1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #include <linux/linkage.h> 4 #include <asm/errno.h> 5 #include <asm/enclu.h> 6 7 #include "extable.h" 8 9 /* Relative to %rbp. */ 10 #define SGX_ENCLAVE_OFFSET_OF_RUN 16 11 12 /* The offsets relative to struct sgx_enclave_run. */ 13 #define SGX_ENCLAVE_RUN_TCS 0 14 #define SGX_ENCLAVE_RUN_LEAF 8 15 #define SGX_ENCLAVE_RUN_EXCEPTION_VECTOR 12 16 #define SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE 14 17 #define SGX_ENCLAVE_RUN_EXCEPTION_ADDR 16 18 #define SGX_ENCLAVE_RUN_USER_HANDLER 24 19 #define SGX_ENCLAVE_RUN_USER_DATA 32 /* not used */ 20 #define SGX_ENCLAVE_RUN_RESERVED_START 40 21 #define SGX_ENCLAVE_RUN_RESERVED_END 256 22 23 .code64 24 .section .text, "ax" 25 26 SYM_FUNC_START(__vdso_sgx_enter_enclave) 27 /* Prolog */ 28 .cfi_startproc 29 push %rbp 30 .cfi_adjust_cfa_offset 8 31 .cfi_rel_offset %rbp, 0 32 mov %rsp, %rbp 33 .cfi_def_cfa_register %rbp 34 push %rbx 35 .cfi_rel_offset %rbx, -8 36 37 mov %ecx, %eax 38 .Lenter_enclave: 39 /* EENTER <= function <= ERESUME */ 40 cmp $EENTER, %eax 41 jb .Linvalid_input 42 cmp $ERESUME, %eax 43 ja .Linvalid_input 44 45 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rcx 46 47 /* Validate that the reserved area contains only zeros. */ 48 mov $SGX_ENCLAVE_RUN_RESERVED_START, %rbx 49 1: 50 cmpq $0, (%rcx, %rbx) 51 jne .Linvalid_input 52 add $8, %rbx 53 cmpq $SGX_ENCLAVE_RUN_RESERVED_END, %rbx 54 jne 1b 55 56 /* Load TCS and AEP */ 57 mov SGX_ENCLAVE_RUN_TCS(%rcx), %rbx 58 lea .Lasync_exit_pointer(%rip), %rcx 59 60 /* Single ENCLU serving as both EENTER and AEP (ERESUME) */ 61 .Lasync_exit_pointer: 62 .Lenclu_eenter_eresume: 63 enclu 64 65 /* EEXIT jumps here unless the enclave is doing something fancy. */ 66 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx 67 68 /* Set exit_reason. */ 69 movl $EEXIT, SGX_ENCLAVE_RUN_LEAF(%rbx) 70 71 /* Invoke userspace's exit handler if one was provided. */ 72 .Lhandle_exit: 73 cmpq $0, SGX_ENCLAVE_RUN_USER_HANDLER(%rbx) 74 jne .Linvoke_userspace_handler 75 76 /* Success, in the sense that ENCLU was attempted. */ 77 xor %eax, %eax 78 79 .Lout: 80 pop %rbx 81 leave 82 .cfi_def_cfa %rsp, 8 83 RET 84 85 /* The out-of-line code runs with the pre-leave stack frame. */ 86 .cfi_def_cfa %rbp, 16 87 88 .Linvalid_input: 89 mov $(-EINVAL), %eax 90 jmp .Lout 91 92 .Lhandle_exception: 93 mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx 94 95 /* Set the exception info. */ 96 mov %eax, (SGX_ENCLAVE_RUN_LEAF)(%rbx) 97 mov %di, (SGX_ENCLAVE_RUN_EXCEPTION_VECTOR)(%rbx) 98 mov %si, (SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE)(%rbx) 99 mov %rdx, (SGX_ENCLAVE_RUN_EXCEPTION_ADDR)(%rbx) 100 jmp .Lhandle_exit 101 102 .Linvoke_userspace_handler: 103 /* Pass the untrusted RSP (at exit) to the callback via %rcx. */ 104 mov %rsp, %rcx 105 106 /* Save struct sgx_enclave_exception %rbx is about to be clobbered. */ 107 mov %rbx, %rax 108 109 /* Save the untrusted RSP offset in %rbx (non-volatile register). */ 110 mov %rsp, %rbx 111 and $0xf, %rbx 112 113 /* 114 * Align stack per x86_64 ABI. Note, %rsp needs to be 16-byte aligned 115 * _after_ pushing the parameters on the stack, hence the bonus push. 116 */ 117 and $-0x10, %rsp 118 push %rax 119 120 /* Push struct sgx_enclave_exception as a param to the callback. */ 121 push %rax 122 123 /* Clear RFLAGS.DF per x86_64 ABI */ 124 cld 125 126 /* 127 * Load the callback pointer to %rax and lfence for LVI (load value 128 * injection) protection before making the call. 129 */ 130 mov SGX_ENCLAVE_RUN_USER_HANDLER(%rax), %rax 131 lfence 132 call *%rax 133 134 /* Undo the post-exit %rsp adjustment. */ 135 lea 0x10(%rsp, %rbx), %rsp 136 137 /* 138 * If the return from callback is zero or negative, return immediately, 139 * else re-execute ENCLU with the positive return value interpreted as 140 * the requested ENCLU function. 141 */ 142 cmp $0, %eax 143 jle .Lout 144 jmp .Lenter_enclave 145 146 .cfi_endproc 147 148 _ASM_VDSO_EXTABLE_HANDLE(.Lenclu_eenter_eresume, .Lhandle_exception) 149 150 SYM_FUNC_END(__vdso_sgx_enter_enclave)
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