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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-07 13:55:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-07 13:55:45 -0700
commitd691b7e7d1b5186eae62fd32adee65d3316bfdf6 (patch)
tree3808f7deab74f68267b9fdd6a35dcda9e50142aa /include/linux
parentb59eea554f57befa2aa3172fcb63e521bdd850dd (diff)
parent1e0fc9d1eb2b0241a03e0a02bcdb9b5b641b9d35 (diff)
Merge tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman: "Highlights include: - Support for STRICT_KERNEL_RWX on 64-bit server CPUs. - Platform support for FSP2 (476fpe) board - Enable ZONE_DEVICE on 64-bit server CPUs. - Generic & powerpc spin loop primitives to optimise busy waiting - Convert VDSO update function to use new update_vsyscall() interface - Optimisations to hypercall/syscall/context-switch paths - Improvements to the CPU idle code on Power8 and Power9. As well as many other fixes and improvements. Thanks to: Akshay Adiga, Andrew Donnellan, Andrew Jeffery, Anshuman Khandual, Anton Blanchard, Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe Lombard, Colin Ian King, Dan Carpenter, Gautham R. Shenoy, Hari Bathini, Ian Munsie, Ivan Mikhaylov, Javier Martinez Canillas, Madhavan Srinivasan, Masahiro Yamada, Matt Brown, Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pavel Machek, Russell Currey, Santosh Sivaraj, Stephen Rothwell, Thiago Jung Bauermann, Yang Li" * tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits) powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs powerpc/mm/radix: Implement STRICT_RWX/mark_rodata_ro() for Radix powerpc/mm/hash: Implement mark_rodata_ro() for hash powerpc/vmlinux.lds: Align __init_begin to 16M powerpc/lib/code-patching: Use alternate map for patch_instruction() powerpc/xmon: Add patch_instruction() support for xmon powerpc/kprobes/optprobes: Use patch_instruction() powerpc/kprobes: Move kprobes over to patch_instruction() powerpc/mm/radix: Fix execute permissions for interrupt_vectors powerpc/pseries: Fix passing of pp0 in updatepp() and updateboltedpp() powerpc/64s: Blacklist rtas entry/exit from kprobes powerpc/64s: Blacklist functions invoked on a trap powerpc/64s: Un-blacklist system_call() from kprobes powerpc/64s: Move system_call() symbol to just after setting MSR_EE powerpc/64s: Blacklist system_call() and system_call_common() from kprobes powerpc/64s: Convert .L__replay_interrupt_return to a local label powerpc64/elfv1: Only dereference function descriptor for non-text symbols cxl: Export library to support IBM XSL powerpc/dts: Use #include "..." to include local DT powerpc/perf/hv-24x7: Aggregate result elements on POWER9 SMT8 ...
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/processor.h70
1 files changed, 70 insertions, 0 deletions
diff --git a/include/linux/processor.h b/include/linux/processor.h
new file mode 100644
index 000000000000..da0c5e56ca02
--- /dev/null
+++ b/include/linux/processor.h
@@ -0,0 +1,70 @@
+/* Misc low level processor primitives */
+#ifndef _LINUX_PROCESSOR_H
+#define _LINUX_PROCESSOR_H
+
+#include <asm/processor.h>
+
+/*
+ * spin_begin is used before beginning a busy-wait loop, and must be paired
+ * with spin_end when the loop is exited. spin_cpu_relax must be called
+ * within the loop.
+ *
+ * The loop body should be as small and fast as possible, on the order of
+ * tens of instructions/cycles as a guide. It should and avoid calling
+ * cpu_relax, or any "spin" or sleep type of primitive including nested uses
+ * of these primitives. It should not lock or take any other resource.
+ * Violations of these guidelies will not cause a bug, but may cause sub
+ * optimal performance.
+ *
+ * These loops are optimized to be used where wait times are expected to be
+ * less than the cost of a context switch (and associated overhead).
+ *
+ * Detection of resource owner and decision to spin or sleep or guest-yield
+ * (e.g., spin lock holder vcpu preempted, or mutex owner not on CPU) can be
+ * tested within the loop body.
+ */
+#ifndef spin_begin
+#define spin_begin()
+#endif
+
+#ifndef spin_cpu_relax
+#define spin_cpu_relax() cpu_relax()
+#endif
+
+/*
+ * spin_cpu_yield may be called to yield (undirected) to the hypervisor if
+ * necessary. This should be used if the wait is expected to take longer
+ * than context switch overhead, but we can't sleep or do a directed yield.
+ */
+#ifndef spin_cpu_yield
+#define spin_cpu_yield() cpu_relax_yield()
+#endif
+
+#ifndef spin_end
+#define spin_end()
+#endif
+
+/*
+ * spin_until_cond can be used to wait for a condition to become true. It
+ * may be expected that the first iteration will true in the common case
+ * (no spinning), so that callers should not require a first "likely" test
+ * for the uncontended case before using this primitive.
+ *
+ * Usage and implementation guidelines are the same as for the spin_begin
+ * primitives, above.
+ */
+#ifndef spin_until_cond
+#define spin_until_cond(cond) \
+do { \
+ if (unlikely(!(cond))) { \
+ spin_begin(); \
+ do { \
+ spin_cpu_relax(); \
+ } while (!(cond)); \
+ spin_end(); \
+ } \
+} while (0)
+
+#endif
+
+#endif /* _LINUX_PROCESSOR_H */