Merge tag 'zynqmp-soc-fixes-for-v5.10-rc6' of https://github.com/Xilinx/linux-xlnx into arm/fixes

arm64: soc: ZynqMP SoC fixes for v5.10-rc6

- Fix SD dll reset issue by using proper macro
- Fix PM feature checking for Xilinx Versal SoC

* tag 'zynqmp-soc-fixes-for-v5.10-rc6' of https://github.com/Xilinx/linux-xlnx: (337 commits)
  firmware: xilinx: Use hash-table for api feature check
  firmware: xilinx: Fix SD DLL node reset issue
  Linux 5.10-rc4
  kvm: mmu: fix is_tdp_mmu_check when the TDP MMU is not in use
  afs: Fix afs_write_end() when called with copied == 0 [ver #3]
  ocfs2: initialize ip_next_orphan
  panic: don't dump stack twice on warn
  hugetlbfs: fix anon huge page migration race
  mm: memcontrol: fix missing wakeup polling thread
  kernel/watchdog: fix watchdog_allowed_mask not used warning
  reboot: fix overflow parsing reboot cpu number
  Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint"
  compiler.h: fix barrier_data() on clang
  mm/gup: use unpin_user_pages() in __gup_longterm_locked()
  mm/slub: fix panic in slab_alloc_node()
  mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov
  mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit
  mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
  mm/compaction: count pages and stop correctly during page isolation
  drm/nouveau/kms/nv50-: Use atomic encoder callbacks everywhere
  ...

Link: https://lore.kernel.org/r/fd5ab967-f3cf-95fb-7947-5477ff85f97e@monstr.eu
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 16 insertions, 2 deletions

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index e512f5505dad..b8fe0c23cfff 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -80,11 +80,25 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 
 /* Optimization barrier */
 #ifndef barrier
-# define barrier() __memory_barrier()
+/* The "volatile" is due to gcc bugs */
+# define barrier() __asm__ __volatile__("": : :"memory")
 #endif
 
 #ifndef barrier_data
-# define barrier_data(ptr) barrier()
+/*
+ * 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 proved 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")
 #endif
 
 /* workaround for GCC PR82365 if needed */