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

2 messages, 2 authors, 2021-09-13 · open the first message on its own page

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

From: Eric W. Biederman <hidden>
Date: 2021-09-13 15:58:10

Christophe Leroy [off-list ref] writes:
quoted hunk
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 <redacted>
---
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?

Otherwise this change looks much cleaner.

Eric

quoted hunk
 
@@ -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;

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

From: Christophe Leroy <hidden>
Date: 2021-09-13 17:15:01


Le 13/09/2021 à 17:57, Eric W. Biederman a écrit :
Christophe Leroy [off-list ref] writes:
quoted
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 <redacted>
---
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
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