4661

Make segment management a little more consistent between initial segments
and add-on segments (using `mmap`).

1 files changed, 10 insertions, 12 deletions

diff --git a/subx/012elf.cc b/subx/012elf.cc
index 85eb406a..2e10246e 100644
--- a/subx/012elf.cc
+++ b/subx/012elf.cc
@@ -80,7 +80,7 @@ void load_elf_contents(uint8_t* elf_contents, size_t size, int argc, char* argv[
       assert(overlap.find(argv_data) == overlap.end());  // don't bother comparing ARGV and STACK
       write_mem_u8(argv_data, argv[i][j]);
       argv_data += sizeof(char);
-      assert(argv_data < ARGV_DATA_SEGMENT + SEGMENT_SIZE);
+      assert(argv_data < ARGV_DATA_SEGMENT + INITIAL_SEGMENT_SIZE);
     }
   }
   push(argc-/*skip 'subx_bin' and 'run'*/2);
@@ -111,7 +111,7 @@ void load_segment_from_program_header(uint8_t* elf_contents, int segment_index,
 
   if (p_offset + p_filesz > size)
     raise << "Invalid binary; segment at offset " << offset << " is too large: wants to end at " << p_offset+p_filesz << " but the file ends at " << size << '\n' << die();
-  if (p_memsz > INITIAL_SEGMENT_SIZE) {
+  if (p_memsz >= INITIAL_SEGMENT_SIZE) {
     raise << "Code segment too small for SubX; for now please manually increase INITIAL_SEGMENT_SIZE.\n" << end();
     return;
   }
@@ -129,16 +129,14 @@ void load_segment_from_program_header(uint8_t* elf_contents, int segment_index,
 
 :(before "End Includes")
 // Very primitive/fixed/insecure ELF segments for now.
-//   code: 0x08048000 -> 0x08048fff
-//   data/heap: 0x08050000 -> 0x08050fff
-//   stack: 0x08060fff -> 0x08060000 (downward)
-const int SEGMENT_SIZE = 0x1000;
-const int CODE_START = 0x08048000;
-const int DATA_SEGMENT = 0x08050000;
-const int HEAP_SEGMENT = DATA_SEGMENT;
-const int STACK_SEGMENT = 0x08060000;
-const int AFTER_STACK = 0x08060ffc;  // forget final word because of the off-by-one with INITIAL_SEGMENT_SIZE;
-const int ARGV_DATA_SEGMENT = 0x08070000;
+//   code: 0x09000000 -> 0x09ffffff
+//   data/heap: 0x0a000000 -> 0x0affffff
+//   stack: 0x0b000ffc -> 0x0b000000 (downward)
+const int CODE_SEGMENT = 0x09000000;
+const int DATA_SEGMENT = 0x0a000000;
+const int STACK_SEGMENT = 0x0b000000;
+const int AFTER_STACK = 0x0b000ffc;  // forget final word because of the off-by-one with INITIAL_SEGMENT_SIZE;
+const int ARGV_DATA_SEGMENT = 0x0c000000;
 :(code)
 inline uint32_t u32_in(uint8_t* p) {
   return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;