From c81611c4e96f595a80d8be9367c385d2c116428b Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Wed, 20 Feb 2013 11:48:06 +0000 Subject: 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 Cc: Jan Beulich Cc: Keir (Xen.org) Cc: Tim Deegan Cc: Stefano Stabellini Cc: linux-arm-kernel@lists.infradead.org Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk Signed-off-by: Konrad Rzeszutek Wilk --- arch/arm/include/asm/xen/events.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h index 94b4e9020b02..5c27696de14f 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 */ -- cgit v1.2.3