10 files changed, 231 insertions, 3 deletions

diff --git a/arch/um/include/sysdep-i386/stub.h b/arch/um/include/sysdep-i386/stub.h
index fed9ff1cea52..d3699fe1c613 100644
--- a/arch/um/include/sysdep-i386/stub.h
+++ b/arch/um/include/sysdep-i386/stub.h
@@ -10,9 +10,56 @@
 #include <asm/unistd.h>
 
 extern void stub_segv_handler(int sig);
+extern void stub_clone_handler(void);
 
 #define STUB_SYSCALL_RET EAX
 #define STUB_MMAP_NR __NR_mmap2
 #define MMAP_OFFSET(o) ((o) >> PAGE_SHIFT)
 
+static inline long stub_syscall2(long syscall, long arg1, long arg2)
+{
+        long ret;
+
+        __asm__("movl %0, %%ecx; " : : "g" (arg2) : "%ecx");
+        __asm__("movl %0, %%ebx; " : : "g" (arg1) : "%ebx");
+        __asm__("movl %0, %%eax; " : : "g" (syscall) : "%eax");
+        __asm__("int $0x80;" : : : "%eax");
+        __asm__ __volatile__("movl %%eax, %0; " : "=g" (ret) :);
+        return(ret);
+}
+
+static inline long stub_syscall3(long syscall, long arg1, long arg2, long arg3)
+{
+        __asm__("movl %0, %%edx; " : : "g" (arg3) : "%edx");
+        return(stub_syscall2(syscall, arg1, arg2));
+}
+
+static inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3,
+                                 long arg4)
+{
+        __asm__("movl %0, %%esi; " : : "g" (arg4) : "%esi");
+        return(stub_syscall3(syscall, arg1, arg2, arg3));
+}
+
+static inline long stub_syscall6(long syscall, long arg1, long arg2, long arg3,
+                                 long arg4, long arg5, long arg6)
+{
+        long ret;
+        __asm__("movl %0, %%eax; " : : "g" (syscall) : "%eax");
+        __asm__("movl %0, %%ebx; " : : "g" (arg1) : "%ebx");
+        __asm__("movl %0, %%ecx; " : : "g" (arg2) : "%ecx");
+        __asm__("movl %0, %%edx; " : : "g" (arg3) : "%edx");
+        __asm__("movl %0, %%esi; " : : "g" (arg4) : "%esi");
+        __asm__("movl %0, %%edi; " : : "g" (arg5) : "%edi");
+        __asm__ __volatile__("pushl %%ebp ; movl %1, %%ebp; "
+                "int $0x80; popl %%ebp ; "
+                "movl %%eax, %0; " : "=g" (ret) : "g" (arg6) : "%eax");
+        return(ret);
+}
+
+static inline void trap_myself(void)
+{
+        __asm("int3");
+}
+
 #endif
diff --git a/arch/um/include/sysdep-x86_64/stub.h b/arch/um/include/sysdep-x86_64/stub.h
index 6b5447ad590d..f599058d8263 100644
--- a/arch/um/include/sysdep-x86_64/stub.h
+++ b/arch/um/include/sysdep-x86_64/stub.h
@@ -11,9 +11,48 @@
 #include <sysdep/ptrace_user.h>
 
 extern void stub_segv_handler(int sig);
+extern void stub_clone_handler(void);
 
 #define STUB_SYSCALL_RET PT_INDEX(RAX)
 #define STUB_MMAP_NR __NR_mmap
 #define MMAP_OFFSET(o) (o)
 
+static inline long stub_syscall2(long syscall, long arg1, long arg2)
+{
+        long ret;
+
+        __asm__("movq %0, %%rsi; " : : "g" (arg2) : "%rsi");
+        __asm__("movq %0, %%rdi; " : : "g" (arg1) : "%rdi");
+        __asm__("movq %0, %%rax; " : : "g" (syscall) : "%rax");
+        __asm__("syscall;" : : : "%rax", "%r11", "%rcx");
+        __asm__ __volatile__("movq %%rax, %0; " : "=g" (ret) :);
+        return(ret);
+}
+
+static inline long stub_syscall3(long syscall, long arg1, long arg2, long arg3)
+{
+        __asm__("movq %0, %%rdx; " : : "g" (arg3) : "%rdx");
+        return(stub_syscall2(syscall, arg1, arg2));
+}
+
+static inline long stub_syscall4(long syscall, long arg1, long arg2, long arg3,
+                                 long arg4)
+{
+        __asm__("movq %0, %%r10; " : : "g" (arg4) : "%r10");
+        return(stub_syscall3(syscall, arg1, arg2, arg3));
+}
+
+static inline long stub_syscall6(long syscall, long arg1, long arg2, long arg3,
+                                 long arg4, long arg5, long arg6)
+{
+        __asm__("movq %0, %%r9; " : : "g" (arg6) : "%r9");
+        __asm__("movq %0, %%r8; " : : "g" (arg5) : "%r8");
+        return(stub_syscall4(syscall, arg1, arg2, arg3, arg4));
+}
+
+static inline void trap_myself(void)
+{
+        __asm("int3");
+}
+
 #endif
diff --git a/arch/um/include/time_user.h b/arch/um/include/time_user.h
index f64ef77019a3..17d7ef2141f4 100644
--- a/arch/um/include/time_user.h
+++ b/arch/um/include/time_user.h
@@ -10,6 +10,7 @@ extern void timer(void);
 extern void switch_timers(int to_real);
 extern void idle_sleep(int secs);
 extern void enable_timer(void);
+extern void prepare_timer(void * ptr);
 extern void disable_timer(void);
 extern unsigned long time_lock(void);
 extern void time_unlock(unsigned long);
diff --git a/arch/um/kernel/skas/Makefile b/arch/um/kernel/skas/Makefile
index ff69c4b312c0..d296d55ade4b 100644
--- a/arch/um/kernel/skas/Makefile
+++ b/arch/um/kernel/skas/Makefile
@@ -3,11 +3,14 @@
 # Licensed under the GPL
 #
 
-obj-y := exec_kern.o mem.o mem_user.o mmu.o process.o process_kern.o \
+obj-y := clone.o exec_kern.o mem.o mem_user.o mmu.o process.o process_kern.o \
         syscall_kern.o syscall_user.o tlb.o trap_user.o uaccess.o \
 
 subdir- := util
 
-USER_OBJS := process.o
+USER_OBJS := process.o clone.o
 
 include arch/um/scripts/Makefile.rules
+
+# clone.o is in the stub, so it can't be built with profiling
+$(obj)/clone.o : c_flags = -Wp,-MD,$(depfile) $(call unprofile,$(USER_CFLAGS))
diff --git a/arch/um/kernel/skas/clone.c b/arch/um/kernel/skas/clone.c
new file mode 100644
index 000000000000..4dc55f10cd18
--- /dev/null
+++ b/arch/um/kernel/skas/clone.c
@@ -0,0 +1,44 @@
+#include <sched.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <asm/unistd.h>
+#include <asm/page.h>
+#include "ptrace_user.h"
+#include "skas.h"
+#include "stub-data.h"
+#include "uml-config.h"
+#include "sysdep/stub.h"
+
+/* This is in a separate file because it needs to be compiled with any
+ * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
+ */
+void __attribute__ ((__section__ (".__syscall_stub")))
+stub_clone_handler(void)
+{
+        long err;
+        struct stub_data *from = (struct stub_data *) UML_CONFIG_STUB_DATA;
+
+        err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
+                            UML_CONFIG_STUB_DATA + PAGE_SIZE / 2 -
+                            sizeof(void *));
+        if(err != 0)
+                goto out;
+
+        err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
+        if(err)
+                goto out;
+
+        err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
+                            (long) &from->timer, 0);
+        if(err)
+                goto out;
+
+        err = stub_syscall6(STUB_MMAP_NR, UML_CONFIG_STUB_DATA, PAGE_SIZE,
+                            PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED,
+                            from->fd, from->offset);
+ out:
+        /* save current result. Parent: pid; child: retcode of mmap */
+        from->err = err;
+        trap_myself();
+}
diff --git a/arch/um/kernel/skas/include/skas.h b/arch/um/kernel/skas/include/skas.h
index d91a60f3830a..d983ea842547 100644
--- a/arch/um/kernel/skas/include/skas.h
+++ b/arch/um/kernel/skas/include/skas.h
@@ -32,6 +32,7 @@ extern int protect(struct mm_id * mm_idp, unsigned long addr,
 extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
 extern int new_mm(int from);
 extern int start_userspace(unsigned long stub_stack);
+extern int copy_context_skas0(unsigned long stack, int pid);
 extern void get_skas_faultinfo(int pid, struct faultinfo * fi);
 extern long execute_syscall_skas(void *r);
 extern unsigned long current_stub_stack(void);
diff --git a/arch/um/kernel/skas/include/stub-data.h b/arch/um/kernel/skas/include/stub-data.h
new file mode 100644
index 000000000000..f6ed92c3727d
--- /dev/null
+++ b/arch/um/kernel/skas/include/stub-data.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2005 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __STUB_DATA_H
+#define __STUB_DATA_H
+
+#include <sys/time.h>
+
+struct stub_data {
+        long offset;
+        int fd;
+        struct itimerval timer;
+        long err;
+};
+
+#endif
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 511a855c9ec0..d232daa42c31 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -75,6 +75,7 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
 int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
 {
         struct mm_struct *cur_mm = current->mm;
+        struct mm_id *cur_mm_id = &cur_mm->context.skas.id;
         struct mm_id *mm_id = &mm->context.skas.id;
         unsigned long stack;
         int from, ret;
@@ -115,7 +116,11 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
                         goto out_free;
 
                 mm->nr_ptes--;
-                mm_id->u.pid = start_userspace(stack);
+
+                if((cur_mm != NULL) && (cur_mm != &init_mm))
+                        mm_id->u.pid = copy_context_skas0(stack,
+                                                          cur_mm_id->u.pid);
+                else mm_id->u.pid = start_userspace(stack);
         }
 
         return 0;
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index 1647abb0d1aa..ba671dab8878 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -13,6 +13,7 @@
 #include <sys/wait.h>
 #include <sys/mman.h>
 #include <sys/user.h>
+#include <sys/time.h>
 #include <asm/unistd.h>
 #include <asm/types.h>
 #include "user.h"
@@ -22,6 +23,7 @@
 #include "user_util.h"
 #include "kern_util.h"
 #include "skas.h"
+#include "stub-data.h"
 #include "mm_id.h"
 #include "sysdep/sigcontext.h"
 #include "sysdep/stub.h"
@@ -296,6 +298,67 @@ void userspace(union uml_pt_regs *regs)
 #define INIT_JMP_HALT 3
 #define INIT_JMP_REBOOT 4
 
+
+int copy_context_skas0(unsigned long new_stack, int pid)
+{
+        int err;
+        unsigned long regs[MAX_REG_NR];
+        unsigned long current_stack = current_stub_stack();
+        struct stub_data *data = (struct stub_data *) current_stack;
+        struct stub_data *child_data = (struct stub_data *) new_stack;
+        __u64 new_offset;
+        int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
+
+        /* prepare offset and fd of child's stack as argument for parent's
+         * and child's mmap2 calls
+         */
+        *data = ((struct stub_data) { .offset   = MMAP_OFFSET(new_offset),
+                                      .fd       = new_fd,
+                                      .timer    = ((struct itimerval)
+                                                   { { 0, 1000000 / hz() },
+                                                     { 0, 1000000 / hz() }})});
+        get_safe_registers(regs);
+
+        /* Set parent's instruction pointer to start of clone-stub */
+        regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+                                (unsigned long) stub_clone_handler -
+                                (unsigned long) &__syscall_stub_start;
+        regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
+                sizeof(void *);
+        err = ptrace_setregs(pid, regs);
+        if(err < 0)
+                panic("copy_context_skas0 : PTRACE_SETREGS failed, "
+                      "pid = %d, errno = %d\n", pid, errno);
+
+        /* set a well known return code for detection of child write failure */
+        child_data->err = 12345678;
+
+        /* Wait, until parent has finished its work: read child's pid from
+         * parent's stack, and check, if bad result.
+         */
+        wait_stub_done(pid, 0, "copy_context_skas0");
+
+        pid = data->err;
+        if(pid < 0)
+                panic("copy_context_skas0 - stub-parent reports error %d\n",
+                      pid);
+
+        /* Wait, until child has finished too: read child's result from
+         * child's stack and check it.
+         */
+        wait_stub_done(pid, -1, "copy_context_skas0");
+        if (child_data->err != UML_CONFIG_STUB_DATA)
+                panic("copy_context_skas0 - stub-child reports error %d\n",
+                      child_data->err);
+
+        if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
+                   (void *)PTRACE_O_TRACESYSGOOD) < 0)
+                panic("copy_context_skas0 : PTRACE_SETOPTIONS failed, "
+                      "errno = %d\n", errno);
+
+        return pid;
+}
+
 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
                 void (*handler)(int))
 {
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index f829b309b63c..c40b611e3d93 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -48,6 +48,13 @@ void enable_timer(void)
         set_interval(ITIMER_VIRTUAL);
 }
 
+void prepare_timer(void * ptr)
+{
+        int usec = 1000000/hz();
+        *(struct itimerval *)ptr = ((struct itimerval) { { 0, usec },
+                                                         { 0, usec }});
+}
+
 void disable_timer(void)
 {
         struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});