152 lines
3.6 KiB
ArmAsm
152 lines
3.6 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/linkage.h>
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#include <asm/export.h>
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#include <asm/errno.h>
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#include <asm/enclu.h>
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#include "extable.h"
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/* Relative to %rbp. */
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#define SGX_ENCLAVE_OFFSET_OF_RUN 16
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/* The offsets relative to struct sgx_enclave_run. */
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#define SGX_ENCLAVE_RUN_TCS 0
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#define SGX_ENCLAVE_RUN_LEAF 8
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#define SGX_ENCLAVE_RUN_EXCEPTION_VECTOR 12
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#define SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE 14
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#define SGX_ENCLAVE_RUN_EXCEPTION_ADDR 16
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#define SGX_ENCLAVE_RUN_USER_HANDLER 24
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#define SGX_ENCLAVE_RUN_USER_DATA 32 /* not used */
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#define SGX_ENCLAVE_RUN_RESERVED_START 40
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#define SGX_ENCLAVE_RUN_RESERVED_END 256
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.code64
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.section .text, "ax"
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SYM_FUNC_START(__vdso_sgx_enter_enclave)
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/* Prolog */
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.cfi_startproc
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push %rbp
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.cfi_adjust_cfa_offset 8
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.cfi_rel_offset %rbp, 0
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mov %rsp, %rbp
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.cfi_def_cfa_register %rbp
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push %rbx
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.cfi_rel_offset %rbx, -8
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mov %ecx, %eax
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.Lenter_enclave:
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/* EENTER <= function <= ERESUME */
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cmp $EENTER, %eax
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jb .Linvalid_input
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cmp $ERESUME, %eax
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ja .Linvalid_input
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mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rcx
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/* Validate that the reserved area contains only zeros. */
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mov $SGX_ENCLAVE_RUN_RESERVED_START, %rbx
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1:
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cmpq $0, (%rcx, %rbx)
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jne .Linvalid_input
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add $8, %rbx
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cmpq $SGX_ENCLAVE_RUN_RESERVED_END, %rbx
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jne 1b
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/* Load TCS and AEP */
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mov SGX_ENCLAVE_RUN_TCS(%rcx), %rbx
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lea .Lasync_exit_pointer(%rip), %rcx
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/* Single ENCLU serving as both EENTER and AEP (ERESUME) */
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.Lasync_exit_pointer:
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.Lenclu_eenter_eresume:
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enclu
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/* EEXIT jumps here unless the enclave is doing something fancy. */
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mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx
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/* Set exit_reason. */
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movl $EEXIT, SGX_ENCLAVE_RUN_LEAF(%rbx)
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/* Invoke userspace's exit handler if one was provided. */
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.Lhandle_exit:
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cmpq $0, SGX_ENCLAVE_RUN_USER_HANDLER(%rbx)
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jne .Linvoke_userspace_handler
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/* Success, in the sense that ENCLU was attempted. */
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xor %eax, %eax
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.Lout:
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pop %rbx
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leave
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.cfi_def_cfa %rsp, 8
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RET
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/* The out-of-line code runs with the pre-leave stack frame. */
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.cfi_def_cfa %rbp, 16
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.Linvalid_input:
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mov $(-EINVAL), %eax
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jmp .Lout
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.Lhandle_exception:
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mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx
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/* Set the exception info. */
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mov %eax, (SGX_ENCLAVE_RUN_LEAF)(%rbx)
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mov %di, (SGX_ENCLAVE_RUN_EXCEPTION_VECTOR)(%rbx)
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mov %si, (SGX_ENCLAVE_RUN_EXCEPTION_ERROR_CODE)(%rbx)
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mov %rdx, (SGX_ENCLAVE_RUN_EXCEPTION_ADDR)(%rbx)
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jmp .Lhandle_exit
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.Linvoke_userspace_handler:
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/* Pass the untrusted RSP (at exit) to the callback via %rcx. */
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mov %rsp, %rcx
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/* Save struct sgx_enclave_exception %rbx is about to be clobbered. */
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mov %rbx, %rax
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/* Save the untrusted RSP offset in %rbx (non-volatile register). */
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mov %rsp, %rbx
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and $0xf, %rbx
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/*
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* Align stack per x86_64 ABI. Note, %rsp needs to be 16-byte aligned
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* _after_ pushing the parameters on the stack, hence the bonus push.
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*/
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and $-0x10, %rsp
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push %rax
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/* Push struct sgx_enclave_exception as a param to the callback. */
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push %rax
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/* Clear RFLAGS.DF per x86_64 ABI */
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cld
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/*
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* Load the callback pointer to %rax and lfence for LVI (load value
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* injection) protection before making the call.
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*/
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mov SGX_ENCLAVE_RUN_USER_HANDLER(%rax), %rax
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lfence
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call *%rax
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/* Undo the post-exit %rsp adjustment. */
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lea 0x10(%rsp, %rbx), %rsp
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/*
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* If the return from callback is zero or negative, return immediately,
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* else re-execute ENCLU with the positive return value interpreted as
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* the requested ENCLU function.
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*/
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cmp $0, %eax
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jle .Lout
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jmp .Lenter_enclave
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.cfi_endproc
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_ASM_VDSO_EXTABLE_HANDLE(.Lenclu_eenter_eresume, .Lhandle_exception)
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SYM_FUNC_END(__vdso_sgx_enter_enclave)
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