diff options
Diffstat (limited to 'subx/012elf.cc')
| -rw-r--r-- | subx/012elf.cc | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/subx/012elf.cc b/subx/012elf.cc index d0a3fbd2..0ae0b108 100644 --- a/subx/012elf.cc +++ b/subx/012elf.cc @@ -90,6 +90,13 @@ void load_elf_contents(uint8_t* elf_contents, size_t size, int argc, char* argv[ void push(uint32_t val) { Reg[ESP].u -= 4; + if (Reg[ESP].u < STACK_SEGMENT) { + raise << "The stack overflowed its segment. " + << "Maybe SPACE_FOR_SEGMENT should be larger? " + << "Or you need to carve out an exception for the stack segment " + << "to be larger.\n" << end(); + exit(1); + } trace(Callstack_depth+1, "run") << "decrementing ESP to 0x" << HEXWORD << Reg[ESP].u << end(); trace(Callstack_depth+1, "run") << "pushing value 0x" << HEXWORD << val << end(); write_mem_u32(Reg[ESP].u, val); @@ -134,18 +141,17 @@ void load_segment_from_program_header(uint8_t* elf_contents, int segment_index, // code: 0x09000000 -> 0x09ffffff (specified in ELF binary) // data: 0x0a000000 -> 0x0affffff (specified in ELF binary) // --- heap gets mmap'd somewhere here --- -// stack: 0x7dffffff -> 0x7d000000 (downward; not in ELF binary) -// argv hack: 0x7f000000 -> 0x7fffffff (not in ELF binary) +// stack: 0xbdffffff -> 0xbd000000 (downward; not in ELF binary) +// argv hack: 0xbf000000 -> 0xbfffffff (not in ELF binary) // -// For now we avoid addresses with the most significant bit set; SubX doesn't -// support unsigned comparison yet (https://github.com/akkartik/mu/issues/30) -// Once we do, we can go up to 0xc0000000; higher addresses are reserved for -// the Linux kernel. -const int CODE_SEGMENT = 0x09000000; -const int DATA_SEGMENT = 0x0a000000; -const int STACK_SEGMENT = 0x7d000000; -const int AFTER_STACK = 0x7e000000; -const int ARGV_DATA_SEGMENT = 0x7f000000; +// Addresses above 0xc0000000 are reserved for the Linux kernel. +const uint32_t CODE_SEGMENT = 0x09000000; +const uint32_t DATA_SEGMENT = 0x0a000000; +const uint32_t START_HEAP = 0x0b000000; +const uint32_t END_HEAP = 0xbd000000; +const uint32_t STACK_SEGMENT = 0xbd000000; +const uint32_t AFTER_STACK = 0xbe000000; +const uint32_t ARGV_DATA_SEGMENT = 0xbf000000; // When updating the above memory map, don't forget to update `mmap`'s // implementation in the 'syscalls' layer. :(before "End Dump Info for Instruction") |