v4.19.13 snapshot.
diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S
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+/******************************************************************************
+ * hypercall.S
+ *
+ * Xen hypercall wrappers
+ *
+ * Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/*
+ * The Xen hypercall calling convention is very similar to the ARM
+ * procedure calling convention: the first paramter is passed in r0, the
+ * second in r1, the third in r2 and the fourth in r3. Considering that
+ * Xen hypercalls have 5 arguments at most, the fifth paramter is passed
+ * in r4, differently from the procedure calling convention of using the
+ * stack for that case.
+ *
+ * The hypercall number is passed in r12.
+ *
+ * The return value is in r0.
+ *
+ * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM
+ * hypercall tag.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/opcodes-virt.h>
+#include <xen/interface/xen.h>
+
+
+#define XEN_IMM 0xEA1
+
+#define HYPERCALL_SIMPLE(hypercall) \
+ENTRY(HYPERVISOR_##hypercall) \
+ mov r12, #__HYPERVISOR_##hypercall; \
+ __HVC(XEN_IMM); \
+ ret lr; \
+ENDPROC(HYPERVISOR_##hypercall)
+
+#define HYPERCALL0 HYPERCALL_SIMPLE
+#define HYPERCALL1 HYPERCALL_SIMPLE
+#define HYPERCALL2 HYPERCALL_SIMPLE
+#define HYPERCALL3 HYPERCALL_SIMPLE
+#define HYPERCALL4 HYPERCALL_SIMPLE
+
+#define HYPERCALL5(hypercall) \
+ENTRY(HYPERVISOR_##hypercall) \
+ stmdb sp!, {r4} \
+ ldr r4, [sp, #4] \
+ mov r12, #__HYPERVISOR_##hypercall; \
+ __HVC(XEN_IMM); \
+ ldm sp!, {r4} \
+ ret lr \
+ENDPROC(HYPERVISOR_##hypercall)
+
+ .text
+
+HYPERCALL2(xen_version);
+HYPERCALL3(console_io);
+HYPERCALL3(grant_table_op);
+HYPERCALL2(sched_op);
+HYPERCALL2(event_channel_op);
+HYPERCALL2(hvm_op);
+HYPERCALL2(memory_op);
+HYPERCALL2(physdev_op);
+HYPERCALL3(vcpu_op);
+HYPERCALL1(tmem_op);
+HYPERCALL1(platform_op_raw);
+HYPERCALL2(multicall);
+HYPERCALL2(vm_assist);
+HYPERCALL3(dm_op);
+
+ENTRY(privcmd_call)
+ stmdb sp!, {r4}
+ mov r12, r0
+ mov r0, r1
+ mov r1, r2
+ mov r2, r3
+ ldr r3, [sp, #8]
+ /*
+ * Privcmd calls are issued by the userspace. We need to allow the
+ * kernel to access the userspace memory before issuing the hypercall.
+ */
+ uaccess_enable r4
+
+ /* r4 is loaded now as we use it as scratch register before */
+ ldr r4, [sp, #4]
+ __HVC(XEN_IMM)
+
+ /*
+ * Disable userspace access from kernel. This is fine to do it
+ * unconditionally as no set_fs(KERNEL_DS)/set_fs(get_ds()) is
+ * called before.
+ */
+ uaccess_disable r4
+
+ ldm sp!, {r4}
+ ret lr
+ENDPROC(privcmd_call);