1 files changed, 74 insertions, 48 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 1f39f2bf7ce9..5c088a55396c 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -34,6 +34,7 @@
 #include "process.h"
 #include "longjmp.h"
 #include "kern_constants.h"
+#include "as-layout.h"
 
 int is_skas_winch(int pid, int fd, void *data)
 {
@@ -60,37 +61,42 @@ static int ptrace_dump_regs(int pid)
         return 0;
 }
 
-void wait_stub_done(int pid, int sig, char * fname)
+/*
+ * Signals that are OK to receive in the stub - we'll just continue it.
+ * SIGWINCH will happen when UML is inside a detached screen.
+ */
+#define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
+
+/* Signals that the stub will finish with - anything else is an error */
+#define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
+
+void wait_stub_done(int pid)
 {
         int n, status, err;
 
-        do {
-                if ( sig != -1 ) {
-                        err = ptrace(PTRACE_CONT, pid, 0, sig);
-                        if(err)
-                                panic("%s : continue failed, errno = %d\n",
-                                      fname, errno);
-                }
-                sig = 0;
-
+        while(1){
                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
-        } while((n >= 0) && WIFSTOPPED(status) &&
-                ((WSTOPSIG(status) == SIGVTALRM) ||
-                 /* running UML inside a detached screen can cause
-                  * SIGWINCHes
-                  */
-                 (WSTOPSIG(status) == SIGWINCH)));
-
-        if((n < 0) || !WIFSTOPPED(status) ||
-           (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
-                err = ptrace_dump_regs(pid);
+                if((n < 0) || !WIFSTOPPED(status))
+                        goto bad_wait;
+
+                if(((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
+                        break;
+
+                err = ptrace(PTRACE_CONT, pid, 0, 0);
                 if(err)
-                        printk("Failed to get registers from stub, "
-                               "errno = %d\n", -err);
-                panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
-                      "pid = %d, n = %d, errno = %d, status = 0x%x\n",
-                      fname, pid, n, errno, status);
+                        panic("wait_stub_done : continue failed, errno = %d\n",
+                              errno);
         }
+
+        if(((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
+                return;
+
+bad_wait:
+        err = ptrace_dump_regs(pid);
+        if(err)
+                printk("Failed to get registers from stub, errno = %d\n", -err);
+        panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
+              "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
 }
 
 extern unsigned long current_stub_stack(void);
@@ -112,7 +118,11 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi)
                                sizeof(struct ptrace_faultinfo));
         }
         else {
-                wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
+                err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
+                if(err)
+                        panic("Failed to continue stub, pid = %d, errno = %d\n",
+                              pid, errno);
+                wait_stub_done(pid);
 
                 /* faultinfo is prepared by the stub-segv-handler at start of
                  * the stub stack page. We just have to copy it.
@@ -304,10 +314,13 @@ void userspace(union uml_pt_regs *regs)
                 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
 
                 if(WIFSTOPPED(status)){
-                        switch(WSTOPSIG(status)){
+                        int sig = WSTOPSIG(status);
+                        switch(sig){
                         case SIGSEGV:
-                                if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
-                                        user_signal(SIGSEGV, regs, pid);
+                                if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo){
+                                        get_skas_faultinfo(pid, &regs->skas.faultinfo);
+                                        (*sig_info[SIGSEGV])(SIGSEGV, regs);
+                                }
                                 else handle_segv(pid, regs);
                                 break;
                         case SIGTRAP + 0x80:
@@ -322,11 +335,13 @@ void userspace(union uml_pt_regs *regs)
                         case SIGBUS:
                         case SIGFPE:
                         case SIGWINCH:
-                                user_signal(WSTOPSIG(status), regs, pid);
+                                block_signals();
+                                (*sig_info[sig])(sig, regs);
+                                unblock_signals();
                                 break;
                         default:
                                 printk("userspace - child stopped with signal "
-                                       "%d\n", WSTOPSIG(status));
+                                       "%d\n", sig);
                         }
                         pid = userspace_pid[0];
                         interrupt_end();
@@ -338,11 +353,29 @@ void userspace(union uml_pt_regs *regs)
         }
 }
 
+static unsigned long thread_regs[MAX_REG_NR];
+static unsigned long thread_fp_regs[HOST_FP_SIZE];
+
+static int __init init_thread_regs(void)
+{
+        get_safe_registers(thread_regs, thread_fp_regs);
+        /* Set parent's instruction pointer to start of clone-stub */
+        thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+                                (unsigned long) stub_clone_handler -
+                                (unsigned long) &__syscall_stub_start;
+        thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
+                sizeof(void *);
+#ifdef __SIGNAL_FRAMESIZE
+        thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
+#endif
+        return 0;
+}
+
+__initcall(init_thread_regs);
+
 int copy_context_skas0(unsigned long new_stack, int pid)
 {
         int err;
-        unsigned long regs[MAX_REG_NR];
-        unsigned long fp_regs[HOST_FP_SIZE];
         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;
@@ -357,23 +390,12 @@ int copy_context_skas0(unsigned long new_stack, int pid)
                                       .timer    = ((struct itimerval)
                                                     { { 0, 1000000 / hz() },
                                                       { 0, 1000000 / hz() }})});
-        get_safe_registers(regs, fp_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 *);
-#ifdef __SIGNAL_FRAMESIZE
-        regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
-#endif
-        err = ptrace_setregs(pid, regs);
+        err = ptrace_setregs(pid, thread_regs);
         if(err < 0)
                 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
                       "pid = %d, errno = %d\n", pid, -err);
 
-        err = ptrace_setfpregs(pid, fp_regs);
+        err = ptrace_setfpregs(pid, thread_fp_regs);
         if(err < 0)
                 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
                       "pid = %d, errno = %d\n", pid, -err);
@@ -384,7 +406,11 @@ int copy_context_skas0(unsigned long new_stack, int pid)
         /* 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");
+        err = ptrace(PTRACE_CONT, pid, 0, 0);
+        if(err)
+                panic("Failed to continue new process, pid = %d, "
+                      "errno = %d\n", pid, errno);
+        wait_stub_done(pid);
 
         pid = data->err;
         if(pid < 0)
@@ -394,7 +420,7 @@ int copy_context_skas0(unsigned long new_stack, int 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");
+        wait_stub_done(pid);
         if (child_data->err != UML_CONFIG_STUB_DATA)
                 panic("copy_context_skas0 - stub-child reports error %ld\n",
                       child_data->err);