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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-11-08 15:28:05 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-11-08 15:28:05 -0500
commitbad97817dece759dd6c0b24f862b7d0ed588edda (patch)
treefcabaa3ae3e2f17236135e60dc875f47e852cc6d /include/linux/timex.h
parent6fe19278ffebdd57e5c5ec10275e6d423404364e (diff)
parent61e6cfa80de5760bbe406f4e815b7739205754d2 (diff)
Merge tag 'v3.12-rc5' into stable/for-linus-3.13
Linux 3.12-rc5 Because the Stefano branch (for SWIOTLB ARM changes) is based on that. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> * tag 'v3.12-rc5': (550 commits) Linux 3.12-rc5 watchdog: sunxi: Fix section mismatch watchdog: kempld_wdt: Fix bit mask definition watchdog: ts72xx_wdt: locking bug in ioctl ARM: exynos: dts: Update 5250 arch timer node with clock frequency parisc: let probe_kernel_read() capture access to page zero parisc: optimize variable initialization in do_page_fault parisc: fix interruption handler to respect pagefault_disable() parisc: mark parisc_terminate() noreturn and cold. parisc: remove unused syscall_ipi() function. parisc: kill SMP single function call interrupt parisc: Export flush_cache_page() (needed by lustre) vfs: allow O_PATH file descriptors for fstatfs() ext4: fix memory leak in xattr ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc" ALSA: hda - Sony VAIO Pro 13 (haswell) now has a working headset jack ALSA: hda - Add a headset mic model for ALC269 and friends ALSA: hda - Fix microphone for Sony VAIO Pro 13 (Haswell model) compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Revert "i915: Update VGA arbiter support for newer devices" ...
Diffstat (limited to 'include/linux/timex.h')
-rw-r--r--include/linux/timex.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/timex.h b/include/linux/timex.h
index dd3edd7dfc94..9d3f1a5b6178 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -64,6 +64,20 @@
#include <asm/timex.h>
+#ifndef random_get_entropy
+/*
+ * The random_get_entropy() function is used by the /dev/random driver
+ * in order to extract entropy via the relative unpredictability of
+ * when an interrupt takes places versus a high speed, fine-grained
+ * timing source or cycle counter. Since it will be occurred on every
+ * single interrupt, it must have a very low cost/overhead.
+ *
+ * By default we use get_cycles() for this purpose, but individual
+ * architectures may override this in their asm/timex.h header file.
+ */
+#define random_get_entropy() get_cycles()
+#endif
+
/*
* SHIFT_PLL is used as a dampening factor to define how much we
* adjust the frequency correction for a given offset in PLL mode.