[PATCH 4.18 148/150] sparc: Fix syscall fallback bugs in VDSO.

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <davem@xxxxxxxxxxxxx>

[ Upstream commit 776ca1543b5fe673aaf1beb244fcc2429d378083 ]

First, the trap number for 32-bit syscalls is 0x10.

Also, only negate the return value when syscall error is indicated by
the carry bit being set.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/sparc/vdso/vclock_gettime.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/arch/sparc/vdso/vclock_gettime.c
+++ b/arch/sparc/vdso/vclock_gettime.c
@@ -33,9 +33,19 @@
 #define	TICK_PRIV_BIT	(1ULL << 63)
 #endif
 
+#ifdef	CONFIG_SPARC64
 #define SYSCALL_STRING							\
 	"ta	0x6d;"							\
-	"sub	%%g0, %%o0, %%o0;"					\
+	"bcs,a	1f;"							\
+	" sub	%%g0, %%o0, %%o0;"					\
+	"1:"
+#else
+#define SYSCALL_STRING							\
+	"ta	0x10;"							\
+	"bcs,a	1f;"							\
+	" sub	%%g0, %%o0, %%o0;"					\
+	"1:"
+#endif
 
 #define SYSCALL_CLOBBERS						\
 	"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",			\