3 files changed, 39 insertions, 49 deletions

diff --git a/arch/x86/um/shared/sysdep/stub.h b/arch/x86/um/shared/sysdep/stub.h
index ce0ca46ad383..dc89f4423454 100644
--- a/arch/x86/um/shared/sysdep/stub.h
+++ b/arch/x86/um/shared/sysdep/stub.h
@@ -12,4 +12,4 @@
 #endif
 
 extern void stub_segv_handler(int, siginfo_t *, void *);
-extern void stub_clone_handler(void);
+extern void stub_syscall_handler(void);
diff --git a/arch/x86/um/shared/sysdep/stub_32.h b/arch/x86/um/shared/sysdep/stub_32.h
index ea8b5a2d67af..0b44a86dd346 100644
--- a/arch/x86/um/shared/sysdep/stub_32.h
+++ b/arch/x86/um/shared/sysdep/stub_32.h
@@ -6,6 +6,7 @@
 #ifndef __SYSDEP_STUB_H
 #define __SYSDEP_STUB_H
 
+#include <stddef.h>
 #include <asm/ptrace.h>
 #include <generated/asm-offsets.h>
 
@@ -79,33 +80,31 @@ static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
 	return ret;
 }
 
-static __always_inline void trap_myself(void)
+static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
+					  long arg3, long arg4, long arg5,
+					  long arg6)
 {
-	__asm("int3");
+	struct syscall_args {
+		int ebx, ebp;
+	} args = { arg1, arg6 };
+	long ret;
+
+	__asm__ volatile ("pushl %%ebp;"
+			"movl 0x4(%%ebx),%%ebp;"
+			"movl (%%ebx),%%ebx;"
+			"int $0x80;"
+			"popl %%ebp"
+			: "=a" (ret)
+			: "0" (syscall), "b" (&args),
+			"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
+			: "memory");
+
+	return ret;
 }
 
-static __always_inline void remap_stack_and_trap(void)
+static __always_inline void trap_myself(void)
 {
-	__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" (~(STUB_DATA_PAGES * 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" (STUB_DATA_PAGES * UM_KERN_PAGE_SIZE),
-		"d" (PROT_READ | PROT_WRITE),
-		"S" (MAP_FIXED | MAP_SHARED)
-		:
-		"memory");
+	__asm("int3");
 }
 
 static __always_inline void *get_stub_data(void)
diff --git a/arch/x86/um/shared/sysdep/stub_64.h b/arch/x86/um/shared/sysdep/stub_64.h
index b24168ef0ac4..67f44284f1aa 100644
--- a/arch/x86/um/shared/sysdep/stub_64.h
+++ b/arch/x86/um/shared/sysdep/stub_64.h
@@ -6,6 +6,7 @@
 #ifndef __SYSDEP_STUB_H
 #define __SYSDEP_STUB_H
 
+#include <stddef.h>
 #include <sysdep/ptrace_user.h>
 #include <generated/asm-offsets.h>
 #include <linux/stddef.h>
@@ -79,35 +80,25 @@ static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
 	return ret;
 }
 
-static __always_inline void trap_myself(void)
+static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
+					  long arg3, long arg4, long arg5,
+					  long arg6)
 {
-	__asm("int3");
+	long ret;
+
+	__asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; movq %7,%%r9 ; "
+		__syscall
+		: "=a" (ret)
+		: "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
+		  "g" (arg4), "g" (arg5), "g" (arg6)
+		: __syscall_clobber, "r10", "r8", "r9");
+
+	return ret;
 }
 
-static __always_inline void remap_stack_and_trap(void)
+static __always_inline void trap_myself(void)
 {
-	__asm__ volatile (
-		"movq %0,%%rax ;"
-		"movq %%rsp,%%rdi ;"
-		"andq %1,%%rdi ;"
-		"movq %2,%%r10 ;"
-		"movq %%rdi,%%r8 ; addq %3,%%r8 ; movq (%%r8),%%r8 ;"
-		"movq %%rdi,%%r9 ; addq %4,%%r9 ; movq (%%r9),%%r9 ;"
-		__syscall ";"
-		"movq %%rsp,%%rdi ; andq %1,%%rdi ;"
-		"addq %5,%%rdi ; movq %%rax, (%%rdi) ;"
-		"int3"
-		: :
-		"g" (STUB_MMAP_NR),
-		"g" (~(STUB_DATA_PAGES * UM_KERN_PAGE_SIZE - 1)),
-		"g" (MAP_FIXED | MAP_SHARED),
-		"g" (UML_STUB_FIELD_FD),
-		"g" (UML_STUB_FIELD_OFFSET),
-		"g" (UML_STUB_FIELD_CHILD_ERR),
-		"S" (STUB_DATA_PAGES * UM_KERN_PAGE_SIZE),
-		"d" (PROT_READ | PROT_WRITE)
-		:
-		__syscall_clobber, "r10", "r8", "r9");
+	__asm("int3");
 }
 
 static __always_inline void *get_stub_data(void)