Re: [PATCH RESEND v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to_user()

[Eric W. Biederman]

ebied...@xmission.com (Eric W. Biederman) writes:

> Christophe Leroy <christophe.le...@csgroup.eu> writes:
>
>> Use unsafe_copy_siginfo_to_user() in order to do the copy
>> within the user access block.
>>
>> On an mpc 8321 (book3s/32) the improvment is about 5% on a process
>> sending a signal to itself.

If you can't make function calls from an unsafe macro there is another
way to handle this that doesn't require everything to be inline.

>From a safety perspective it is probably even a better approach.

Eric

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 0608581967f0..1b30bb78b863 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -205,6 +205,12 @@ struct sigframe {
        int                     abigap[56];
 };
 
+#ifdef CONFIG_PPC64
+# define user_siginfo_t                compat_siginfo_t
+#else
+# define user_siginfo_t                siginfo_t
+#endif
+
 /*
  *  When we have rt signals to deliver, we set up on the
  *  user stack, going down from the original stack pointer:
@@ -217,11 +223,7 @@ struct sigframe {
  *
  */
 struct rt_sigframe {
-#ifdef CONFIG_PPC64
-       compat_siginfo_t info;
-#else
-       struct siginfo info;
-#endif
+       user_siginfo_t info;
        struct ucontext uc;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        struct ucontext uc_transact;
@@ -712,7 +714,7 @@ static long restore_tm_user_regs(struct pt_regs *regs, 
struct mcontext __user *s
 
 #ifdef CONFIG_PPC64
 
-#define copy_siginfo_to_user   copy_siginfo_to_user32
+#define copy_siginfo_to_external       copy_siginfo_to_external32
 
 #endif /* CONFIG_PPC64 */
 
@@ -731,6 +733,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t 
*oldset,
        struct pt_regs *regs = tsk->thread.regs;
        /* Save the thread's msr before get_tm_stackpointer() changes it */
        unsigned long msr = regs->msr;
+       user_siginfo_t uinfo;
 
        /* Set up Signal Frame */
        frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
@@ -743,6 +746,8 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t 
*oldset,
        else
                prepare_save_user_regs(1);
 
+       copy_siginfo_to_external(&uinfo, &ksig->info);
+
        if (!user_access_begin(frame, sizeof(*frame)))
                goto badframe;
 
@@ -778,12 +783,10 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t 
*oldset,
                asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0]));
        }
        unsafe_put_sigset_t(&frame->uc.uc_sigmask, oldset, failed);
+       unsafe_copy_to_user(&frame->info, &uinfo, failed);
 
        user_access_end();
 
-       if (copy_siginfo_to_user(&frame->info, &ksig->info))
-               goto badframe;
-
        regs->link = tramp;
 
 #ifdef CONFIG_PPC_FPU_REGS

Eric