sh: switch to generic kernel_thread()/kernel_execve()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

10 files changed, 71 insertions, 174 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index babc2b826c5c..8451317eed58 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -40,6 +40,8 @@ config SUPERH
         select GENERIC_STRNLEN_USER
         select HAVE_MOD_ARCH_SPECIFIC if DWARF_UNWINDER
         select MODULES_USE_ELF_RELA
+        select GENERIC_KERNEL_THREAD
+        select GENERIC_KERNEL_EXECVE
         help
           The SuperH is a RISC processor targeted for use in embedded systems
           and consumer electronics; it was also used in the Sega Dreamcast
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index b6311fd2d066..b1320d55ca30 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -126,11 +126,6 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_pc, unsigned lo
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 /* Copy and release all segment info associated with a VM */
 #define copy_segments(p, mm)    do { } while(0)
 #define release_segments(mm)    do { } while(0)
diff --git a/arch/sh/include/asm/processor_64.h b/arch/sh/include/asm/processor_64.h
index cd6029fb2c01..1ee8946f0952 100644
--- a/arch/sh/include/asm/processor_64.h
+++ b/arch/sh/include/asm/processor_64.h
@@ -159,11 +159,6 @@ struct mm_struct;
 
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 
 /* Copy and release all segment info associated with a VM */
 #define copy_segments(p, mm)    do { } while (0)
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index 88571ff8eeec..f259b37874e9 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -16,7 +16,7 @@ obj-y	:= debugtraps.o dma-nommu.o dumpstack.o 		\
            machvec.o nmi_debug.o process.o                              \
            process_$(BITS).o ptrace.o ptrace_$(BITS).o                  \
            reboot.o return_address.o                                    \
-           setup.o signal_$(BITS).o sys_sh.o sys_sh$(BITS).o            \
+           setup.o signal_$(BITS).o sys_sh.o                            \
            syscalls_$(BITS).o time.o topology.o traps.o                 \
            traps_$(BITS).o unwinder.o
 
@@ -25,6 +25,7 @@ obj-y				+= iomap.o
 obj-$(CONFIG_HAS_IOPORT)        += ioport.o
 endif
 
+obj-$(CONFIG_SUPERH32)          += sys_sh32.o
 obj-y                           += cpu/
 obj-$(CONFIG_VSYSCALL)          += vsyscall/
 obj-$(CONFIG_SMP)               += smp.o
diff --git a/arch/sh/kernel/cpu/sh5/entry.S b/arch/sh/kernel/cpu/sh5/entry.S
index 7e605b95592a..0c8d0377d40b 100644
--- a/arch/sh/kernel/cpu/sh5/entry.S
+++ b/arch/sh/kernel/cpu/sh5/entry.S
@@ -1228,6 +1228,25 @@ ret_from_fork:
         pta     ret_from_syscall, tr0
         blink   tr0, ZERO
 
+.global ret_from_kernel_thread
+ret_from_kernel_thread:
+
+        movi    schedule_tail,r5
+        ori     r5, 1, r5
+        ptabs   r5, tr0
+        blink   tr0, LINK
+
+        ld.q    SP, FRAME_R(2), r2
+        ld.q    SP, FRAME_R(3), r3
+        ptabs   r3, tr0
+        blink   tr0, LINK
+
+        ld.q    SP, FRAME_S(FSPC), r2
+        addi    r2, 4, r2               /* Move PC, being pre-execution event */
+        st.q    SP, FRAME_S(FSPC), r2
+        pta     ret_from_syscall, tr0
+        blink   tr0, ZERO
+
 syscall_allowed:
         /* Use LINK to deflect the exit point, default is syscall_ret */
         pta     syscall_ret, tr0
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index b96489d8b27d..9b6e4beeb296 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -297,6 +297,19 @@ ret_from_fork:
          mov    r0, r4
         bra     syscall_exit
          nop
+
+        .align  2
+        .globl  ret_from_kernel_thread
+ret_from_kernel_thread:
+        mov.l   1f, r8
+        jsr     @r8
+         mov    r0, r4
+        mov.l   @(OFF_R5,r15), r5   ! fn
+        jsr     @r5
+         mov.l  @(OFF_R4,r15), r4   ! arg
+        bra     syscall_exit
+         nop
+
         .align  2
 1:      .long   schedule_tail
 
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index ba7345f37bc9..b55070b9a634 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -68,38 +68,6 @@ void show_regs(struct pt_regs * regs)
         show_code(regs);
 }
 
-/*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-        do_exit(fn(arg));
-}
-
-/* Don't use this in BL=1(cli).  Or else, CPU resets! */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-        struct pt_regs regs;
-        int pid;
-
-        memset(&regs, 0, sizeof(regs));
-        regs.regs[4] = (unsigned long)arg;
-        regs.regs[5] = (unsigned long)fn;
-
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.sr = SR_MD;
-#if defined(CONFIG_SH_FPU)
-        regs.sr |= SR_FD;
-#endif
-
-        /* Ok, create the new process.. */
-        pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-                      &regs, 0, NULL, NULL);
-
-        return pid;
-}
-EXPORT_SYMBOL(kernel_thread);
-
 void start_thread(struct pt_regs *regs, unsigned long new_pc,
                   unsigned long new_sp)
 {
@@ -157,9 +125,10 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 EXPORT_SYMBOL(dump_fpu);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-                unsigned long unused,
+                unsigned long arg,
                 struct task_struct *p, struct pt_regs *regs)
 {
         struct thread_info *ti = task_thread_info(p);
@@ -177,29 +146,34 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
         }
 #endif
 
-        childregs = task_pt_regs(p);
-        *childregs = *regs;
+        memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 
-        if (user_mode(regs)) {
-                childregs->regs[15] = usp;
-                ti->addr_limit = USER_DS;
-        } else {
-                childregs->regs[15] = (unsigned long)childregs;
+        childregs = task_pt_regs(p);
+        p->thread.sp = (unsigned long) childregs;
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                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->sr = SR_MD;
+#if defined(CONFIG_SH_FPU)
+                childregs->sr |= SR_FD;
+#endif
                 ti->addr_limit = KERNEL_DS;
                 ti->status &= ~TS_USEDFPU;
                 p->fpu_counter = 0;
+                return 0;
         }
+        *childregs = *regs;
+
+        childregs->regs[15] = usp;
+        ti->addr_limit = USER_DS;
 
         if (clone_flags & CLONE_SETTLS)
                 childregs->gbr = childregs->regs[0];
 
         childregs->regs[0] = 0; /* Set return value for child */
-
-        p->thread.sp = (unsigned long) childregs;
         p->thread.pc = (unsigned long) ret_from_fork;
-
-        memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
-
         return 0;
 }
 
diff --git a/arch/sh/kernel/process_64.c b/arch/sh/kernel/process_64.c
index 98a709f0c3c4..fd338b030fd9 100644
--- a/arch/sh/kernel/process_64.c
+++ b/arch/sh/kernel/process_64.c
@@ -285,39 +285,6 @@ void show_regs(struct pt_regs *regs)
 }
 
 /*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-        do_exit(fn(arg));
-}
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! 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 freed until both the parent and the child have exited.
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-        regs.regs[2] = (unsigned long)arg;
-        regs.regs[3] = (unsigned long)fn;
-
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.sr = (1 << 30);
-
-        /* Ok, create the new process.. */
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-                      &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
@@ -401,15 +368,17 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 EXPORT_SYMBOL(dump_fpu);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-                unsigned long unused,
+                unsigned long arg,
                 struct task_struct *p, struct pt_regs *regs)
 {
         struct pt_regs *childregs;
 
 #ifdef CONFIG_SH_FPU
-        if(last_task_used_math == current) {
+        /* can't happen for a kernel thread */
+        if (last_task_used_math == current) {
                 enable_fpu();
                 save_fpu(current);
                 disable_fpu();
@@ -419,7 +388,17 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 #endif
         /* Copy from sh version */
         childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
+        p->thread.sp = (unsigned long) childregs;
 
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                memset(childregs, 0, sizeof(struct pt_regs));
+                childregs->regs[2] = (unsigned long)arg;
+                childregs->regs[3] = (unsigned long)fn;
+                childregs->sr = (1 << 30); /* not user_mode */
+                childregs->sr |= SR_FD; /* Invalidate FPU flag */
+                p->thread.pc = (unsigned long) ret_from_kernel_thread;
+                return 0;
+        }
         *childregs = *regs;
 
         /*
@@ -428,19 +407,12 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
          * 32-bit wide and context switch must take care
          * of NEFF sign extension.
          */
-        if (user_mode(regs)) {
-                childregs->regs[15] = neff_sign_extend(usp);
-                p->thread.uregs = childregs;
-        } else {
-                childregs->regs[15] =
-                        neff_sign_extend((unsigned long)task_stack_page(p) +
-                                         THREAD_SIZE);
-        }
+        childregs->regs[15] = neff_sign_extend(usp);
+        p->thread.uregs = childregs;
 
         childregs->regs[9] = 0; /* Set return value for child */
         childregs->sr |= SR_FD; /* Invalidate FPU flag */
 
-        p->thread.sp = (unsigned long) childregs;
         p->thread.pc = (unsigned long) ret_from_fork;
 
         return 0;
diff --git a/arch/sh/kernel/sys_sh32.c b/arch/sh/kernel/sys_sh32.c
index f56b6fe5c5d0..497bab3a0401 100644
--- a/arch/sh/kernel/sys_sh32.c
+++ b/arch/sh/kernel/sys_sh32.c
@@ -60,27 +60,3 @@ asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,
                                 (u64)len0 << 32 | len1, advice);
 #endif
 }
-
-#if defined(CONFIG_CPU_SH2) || defined(CONFIG_CPU_SH2A)
-#define SYSCALL_ARG3    "trapa #0x23"
-#else
-#define SYSCALL_ARG3    "trapa #0x13"
-#endif
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-                  const char *const argv[],
-                  const char *const envp[])
-{
-        register long __sc0 __asm__ ("r3") = __NR_execve;
-        register long __sc4 __asm__ ("r4") = (long) filename;
-        register long __sc5 __asm__ ("r5") = (long) argv;
-        register long __sc6 __asm__ ("r6") = (long) envp;
-        __asm__ __volatile__ (SYSCALL_ARG3 : "=z" (__sc0)
-                        : "0" (__sc0), "r" (__sc4), "r" (__sc5), "r" (__sc6)
-                        : "memory");
-        return __sc0;
-}
diff --git a/arch/sh/kernel/sys_sh64.c b/arch/sh/kernel/sys_sh64.c
deleted file mode 100644
index c5a38c4bf410..000000000000
--- a/arch/sh/kernel/sys_sh64.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * arch/sh/kernel/sys_sh64.c
- *
- * Copyright (C) 2000, 2001  Paolo Alberelli
- *
- * This file contains various random system calls that
- * have a non-standard calling sequence on the Linux/SH5
- * platform.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-#include <linux/errno.h>
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/smp.h>
-#include <linux/sem.h>
-#include <linux/msg.h>
-#include <linux/shm.h>
-#include <linux/stat.h>
-#include <linux/mman.h>
-#include <linux/file.h>
-#include <linux/syscalls.h>
-#include <linux/ipc.h>
-#include <asm/uaccess.h>
-#include <asm/ptrace.h>
-#include <asm/unistd.h>
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-                  const char *const argv[],
-                  const char *const envp[])
-{
-        register unsigned long __sc0 __asm__ ("r9") = ((0x13 << 16) | __NR_execve);
-        register unsigned long __sc2 __asm__ ("r2") = (unsigned long) filename;
-        register unsigned long __sc3 __asm__ ("r3") = (unsigned long) argv;
-        register unsigned long __sc4 __asm__ ("r4") = (unsigned long) envp;
-        __asm__ __volatile__ ("trapa    %1 !\t\t\t execve(%2,%3,%4)"
-        : "=r" (__sc0)
-        : "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) );
-        __asm__ __volatile__ ("!dummy   %0 %1 %2 %3"
-        : : "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) : "memory");
-        return __sc0;
-}