From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: [PATCH] x86: kill handle_signal()->set_fs()
Date: Sun, 10 Jul 2011 18:44:24 +0200 [thread overview]
Message-ID: <20110710164424.GA20261@redhat.com> (raw)
handle_signal()->set_fs() has a nice comment which explains what
set_fs() is, but it doesn't explain why it is needed and why it
depends on CONFIG_X86_64.
Afaics, the history of this confusion is:
1. I guess today nobody can explain why it was needed
in arch/i386/kernel/signal.c, perhaps it was always
wrong. This predates 2.4.0 kernel.
2. then it was copy-and-past'ed to the new x86_64 arch.
3. then it was removed from i386 (but not from x86_64)
by b93b6ca3 "i386: remove unnecessary code".
4. then it was reintroduced under CONFIG_X86_64 when x86
unified i386 and x86_64, because the patch above didn't
touch x86_64.
Remove it. ->addr_limit should be correct. Even if it was possible
that it is wrong, it is too late to fix it after setup_rt_frame().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
arch/x86/kernel/signal.c | 9 ---------
1 file changed, 9 deletions(-)
--- ptrace/arch/x86/kernel/signal.c~1_kill_set_fs 2011-05-22 16:27:28.000000000 +0200
+++ ptrace/arch/x86/kernel/signal.c 2011-07-10 18:06:30.000000000 +0200
@@ -717,15 +717,6 @@ handle_signal(unsigned long sig, siginfo
if (ret)
return ret;
-#ifdef CONFIG_X86_64
- /*
- * This has nothing to do with segment registers,
- * despite the name. This magic affects uaccess.h
- * macros' behavior. Reset it to the normal setting.
- */
- set_fs(USER_DS);
-#endif
-
/*
* Clear the direction flag as per the ABI for function entry.
*/
next reply other threads:[~2011-07-10 16:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-10 16:44 Oleg Nesterov [this message]
2011-07-10 18:26 ` [PATCH] x86: kill handle_signal()->set_fs() H. Peter Anvin
2011-07-10 18:40 ` Oleg Nesterov
2011-07-14 19:02 ` Oleg Nesterov
2011-07-15 5:47 ` [tip:x86/signal] x86: Kill handle_signal()->set_fs() tip-bot for Oleg Nesterov
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