1 files changed, 37 insertions, 26 deletions

diff --git a/arch/x86/um/shared/sysdep/stub_32.h b/arch/x86/um/shared/sysdep/stub_32.h
index ea8b5a2d67af..390988132c0a 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)
@@ -113,11 +112,23 @@ static __always_inline void *get_stub_data(void)
 	unsigned long ret;
 
 	asm volatile (
-		"movl %%esp,%0 ;"
-		"andl %1,%0"
+		"call _here_%=;"
+		"_here_%=:"
+		"popl %0;"
+		"andl %1, %0 ;"
+		"addl %2, %0 ;"
 		: "=a" (ret)
-		: "g" (~(STUB_DATA_PAGES * UM_KERN_PAGE_SIZE - 1)));
+		: "g" (~(UM_KERN_PAGE_SIZE - 1)),
+		  "g" (UM_KERN_PAGE_SIZE));
 
 	return (void *)ret;
 }
+
+#define stub_start(fn)							\
+	asm volatile (							\
+		"subl %0,%%esp ;"					\
+		"movl %1, %%eax ; "					\
+		"call *%%eax ;"						\
+		:: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE),	\
+		   "i" (&fn))
 #endif