um: switch stub_segv_handler to SA_SIGINFO variant, get rid of magic crap in there

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/os-Linux/skas/process.c

@@ -255,8 +255,8 @@ static int userspace_tramp(void *stack)
 
 		set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
 		sigemptyset(&sa.sa_mask);
-		sa.sa_flags = SA_ONSTACK | SA_NODEFER;
-		sa.sa_handler = (void *) v;
+		sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
+		sa.sa_sigaction = (void *) v;
 		sa.sa_restorer = NULL;
 		if (sigaction(SIGSEGV, &sa, NULL) < 0) {
 			printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "

arch/um/sys-x86/Makefile

@@ -10,7 +10,7 @@ endif
 
 obj-y = bug.o bugs_$(BITS).o delay_$(BITS).o fault.o ksyms.o ldt.o \
 	ptrace_$(BITS).o ptrace_user.o setjmp_$(BITS).o signal_$(BITS).o \
-	stub_$(BITS).o stub_segv_$(BITS).o syscalls_$(BITS).o \
+	stub_$(BITS).o stub_segv.o syscalls_$(BITS).o \
 	sys_call_table_$(BITS).o sysrq_$(BITS).o tls_$(BITS).o mem_$(BITS).o
 
 ifeq ($(CONFIG_X86_32),y)

arch/um/sys-x86/shared/sysdep/stub.h

@@ -1,5 +1,14 @@
+#include <asm/unistd.h>
+#include <sys/mman.h>
+#include <signal.h>
+#include "as-layout.h"
+#include "stub-data.h"
+
 #ifdef __i386__
 #include "stub_32.h"
 #else
 #include "stub_64.h"
 #endif
+
+extern void stub_segv_handler(int, siginfo_t *, void *);
+extern void stub_clone_handler(void);

arch/um/sys-x86/shared/sysdep/stub_32.h

@@ -6,14 +6,7 @@
 #ifndef __SYSDEP_STUB_H
 #define __SYSDEP_STUB_H
 
-#include <sys/mman.h>
 #include <asm/ptrace.h>
-#include <asm/unistd.h>
-#include "as-layout.h"
-#include "stub-data.h"
-
-extern void stub_segv_handler(int sig);
-extern void stub_clone_handler(void);
 
 #define STUB_SYSCALL_RET EAX
 #define STUB_MMAP_NR __NR_mmap2

arch/um/sys-x86/shared/sysdep/stub_64.h

@@ -6,14 +6,7 @@
 #ifndef __SYSDEP_STUB_H
 #define __SYSDEP_STUB_H
 
-#include <sys/mman.h>
-#include <asm/unistd.h>
 #include <sysdep/ptrace_user.h>
-#include "as-layout.h"
-#include "stub-data.h"
-
-extern void stub_segv_handler(int sig);
-extern void stub_clone_handler(void);
 
 #define STUB_SYSCALL_RET PT_INDEX(RAX)
 #define STUB_MMAP_NR __NR_mmap

arch/um/sys-x86/stub_segv.c

@@ -3,18 +3,15 @@
  * Licensed under the GPL
  */
 
-#include <signal.h>
-#include "as-layout.h"
 #include "sysdep/stub.h"
 #include "sysdep/faultinfo.h"
 #include "sysdep/sigcontext.h"
 
 void __attribute__ ((__section__ (".__syscall_stub")))
-stub_segv_handler(int sig)
+stub_segv_handler(int sig, siginfo_t *info, void *p)
 {
-	struct ucontext *uc;
+	struct ucontext *uc = p;
 
-	__asm__ __volatile__("movq %%rdx, %0" : "=g" (uc) :);
 	GET_FAULTINFO_FROM_SC(*((struct faultinfo *) STUB_DATA),
 			      &uc->uc_mcontext);
 	trap_myself();

arch/um/sys-x86/stub_segv_32.c

@@ -1,17 +0,0 @@
-/*
- * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- * Licensed under the GPL
- */
-
-#include "sysdep/stub.h"
-#include "sysdep/sigcontext.h"
-
-void __attribute__ ((__section__ (".__syscall_stub")))
-stub_segv_handler(int sig)
-{
-	struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
-
-	GET_FAULTINFO_FROM_SC(*((struct faultinfo *) STUB_DATA), sc);
-
-	trap_myself();
-}