linux-kernel - [PATCH RESEND v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to

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Date:   Mon, 13 Sep 2021 17:19:10 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, ebiederm@...ssion.com,
        hch@...radead.org
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH RESEND v3 6/6] powerpc/signal: Use unsafe_copy_siginfo_to_user()

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.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
v3: Don't leave compat aside, use the new unsafe_copy_siginfo_to_user32()
---
 arch/powerpc/kernel/signal_32.c | 8 +++-----
 arch/powerpc/kernel/signal_64.c | 5 +----
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ff101e2b3bab..3a2db8af2d65 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -710,9 +710,9 @@ static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *s
 }
 #endif
 
-#ifdef CONFIG_PPC64
+#ifndef CONFIG_PPC64
 
-#define copy_siginfo_to_user	copy_siginfo_to_user32
+#define unsafe_copy_siginfo_to_user32	unsafe_copy_siginfo_to_user
 
 #endif /* CONFIG_PPC64 */
 
@@ -779,15 +779,13 @@ 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_siginfo_to_user32(&frame->info, &ksig->info, failed);
 
 	/* create a stack frame for the caller of the handler */
 	unsafe_put_user(regs->gpr[1], newsp, failed);
 
 	user_access_end();
 
-	if (copy_siginfo_to_user(&frame->info, &ksig->info))
-		goto badframe;
-
 	regs->link = tramp;
 
 #ifdef CONFIG_PPC_FPU_REGS
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index d80ff83cacb9..56c0c74aa28c 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -901,15 +901,12 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	}
 
 	unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
+	unsafe_copy_siginfo_to_user(&frame->info, &ksig->info, badframe_block);
 	/* Allocate a dummy caller frame for the signal handler. */
 	unsafe_put_user(regs->gpr[1], newsp, badframe_block);
 
 	user_write_access_end();
 
-	/* Save the siginfo outside of the unsafe block. */
-	if (copy_siginfo_to_user(&frame->info, &ksig->info))
-		goto badframe;
-
 	/* Make sure signal handler doesn't get spurious FP exceptions */
 	tsk->thread.fp_state.fpscr = 0;
 
-- 
2.31.1