From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
valentin.schneider@arm.com, brgerst@gmail.com,
jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
dvyukov@google.com, rostedt@goodmis.org
Subject: [PATCH 10/25] x86/uaccess,signal: Fix AC=1 bloat
Date: Mon, 18 Mar 2019 16:38:50 +0100 [thread overview]
Message-ID: <20190318155140.820823912@infradead.org> (raw)
In-Reply-To: 20190318153840.906404905@infradead.org
Occasionally GCC is less agressive with inlining and the following is
observed:
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x3cc: call to force_valid_ss.isra.5() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x384: call to frame_uc_flags.isra.0() with UACCESS enabled
Cure this by moving this code out of the AC=1 region, since it really
isn't needed for the user access.
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/signal.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -132,16 +132,6 @@ static int restore_sigcontext(struct pt_
COPY_SEG_CPL3(cs);
COPY_SEG_CPL3(ss);
-#ifdef CONFIG_X86_64
- /*
- * Fix up SS if needed for the benefit of old DOSEMU and
- * CRIU.
- */
- if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) &&
- user_64bit_mode(regs)))
- force_valid_ss(regs);
-#endif
-
get_user_ex(tmpflags, &sc->flags);
regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
regs->orig_ax = -1; /* disable syscall checks */
@@ -150,6 +140,15 @@ static int restore_sigcontext(struct pt_
buf = (void __user *)buf_val;
} get_user_catch(err);
+#ifdef CONFIG_X86_64
+ /*
+ * Fix up SS if needed for the benefit of old DOSEMU and
+ * CRIU.
+ */
+ if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs)))
+ force_valid_ss(regs);
+#endif
+
err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));
force_iret();
@@ -461,6 +460,7 @@ static int __setup_rt_frame(int sig, str
{
struct rt_sigframe __user *frame;
void __user *fp = NULL;
+ unsigned long uc_flags;
int err = 0;
frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
@@ -473,9 +473,11 @@ static int __setup_rt_frame(int sig, str
return -EFAULT;
}
+ uc_flags = frame_uc_flags(regs);
+
put_user_try {
/* Create the ucontext. */
- put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags);
+ put_user_ex(uc_flags, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
save_altstack_ex(&frame->uc.uc_stack, regs->sp);
@@ -541,6 +543,7 @@ static int x32_setup_rt_frame(struct ksi
{
#ifdef CONFIG_X86_X32_ABI
struct rt_sigframe_x32 __user *frame;
+ unsigned long uc_flags;
void __user *restorer;
int err = 0;
void __user *fpstate = NULL;
@@ -555,9 +558,11 @@ static int x32_setup_rt_frame(struct ksi
return -EFAULT;
}
+ uc_flags = frame_uc_flags(regs);
+
put_user_try {
/* Create the ucontext. */
- put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags);
+ put_user_ex(uc_flags, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
put_user_ex(0, &frame->uc.uc__pad0);
next prev parent reply other threads:[~2019-03-18 15:53 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 15:38 [PATCH 00/25] objtool: UACCESS validation v4 Peter Zijlstra
2019-03-18 15:38 ` [PATCH 01/25] x86: Make SMAP 64-bit only Peter Zijlstra
2019-03-18 16:58 ` Linus Torvalds
2019-03-18 17:36 ` Peter Zijlstra
2019-03-18 17:51 ` Peter Zijlstra
2019-03-18 18:10 ` Linus Torvalds
2019-03-21 17:12 ` hpa
2019-03-21 17:25 ` Denys Vlasenko
2019-03-21 18:18 ` hpa
2019-03-21 21:03 ` Peter Zijlstra
2019-03-21 18:21 ` Linus Torvalds
2019-03-19 11:16 ` [PATCH 01/25] sched/x86: Save [ER]FLAGS on context switch Peter Zijlstra
2019-03-18 15:38 ` [PATCH 02/25] tracing: Improve "if" macro code generation Peter Zijlstra
2019-03-18 17:41 ` Steven Rostedt
2019-03-18 23:37 ` Josh Poimboeuf
2019-03-19 10:11 ` Peter Zijlstra
2019-03-20 11:18 ` David Laight
2019-03-20 17:26 ` Linus Torvalds
2019-03-20 17:37 ` David Laight
2019-03-20 17:38 ` Linus Torvalds
2019-03-20 18:18 ` Steven Rostedt
2019-05-09 13:00 ` Steven Rostedt
2019-05-09 16:51 ` Linus Torvalds
2019-05-09 18:29 ` Steven Rostedt
2019-05-09 18:45 ` Josh Poimboeuf
2019-05-09 18:47 ` Josh Poimboeuf
2019-05-09 18:48 ` Randy Dunlap
2019-05-09 18:57 ` Josh Poimboeuf
2019-05-09 19:06 ` Steven Rostedt
2019-05-09 19:28 ` Steven Rostedt
2019-05-09 19:44 ` Linus Torvalds
2019-03-18 15:38 ` [PATCH 03/25] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-03-18 15:38 ` [PATCH 04/25] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-03-18 15:38 ` [PATCH 05/25] x86/uaccess: Move copy_user_handle_tail into asm Peter Zijlstra
2019-03-18 15:38 ` [PATCH 06/25] x86/uaccess: Fix up the fixup Peter Zijlstra
2019-03-18 15:38 ` [PATCH 07/25] x86/nospec,objtool: Introduce ANNOTATE_IGNORE_ALTERNATIVE Peter Zijlstra
2019-03-18 15:38 ` [PATCH 08/25] x86/uaccess,xen: Suppress SMAP warnings Peter Zijlstra
2019-03-18 15:38 ` [PATCH 09/25] x86/uaccess: Always inline user_access_begin() Peter Zijlstra
2019-03-18 15:38 ` Peter Zijlstra [this message]
2019-03-18 15:38 ` [PATCH 11/25] x86/uaccess: Introduce user_access_{save,restore}() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 12/25] x86/smap: Ditch __stringify() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 13/25] x86/uaccess,kasan: Fix KASAN vs SMAP Peter Zijlstra
2019-03-18 15:38 ` [PATCH 14/25] x86/uaccess,ubsan: Fix UBSAN " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 15/25] x86/uaccess,ftrace: Fix ftrace_likely_update() " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 16/25] x86/uaccess,kcov: Disable stack protector Peter Zijlstra
2019-03-18 15:38 ` [PATCH 17/25] objtool: Set insn->func for alternatives Peter Zijlstra
2019-03-18 15:38 ` [PATCH 18/25] objtool: Handle function aliases Peter Zijlstra
2019-03-18 15:38 ` [PATCH 19/25] objtool: Rewrite add_ignores() Peter Zijlstra
2019-03-18 15:39 ` [PATCH 20/25] objtool: Add --backtrace support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 21/25] objtool: Rewrite alt->skip_orig Peter Zijlstra
2019-03-18 15:39 ` [PATCH 22/25] objtool: Fix sibling call detection Peter Zijlstra
2019-03-18 15:39 ` [PATCH 23/25] objtool: Add UACCESS validation Peter Zijlstra
2019-03-18 23:51 ` Josh Poimboeuf
2019-05-07 11:52 ` Peter Zijlstra
2019-03-18 15:39 ` [PATCH 24/25] objtool: uaccess PUSHF/POPF support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 25/25] objtool: Add Direction Flag validation Peter Zijlstra
2019-03-18 23:57 ` [PATCH 00/25] objtool: UACCESS validation v4 Josh Poimboeuf
2019-03-19 11:20 ` Peter Zijlstra
2019-03-19 11:17 ` [PATCH 26/25] sched/x86_64: Don't save flags on context switch Peter Zijlstra
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