um: rework userspace stubs to not hard-code stub location

[linux-2.6-microblaze.git] / arch / x86 / um / shared / sysdep / stub_32.h

diff --git a/arch/x86/um/shared/sysdep/stub_32.h b/arch/x86/um/shared/sysdep/stub_32.h
index 8ea6921..c3891c1 100644 (file)
--- a/arch/x86/um/shared/sysdep/stub_32.h
+++ b/arch/x86/um/shared/sysdep/stub_32.h
@@ -7,8 +7,8 @@
 #define __SYSDEP_STUB_H
 
 #include <asm/ptrace.h>
+#include <generated/asm-offsets.h>
 
-#define STUB_SYSCALL_RET EAX
 #define STUB_MMAP_NR __NR_mmap2
 #define MMAP_OFFSET(o) ((o) >> UM_KERN_PAGE_SHIFT)
 
@@ -77,17 +77,28 @@ static inline void trap_myself(void)
        __asm("int3");
 }
 
-static inline void remap_stack(int fd, unsigned long offset)
+static void inline remap_stack_and_trap(void)
 {
-       __asm__ volatile ("movl %%eax,%%ebp ; movl %0,%%eax ; int $0x80 ;"
-                         "movl %7, %%ebx ; movl %%eax, (%%ebx)"
-                         : : "g" (STUB_MMAP_NR), "b" (STUB_DATA),
-                           "c" (UM_KERN_PAGE_SIZE),
-                           "d" (PROT_READ | PROT_WRITE),
-                           "S" (MAP_FIXED | MAP_SHARED), "D" (fd),
-                           "a" (offset),
-                           "i" (&((struct stub_data *) STUB_DATA)->child_err)
-                         : "memory");
+       __asm__ volatile (
+               "movl %%esp,%%ebx ;"
+               "andl %0,%%ebx ;"
+               "movl %1,%%eax ;"
+               "movl %%ebx,%%edi ; addl %2,%%edi ; movl (%%edi),%%edi ;"
+               "movl %%ebx,%%ebp ; addl %3,%%ebp ; movl (%%ebp),%%ebp ;"
+               "int $0x80 ;"
+               "addl %4,%%ebx ; movl %%eax, (%%ebx) ;"
+               "int $3"
+               : :
+               "g" (~(UM_KERN_PAGE_SIZE - 1)),
+               "g" (STUB_MMAP_NR),
+               "g" (UML_STUB_FIELD_FD),
+               "g" (UML_STUB_FIELD_OFFSET),
+               "g" (UML_STUB_FIELD_CHILD_ERR),
+               "c" (UM_KERN_PAGE_SIZE),
+               "d" (PROT_READ | PROT_WRITE),
+               "S" (MAP_FIXED | MAP_SHARED)
+               :
+               "memory");
 }
 
 #endif