kc3-lang/libffi/src/x86/ffitarget.h
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9ba55921 | 2021-03-05 10:07:30 | Static tramp v5 (#624) * Static Trampolines Closure Trampoline Security Issue ================================= Currently, the trampoline code used in libffi is not statically defined in a source file (except for MACH). The trampoline is either pre-defined machine code in a data buffer. Or, it is generated at runtime. In order to execute a trampoline, it needs to be placed in a page with executable permissions. Executable data pages are attack surfaces for attackers who may try to inject their own code into the page and contrive to have it executed. The security settings in a system may prevent various tricks used in user land to write code into a page and to have it executed somehow. On such systems, libffi trampolines would not be able to run. Static Trampoline ================= To solve this problem, the trampoline code needs to be defined statically in a source file, compiled and placed in the text segment so it can be mapped and executed naturally without any tricks. However, the trampoline needs to be able to access the closure pointer at runtime. PC-relative data referencing ============================ The solution implemented in this patch set uses PC-relative data references. The trampoline is mapped in a code page. Adjacent to the code page, a data page is mapped that contains the parameters of the trampoline: - the closure pointer - pointer to the ABI handler to jump to The trampoline code uses an offset relative to its current PC to access its data. Some architectures support PC-relative data references in the ISA itself. E.g., X64 supports RIP-relative references. For others, the PC has to somehow be loaded into a general purpose register to do PC-relative data referencing. To do this, we need to define a get_pc() kind of function and call it to load the PC in a desired register. There are two cases: 1. The call instruction pushes the return address on the stack. In this case, get_pc() will extract the return address from the stack and load it in the desired register and return. 2. The call instruction stores the return address in a designated register. In this case, get_pc() will copy the return address to the desired register and return. Either way, the PC next to the call instruction is obtained. Scratch register ================ In order to do its job, the trampoline code would need to use a scratch register. Depending on the ABI, there may not be a register available for scratch. This problem needs to be solved so that all ABIs will work. The trampoline will save two values on the stack: - the closure pointer - the original value of the scratch register This is what the stack will look like: sp before trampoline ------> -------------------- | closure pointer | -------------------- | scratch register | sp after trampoline -------> -------------------- The ABI handler can do the following as needed by the ABI: - the closure pointer can be loaded in a desired register - the scratch register can be restored to its original value - the stack pointer can be restored to its original value (the value when the trampoline was invoked) To do this, I have defined prolog code for each ABI handler. The legacy trampoline jumps to the ABI handler directly. But the static trampoline defined in this patch jumps tp the prolog code which performs the above actions before jumping to the ABI handler. Trampoline Table ================ In order to reduce the trampoline memory footprint, the trampoline code would be defined as a code array in the text segment. This array would be mapped into the address space of the caller. The mapping would, therefore, contain a trampoline table. Adjacent to the trampoline table mapping, there will be a data mapping that contains a parameter table, one parameter block for each trampoline. The parameter block will contain: - a pointer to the closure - a pointer to the ABI handler The static trampoline code would finally look like this: - Make space on the stack for the closure and the scratch register by moving the stack pointer down - Store the original value of the scratch register on the stack - Using PC-relative reference, get the closure pointer - Store the closure pointer on the stack - Using PC-relative reference, get the ABI handler pointer - Jump to the ABI handler Mapping size ============ The size of the code mapping that contains the trampoline table needs to be determined on a per architecture basis. If a particular architecture supports multiple base page sizes, then the largest supported base page size needs to be chosen. E.g., we choose 16K for ARM64. Trampoline allocation and free ============================== Static trampolines are allocated in ffi_closure_alloc() and freed in ffi_closure_free(). Normally, applications use these functions. But there are some cases out there where the user of libffi allocates and manages its own closure memory. In such cases, static trampolines cannot be used. These will fall back to using legacy trampolines. The user has to make sure that the memory is executable. ffi_closure structure ===================== I did not want to make any changes to the size of the closure structure for this feature to guarantee compatibility. But the opaque static trampoline handle needs to be stored in the closure. I have defined it as follows: - char tramp[FFI_TRAMPOLINE_SIZE]; + union { + char tramp[FFI_TRAMPOLINE_SIZE]; + void *ftramp; + }; If static trampolines are used, then tramp[] is not needed to store a dynamic trampoline. That space can be reused to store the handle. Hence, the union. Architecture Support ==================== Support has been added for x64, i386, aarch64 and arm. Support for other architectures can be added very easily in the future. OS Support ========== Support has been added for Linux. Support for other OSes can be added very easily. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> * x86: Support for Static Trampolines - Define the arch-specific initialization function ffi_tramp_arch () that returns trampoline size information to common code. - Define the trampoline code mapping and data mapping sizes. - Define the trampoline code table statically. Define two tables, actually, one with CET and one without. - Introduce a tiny prolog for each ABI handling function. The ABI handlers addressed are: - ffi_closure_unix64 - ffi_closure_unix64_sse - ffi_closure_win64 The prolog functions are called: - ffi_closure_unix64_alt - ffi_closure_unix64_sse_alt - ffi_closure_win64_alt The legacy trampoline jumps to the ABI handler. The static trampoline jumps to the prolog function. The prolog function uses the information provided by the static trampoline, sets things up for the ABI handler and then jumps to the ABI handler. - Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to initialize static trampoline parameters. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> * i386: Support for Static Trampolines - Define the arch-specific initialization function ffi_tramp_arch () that returns trampoline size information to common code. - Define the trampoline code table statically. Define two tables, actually, one with CET and one without. - Define the trampoline code table statically. - Introduce a tiny prolog for each ABI handling function. The ABI handlers addressed are: - ffi_closure_i386 - ffi_closure_STDCALL - ffi_closure_REGISTER The prolog functions are called: - ffi_closure_i386_alt - ffi_closure_STDCALL_alt - ffi_closure_REGISTER_alt The legacy trampoline jumps to the ABI handler. The static trampoline jumps to the prolog function. The prolog function uses the information provided by the static trampoline, sets things up for the ABI handler and then jumps to the ABI handler. - Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to initialize static trampoline parameters. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> * arm64: Support for Static Trampolines - Define the arch-specific initialization function ffi_tramp_arch () that returns trampoline size information to common code. - Define the trampoline code mapping and data mapping sizes. - Define the trampoline code table statically. - Introduce a tiny prolog for each ABI handling function. The ABI handlers addressed are: - ffi_closure_SYSV - ffi_closure_SYSV_V The prolog functions are called: - ffi_closure_SYSV_alt - ffi_closure_SYSV_V_alt The legacy trampoline jumps to the ABI handler. The static trampoline jumps to the prolog function. The prolog function uses the information provided by the static trampoline, sets things up for the ABI handler and then jumps to the ABI handler. - Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to initialize static trampoline parameters. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> * arm: Support for Static Trampolines - Define the arch-specific initialization function ffi_tramp_arch () that returns trampoline size information to common code. - Define the trampoline code mapping and data mapping sizes. - Define the trampoline code table statically. - Introduce a tiny prolog for each ABI handling function. The ABI handlers addressed are: - ffi_closure_SYSV - ffi_closure_VFP The prolog functions are called: - ffi_closure_SYSV_alt - ffi_closure_VFP_alt The legacy trampoline jumps to the ABI handler. The static trampoline jumps to the prolog function. The prolog function uses the information provided by the static trampoline, sets things up for the ABI handler and then jumps to the ABI handler. - Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to initialize static trampoline parameters. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> | |
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78556561 | 2020-02-21 19:08:06 | x86: Add indirect branch tracking support (#540) Intel Control-flow Enforcement Technology (CET): https://software.intel.com/en-us/articles/intel-sdm contains shadow stack (SHSTK) and indirect branch tracking (IBT). When CET is enabled, ELF object files must be marked with .note.gnu.property section. When Intel CET is enabled, include <cet.h> in assembly codes to mark Intel CET support. Also when IBT is enabled, all indirect branch targets must start with ENDBR instruction and notrack prefix can be used to disable IBT on indirect branch. <cet.h> defines _CET_ENDBR which can be used in assembly codes for ENDBR instruction. If <cet.h> isn't included, define _CET_ENDBR as empty so that _CET_ENDBR can be used in assembly codes. Trampoline must be enlarged to add ENDBR instruction unconditionally, which is NOP on non-CET processors. This is required regardless if libffi is enabled with CET since libffi.so will be marked in legacy bitmap, but trampoline won't. Update library version for larger FFI_TRAMPOLINE_SIZE. This fixed: https://github.com/libffi/libffi/issues/474 Tested with $ CC="gcc -Wl,-z,cet-report=error -fcf-protection" CXX="g++ -Wl,-z,cet-report=error -fcf-protection" .../configure on Linux CET machines in i686, x32 and x86-64 modes. | |
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369ef49f | 2018-03-18 12:53:42 | Add missing FFI_GNUW64 enum | |
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43980dd1 | 2018-03-18 12:32:10 | Add FFI_GNUW64 ABI for GNU 80-bit long double support | |
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9bc40d87 | 2018-03-18 12:32:10 | Add FFI_GWIN64 ABI for GNU 80-bit long double support | |
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1f6b5a91 | 2015-07-26 16:27:34 | Support the WIN64/EFI64 calling convention on all X86_64 platforms Add a new calling convention FFI_EFI64, alias FFI_WIN64, on all X86_64 platforms. This allows libffi compiled on a 64-bit x86 platform to call EFI functions. Compile in ffiw64.c and win64.S on all X86_64 platforms. When compiled for a platform other than X86_WIN64, ffiw64.c suffixes its functions with _efi64, to avoid conflict with the platform's actual implementations of those functions. | |
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7282d328 | 2014-12-22 17:14:40 | x86: MSVC does not support Complex type | |
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f8c64e24 | 2014-11-05 17:04:29 | x86: Add support for Go closures | |
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b21ec1ce | 2014-11-05 10:15:25 | x86: Rewrite closures Move everything into sysv.S, removing win32.S and freebsd.S. Handle all abis with a single ffi_closure_inner function. Move complexity of the raw THISCALL trampoline into assembly instead of the trampoline itself. Only push the context for the REGISTER abi; let the rest receive it in a register. | |
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99db4d42 | 2014-10-23 14:12:18 | win64: Rewrite It's way too different from the 32-bit ABIs with which it is currently associated. As seen from all of the existing XFAILs. | |
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b9ac94f3 | 2014-11-01 15:10:34 | x86: Rewrite ffi_call Decouple the assembly from FFI_TYPE_*. Merge prep_args with ffi_call, passing the frame and the stack to the assembly. Note that this patch isn't really standalone, as this breaks closures. | |
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ef762056 | 2014-10-30 12:13:31 | x86: Tidy ffi_abi The x86_64 unix port only handles one ABI; don't define all of the other symbols. The UNIX64 symbol retains the same value. The i386 ports ought to have the same symbols, even if we can't yet unify the values without incrementing the libffi soname. | |
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6b62fb4a | 2014-10-17 11:11:58 | x86-64: Support go closures Dumps all of the hand-coded unwind info for gas generated. Move jump table data into .rodata. Adjust ffi_call_unix64 to load the static chain. Split out sse portions of ffi_closure_unix64 to ffi_closure_unix64_sse rather than test cif->flags at runtime. | |
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6695983d | 2014-09-20 07:44:37 | Add complex type support. Mostly broken right now | |
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6e8a4460 | 2014-09-20 06:21:19 | 2014-07-22 Dominik Vogt <vogt@linux.vnet.ibm.com> * src/types.c (FFI_TYPEDEF, FFI_NONCONST_TYPEDEF): Merge the macros by adding another argument that controls whether the result is const or not (FFI_LDBL_CONST): Temporary macro to reduce ifdef confusion * src/prep_cif.c (ffi_prep_cif_core): Replace list of systems with new macro FFI_TARGET_SPECIFIC_STACK_SPACE_ALLOCATION * src/pa/ffitarget.h (FFI_TARGET_SPECIFIC_STACK_SPACE_ALLOCATION): Define. * src/s390/ffitarget.h (FFI_TARGET_SPECIFIC_STACK_SPACE_ALLOCATION): Define. * src/x86/ffitarget.h (FFI_TARGET_SPECIFIC_STACK_SPACE_ALLOCATION): Define. 2014-07-22 Dominik Vogt <vogt@linux.vnet.ibm.com> * doc/libffi.texi (Primitive Types): Document ffi_type_complex_float, ffi_type_complex_double and ffi_type_complex_longdouble (Complex Types): New subsection. (Complex Type Example): Ditto. * testsuite/libffi.call/cls_align_complex_double.c: New FFI_TYPE_COMPLEX test. * testsuite/libffi.call/cls_align_complex_float.c: Ditto. * testsuite/libffi.call/cls_align_complex_longdouble.c: Ditto. * testsuite/libffi.call/cls_complex_double.c: Ditto. * testsuite/libffi.call/cls_complex_float.c: Ditto. * testsuite/libffi.call/cls_complex_longdouble.c: Ditto. * testsuite/libffi.call/cls_complex_struct_double.c: Ditto. * testsuite/libffi.call/cls_complex_struct_float.c: Ditto. * testsuite/libffi.call/cls_complex_struct_longdouble.c: Ditto. * testsuite/libffi.call/cls_complex_va_double.c: Ditto. * testsuite/libffi.call/cls_complex_va_float.c: Ditto. * testsuite/libffi.call/cls_complex_va_longdouble.c: Ditto. * testsuite/libffi.call/complex_double.c: Ditto. * testsuite/libffi.call/complex_defs_double.c: Ditto. * testsuite/libffi.call/complex_float.c: Ditto. * testsuite/libffi.call/complex_defs_float.c: Ditto. * testsuite/libffi.call/complex_longdouble.c: Ditto. * testsuite/libffi.call/complex_defs_longdouble.c: Ditto. * testsuite/libffi.call/complex_int.c: Ditto. * testsuite/libffi.call/many_complex_double.c: Ditto. * testsuite/libffi.call/many_complex_float.c: Ditto. * testsuite/libffi.call/many_complex_longdouble.c: Ditto. * testsuite/libffi.call/return_complex1_double.c: Ditto. * testsuite/libffi.call/return_complex1_float.c: Ditto. * testsuite/libffi.call/return_complex1_longdouble.c: Ditto. * testsuite/libffi.call/return_complex2_double.c: Ditto. * testsuite/libffi.call/return_complex2_float.c: Ditto. * testsuite/libffi.call/return_complex2_longdouble.c: Ditto. * testsuite/libffi.call/return_complex_double.c: Ditto. * testsuite/libffi.call/return_complex_float.c: Ditto. * testsuite/libffi.call/return_complex_longdouble.c: Ditto. * src/raw_api.c (ffi_raw_to_ptrarray): Handle FFI_TYPE_COMPLEX (ffi_ptrarray_to_raw): Ditto. * src/prep_cif.c (ffi_prep_cif_core): Abort if FFI_TYPE_COMPLEX is not implemented in libffi for the target. * src/java_raw_api.c (ffi_java_raw_size): FFI_TYPE_COMPLEX not supported yet (abort). (ffi_java_raw_to_ptrarray): Ditto. (ffi_java_rvalue_to_raw): Ditto. (ffi_java_raw_to_rvalue): Ditto. * src/debug.c (ffi_type_test): Add debug tests for complex types. * include/ffi.h.in (FFI_TYPE_COMPLEX): Add new FFI_TYPE_COMPLEX. (FFI_TYPE_LAST): Bump. (ffi_type_complex_float): Add new ffi_type_.... (ffi_type_complex_double): Ditto. (ffi_type_complex_longdouble): Ditto. 2014-07-22 Dominik Vogt <vogt@linux.vnet.ibm.com> * src/s390/ffitarget.h (FFI_TARGET_HAS_COMPLEX_TYPE): Define to provide FFI_TYPE_COMPLEX support. * src/s390/ffi.c (ffi_check_struct_type): Implement FFI_TYPE_COMPLEX (ffi_prep_args): Ditto. (ffi_prep_cif_machdep): Ditto. (ffi_closure_helper_SYSV): Ditto. | |
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5d6340ef | 2014-08-25 17:29:44 | Determine whether register arguments (THISCALL/FASTCALL/REGISTER) are really passed via register to closures. Use stack if not. | |
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098dca6b | 2014-08-23 00:18:47 | Support for calling functions with PASCAL and REGISTER calling conventions on x86 Windows/Linux. Also changed indentation to be more consistent throughout the (adjusted) files. | |
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b5fed601 | 2014-04-05 17:33:42 | Fix ABI on 32-bit non-Windows x86: go back to trampoline size 10 The trampoline size is part of the ABI, so it cannot change. Move the logic from the stdcall and thiscall trampolines to the functions they call, to reduce them both to 10 bytes. This drops the previously added support for raw THISCALL closures on non-Windows. (Non-raw THISCALL closures still work.) | |
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e1911f78 | 2014-03-16 03:25:53 | Add support for stdcall, thiscall, and fastcall on non-Windows x86-32 Linux supports the stdcall calling convention, either via functions explicitly declared with the stdcall attribute, or via code compiled with -mrtd which effectively makes stdcall the default. This introduces FFI_STDCALL, FFI_THISCALL, and FFI_FASTCALL on non-Windows x86-32 platforms, as non-default calling conventions. | |
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048d2f41 | 2012-10-11 10:55:25 | Rebase | |
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0a1ab12a | 2012-03-30 08:14:08 | Various MSVC-related changes. | |
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964c5b93 | 2012-03-03 14:46:20 | abi check fixes and Linux/x32 support | |
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8360bf1c | 2012-02-23 07:01:13 | Ensure that users don't include ffitarget.h directly | |
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dee20f8e | 2012-02-10 13:06:46 | Rebased from gcc | |
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1ff9c604 | 2012-02-01 16:34:30 | Rebase from GCC | |
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c1d28ba8 | 2010-08-05 08:48:16 | stdcall-x86-closure-fix | |
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d14178be | 2010-07-23 09:14:00 | FFI_LAST_ABI fix | |
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f2c2a4fc | 2010-04-13 10:19:28 | Remove warnings and add OS/2 support | |
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0739e7dc | 2010-01-15 09:48:33 | Add x86 Sun Studio compiler support | |
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c6dddbd0 | 2009-10-04 08:11:33 | Initial commit |