arm64: get rid of fork/vfork/clone wrappers

[fixes from Catalin Marinas folded]

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 25 insertions, 52 deletions

diff --git a/arch/arm64/include/asm/syscalls.h b/arch/arm64/include/asm/syscalls.h
index 81680a0ae913..a1b00cd6f786 100644
--- a/arch/arm64/include/asm/syscalls.h
+++ b/arch/arm64/include/asm/syscalls.h
@@ -23,15 +23,16 @@
 /*
  * System call wrappers implemented in kernel/entry.S.
  */
-asmlinkage long sys_clone_wrapper(unsigned long clone_flags,
-                                  unsigned long newsp,
-                                  void __user *parent_tid,
-                                  unsigned long tls_val,
-                                  void __user *child_tid);
 asmlinkage long sys_rt_sigreturn_wrapper(void);
 asmlinkage long sys_sigaltstack_wrapper(const stack_t __user *uss,
                                         stack_t __user *uoss);
 
+/*
+ * AArch64 sys_clone implementation has a different prototype than the generic
+ * one (additional TLS value argument).
+ */
+#define sys_clone       sys_clone
+
 #include <asm-generic/syscalls.h>
 
 #endif  /* __ASM_SYSCALLS_H */
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 9035e6add3e4..d9850cf9870d 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -23,7 +23,7 @@
 
 __SYSCALL(0,   sys_restart_syscall)
 __SYSCALL(1,   sys_exit)
-__SYSCALL(2,   compat_sys_fork_wrapper)
+__SYSCALL(2,   compat_sys_fork)
 __SYSCALL(3,   sys_read)
 __SYSCALL(4,   sys_write)
 __SYSCALL(5,   compat_sys_open)
@@ -141,7 +141,7 @@ __SYSCALL(116, compat_sys_sysinfo)
 __SYSCALL(117, sys_ni_syscall)                  /* 117 was sys_ipc */
 __SYSCALL(118, sys_fsync)
 __SYSCALL(119, compat_sys_sigreturn_wrapper)
-__SYSCALL(120, compat_sys_clone_wrapper)
+__SYSCALL(120, sys_clone)
 __SYSCALL(121, sys_setdomainname)
 __SYSCALL(122, sys_newuname)
 __SYSCALL(123, sys_ni_syscall)                  /* 123 was sys_modify_ldt */
@@ -211,7 +211,7 @@ __SYSCALL(186, compat_sys_sigaltstack_wrapper)
 __SYSCALL(187, compat_sys_sendfile)
 __SYSCALL(188, sys_ni_syscall)                  /* 188 reserved */
 __SYSCALL(189, sys_ni_syscall)                  /* 189 reserved */
-__SYSCALL(190, compat_sys_vfork_wrapper)
+__SYSCALL(190, compat_sys_vfork)
 __SYSCALL(191, compat_sys_getrlimit)            /* SuS compliant getrlimit */
 __SYSCALL(192, sys_mmap_pgoff)
 __SYSCALL(193, compat_sys_truncate64_wrapper)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 616531862d52..cbfa4d28100e 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -676,11 +676,6 @@ __sys_trace_return:
 /*
  * Special system call wrappers.
  */
-ENTRY(sys_clone_wrapper)
-        mov     x5, sp
-        b       sys_clone
-ENDPROC(sys_clone_wrapper)
-
 ENTRY(sys_rt_sigreturn_wrapper)
         mov     x0, sp
         b       sys_rt_sigreturn
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index bf615e212c6c..f82987a784af 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -246,14 +246,20 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
                 *childregs = *regs;
                 childregs->regs[0] = 0;
                 if (is_compat_thread(task_thread_info(p))) {
-                        childregs->compat_sp = stack_start;
+                        if (stack_start)
+                                childregs->compat_sp = stack_start;
                 } else {
                         /*
                          * Read the current TLS pointer from tpidr_el0 as it may be
                          * out-of-sync with the saved value.
                          */
                         asm("mrs %0, tpidr_el0" : "=r" (tls));
-                        childregs->sp = stack_start;
+                        if (stack_start) {
+                                /* 16-byte aligned stack mandatory on AArch64 */
+                                if (stack_start & 15)
+                                        return -EINVAL;
+                                childregs->sp = stack_start;
+                        }
                 }
                 /*
                  * If a TLS pointer was passed to clone (4th argument), use it
diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 9c77c0bacc1d..4364df85050e 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -31,14 +31,10 @@
  */
 asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
                           int __user *parent_tidptr, unsigned long tls_val,
-                          int __user *child_tidptr, struct pt_regs *regs)
+                          int __user *child_tidptr)
 {
-        if (!newsp)
-                newsp = regs->sp;
-        /* 16-byte aligned stack mandatory on AArch64 */
-        if (newsp & 15)
-                return -EINVAL;
-        return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
+        return do_fork(clone_flags, newsp, current_pt_regs(), 0,
+                        parent_tidptr, child_tidptr);
 }
 
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
@@ -54,7 +50,6 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 /*
  * Wrappers to pass the pt_regs argument.
  */
-#define sys_clone               sys_clone_wrapper
 #define sys_rt_sigreturn        sys_rt_sigreturn_wrapper
 #define sys_sigaltstack         sys_sigaltstack_wrapper
 
diff --git a/arch/arm64/kernel/sys32.S b/arch/arm64/kernel/sys32.S
index 92145d402cf1..7ef59e9245ef 100644
--- a/arch/arm64/kernel/sys32.S
+++ b/arch/arm64/kernel/sys32.S
@@ -26,20 +26,6 @@
 /*
  * System call wrappers for the AArch32 compatibility layer.
  */
-compat_sys_fork_wrapper:
-        mov     x0, sp
-        b       compat_sys_fork
-ENDPROC(compat_sys_fork_wrapper)
-
-compat_sys_vfork_wrapper:
-        mov     x0, sp
-        b       compat_sys_vfork
-ENDPROC(compat_sys_vfork_wrapper)
-
-compat_sys_clone_wrapper:
-        mov     x5, sp
-        b       compat_sys_clone
-ENDPROC(compat_sys_clone_wrapper)
 
 compat_sys_sigreturn_wrapper:
         mov     x0, sp
diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c
index d140b73a8bc4..6fabc1912da0 100644
--- a/arch/arm64/kernel/sys_compat.c
+++ b/arch/arm64/kernel/sys_compat.c
@@ -28,25 +28,15 @@
 #include <asm/cacheflush.h>
 #include <asm/unistd32.h>
 
-asmlinkage int compat_sys_fork(struct pt_regs *regs)
+asmlinkage int compat_sys_fork(void)
 {
-        return do_fork(SIGCHLD, regs->compat_sp, regs, 0, NULL, NULL);
+        return do_fork(SIGCHLD, 0, current_pt_regs(), 0, NULL, NULL);
 }
 
-asmlinkage int compat_sys_clone(unsigned long clone_flags, unsigned long newsp,
-                          int __user *parent_tidptr, int tls_val,
-                          int __user *child_tidptr, struct pt_regs *regs)
+asmlinkage int compat_sys_vfork(void)
 {
-        if (!newsp)
-                newsp = regs->compat_sp;
-
-        return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
-}
-
-asmlinkage int compat_sys_vfork(struct pt_regs *regs)
-{
-        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->compat_sp,
-                       regs, 0, NULL, NULL);
+        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
+                       current_pt_regs(), 0, NULL, NULL);
 }
 
 asmlinkage int compat_sys_sched_rr_get_interval(compat_pid_t pid,