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authorMark Brown <[email protected]>2015-06-10 18:31:55 +0100
committerMark Brown <[email protected]>2015-06-10 18:31:55 +0100
commit5ae4f63b5062bc4e329940cc5cecdf0856b85849 (patch)
tree63f389874f6d330f84a9d36abec2c127bd71066e /include/linux/compiler-gcc.h
parentfb5ab0e7473d41e2a9db0fcb569faf337d595838 (diff)
parent11e688862c4c8162119a4ca51c3326555966c8bb (diff)
Merge tag 'asoc-v4.2' into asoc-rt5645
ASoC: Updates for v4.2 The big thing this release has been Liam's addition of topology support to the core. We've also seen quite a bit of driver work and the continuation of Lars' refactoring for component support. - Support for loading ASoC topology maps from firmware, intended to be used to allow self-describing DSP firmware images to be built which can map controls added by the DSP to userspace without the kernel needing to know about individual DSP firmwares. - Lots of refactoring to avoid direct access to snd_soc_codec where it's not needed supporting future refactoring. - Big refactoring and cleanup serieses for the Wolfson ADSP and TI TAS2552 drivers. - Support for TI TAS571x power amplifiers. - Support for Qualcomm APQ8016 and ZTE ZX296702 SoCs. - Support for x86 systems with RT5650 and Qualcomm Storm.
Diffstat (limited to 'include/linux/compiler-gcc.h')
-rw-r--r--include/linux/compiler-gcc.h16
1 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index cdf13ca7cac3..371e560d13cf 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -9,10 +9,24 @@
+ __GNUC_MINOR__ * 100 \
+ __GNUC_PATCHLEVEL__)
-
/* Optimization barrier */
+
/* The "volatile" is due to gcc bugs */
#define barrier() __asm__ __volatile__("": : :"memory")
+/*
+ * This version is i.e. to prevent dead stores elimination on @ptr
+ * where gcc and llvm may behave differently when otherwise using
+ * normal barrier(): while gcc behavior gets along with a normal
+ * barrier(), llvm needs an explicit input variable to be assumed
+ * clobbered. The issue is as follows: while the inline asm might
+ * access any memory it wants, the compiler could have fit all of
+ * @ptr into memory registers instead, and since @ptr never escaped
+ * from that, it proofed that the inline asm wasn't touching any of
+ * it. This version works well with both compilers, i.e. we're telling
+ * the compiler that the inline asm absolutely may see the contents
+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
+ */
+#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
/*
* This macro obfuscates arithmetic on a variable address so that gcc