Vardhan/issue 123

libunwind/CMakeLists.txt

@@ -272,7 +272,7 @@ if (LIBUNWIND_ENABLE_ASSERTIONS)
 
   # On Release builds cmake automatically defines NDEBUG, so we
   # explicitly undefine it:
-  if (uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE")
+  if ((uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE") AND (NOT RUST_SGX))
     list(APPEND LIBUNWIND_COMPILE_FLAGS -UNDEBUG)
   endif()
 else()

libunwind/README_RUST_SGX.md

@@ -0,0 +1,22 @@
+# Libunwind customizations for linking with x86_64-fortanix-unknown-sgx Rust target.
+
+## Description
+### Initial Fork
+Initial Fork has been made from 5.0 release of llvm (commit: 6a075b6de4)
+### Detailed Description
+#### Header files that we do not include for this target
+1. pthread.h
+#### Library that we do not link to for this target.
+1. pthread (Locks used by libunwind is provided by rust stdlib for this target)
+
+## Building unwind for rust-sgx target
+### Generate Make files:
+* `cd where you want to build libunwind`
+* `mkdir build`
+* `cd build`
+* `cmake -DCMAKE_BUILD_TYPE="RELEASE" -DRUST_SGX=1 -G "Unix Makefiles" -DLLVM_ENABLE_WARNINGS=1 -DLIBUNWIND_ENABLE_WERROR=1 -DLIBUNWIND_ENABLE_PEDANTIC=0 -DLLVM_PATH=<path/to/llvm> <path/to/libunwind>`
+* `"DEBUG"` could be used instead of `"RELEASE"` to enable debug logs of libunwind.
+
+### Build:
+* `make unwind_static`
+* `build/lib/` will have the built library.

libunwind/docs/BuildingLibunwind.rst

@@ -165,3 +165,8 @@ libunwind specific options
 .. option:: LIBUNWIND_SYSROOT
 
   Sysroot for cross compiling
+
+.. option:: LIBUNWIND_ENABLE_RUST_SGX:BOOL
+
+  **Default**: ``OFF``
+

libunwind/src/CMakeLists.txt

@@ -9,16 +9,10 @@ set(LIBUNWIND_C_SOURCES
     UnwindLevel1.c
     UnwindLevel1-gcc-ext.c
     Unwind-sjlj.c)
-set_source_files_properties(${LIBUNWIND_C_SOURCES}
-                            PROPERTIES
-                              COMPILE_FLAGS "-std=c99")
 
 set(LIBUNWIND_ASM_SOURCES
     UnwindRegistersRestore.S
     UnwindRegistersSave.S)
-set_source_files_properties(${LIBUNWIND_ASM_SOURCES}
-                            PROPERTIES
-                              LANGUAGE C)
 
 set(LIBUNWIND_HEADERS
     AddressSpace.hpp
@@ -32,6 +26,7 @@ set(LIBUNWIND_HEADERS
     Registers.hpp
     UnwindCursor.hpp
     unwind_ext.h
+    UnwindRustSgx.h
     ${CMAKE_CURRENT_SOURCE_DIR}/../include/libunwind.h
     ${CMAKE_CURRENT_SOURCE_DIR}/../include/unwind.h)
 
@@ -44,6 +39,38 @@ if (MSVC_IDE)
   source_group("Header Files" FILES ${LIBUNWIND_HEADERS})
 endif()
 
+if (RUST_SGX)
+    # Compile Flags
+    add_definitions(-DRUST_SGX)
+    add_definitions(-D__NO_STRING_INLINES)
+    add_definitions(-D__NO_MATH_INLINES)
+    add_definitions(-D_LIBUNWIND_IS_BAREMETAL)
+    # Can't use add_definitions because CMake will reorder these arguments
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -U_FORTIFY_SOURCE)
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -D_FORTIFY_SOURCE=0)
+
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -fno-stack-protector)
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -ffreestanding)
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -fexceptions)
+    # Avoid too new relocation types being emitted, which might prevent linking
+    # on older platforms.
+    #
+    # See https://github.com/rust-lang/rust/issues/34978
+    list(APPEND LIBUNWIND_COMPILE_FLAGS -Wa,-mrelax-relocations=no)
+
+    # Sources
+    list(APPEND LIBUNWIND_C_SOURCES UnwindRustSgx.c)
+    list(APPEND LIBUNWIND_C_SOURCES UnwindRustSgxSnprintf.c)
+endif()
+
+
+set_source_files_properties(${LIBUNWIND_C_SOURCES}
+                            PROPERTIES
+                              COMPILE_FLAGS "-std=c99")
+set_source_files_properties(${LIBUNWIND_ASM_SOURCES}
+                            PROPERTIES
+                              LANGUAGE C)
+
 set(LIBUNWIND_SOURCES
     ${LIBUNWIND_CXX_SOURCES}
     ${LIBUNWIND_C_SOURCES}
@@ -53,7 +80,7 @@ set(LIBUNWIND_SOURCES
 set(libraries ${LIBUNWINDCXX_ABI_LIBRARIES})
 append_if(libraries LIBUNWIND_HAS_C_LIB c)
 append_if(libraries LIBUNWIND_HAS_DL_LIB dl)
-if (LIBUNWIND_ENABLE_THREADS)
+if (LIBUNWIND_ENABLE_THREADS AND (NOT RUST_SGX))
   append_if(libraries LIBUNWIND_HAS_PTHREAD_LIB pthread)
 endif()
 

libunwind/src/UnwindCursor.hpp

@@ -16,7 +16,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-#ifndef _LIBUNWIND_HAS_NO_THREADS
+#if !defined(_LIBUNWIND_HAS_NO_THREADS) && !defined(RUST_SGX)
   #include <pthread.h>
 #endif
 #include <unwind.h>

libunwind/src/UnwindLevel1-gcc-ext.c

@@ -10,6 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdint.h>

libunwind/src/UnwindLevel1.c

@@ -19,6 +19,9 @@
 // to export these functions from libunwind.so as well.
 #define _LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE 1
 
+#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
+#pragma GCC diagnostic ignored "-Wempty-body"
+
 #include <inttypes.h>
 #include <stdint.h>
 #include <stdbool.h>

libunwind/src/UnwindRustSgx.c

@@ -0,0 +1,181 @@
+//===--------------------- UnwindRustSgx.c ----------------------------------===//
+//
+////                     The LLVM Compiler Infrastructure
+////
+//// This file is dual licensed under the MIT and the University of Illinois Open
+//// Source Licenses. See LICENSE.TXT for details.
+////
+////
+////===----------------------------------------------------------------------===//
+
+#define _GNU_SOURCE
+#include <link.h>
+
+#include <elf.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stddef.h>
+#include "UnwindRustSgx.h"
+
+
+#define max_log 256
+
+
+__attribute__((weak)) struct _IO_FILE *stderr  = (_IO_FILE *)-1;
+
+static int vwrite_err(const char *format, va_list ap)
+{
+    char s[max_log];
+    int len = 0;
+    s[0]='\0';
+    len = vsnprintf(s, max_log, format, ap);
+    __rust_print_err((uint8_t *)s, len);
+    return len;
+}
+
+static int write_err(const char *format, ...)
+{
+    int ret;
+    va_list args;
+        va_start(args, format);
+    ret = vwrite_err(format, args);
+    va_end(args);
+
+
+    return ret;
+}
+
+__attribute__((weak)) int fprintf (FILE *__restrict __stream,
+            const char *__restrict __format, ...)
+{
+
+    int ret;
+    if (__stream != stderr) {
+        write_err("Rust SGX Unwind supports only writing to stderr\n");
+        return -1;
+    } else {
+        va_list args;
+        ret = 0;
+        va_start(args, __format);
+        ret += vwrite_err(__format, args);
+        va_end(args);
+    }
+
+    return ret;
+}
+
+__attribute__((weak)) int fflush (FILE *__stream)
+{
+    // We do not need to do anything here.
+    return 0;
+}
+
+
+
+
+__attribute__((weak)) void __assert_fail(const char * assertion,
+                                       const char * file,
+                           unsigned int line,
+                           const char * function)
+{
+    write_err("%s:%d %s %s\n", file, line, function, assertion);
+    abort();
+}
+
+
+
+// We do not report stack over flow detected.
+// Calling write_err uses more stack due to the way we have implemented it.
+// With possible enabling of stack probes, we should not
+// get into __stack_chk_fail() at all.
+__attribute__((weak))  void __stack_chk_fail() {
+    abort();
+}
+
+/*
+ * Below are defined for all executibles compiled for
+ * x86_64-fortanix-unknown-sgx rust target.
+ * Ref: rust/src/libstd/sys/sgx/abi/entry.S
+ */
+
+extern uint64_t TEXT_BASE;
+extern uint64_t TEXT_SIZE;
+extern uint64_t EH_FRM_HDR_BASE;
+extern uint64_t EH_FRM_HDR_SIZE;
+extern char IMAGE_BASE;
+
+typedef Elf64_Phdr Elf_Phdr; 
+int
+dl_iterate_phdr (int (*callback) (struct dl_phdr_info *,
+                  size_t, void *),
+         void *data)
+{
+    struct dl_phdr_info info;
+    struct dl_phdr_info *pinfo = &info;
+    Elf_Phdr phdr[2];
+    int ret = 0;
+
+
+    size_t text_size = TEXT_SIZE;
+    size_t eh_base_size = EH_FRM_HDR_SIZE;
+
+    if (text_size == 0) {
+        write_err("%s:%d %s: Warning: text_size is 0.\n", __FILE__, __LINE__, __func__);
+    }
+
+    if (eh_base_size == 0) {
+        write_err("%s:%d %s: Warning: eh_base_size is 0.\n",  __FILE__, __LINE__, __func__);
+    }
+
+    memset(pinfo, 0, sizeof(*pinfo));
+
+    pinfo->dlpi_addr = (ElfW(Addr))&IMAGE_BASE;
+    pinfo->dlpi_phnum = 2;
+
+    pinfo->dlpi_phdr = phdr;
+    memset(phdr, 0, 2*sizeof(*phdr));
+
+
+    phdr[0].p_type = PT_LOAD;
+    phdr[0].p_vaddr = (size_t)TEXT_BASE;
+    phdr[0].p_memsz = text_size;
+
+    phdr[1].p_type = PT_GNU_EH_FRAME;
+    phdr[1].p_vaddr = (size_t)EH_FRM_HDR_BASE;
+    phdr[1].p_memsz = eh_base_size;
+
+
+    ret = callback (&info, sizeof (struct dl_phdr_info), data);
+    return ret;
+}
+
+struct libwu_rs_alloc_meta {
+    size_t alloc_size;
+    // Should we put a signatre guard before ptr for oob access?
+    unsigned char ptr[0];
+};
+
+#define META_FROM_PTR(__PTR) (struct libwu_rs_alloc_meta *) \
+    ((unsigned char *)__PTR - offsetof(struct libwu_rs_alloc_meta, ptr))
+
+void *libuw_malloc(size_t size)
+{
+    struct libwu_rs_alloc_meta *meta;
+    size_t alloc_size = size + sizeof(struct libwu_rs_alloc_meta);
+    meta = (void *)__rust_c_alloc(alloc_size, sizeof(size_t));
+    if (!meta) {
+        return NULL;
+    }
+    meta->alloc_size = alloc_size;
+    return (void *)meta->ptr;
+}
+
+void libuw_free(void *p)
+{
+    struct libwu_rs_alloc_meta *meta;
+    if (!p) {
+        return;
+    }
+    meta = META_FROM_PTR(p);
+    __rust_c_dealloc((unsigned char *)meta, meta->alloc_size, sizeof(size_t));
+}