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authorIan Campbell <ian.campbell@citrix.com>2013-02-20 11:48:06 +0000
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-02-20 08:45:07 -0500
commitc81611c4e96f595a80d8be9367c385d2c116428b (patch)
tree94c1b31034506d8b73b6d9b2c2e0e2331d0fd450 /arch/arm/include
parent76eaca031f0af2bb303e405986f637811956a422 (diff)
downloadlinux-c81611c4e96f595a80d8be9367c385d2c116428b.tar.gz
xen: event channel arrays are xen_ulong_t and not unsigned long
On ARM we want these to be the same size on 32- and 64-bit. This is an ABI change on ARM. X86 does not change. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Keir (Xen.org) <keir@xen.org> Cc: Tim Deegan <tim@xen.org> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: linux-arm-kernel@lists.infradead.org Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch/arm/include')
-rw-r--r--arch/arm/include/asm/xen/events.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
index 94b4e9020b0..5c27696de14 100644
--- a/arch/arm/include/asm/xen/events.h
+++ b/arch/arm/include/asm/xen/events.h
@@ -15,4 +15,26 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
return raw_irqs_disabled_flags(regs->ARM_cpsr);
}
+/*
+ * We cannot use xchg because it does not support 8-byte
+ * values. However it is safe to use {ldr,dtd}exd directly because all
+ * platforms which Xen can run on support those instructions.
+ */
+static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
+{
+ xen_ulong_t oldval;
+ unsigned int tmp;
+
+ wmb();
+ asm volatile("@ xchg_xen_ulong\n"
+ "1: ldrexd %0, %H0, [%3]\n"
+ " strexd %1, %2, %H2, [%3]\n"
+ " teq %1, #0\n"
+ " bne 1b"
+ : "=&r" (oldval), "=&r" (tmp)
+ : "r" (val), "r" (ptr)
+ : "memory", "cc");
+ return oldval;
+}
+
#endif /* _ASM_ARM_XEN_EVENTS_H */