Redox TLS difference

gistfile1.txt

$ cat test.c
static int __thread x = 0;
int main(void) {
        x++;
}

$ riscv64-linux-gnu-objdump -dr test.o

test.o:     file format elf64-littleriscv


Disassembly of section .text.startup:

0000000000000000 <main>:
   0:   00000517                auipc   a0,0x0
                        0: R_RISCV_TLS_GD_HI20  .LANCHOR0
   4:   00050513                mv      a0,a0
                        4: R_RISCV_PCREL_LO12_I .L0
                        4: R_RISCV_RELAX        *ABS*
   8:   1141                    addi    sp,sp,-16
   a:   e406                    sd      ra,8(sp)
   c:   00000097                auipc   ra,0x0
                        c: R_RISCV_CALL_PLT     __tls_get_addr
                        c: R_RISCV_RELAX        *ABS*
  10:   000080e7                jalr    ra # c <main+0xc>
  14:   4118                    lw      a4,0(a0)
  16:   60a2                    ld      ra,8(sp)
  18:   87aa                    mv      a5,a0
  1a:   2705                    addiw   a4,a4,1
  1c:   c398                    sw      a4,0(a5)
  1e:   4501                    li      a0,0
  20:   0141                    addi    sp,sp,16
  22:   8082                    ret

$ riscv64-linux-gnu-objdump -sr test.o

test.o:     file format elf64-littleriscv

RELOCATION RECORDS FOR [.text.startup]:
OFFSET           TYPE              VALUE
0000000000000000 R_RISCV_TLS_GD_HI20  .LANCHOR0
0000000000000004 R_RISCV_PCREL_LO12_I  .L0
0000000000000004 R_RISCV_RELAX     *ABS*
000000000000000c R_RISCV_CALL_PLT  __tls_get_addr
000000000000000c R_RISCV_RELAX     *ABS*

$ riscv64-linux-gnu-gcc -o test_linux test.o

$ riscv64-linux-gnu-objdump -dr test_linux
...
0000000000000650 <main>:
 650:   00002517                auipc   a0,0x2
 654:   9e050513                addi    a0,a0,-1568 # 2030 <_GLOBAL_OFFSET_TABLE_+0x8>
 658:   1141                    addi    sp,sp,-16
 65a:   e406                    sd      ra,8(sp)
 65c:   fe5ff0ef                jal     ra,640 <__tls_get_addr@plt>
...

$ riscv64-linux-gnu-objdump -sr test_linux

...
Contents of section .got:
 2030 00000000 00000000  00f8ffff ffffffff
...

$ riscv64-unknown-redox-gcc -o test_redox test.o

$ riscv64-linux-gnu-objdump -dr test_redox
...
00000000000123c0 <main>:
   123c0:       00105517                auipc   a0,0x105
   123c4:       df050513                addi    a0,a0,-528 # 1171b0 <_GLOBAL_OFFSET_TABLE_+0x8>
   123c8:       1141                    addi    sp,sp,-16
   123ca:       e406                    sd      ra,8(sp)
   123cc:       313210ef                jal     ra,33ede <__tls_get_addr>
...

$ riscv64-linux-gnu-objdump -sr test_redox
...
1171b0 01000000 00000000  08f8ffff ffffffff
...