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Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/xen/hypercall.S | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/arch/arm64/xen/hypercall.S b/arch/arm64/xen/hypercall.S new file mode 100644 index 000000000..9d0136169 --- /dev/null +++ b/arch/arm64/xen/hypercall.S @@ -0,0 +1,111 @@ +/****************************************************************************** + * 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 procedure + * call standard for the ARM 64-bit architecture: the first parameter is + * passed in x0, the second in x1, the third in x2, the fourth in x3 and + * the fifth in x4. + * + * The hypercall number is passed in x16. + * + * The return value is in x0. + * + * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM + * hypercall tag. + * + * Parameter structs passed to hypercalls are laid out according to + * the ARM 64-bit EABI standard. + */ + +#include <linux/linkage.h> +#include <asm/assembler.h> +#include <asm/asm-uaccess.h> +#include <xen/interface/xen.h> + + +#define XEN_IMM 0xEA1 + +#define HYPERCALL_SIMPLE(hypercall) \ +SYM_FUNC_START(HYPERVISOR_##hypercall) \ + mov x16, #__HYPERVISOR_##hypercall; \ + hvc XEN_IMM; \ + ret; \ +SYM_FUNC_END(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_SIMPLE + + .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(platform_op_raw); +HYPERCALL2(multicall); +HYPERCALL2(vm_assist); +HYPERCALL3(dm_op); + +SYM_FUNC_START(privcmd_call) + mov x16, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + mov x3, x4 + mov x4, x5 + /* + * Privcmd calls are issued by the userspace. The kernel needs to + * enable access to TTBR0_EL1 as the hypervisor would issue stage 1 + * translations to user memory via AT instructions. Since AT + * instructions are not affected by the PAN bit (ARMv8.1), we only + * need the explicit uaccess_enable/disable if the TTBR0 PAN emulation + * is enabled (it implies that hardware UAO and PAN disabled). + */ + uaccess_ttbr0_enable x6, x7, x8 + hvc XEN_IMM + + /* + * Disable userspace access from kernel once the hyp call completed. + */ + uaccess_ttbr0_disable x6, x7 + ret +SYM_FUNC_END(privcmd_call); |