diff options
Diffstat (limited to 'data.S')
| -rw-r--r-- | data.S | 23 |
1 files changed, 21 insertions, 2 deletions
@@ -1,5 +1,24 @@ -# Define "data" symbol to mark beginning of data segment. -# Must be linked before any other data on ld command line. +// The kernel layout is: +// +// text +// rodata +// data +// bss +// +// Conventionally, Unix linkers provide pseudo-symbols +// etext, edata, and end, at the end of the text, data, and bss. +// For the kernel mapping, we need the address at the beginning +// of the data section, but that's not one of the conventional +// symbols, because the convention started before there was a +// read-only rodata section between text and data. +// +// To get the address of the data section, we define a symbol +// named data and make sure this is the first object passed to +// the linker, so that it will be the first symbol in the data section. +// +// Alternative approaches would be to parse our own ELF header +// or to write a linker script, but this is simplest. + .data .globl data data: |