[2/3] ARC: introduce explicit support for atomics

Submitted by Vineet Gupta on Nov. 8, 2016, 12:31 a.m.

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Message ID 1478565100-23924-3-git-send-email-vgupta@synopsys.com
State New
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Commit Message

Vineet Gupta Nov. 8, 2016, 12:31 a.m.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 extra/Configs/Config.arc | 8 ++++++++
 1 file changed, 8 insertions(+)

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diff --git a/extra/Configs/Config.arc b/extra/Configs/Config.arc
index 0c0bc71ce2fc..c263dbf46028 100644
--- a/extra/Configs/Config.arc
+++ b/extra/Configs/Config.arc
@@ -28,6 +28,14 @@  config CONFIG_ARC_CPU_HS
 
 endchoice
 
+config CONFIG_ARC_HAS_ATOMICS
+	bool "Support for LLOCK/SCOND instructions"
+	default y
+	help
+	  LLOCK/SCOND instructions are needed to implement atomic r-m-w
+	  Otherwise libc needs kernel assisted atomic cmpxchg available
+	  since v4.9 kernel
+
 choice
 	prompt "MMU Page Size"
 	default CONFIG_ARC_PAGE_SIZE_8K