFSET) - 1;
child_stack = (struct switch_stack *) child_ptregs - 1;
- /* copy parent's switch_stack & pt_regs to child: */
- memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
-
rbs = (unsigned long) current + IA64_RBS_OFFSET;
child_rbs = (unsigned long) p + IA64_RBS_OFFSET;
- if (likely(user_mode(child_ptregs))) {
- /* copy the parent's register backing store to the child: */
- rbs_size = stack->ar_bspstore - rbs;
- memcpy((void *) child_rbs, (void *) rbs, rbs_size);
- if (clone_flags & CLONE_SETTLS)
- child_ptregs->r13 = regs->r16; /* see sys_clone2() in entry.S */
- if (user_stack_base) {
- child_ptregs->r12 = user_stack_base + user_stack_size - 16;
- child_ptregs->ar_bspstore = user_stack_base;
- child_ptregs->ar_rnat = 0;
- child_ptregs->loadrs = 0;
- }
- } else {
- /*
- * Note: we simply preserve the relative position of
- * the stack pointer here. There is no need to
- * allocate a scratch area here, since that will have
- * been taken care of by the caller of sys_clone()
- * already.
- */
- rbs_size = 0;
- child_ptregs->r12 = (unsigned long) child_ptregs - 16; /* kernel sp */
- child_ptregs->r13 = (unsigned long) p; /* set `current' pointer */
- }
- child_stack->ar_bspstore = child_rbs + rbs_size;
- child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
-
/* copy parts of thread_struct: */
p->thread.ksp = (unsigned long) child_stack - 16;
- /* stop some PSR bits from being inherited.
- * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
- * therefore we must specify them explicitly here and not include them in
- * IA64_PSR_BITS_TO_CLEAR.
- */
- child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
- & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
-
/*
* NOTE: The calling convention considers all floating point
* registers in the high partition (fph) to be scratch. Since
@@ -471,8 +431,66 @@
# define THREAD_FLAGS_TO_SET 0
p->thread.flags = ((current->thread.flags & ~THREAD_FLAGS_TO_CLEAR)
| THREAD_FLAGS_TO_SET);
+
ia64_drop_fpu(p); /* don't pick up stale state from a CPU's fph */
+ if (unlikely(p->flags & PF_KTHREAD)) {
+ if (unlikely(!user_stack_base)) {
+ /* 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 */
+ /*
+ * Preserve PSR bits, except for bits 32-34 and 37-45,
+ * which we can't read.
+ */
+ child_ptregs->cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
+ /* mark as valid, empty frame */
+ child_ptregs->cr_ifs = 1UL << 63;
+ child_stack->ar_fpsr = child_ptregs->ar_fpsr
+ = ia64_getreg(_IA64_REG_AR_FPSR);
+ child_stack->pr = (1 << PRED_KERNEL_STACK);
+ child_stack->ar_bspstore = child_rbs;
+ child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+ /* stop some PSR bits from being inherited.
+ * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+ * therefore we must specify them explicitly here and not include them in
+ * IA64_PSR_BITS_TO_CLEAR.
+ */
+ child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+ & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
+
+ return 0;
+ }
+ stack = ((struct switch_stack *) regs) - 1;
+ /* copy parent's switch_stack & pt_regs to child: */
+ memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
+
+ /* copy the parent's register backing store to the child: */
+ rbs_size = stack->ar_bspstore - rbs;
+ memcpy((void *) child_rbs, (void *) rbs, rbs_size);
+ if (clone_flags & CLONE_SETTLS)
+ child_ptregs->r13 = regs->r16; /* see sys_clone2() in entry.S */
+ if (user_stack_base) {
+ child_ptregs->r12 = user_stack_base + user_stack_size - 16;
+ child_ptregs->ar_bspstore = user_stack_base;
+ child_ptregs->ar_rnat = 0;
+ child_ptregs->loadrs = 0;
+ }
+ child_stack->ar_bspstore = child_rbs + rbs_size;
+ child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+ /* stop some PSR bits from being inherited.
+ * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+ * therefore we must specify them explicitly here and not include them in
+ * IA64_PSR_BITS_TO_CLEAR.
+ */
+ child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+ & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
+
#ifdef CONFIG_PERFMON
if (current->thread.pfm_context)
pfm_inherit(p, child_ptregs);
@@ -618,37 +636,6 @@
return error;
}
-pid_t
-kernel_thread (int (*fn)(void *), void *arg, unsigned long flags)
-{
- extern void start_kernel_thread (void);
- unsigned long *helper_fptr = (unsigned long *) &start_kernel_thread;
- struct {
- struct switch_stack sw;
- struct pt_regs pt;
- } regs;
-
- memset(®s, 0, sizeof(regs));
- regs.pt.cr_iip = helper_fptr[0]; /* set entry point (IP) */
- regs.pt.r1 = helper_fptr[1]; /* set GP */
- regs.pt.r9 = (unsigned long) fn; /* 1st argument */
- regs.pt.r11 = (unsigned long) arg; /* 2nd argument */
- /* Preserve PSR bits, except for bits 32-34 and 37-45, which we can't read. */
- regs.pt.cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
- regs.pt.cr_ifs = 1UL << 63; /* mark as valid, empty frame */
- regs.sw.ar_fpsr = regs.pt.ar_fpsr = ia64_getreg(_IA64_REG_AR_FPSR);
- regs.sw.pr = (1 << PRED_KERNEL_STACK);
- return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s.pt, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/* This gets called from kernel_thread() via ia64_invoke_thread_helper(). */
-int
-kernel_thread_helper (int (*fn)(void *), void *arg)
-{
- return (*fn)(arg);
-}
-
/*
* Flush thread state. This is called when a thread does an execve().
*/