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Diffstat (limited to 'arch/arm/xen/hypercall.S')
| -rw-r--r-- | arch/arm/xen/hypercall.S | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S new file mode 100644 index 000000000..b11bba542 --- /dev/null +++ b/arch/arm/xen/hypercall.S @@ -0,0 +1,122 @@ +/****************************************************************************** + * 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) is called before. + */ + uaccess_disable r4 + + ldm sp!, {r4} + ret lr +ENDPROC(privcmd_call); |