[PATCH 1/4] signal: add a helper to restore a process state from sigcontex

[Andrei Vagin]

It will be used to implement process_vm_exec.

Signed-off-by: Andrei Vagin <ava...@gmail.com>
---
 arch/x86/kernel/signal.c | 78 ++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index be0d7d4152ec..cc269a20dd5f 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -79,51 +79,43 @@ static void force_valid_ss(struct pt_regs *regs)
 # define CONTEXT_COPY_SIZE     sizeof(struct sigcontext)
 #endif
 
-static int restore_sigcontext(struct pt_regs *regs,
-                             struct sigcontext __user *usc,
+static int __restore_sigcontext(struct pt_regs *regs,
+                             struct sigcontext __user *sc,
                              unsigned long uc_flags)
 {
-       struct sigcontext sc;
-
-       /* Always make any pending restarted system calls return -EINTR */
-       current->restart_block.fn = do_no_restart_syscall;
-
-       if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))
-               return -EFAULT;
-
 #ifdef CONFIG_X86_32
-       set_user_gs(regs, sc.gs);
-       regs->fs = sc.fs;
-       regs->es = sc.es;
-       regs->ds = sc.ds;
+       set_user_gs(regs, sc->gs);
+       regs->fs = sc->fs;
+       regs->es = sc->es;
+       regs->ds = sc->ds;
 #endif /* CONFIG_X86_32 */
 
-       regs->bx = sc.bx;
-       regs->cx = sc.cx;
-       regs->dx = sc.dx;
-       regs->si = sc.si;
-       regs->di = sc.di;
-       regs->bp = sc.bp;
-       regs->ax = sc.ax;
-       regs->sp = sc.sp;
-       regs->ip = sc.ip;
+       regs->bx = sc->bx;
+       regs->cx = sc->cx;
+       regs->dx = sc->dx;
+       regs->si = sc->si;
+       regs->di = sc->di;
+       regs->bp = sc->bp;
+       regs->ax = sc->ax;
+       regs->sp = sc->sp;
+       regs->ip = sc->ip;
 
 #ifdef CONFIG_X86_64
-       regs->r8 = sc.r8;
-       regs->r9 = sc.r9;
-       regs->r10 = sc.r10;
-       regs->r11 = sc.r11;
-       regs->r12 = sc.r12;
-       regs->r13 = sc.r13;
-       regs->r14 = sc.r14;
-       regs->r15 = sc.r15;
+       regs->r8 = sc->r8;
+       regs->r9 = sc->r9;
+       regs->r10 = sc->r10;
+       regs->r11 = sc->r11;
+       regs->r12 = sc->r12;
+       regs->r13 = sc->r13;
+       regs->r14 = sc->r14;
+       regs->r15 = sc->r15;
 #endif /* CONFIG_X86_64 */
 
        /* Get CS/SS and force CPL3 */
-       regs->cs = sc.cs | 0x03;
-       regs->ss = sc.ss | 0x03;
+       regs->cs = sc->cs | 0x03;
+       regs->ss = sc->ss | 0x03;
 
-       regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
+       regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc->flags & FIX_EFLAGS);
        /* disable syscall checks */
        regs->orig_ax = -1;
 
@@ -136,10 +128,26 @@ static int restore_sigcontext(struct pt_regs *regs,
                force_valid_ss(regs);
 #endif
 
-       return fpu__restore_sig((void __user *)sc.fpstate,
+       return fpu__restore_sig((void __user *)sc->fpstate,
                               IS_ENABLED(CONFIG_X86_32));
 }
 
+static int restore_sigcontext(struct pt_regs *regs,
+                             struct sigcontext __user *usc,
+                             unsigned long uc_flags)
+{
+       struct sigcontext sc;
+
+       /* Always make any pending restarted system calls return -EINTR */
+       current->restart_block.fn = do_no_restart_syscall;
+
+       if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))
+               return -EFAULT;
+
+       return __restore_sigcontext(regs, &sc, uc_flags);
+}
+
+
 static __always_inline int
 __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
                     struct pt_regs *regs, unsigned long mask)
-- 
2.29.2