nooc

commit 60bd5daa03ca455e1ad8ea3f37124a95463935f6
parent 4b9ba4cbd1a6e420012c76319c7facfce89ed612
Author: Nihal Jere <nihal@nihaljere.xyz>
Date:   Fri,  3 Dec 2021 20:16:53 -0600

push starting virtual address to 0x10000

On Linux, virtual memory can only be mapped higher than the
address in /proc/sys/vm/mmap_min_addr. My personal machine with
the highest value has the value 0x10000

Diffstat:
M
elf.c
 | 
8
++++----
M
nooc.h
 | 
3
++-

2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/elf.c b/elf.c
@@ -24,7 +24,7 @@ elf(char *text, size_t len, char* data, size_t dlen, FILE *f)
 	ehdr.e_machine = EM_X86_64;
 	ehdr.e_version = EV_CURRENT;
 
-	ehdr.e_entry = 0x1000;
+	ehdr.e_entry = TEXT_OFFSET;
 	ehdr.e_phoff = sizeof(ehdr);
 	ehdr.e_phentsize = sizeof(phdr_text);
 	ehdr.e_phnum = 2;
@@ -35,15 +35,15 @@ elf(char *text, size_t len, char* data, size_t dlen, FILE *f)
 
 	phdr_text.p_type = PT_LOAD;
 	phdr_text.p_offset = 0x1000;
-	phdr_text.p_vaddr = 0x1000;
-	phdr_text.p_paddr = 0x1000;
+	phdr_text.p_vaddr = TEXT_OFFSET;
+	phdr_text.p_paddr = TEXT_OFFSET;
 	phdr_text.p_filesz = len;
 	phdr_text.p_memsz = len;
 	phdr_text.p_flags = PF_R | PF_X;
 	phdr_text.p_align = 0x1000;
 
 	phdr_data.p_type = PT_LOAD;
-	phdr_data.p_offset = DATA_OFFSET;
+	phdr_data.p_offset = 0x2000;
 	phdr_data.p_vaddr = DATA_OFFSET;
 	phdr_data.p_paddr = DATA_OFFSET;
 	phdr_data.p_filesz = dlen;
diff --git a/nooc.h b/nooc.h
@@ -1,4 +1,5 @@
-#define DATA_OFFSET 0x2000
+#define TEXT_OFFSET 0x101000
+#define DATA_OFFSET 0x102000
 
 enum tokentype {
 	TOK_NONE = 0,