[PATCH AUTOSEL 4.14 05/14] parisc: Provide an extru_safe() macro to extract unsigned bits

[Sasha Levin]

From: Helge Deller <deller@xxxxxx>

[ Upstream commit 169d1a4a2adb2c246396c56aa2f9eec3868546f1 ]

The extru instruction leaves the most significant 32 bits of the
target register in an undefined state on PA 2.0 systems.
Provide a macro to safely use extru on 32- and 64-bit machines.

Suggested-by: John David Anglin <dave.anglin@xxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/parisc/include/asm/assembly.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index eb83d65153b83..2272cbeb65f22 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -153,6 +153,17 @@
 	extrd,u \r, 63-(\sa), 64-(\sa), \t
 	.endm
 
+	/* Extract unsigned for 32- and 64-bit
+	 * The extru instruction leaves the most significant 32 bits of the
+	 * target register in an undefined state on PA 2.0 systems. */
+	.macro extru_safe r, p, len, t
+#ifdef CONFIG_64BIT
+	extrd,u	\r, 32+(\p), \len, \t
+#else
+	extru	\r, \p, \len, \t
+#endif
+	.endm
+
 	/* load 32-bit 'value' into 'reg' compensating for the ldil
 	 * sign-extension when running in wide mode.
 	 * WARNING!! neither 'value' nor 'reg' can be expressions
-- 
2.33.0