arch, base: Stop assuming object files have three segments.

The ObjectFile class has hardcoded assumptions that there are three
segments, text, bss and data. There are some files which have one
"segment" like raw files, where the entire file's contents are
considered a single segment. There are also ELF files which can have
an arbitrary number of segments, and those segments can hold any
number of sections, including the text, data and/or bss sections.

Removing this assumption frees up some object file formats from having
to twist themselves to fit in that structure, possibly introducing
ambiguities when some segments may fulfill multiple roles.

Change-Id: I976e06a3a90ef852b17a6485e2595b006b2090d5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21463
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

1 files changed, 22 insertions, 29 deletions

diff --git a/src/base/loader/dtb_object.cc b/src/base/loader/dtb_object.cc
index 92e305ffa..275139a8c 100644
--- a/src/base/loader/dtb_object.cc
+++ b/src/base/loader/dtb_object.cc
@@ -53,20 +53,10 @@ DtbObject::tryFile(const std::string &fname, size_t len, uint8_t *data)
 
 DtbObject::DtbObject(const std::string &_filename, size_t _len, uint8_t *_data,
                      Arch _arch, OpSys _opSys)
-    : ObjectFile(_filename, _len, _data, _arch, _opSys)
+    : ObjectFile(_filename, _len, _data, _arch, _opSys),
+    data(new Segment{ "data", 0, fileData, len })
 {
-    text.base = 0;
-    text.size = len;
-    text.data = fileData;
-
-    data.base = 0;
-    data.size = 0;
-    data.data = nullptr;
-
-    bss.base = 0;
-    bss.size = 0;
-    bss.data = nullptr;
-
+    segments.emplace_back(data);
     fileDataMmapped = true;
 }
 
@@ -92,10 +82,10 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
     const char* property_name = "bootargs";
 
     // Make a new buffer that has extra space to add nodes/properties
-    int newLen = 2*this->len;
-    uint8_t* fdt_buf_w_space = new uint8_t[newLen];
+    int newLen = 2 * this->len;
+    uint8_t *fdt_buf_w_space = new uint8_t[newLen];
     // Copy and unpack flattened device tree into new buffer
-    int ret = fdt_open_into((void*)fileData, (void*)fdt_buf_w_space, (newLen));
+    int ret = fdt_open_into((void *)fileData, (void *)fdt_buf_w_space, newLen);
     if (ret < 0) {
         warn("Error resizing buffer of flattened device tree, "
              "errno: %d\n", ret);
@@ -104,14 +94,15 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
     }
 
     // First try finding the /chosen node in the dtb
-    int offset = fdt_path_offset((void*)fdt_buf_w_space, full_path_node_name);
+    int offset = fdt_path_offset((void *)fdt_buf_w_space, full_path_node_name);
     if (offset < 0) {
         // try adding the node by walking dtb tree to proper insertion point
-        offset = fdt_path_offset((void*)fdt_buf_w_space, root_path);
-        offset = fdt_add_subnode((void*)fdt_buf_w_space, offset, node_name);
+        offset = fdt_path_offset((void *)fdt_buf_w_space, root_path);
+        offset = fdt_add_subnode((void *)fdt_buf_w_space, offset, node_name);
         // if we successfully add the subnode, get the offset
         if (offset >= 0)
-          offset = fdt_path_offset((void*)fdt_buf_w_space, full_path_node_name);
+          offset = fdt_path_offset((void *)fdt_buf_w_space,
+                                   full_path_node_name);
 
         if (offset < 0) {
             warn("Error finding or adding \"chosen\" subnode to flattened "
@@ -122,8 +113,8 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
     }
 
     // Set the bootargs property in the /chosen node
-    ret = fdt_setprop((void*)fdt_buf_w_space, offset, property_name,
-                      (const void*)_args, len+1);
+    ret = fdt_setprop((void *)fdt_buf_w_space, offset, property_name,
+                      (const void *)_args, len+1);
     if (ret < 0) {
         warn("Error setting \"bootargs\" property to flattened device tree, "
              "errno: %d\n", ret);
@@ -132,7 +123,7 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
     }
 
     // Repack the dtb for kernel use
-    ret = fdt_pack((void*)fdt_buf_w_space);
+    ret = fdt_pack((void *)fdt_buf_w_space);
     if (ret < 0) {
         warn("Error re-packing flattened device tree structure, "
              "errno: %d\n", ret);
@@ -140,8 +131,8 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
         return false;
     }
 
-    text.size = newLen;
-    text.data = fdt_buf_w_space;
+    data->size = newLen;
+    data->data = fdt_buf_w_space;
 
     // clean up old buffer and set to new fdt blob
     munmap(fileData, this->len);
@@ -155,7 +146,7 @@ DtbObject::addBootCmdLine(const char* _args, size_t len)
 Addr
 DtbObject::findReleaseAddr()
 {
-    void *fd = (void*)fileData;
+    void *fd = (void *)fileData;
 
     int offset = fdt_path_offset(fd, "/cpus/cpu@0");
     int len;
@@ -164,9 +155,11 @@ DtbObject::findReleaseAddr()
     Addr rel_addr = 0;
 
     if (len > 3)
-        rel_addr = betoh(*static_cast<const uint32_t*>(temp));
-    if (len == 8)
-        rel_addr = (rel_addr << 32) | betoh(*(static_cast<const uint32_t*>(temp)+1));
+        rel_addr = betoh(*static_cast<const uint32_t *>(temp));
+    if (len == 8) {
+        rel_addr = (rel_addr << 32) |
+            betoh(*(static_cast<const uint32_t *>(temp) + 1));
+    }
 
     return rel_addr;
 }