commit f3729556ee9fdf381bdd7a99f737804f0c44b69f
parent 60c196243360163e4cb21c7d1d46cb8883410363
Author: Henry Wilson <henry@henryandlizzy.uk>
Date: Thu, 19 Dec 2024 16:41:07 +0000
Trim program headers
Diffstat:
3 files changed, 39 insertions(+), 25 deletions(-)
diff --git a/echo.c b/echo.c
@@ -1,19 +1,22 @@
#include "syscall.h"
-static unsigned short bufsize;
-static char buf[0x1000 - sizeof bufsize];
+static struct
+{
+ unsigned short size;
+ char data[0x1000 - sizeof(unsigned short)];
+} buf;
static void putflush()
{
- if (bufsize && write(1, buf, bufsize) != bufsize)
+ if (buf.size && write(1, buf.data, buf.size) != buf.size)
exit(1);
- bufsize = 0;
+ buf.size = 0;
}
static void putch(char c)
{
- buf[bufsize++] = c;
- if (c == '\n' || bufsize == sizeof buf)
+ buf.data[buf.size++] = c;
+ if (c == '\n' || buf.size == sizeof buf.data)
putflush();
}
diff --git a/start.s b/start.s
@@ -5,7 +5,7 @@
.text
start: # start is the entry point known to the linker
- mov rdi, [rsp] # get argc from the stack
+ mov edi, [rsp] # get argc from the stack
lea rsi, [rsp+8] # take the address of argv from the stack
lea rdx, [rsp+16] # take the address of envp from the stack
call main # %edi, %rsi, %rdx are the three args (of which first two are C standard) to main
diff --git a/x86_64.ld b/x86_64.ld
@@ -1,35 +1,46 @@
-SECTIONS
+PHDRS
{
- . = 0x10000;
- .text (READONLY) :
- {
- *(.text)
- }
+ rodata PT_LOAD;
+ text PT_LOAD;
+ data PT_LOAD;
+}
+
+MEMORY
+{
+ userspace (rwx) : ORIGIN = 0x10000, LENGTH = 0x7ffff7000000 - ORIGIN(userspace)
+}
+SECTIONS
+{
.rodata (READONLY) :
- ALIGN(0x1000)
+ ALIGN(CONSTANT(MAXPAGESIZE))
{
- *(.rodata.*)
- *(.rodata)
- }
+ *(.rodata*)
+ } >userspace :rodata
+ .text (READONLY) :
+ ALIGN(CONSTANT(MAXPAGESIZE))
+ {
+ *(.text*)
+ } >userspace :text
+
.data :
- ALIGN(0x1000)
+ ALIGN(CONSTANT(MAXPAGESIZE))
{
- *(.data)
- }
+ *(.data*)
+ } >userspace :data
.bss (NOLOAD) :
- ALIGN(0x1000)
{
- *(.bss)
- }
+ *(.bss*)
+ } >userspace :data
.mappable (OVERLAY) :
- ALIGN(0x1000)
+ ALIGN(CONSTANT(MAXPAGESIZE))
{
+ *(.mappable*)
mappable = .;
- }
+ } >userspace
}
ENTRY(start)
