diff options
Diffstat (limited to 'library/std/src/sys/sgx/abi/entry.S')
| -rw-r--r-- | library/std/src/sys/sgx/abi/entry.S | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/library/std/src/sys/sgx/abi/entry.S b/library/std/src/sys/sgx/abi/entry.S new file mode 100644 index 000000000..f61bcf06f --- /dev/null +++ b/library/std/src/sys/sgx/abi/entry.S @@ -0,0 +1,372 @@ +/* This symbol is used at runtime to figure out the virtual address that the */ +/* enclave is loaded at. */ +.section absolute +.global IMAGE_BASE +IMAGE_BASE: + +.section ".note.x86_64-fortanix-unknown-sgx", "", @note + .align 4 + .long 1f - 0f /* name length (not including padding) */ + .long 3f - 2f /* desc length (not including padding) */ + .long 1 /* type = NT_VERSION */ +0: .asciz "toolchain-version" /* name */ +1: .align 4 +2: .long 1 /* desc - toolchain version number, 32-bit LE */ +3: .align 4 + +.section .rodata +/* The XSAVE area needs to be a large chunk of readable memory, but since we are */ +/* going to restore everything to its initial state (XSTATE_BV=0), only certain */ +/* parts need to have a defined value. In particular: */ +/* */ +/* * MXCSR in the legacy area. This register is always restored if RFBM[1] or */ +/* RFBM[2] is set, regardless of the value of XSTATE_BV */ +/* * XSAVE header */ +.align 64 +.Lxsave_clear: +.org .+24 +.Lxsave_mxcsr: + .short 0x1f80 + +/* We can store a bunch of data in the gap between MXCSR and the XSAVE header */ + +/* The following symbols point at read-only data that will be filled in by the */ +/* post-linker. */ + +/* When using this macro, don't forget to adjust the linker version script! */ +.macro globvar name:req size:req + .global \name + .protected \name + .align \size + .size \name , \size + \name : + .org .+\size +.endm + /* The base address (relative to enclave start) of the heap area */ + globvar HEAP_BASE 8 + /* The heap size in bytes */ + globvar HEAP_SIZE 8 + /* Value of the RELA entry in the dynamic table */ + globvar RELA 8 + /* Value of the RELACOUNT entry in the dynamic table */ + globvar RELACOUNT 8 + /* The enclave size in bytes */ + globvar ENCLAVE_SIZE 8 + /* The base address (relative to enclave start) of the enclave configuration area */ + globvar CFGDATA_BASE 8 + /* Non-zero if debugging is enabled, zero otherwise */ + globvar DEBUG 1 + /* The base address (relative to enclave start) of the enclave text section */ + globvar TEXT_BASE 8 + /* The size in bytes of enclacve text section */ + globvar TEXT_SIZE 8 + /* The base address (relative to enclave start) of the enclave .eh_frame_hdr section */ + globvar EH_FRM_HDR_OFFSET 8 + /* The size in bytes of enclave .eh_frame_hdr section */ + globvar EH_FRM_HDR_LEN 8 + /* The base address (relative to enclave start) of the enclave .eh_frame section */ + globvar EH_FRM_OFFSET 8 + /* The size in bytes of enclacve .eh_frame section */ + globvar EH_FRM_LEN 8 + +.org .Lxsave_clear+512 +.Lxsave_header: + .int 0, 0 /* XSTATE_BV */ + .int 0, 0 /* XCOMP_BV */ + .org .+48 /* reserved bits */ + +.data +.Laborted: + .byte 0 + +/* TCS local storage section */ +.equ tcsls_tos, 0x00 /* initialized by loader to *offset* from image base to TOS */ +.equ tcsls_flags, 0x08 /* initialized by loader */ +.equ tcsls_flag_secondary, 0 /* initialized by loader; 0 = standard TCS, 1 = secondary TCS */ +.equ tcsls_flag_init_once, 1 /* initialized by loader to 0 */ +/* 14 unused bits */ +.equ tcsls_user_fcw, 0x0a +.equ tcsls_user_mxcsr, 0x0c +.equ tcsls_last_rsp, 0x10 /* initialized by loader to 0 */ +.equ tcsls_panic_last_rsp, 0x18 /* initialized by loader to 0 */ +.equ tcsls_debug_panic_buf_ptr, 0x20 /* initialized by loader to 0 */ +.equ tcsls_user_rsp, 0x28 +.equ tcsls_user_retip, 0x30 +.equ tcsls_user_rbp, 0x38 +.equ tcsls_user_r12, 0x40 +.equ tcsls_user_r13, 0x48 +.equ tcsls_user_r14, 0x50 +.equ tcsls_user_r15, 0x58 +.equ tcsls_tls_ptr, 0x60 +.equ tcsls_tcs_addr, 0x68 + +.macro load_tcsls_flag_secondary_bool reg:req comments:vararg + .ifne tcsls_flag_secondary /* to convert to a bool, must be the first bit */ + .abort + .endif + mov $(1<<tcsls_flag_secondary),%e\reg + and %gs:tcsls_flags,%\reg +.endm + +/* We place the ELF entry point in a separate section so it can be removed by + elf2sgxs */ +.section .text_no_sgx, "ax" +.Lelf_entry_error_msg: + .ascii "Error: This file is an SGX enclave which cannot be executed as a standard Linux binary.\nSee the installation guide at https://edp.fortanix.com/docs/installation/guide/ on how to use 'cargo run' or follow the steps at https://edp.fortanix.com/docs/tasks/deployment/ for manual deployment.\n" +.Lelf_entry_error_msg_end: + +.global elf_entry +.type elf_entry,function +elf_entry: +/* print error message */ + movq $2,%rdi /* write to stderr (fd 2) */ + lea .Lelf_entry_error_msg(%rip),%rsi + movq $.Lelf_entry_error_msg_end-.Lelf_entry_error_msg,%rdx +.Lelf_entry_call: + movq $1,%rax /* write() syscall */ + syscall + test %rax,%rax + jle .Lelf_exit /* exit on error */ + add %rax,%rsi + sub %rax,%rdx /* all chars written? */ + jnz .Lelf_entry_call + +.Lelf_exit: + movq $60,%rax /* exit() syscall */ + movq $1,%rdi /* exit code 1 */ + syscall + ud2 /* should not be reached */ +/* end elf_entry */ + +/* This code needs to be called *after* the enclave stack has been setup. */ +/* There are 3 places where this needs to happen, so this is put in a macro. */ +.macro entry_sanitize_final +/* Sanitize rflags received from user */ +/* - DF flag: x86-64 ABI requires DF to be unset at function entry/exit */ +/* - AC flag: AEX on misaligned memory accesses leaks side channel info */ + pushfq + andq $~0x40400, (%rsp) + popfq +/* check for abort */ + bt $0,.Laborted(%rip) + jc .Lreentry_panic +.endm + +.text +.global sgx_entry +.type sgx_entry,function +sgx_entry: +/* save user registers */ + mov %rcx,%gs:tcsls_user_retip + mov %rsp,%gs:tcsls_user_rsp + mov %rbp,%gs:tcsls_user_rbp + mov %r12,%gs:tcsls_user_r12 + mov %r13,%gs:tcsls_user_r13 + mov %r14,%gs:tcsls_user_r14 + mov %r15,%gs:tcsls_user_r15 + mov %rbx,%gs:tcsls_tcs_addr + stmxcsr %gs:tcsls_user_mxcsr + fnstcw %gs:tcsls_user_fcw + +/* check for debug buffer pointer */ + testb $0xff,DEBUG(%rip) + jz .Lskip_debug_init + mov %r10,%gs:tcsls_debug_panic_buf_ptr +.Lskip_debug_init: +/* reset cpu state */ + mov %rdx, %r10 + mov $-1, %rax + mov $-1, %rdx + xrstor .Lxsave_clear(%rip) + mov %r10, %rdx + +/* check if returning from usercall */ + mov %gs:tcsls_last_rsp,%r11 + test %r11,%r11 + jnz .Lusercall_ret +/* setup stack */ + mov %gs:tcsls_tos,%rsp /* initially, RSP is not set to the correct value */ + /* here. This is fixed below under "adjust stack". */ +/* check for thread init */ + bts $tcsls_flag_init_once,%gs:tcsls_flags + jc .Lskip_init +/* adjust stack */ + lea IMAGE_BASE(%rip),%rax + add %rax,%rsp + mov %rsp,%gs:tcsls_tos + entry_sanitize_final +/* call tcs_init */ +/* store caller-saved registers in callee-saved registers */ + mov %rdi,%rbx + mov %rsi,%r12 + mov %rdx,%r13 + mov %r8,%r14 + mov %r9,%r15 + load_tcsls_flag_secondary_bool di /* RDI = tcs_init() argument: secondary: bool */ + call tcs_init +/* reload caller-saved registers */ + mov %rbx,%rdi + mov %r12,%rsi + mov %r13,%rdx + mov %r14,%r8 + mov %r15,%r9 + jmp .Lafter_init +.Lskip_init: + entry_sanitize_final +.Lafter_init: +/* call into main entry point */ + load_tcsls_flag_secondary_bool cx /* RCX = entry() argument: secondary: bool */ + call entry /* RDI, RSI, RDX, R8, R9 passed in from userspace */ + mov %rax,%rsi /* RSI = return value */ + /* NOP: mov %rdx,%rdx */ /* RDX = return value */ + xor %rdi,%rdi /* RDI = normal exit */ +.Lexit: +/* clear general purpose register state */ + /* RAX overwritten by ENCLU */ + /* RBX set later */ + /* RCX overwritten by ENCLU */ + /* RDX contains return value */ + /* RSP set later */ + /* RBP set later */ + /* RDI contains exit mode */ + /* RSI contains return value */ + xor %r8,%r8 + xor %r9,%r9 + xor %r10,%r10 + xor %r11,%r11 + /* R12 ~ R15 set by sgx_exit */ +.Lsgx_exit: +/* clear extended register state */ + mov %rdx, %rcx /* save RDX */ + mov $-1, %rax + mov %rax, %rdx + xrstor .Lxsave_clear(%rip) + mov %rcx, %rdx /* restore RDX */ +/* clear flags */ + pushq $0 + popfq +/* restore user registers */ + mov %gs:tcsls_user_r12,%r12 + mov %gs:tcsls_user_r13,%r13 + mov %gs:tcsls_user_r14,%r14 + mov %gs:tcsls_user_r15,%r15 + mov %gs:tcsls_user_retip,%rbx + mov %gs:tcsls_user_rsp,%rsp + mov %gs:tcsls_user_rbp,%rbp + fldcw %gs:tcsls_user_fcw + ldmxcsr %gs:tcsls_user_mxcsr +/* exit enclave */ + mov $0x4,%eax /* EEXIT */ + enclu +/* end sgx_entry */ + +.Lreentry_panic: + orq $8,%rsp + jmp abort_reentry + +/* This *MUST* be called with 6 parameters, otherwise register information */ +/* might leak! */ +.global usercall +usercall: + test %rcx,%rcx /* check `abort` function argument */ + jnz .Lusercall_abort /* abort is set, jump to abort code (unlikely forward conditional) */ + jmp .Lusercall_save_state /* non-aborting usercall */ +.Lusercall_abort: +/* set aborted bit */ + movb $1,.Laborted(%rip) +/* save registers in DEBUG mode, so that debugger can reconstruct the stack */ + testb $0xff,DEBUG(%rip) + jz .Lusercall_noreturn +.Lusercall_save_state: +/* save callee-saved state */ + push %r15 + push %r14 + push %r13 + push %r12 + push %rbp + push %rbx + sub $8, %rsp + fstcw 4(%rsp) + stmxcsr (%rsp) + movq %rsp,%gs:tcsls_last_rsp +.Lusercall_noreturn: +/* clear general purpose register state */ + /* RAX overwritten by ENCLU */ + /* RBX set by sgx_exit */ + /* RCX overwritten by ENCLU */ + /* RDX contains parameter */ + /* RSP set by sgx_exit */ + /* RBP set by sgx_exit */ + /* RDI contains parameter */ + /* RSI contains parameter */ + /* R8 contains parameter */ + /* R9 contains parameter */ + xor %r10,%r10 + xor %r11,%r11 + /* R12 ~ R15 set by sgx_exit */ +/* extended registers/flags cleared by sgx_exit */ +/* exit */ + jmp .Lsgx_exit +.Lusercall_ret: + movq $0,%gs:tcsls_last_rsp +/* restore callee-saved state, cf. "save" above */ + mov %r11,%rsp + ldmxcsr (%rsp) + fldcw 4(%rsp) + add $8, %rsp + entry_sanitize_final + pop %rbx + pop %rbp + pop %r12 + pop %r13 + pop %r14 + pop %r15 +/* return */ + mov %rsi,%rax /* RAX = return value */ + /* NOP: mov %rdx,%rdx */ /* RDX = return value */ + pop %r11 + lfence + jmp *%r11 + +/* +The following functions need to be defined externally: +``` +// Called by entry code on re-entry after exit +extern "C" fn abort_reentry() -> !; + +// Called once when a TCS is first entered +extern "C" fn tcs_init(secondary: bool); + +// Standard TCS entrypoint +extern "C" fn entry(p1: u64, p2: u64, p3: u64, secondary: bool, p4: u64, p5: u64) -> (u64, u64); +``` +*/ + +.global get_tcs_addr +get_tcs_addr: + mov %gs:tcsls_tcs_addr,%rax + pop %r11 + lfence + jmp *%r11 + +.global get_tls_ptr +get_tls_ptr: + mov %gs:tcsls_tls_ptr,%rax + pop %r11 + lfence + jmp *%r11 + +.global set_tls_ptr +set_tls_ptr: + mov %rdi,%gs:tcsls_tls_ptr + pop %r11 + lfence + jmp *%r11 + +.global take_debug_panic_buf_ptr +take_debug_panic_buf_ptr: + xor %rax,%rax + xchg %gs:tcsls_debug_panic_buf_ptr,%rax + pop %r11 + lfence + jmp *%r11 |