[PATCH] uml: eliminate some globals

Stop using global variables to hold the file descriptor and offset used to map
the skas0 stubs.  Instead, calculate them using the page physical addresses.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 16 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index f787854322c4..b959b2618b7f 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -151,8 +151,6 @@ static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu
 }
 
 extern int __syscall_stub_start;
-int stub_code_fd = -1;
-__u64 stub_code_offset;
 
 static int userspace_tramp(void *stack)
 {
@@ -167,30 +165,30 @@ static int userspace_tramp(void *stack)
                 /* This has a pte, but it can't be mapped in with the usual
                  * tlb_flush mechanism because this is part of that mechanism
                  */
+                int fd;
+                __u64 offset;
+                fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
                 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
-                              PROT_EXEC, MAP_FIXED | MAP_PRIVATE,
-                              stub_code_fd, stub_code_offset);
+                              PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
                 if(addr == MAP_FAILED){
-                        printk("mapping stub code failed, errno = %d\n",
+                        printk("mapping mmap stub failed, errno = %d\n",
                                errno);
                         exit(1);
                 }
 
                 if(stack != NULL){
-                        int fd;
-                        __u64 offset;
                         fd = phys_mapping(to_phys(stack), &offset);
                         addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
                                     PROT_READ | PROT_WRITE,
                                     MAP_FIXED | MAP_SHARED, fd, offset);
                         if(addr == MAP_FAILED){
-                                printk("mapping stub stack failed, "
+                                printk("mapping segfault stack failed, "
                                        "errno = %d\n", errno);
                                 exit(1);
                         }
                 }
         }
-        if(!ptrace_faultinfo){
+        if(!ptrace_faultinfo && (stack != NULL)){
                 unsigned long v = UML_CONFIG_STUB_CODE +
                                   (unsigned long) stub_segv_handler -
                                   (unsigned long) &__syscall_stub_start;
@@ -216,10 +214,6 @@ int start_userspace(unsigned long stub_stack)
         unsigned long sp;
         int pid, status, n, flags;
 
-        if ( stub_code_fd == -1 )
-                stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start),
-                                            &stub_code_offset);
-
         stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
         if(stack == MAP_FAILED)
@@ -306,7 +300,6 @@ void userspace(union uml_pt_regs *regs)
                                 printk("userspace - child stopped with signal "
                                        "%d\n", WSTOPSIG(status));
                         }
-                    again:
                         pid = userspace_pid[0];
                         interrupt_end();
 
@@ -395,6 +388,9 @@ void map_stub_pages(int fd, unsigned long code,
 {
         struct proc_mm_op mmop;
         int n;
+        __u64 code_offset;
+        int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
+                                   &code_offset);
 
         mmop = ((struct proc_mm_op) { .op        = MM_MMAP,
                                       .u         =
@@ -403,8 +399,8 @@ void map_stub_pages(int fd, unsigned long code,
                                           .len     = PAGE_SIZE,
                                           .prot    = PROT_EXEC,
                                           .flags   = MAP_FIXED | MAP_PRIVATE,
-                                          .fd      = stub_code_fd,
-                                          .offset  = stub_code_offset
+                                          .fd      = code_fd,
+                                          .offset  = code_offset
         } } });
         n = os_write_file(fd, &mmop, sizeof(mmop));
         if(n != sizeof(mmop))