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, 2 insertions, 4 deletions

diff --git a/src/arch/riscv/process.cc b/src/arch/riscv/process.cc
index ca3f0e2b8..e15197d78 100644
--- a/src/arch/riscv/process.cc
+++ b/src/arch/riscv/process.cc
@@ -75,8 +75,7 @@ RiscvProcess64::RiscvProcess64(ProcessParams *params, ObjectFile *objFile) :
     const Addr stack_base = 0x7FFFFFFFFFFFFFFFL;
     const Addr max_stack_size = 8 * 1024 * 1024;
     const Addr next_thread_stack_base = stack_base - max_stack_size;
-    const Addr brk_point = roundUp(objFile->bssBase() + objFile->bssSize(),
-            PageBytes);
+    const Addr brk_point = roundUp(objFile->maxSegmentAddr(), PageBytes);
     const Addr mmap_end = 0x4000000000000000L;
     memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
             next_thread_stack_base, mmap_end);
@@ -88,8 +87,7 @@ RiscvProcess32::RiscvProcess32(ProcessParams *params, ObjectFile *objFile) :
     const Addr stack_base = 0x7FFFFFFF;
     const Addr max_stack_size = 8 * 1024 * 1024;
     const Addr next_thread_stack_base = stack_base - max_stack_size;
-    const Addr brk_point = roundUp(objFile->bssBase() + objFile->bssSize(),
-            PageBytes);
+    const Addr brk_point = roundUp(objFile->maxSegmentAddr(), PageBytes);
     const Addr mmap_end = 0x40000000L;
     memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
                                      next_thread_stack_base, mmap_end);