arm64: Use generic kernel_execve() implementation

This patch converts the arm64 port to use the generic kernel_execve()
implementation. It introduces the ret_from_kernel_execve() function for
starting the new user context.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4077b71b12580a5fac6f6713a8178e6632bedce6..31e3b5eb4047a8f10470a855e4930518382a0a78 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -7,6 +7,7 @@ config ARM64
        select GENERIC_IRQ_PROBE
        select GENERIC_IRQ_SHOW
        select GENERIC_KERNEL_THREAD
+       select GENERIC_KERNEL_EXECVE
        select GENERIC_SMP_IDLE_THREAD
        select GENERIC_TIME_VSYSCALL
        select HARDIRQS_SW_RESEND

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 883043d3a1d010b2492e23301778a571b48c56c8..9138db4eeb35495e459a004b85498f2b47f0438b 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -594,7 +594,7 @@ work_resched:
 /*
  * "slow" syscall return path.
  */
-ENTRY(ret_to_user)
+ret_to_user:
        disable_irq                             // disable interrupts
        ldr     x1, [tsk, #TI_FLAGS]
        and     x2, x1, #_TIF_WORK_MASK
@@ -611,17 +611,13 @@ ENDPROC(ret_to_user)
  */
 ENTRY(ret_from_fork)
        bl      schedule_tail
+       cmp     x19, #0
+       movne   x0, x20
+       blne    x19
        get_thread_info tsk
        b       ret_to_user
 ENDPROC(ret_from_fork)
 
-ENTRY(ret_from_kernel_thread)
-       bl      schedule_tail
-       mov     x0, x20
-       adr     lr, do_exit                     // kernel threads should not exit
-       br      x19
-ENDPROC(ret_from_kernel_thread)
-
 /*
  * SVC handler.
  */

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 2d074ac6a00a39777e070548ae2ffc534f48be66..bf615e212c6c1bc42ef526c673f5493566ef3597 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -232,7 +232,6 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 }
 
 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
-asmlinkage void ret_from_kernel_thread(void) asm("ret_from_kernel_thread");
 
 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
                unsigned long stk_sz, struct task_struct *p,
@@ -262,13 +261,13 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
                 */
                if (clone_flags & CLONE_SETTLS)
                        tls = regs->regs[3];
-               p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
        } else {
+               memset(childregs, 0, sizeof(struct pt_regs));
                childregs->pstate = PSR_MODE_EL1h;
                p->thread.cpu_context.x19 = stack_start;
                p->thread.cpu_context.x20 = stk_sz;
-               p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
        }
+       p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
        p->thread.cpu_context.sp = (unsigned long)childregs;
        p->thread.tp_value = tls;
 

diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index b120df37de3552e5a68479294ef9e6b037ea97fb..4deb0d0093cdf761929191e7a71ddedbbe73d087 100644 (file)
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -62,49 +62,6 @@ out:
        return error;
 }
 
-int kernel_execve(const char *filename,
-                 const char *const argv[],
-                 const char *const envp[])
-{
-       struct pt_regs regs;
-       int ret;
-
-       memset(&regs, 0, sizeof(struct pt_regs));
-       ret = do_execve(filename,
-                       (const char __user *const __user *)argv,
-                       (const char __user *const __user *)envp, &regs);
-       if (ret < 0)
-               goto out;
-
-       /*
-        * Save argc to the register structure for userspace.
-        */
-       regs.regs[0] = ret;
-
-       /*
-        * We were successful.  We won't be returning to our caller, but
-        * instead to user space by manipulating the kernel stack.
-        */
-       asm(    "add    x0, %0, %1\n\t"
-               "mov    x1, %2\n\t"
-               "mov    x2, %3\n\t"
-               "bl     memmove\n\t"    /* copy regs to top of stack */
-               "mov    x27, #0\n\t"    /* not a syscall */
-               "mov    x28, %0\n\t"    /* thread structure */
-               "mov    sp, x0\n\t"     /* reposition stack pointer */
-               "b      ret_to_user"
-               :
-               : "r" (current_thread_info()),
-                 "Ir" (THREAD_START_SP - sizeof(regs)),
-                 "r" (&regs),
-                 "Ir" (sizeof(regs))
-               : "x0", "x1", "x2", "x27", "x28", "x30", "memory");
-
- out:
-       return ret;
-}
-EXPORT_SYMBOL(kernel_execve);
-
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
                         unsigned long prot, unsigned long flags,
                         unsigned long fd, off_t off)