1 /****************************************************************************** 2 * hypercall.S 3 * 4 * Xen hypercall wrappers 5 * 6 * Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License version 2 10 * as published by the Free Software Foundation; or, when distributed 11 * separately from the Linux kernel or incorporated into other 12 * software packages, subject to the following license: 13 * 14 * Permission is hereby granted, free of charge, to any person obtaining a copy 15 * of this source file (the "Software"), to deal in the Software without 16 * restriction, including without limitation the rights to use, copy, modify, 17 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 18 * and to permit persons to whom the Software is furnished to do so, subject to 19 * the following conditions: 20 * 21 * The above copyright notice and this permission notice shall be included in 22 * all copies or substantial portions of the Software. 23 * 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 30 * IN THE SOFTWARE. 31 */ 32 33 /* 34 * The Xen hypercall calling convention is very similar to the procedure 35 * call standard for the ARM 64-bit architecture: the first parameter is 36 * passed in x0, the second in x1, the third in x2, the fourth in x3 and 37 * the fifth in x4. 38 * 39 * The hypercall number is passed in x16. 40 * 41 * The return value is in x0. 42 * 43 * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM 44 * hypercall tag. 45 * 46 * Parameter structs passed to hypercalls are laid out according to 47 * the ARM 64-bit EABI standard. 48 */ 49 50 #include <linux/linkage.h> 51 #include <asm/assembler.h> 52 #include <asm/asm-uaccess.h> 53 #include <xen/interface/xen.h> 54 55 56 #define XEN_IMM 0xEA1 57 58 #define HYPERCALL_SIMPLE(hypercall) \ 59 ENTRY(HYPERVISOR_##hypercall) \ 60 mov x16, #__HYPERVISOR_##hypercall; \ 61 hvc XEN_IMM; \ 62 ret; \ 63 ENDPROC(HYPERVISOR_##hypercall) 64 65 #define HYPERCALL0 HYPERCALL_SIMPLE 66 #define HYPERCALL1 HYPERCALL_SIMPLE 67 #define HYPERCALL2 HYPERCALL_SIMPLE 68 #define HYPERCALL3 HYPERCALL_SIMPLE 69 #define HYPERCALL4 HYPERCALL_SIMPLE 70 #define HYPERCALL5 HYPERCALL_SIMPLE 71 72 .text 73 74 HYPERCALL2(xen_version); 75 HYPERCALL3(console_io); 76 HYPERCALL3(grant_table_op); 77 HYPERCALL2(sched_op); 78 HYPERCALL2(event_channel_op); 79 HYPERCALL2(hvm_op); 80 HYPERCALL2(memory_op); 81 HYPERCALL2(physdev_op); 82 HYPERCALL3(vcpu_op); 83 HYPERCALL1(tmem_op); 84 HYPERCALL1(platform_op_raw); 85 HYPERCALL2(multicall); 86 HYPERCALL2(vm_assist); 87 HYPERCALL3(dm_op); 88 89 ENTRY(privcmd_call) 90 mov x16, x0 91 mov x0, x1 92 mov x1, x2 93 mov x2, x3 94 mov x3, x4 95 mov x4, x5 96 /* 97 * Privcmd calls are issued by the userspace. The kernel needs to 98 * enable access to TTBR0_EL1 as the hypervisor would issue stage 1 99 * translations to user memory via AT instructions. Since AT 100 * instructions are not affected by the PAN bit (ARMv8.1), we only 101 * need the explicit uaccess_enable/disable if the TTBR0 PAN emulation 102 * is enabled (it implies that hardware UAO and PAN disabled). 103 */ 104 uaccess_ttbr0_enable x6, x7, x8 105 hvc XEN_IMM 106 107 /* 108 * Disable userspace access from kernel once the hyp call completed. 109 */ 110 uaccess_ttbr0_disable x6, x7 111 ret 112 ENDPROC(privcmd_call);