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

From: Christophe Leroy
Date: Mon Sep 13 2021 - 13:15:01 EST




Le 13/09/2021 à 17:57, Eric W. Biederman a écrit :
Christophe Leroy <christophe.leroy@xxxxxxxxxx> 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.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
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 */

Any particular reason to reverse the sense of this #ifdef?

Yes I had double definition of unsafe_copy_siginfo_to_user(), I could have ifdefed out unsafe_copy_siginfo_to_user() in signal.h, but I prefered to ifdef out copy_siginfo_to_user32() in compat.h


Otherwise this change looks much cleaner.

Thanks
Christophe