Hello, I am developing a small kernel for a research project and I
intend to make it compatible with linux binaries.
I can't find information (neither in google or linux sources) about
how linux treats ths thread local storage.
In this small sample program:
#include <stdio.h>
__thread a = 5;
int main()
{
printf("%u\n", a);
return 0;
}
this is the assembly code of the printf call in main:
400558: 64 8b 14 25 fc ff ff mov %fs:0xfffffffffffffffc,%edx
40055f: ff
400560: b8 6c 06 40 00 mov $0x40066c,%eax
400565: 89 d6 mov %edx,%esi
400567: 48 89 c7 mov %rax,%rdi
40056a: b8 00 00 00 00 mov $0x0,%eax
40056f: e8 dc fe ff ff callq 400450 <printf@plt>
Where does the fs segment points to? How linux sets up the virtual
memory for TLS?
Or, at least, where do I find this information? Or where this is done
in linux source?
I get the following with readelf:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz
Flags Align
LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000
0x0000000000000714 0x0000000000000714 R E 200000
LOAD 0x0000000000000e14 0x0000000000600e14 0x0000000000600e14
0x000000000000020c 0x000000000000021c RW 200000
TLS 0x0000000000000e14 0x0000000000600e14 0x0000000000600e14
0x0000000000000004 0x0000000000000004 R 4
Thanks in advance
--
Eduardo Henrique Molina da Cruz
Bacharelado em Ciência da Computação
Universidade Estadual de Maringá
"Ciência da computação tem tanto a ver com o computador como a
Astronomia com o telescópio, a Biologia com o microscópio, ou a
Química com os tubos de ensaio. A Ciência não estuda ferramentas, mas
o que fazemos e o que descobrimos com elas." (Edsger Dijkstra)
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