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authorLinus Torvalds <torvalds@linux-foundation.org>2017-04-30 11:44:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-04-30 11:44:18 -0700
commit97ce89f8a4eb15a1e82be419fcd6218fe4da1fbd (patch)
tree9860f04d4ddbb527d068493c233d2a2ed373b1e9
parent14e07f023ff6ed3e38850a9935a05b0b8e52fa49 (diff)
parent88d879d29f9cc0de2d930b584285638cdada6625 (diff)
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner: "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" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Prevent timer value 0 for MWAITX x86/build: convert function graph '-Os' error to warning ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram
-rw-r--r--arch/x86/Makefile8
-rw-r--r--arch/x86/kernel/ftrace.c18
-rw-r--r--arch/x86/lib/delay.c7
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 (;;) {