From: ebiederm@xmission.com (Eric W. Biederman)
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
hch@infradead.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH RESEND v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to_user()
Date: Mon, 13 Sep 2021 11:21:41 -0500 [thread overview]
Message-ID: <87y280o38q.fsf@disp2133> (raw)
In-Reply-To: <87h7eopixa.fsf@disp2133> (Eric W. Biederman's message of "Mon, 13 Sep 2021 10:57:37 -0500")
ebiederm@xmission.com (Eric W. Biederman) writes:
> Christophe Leroy <christophe.leroy@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
next prev parent reply other threads:[~2021-09-13 16:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 15:19 [PATCH RESEND v3 1/6] powerpc/signal64: Access function descriptor with user access block Christophe Leroy
2021-09-13 15:19 ` [PATCH RESEND v3 2/6] powerpc/signal: Include the new stack frame inside the " Christophe Leroy
2021-09-13 15:19 ` [PATCH RESEND v3 3/6] signal: Add unsafe_copy_siginfo_to_user() Christophe Leroy
2021-09-13 15:19 ` [PATCH RESEND v3 4/6] signal: Add unsafe_copy_siginfo_to_user32() Christophe Leroy
2021-09-13 15:54 ` Eric W. Biederman
2021-09-13 17:01 ` Christophe Leroy
2021-09-13 15:19 ` [PATCH RESEND v3 5/6] powerpc/uaccess: Add unsafe_clear_user() Christophe Leroy
2021-09-13 15:19 ` [PATCH RESEND v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to_user() Christophe Leroy
2021-09-13 15:57 ` Eric W. Biederman
2021-09-13 16:21 ` Eric W. Biederman [this message]
2021-09-13 17:19 ` Christophe Leroy
2021-09-13 19:11 ` Eric W. Biederman
2021-09-14 14:00 ` Christophe Leroy
2021-09-13 17:14 ` Christophe Leroy
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