1/* SPDX-License-Identifier: GPL-2.0 */ 2 3#include <linux/linkage.h> 4#include <asm/export.h> 5#include <asm/errno.h> 6#include <asm/enclu.h> 7 8#include "extable.h" 9 10/* Relative to %rbp. */ 11#define SGX_ENCLAVE_OFFSET_OF_RUN 16 12 13/* The offsets relative to struct sgx_enclave_run. */ 14#define SGX_ENCLAVE_RUN_TCS 0 15#define SGX_ENCLAVE_RUN_LEAF 8 16#define SGX_ENCLAVE_RUN_EXCEPTION_VECTOR 12 17#define SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE 14 18#define SGX_ENCLAVE_RUN_EXCEPTION_ADDR 16 19#define SGX_ENCLAVE_RUN_USER_HANDLER 24 20#define SGX_ENCLAVE_RUN_USER_DATA 32 /* not used */ 21#define SGX_ENCLAVE_RUN_RESERVED_START 40 22#define SGX_ENCLAVE_RUN_RESERVED_END 256 23 24.code64 25.section .text, "ax" 26 27SYM_FUNC_START(__vdso_sgx_enter_enclave) 28 /* Prolog */ 29 .cfi_startproc 30 push %rbp 31 .cfi_adjust_cfa_offset 8 32 .cfi_rel_offset %rbp, 0 33 mov %rsp, %rbp 34 .cfi_def_cfa_register %rbp 35 push %rbx 36 .cfi_rel_offset %rbx, -8 37 38 mov %ecx, %eax 39.Lenter_enclave: 40 /* EENTER <= function <= ERESUME */ 41 cmp $EENTER, %eax 42 jb .Linvalid_input 43 cmp $ERESUME, %eax 44 ja .Linvalid_input 45 46 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rcx 47 48 /* Validate that the reserved area contains only zeros. */ 49 mov $SGX_ENCLAVE_RUN_RESERVED_START, %rbx 501: 51 cmpq $0, (%rcx, %rbx) 52 jne .Linvalid_input 53 add $8, %rbx 54 cmpq $SGX_ENCLAVE_RUN_RESERVED_END, %rbx 55 jne 1b 56 57 /* Load TCS and AEP */ 58 mov SGX_ENCLAVE_RUN_TCS(%rcx), %rbx 59 lea .Lasync_exit_pointer(%rip), %rcx 60 61 /* Single ENCLU serving as both EENTER and AEP (ERESUME) */ 62.Lasync_exit_pointer: 63.Lenclu_eenter_eresume: 64 enclu 65 66 /* EEXIT jumps here unless the enclave is doing something fancy. */ 67 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx 68 69 /* Set exit_reason. */ 70 movl $EEXIT, SGX_ENCLAVE_RUN_LEAF(%rbx) 71 72 /* Invoke userspace's exit handler if one was provided. */ 73.Lhandle_exit: 74 cmpq $0, SGX_ENCLAVE_RUN_USER_HANDLER(%rbx) 75 jne .Linvoke_userspace_handler 76 77 /* Success, in the sense that ENCLU was attempted. */ 78 xor %eax, %eax 79 80.Lout: 81 pop %rbx 82 leave 83 .cfi_def_cfa %rsp, 8 84 ret 85 86 /* The out-of-line code runs with the pre-leave stack frame. */ 87 .cfi_def_cfa %rbp, 16 88 89.Linvalid_input: 90 mov $(-EINVAL), %eax 91 jmp .Lout 92 93.Lhandle_exception: 94 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx 95 96 /* Set the exception info. */ 97 mov %eax, (SGX_ENCLAVE_RUN_LEAF)(%rbx) 98 mov %di, (SGX_ENCLAVE_RUN_EXCEPTION_VECTOR)(%rbx) 99 mov %si, (SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE)(%rbx) 100 mov %rdx, (SGX_ENCLAVE_RUN_EXCEPTION_ADDR)(%rbx) 101 jmp .Lhandle_exit 102 103.Linvoke_userspace_handler: 104 /* Pass the untrusted RSP (at exit) to the callback via %rcx. */ 105 mov %rsp, %rcx 106 107 /* Save struct sgx_enclave_exception %rbx is about to be clobbered. */ 108 mov %rbx, %rax 109 110 /* Save the untrusted RSP offset in %rbx (non-volatile register). */ 111 mov %rsp, %rbx 112 and $0xf, %rbx 113 114 /* 115 * Align stack per x86_64 ABI. Note, %rsp needs to be 16-byte aligned 116 * _after_ pushing the parameters on the stack, hence the bonus push. 117 */ 118 and $-0x10, %rsp 119 push %rax 120 121 /* Push struct sgx_enclave_exception as a param to the callback. */ 122 push %rax 123 124 /* Clear RFLAGS.DF per x86_64 ABI */ 125 cld 126 127 /* 128 * Load the callback pointer to %rax and lfence for LVI (load value 129 * injection) protection before making the call. 130 */ 131 mov SGX_ENCLAVE_RUN_USER_HANDLER(%rax), %rax 132 lfence 133 call *%rax 134 135 /* Undo the post-exit %rsp adjustment. */ 136 lea 0x10(%rsp, %rbx), %rsp 137 138 /* 139 * If the return from callback is zero or negative, return immediately, 140 * else re-execute ENCLU with the postive return value interpreted as 141 * the requested ENCLU function. 142 */ 143 cmp $0, %eax 144 jle .Lout 145 jmp .Lenter_enclave 146 147 .cfi_endproc 148 149_ASM_VDSO_EXTABLE_HANDLE(.Lenclu_eenter_eresume, .Lhandle_exception) 150 151SYM_FUNC_END(__vdso_sgx_enter_enclave) 152