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Date: Sun, 30 Apr 2017 13:44:58 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: Linus Torvalds <torvalds@...ux-foundation.org>
cc: LKML <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Ingo Molnar <mingo@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>
Subject: [GIT pull] x86 fixes for 4.11
Linus,
please pull the latest x86-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-for-linus
The final fixes for 4.11:
- Prevent a triple fault with function graph tracing triggered via suspend
to ram.
- Prevent optimizing for size when function graph tracing is enabled and
the compiler does not support -mfentry
- Prevent mwaitx() being called with a zero timeout as mwaitx() might
never return. Observed on the new Ryzen CPUs.
Thanks,
tglx
------------------>
Janakarajan Natarajan (1):
Prevent timer value 0 for MWAITX
Josh Poimboeuf (2):
ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram
x86/build: convert function graph '-Os' error to warning
arch/x86/Makefile | 8 ++++++++
arch/x86/kernel/ftrace.c | 18 ++++++++++++------
arch/x86/lib/delay.c | 7 +++++++
3 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index a94a4d10f2df..49d160b781f0 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -154,6 +154,14 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER
else
ifeq ($(call cc-option-yn, -mfentry), n)
ACCUMULATE_OUTGOING_ARGS := 1
+
+ # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
+ # If '-Os' is enabled, disable it and print a warning.
+ ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
+ undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
+ $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
+ endif
+
endif
endif
endif
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index cbd73eb42170..5b7153540727 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -29,12 +29,6 @@
#include <asm/ftrace.h>
#include <asm/nops.h>
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && \
- !defined(CC_USING_FENTRY) && \
- !defined(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE)
-# error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE
-#endif
-
#ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_arch_code_modify_prepare(void)
@@ -989,6 +983,18 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
unsigned long return_hooker = (unsigned long)
&return_to_handler;
+ /*
+ * When resuming from suspend-to-ram, this function can be indirectly
+ * called from early CPU startup code while the CPU is in real mode,
+ * which would fail miserably. Make sure the stack pointer is a
+ * virtual address.
+ *
+ * This check isn't as accurate as virt_addr_valid(), but it should be
+ * good enough for this purpose, and it's fast.
+ */
+ if (unlikely((long)__builtin_frame_address(0) >= 0))
+ return;
+
if (unlikely(ftrace_graph_is_dead()))
return;
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index a8e91ae89fb3..29df077cb089 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -93,6 +93,13 @@ static void delay_mwaitx(unsigned long __loops)
{
u64 start, end, delay, loops = __loops;
+ /*
+ * Timer value of 0 causes MWAITX to wait indefinitely, unless there
+ * is a store on the memory monitored by MONITORX.
+ */
+ if (loops == 0)
+ return;
+
start = rdtsc_ordered();
for (;;) {
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