MaskRay

llvm/llvm-project#113838 "[RISCV] ld.lld: error: relaxation not converged with openssl"

ld.lld @response.txt --noinhibit-exec -o out.30
S=1 ld.lld @response.txt --noinhibit-exec -o out.31

MaskRay

#!/usr/bin/env python
import os, re, sys
from ipdb import set_trace as bp

X = 'log'
Y = 'Log'

def update(lines):
    ret = []
    s = 0

MaskRay

linux/arch/arm/mach-rockchip/sleep.S:20:23: error: too many positional arguments
 setmode 0x00000080 | 0x00000040 | 0x00000013, r1 @ set svc, irqs off
                      ^
make[5]: *** [linux/scripts/Makefile.build:362: arch/arm/mach-rockchip/sleep.o] Error 1
make[5]: Target 'arch/arm/mach-rockchip/' not remade because of errors.
make[4]: *** [linux/scripts/Makefile.build:485: arch/arm/mach-rockchip] Error 2
linux/arch/arm/mach-tegra/sleep.S:127:23: error: too many positional arguments
 mov32 r2, 0x50040000 + 0x3000
                      ^
linux/arch/arm/mach-tegra/reset-handler.S:95:23: error: too many positional arguments

MaskRay

void f0(void);
void f1(void);
void f2(void);
void g() { f0(); f1(); f2(); }
g:
  push    {r4, lr}
  mov     r4, r9
  bl      f(PLT)
 mov r9, r4

MaskRay

#!/usr/bin/env python
import os, re, subprocess, sys
from ipdb import set_trace as bp

def main(filename):
    last = 0
    while 1:
        p = subprocess.run(['/tmp/Rel/bin/llvm-lit', '-v', filename], capture_output=True)
        if p.returncode != 1: break
        lines = p.stdout.decode().split('\n')

MaskRay

## Linux binfmt loaders

`fs/Kconfig.binfmt` defines a few loaders.

* `BINFMT_ELF` defaults to y and depends on `MMU`.
* `BINFMT_ELF_FDPIC` defaults to y when `BINFMT_ELF` is not selected. A few architecture support `BINFMT_ELF_FDPIC` for NOMMU. ARM supports FDPIC even with a MMU.
* `BINFMT_FLAT` is provided for a few architectures.

`BINFMT_AOUT`, removed in 2022, had been supported for alpha/arm/x86-32.

MaskRay

% echo 'int main(){}' > a.cc
% clang -fuse-ld=lld a.cc -z separate-code
% readelf -WSl a.out
There are 30 section headers, starting at offset 0x2868:

Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
  [ 1] .interp           PROGBITS        00000000000002a8 0002a8 00001c 00   A  0   0  1
  [ 2] .note.ABI-tag     NOTE            00000000000002c4 0002c4 000020 00   A  0   0  4

MaskRay

Published to https://maskray.me/blog/2024-01-23-riscv-tlsdesc-works

Patch musl

--- c/arch/riscv64/reloc.h
+++ i/arch/riscv64/reloc.h
@@ -17,6 +17,7 @@
 #define REL_DTPMOD      R_RISCV_TLS_DTPMOD64
 #define REL_DTPOFF      R_RISCV_TLS_DTPREL64
 #define REL_TPOFF       R_RISCV_TLS_TPREL64

MaskRay

PATH=/tmp/Rel/bin:$PATH
cat > switch.cc <<e
#define DO A(0) A(1) A(2) A(3) A(4) A(5) A(6) A(7) A(8) A(9) A(10) A(11) A(12) A(13)
#define A(i) void bar##i();
DO
#undef A
void ext();
void foo(int i) {
  switch (i) {
#define A(i) case i: bar##i(); break;

MaskRay

#
# Automatically generated file; DO NOT EDIT.
# Linux/x86 6.7.0 Kernel Configuration
#
CONFIG_CC_VERSION_TEXT="gcc (Debian 13.2.0-5) 13.2.0"
CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=130200
CONFIG_CLANG_VERSION=0
CONFIG_AS_IS_GNU=y
CONFIG_AS_VERSION=24100