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Use %gs as TLS register when dlopen() is linked

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Fixes #938
This commit is contained in:
Justine Tunney 2023-11-08 01:11:17 -08:00
parent e961385e55
commit d71da7fc72
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GPG key ID: BE714B4575D6E328
13 changed files with 71 additions and 40 deletions
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5
libc/runtime/morph_tls.c
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@ -55,11 +55,13 @@ privileged void __morph_tls(void) {
// address 0x30 was promised to us, according to Go team
// https://github.com/golang/go/issues/23617
dis = 0x30;
} else {
} else if (IsWindows()) {
// MSVC __declspec(thread) generates binary code for this
// %gs:0x1480 abi. So long as TlsAlloc() isn't called >64
// times we should be good.
dis = 0x1480 + __tls_index * 8;
} else {
dis = 0;
}
// iterate over modifiable code looking for 9 byte instruction
@ -112,6 +114,7 @@ privileged void __morph_tls(void) {
}
}
__tls_morphed = true;
__morph_end();
#endif
}

7
libc/runtime/set_tls.c
View file

@ -26,6 +26,9 @@
#include "libc/thread/tls.h"
#include "libc/thread/tls2.internal.h"
#define AMD64_SET_FSBASE 129
#define AMD64_SET_GSBASE 131
int sys_set_tls();
textstartup void __set_tls(struct CosmoTib *tib) {
@ -36,9 +39,9 @@ textstartup void __set_tls(struct CosmoTib *tib) {
npassert(0 <= __tls_index && __tls_index < 64);
asm("mov\t%1,%%gs:%0" : "=m"(*((long *)0x1480 + __tls_index)) : "r"(tib));
} else if (IsFreebsd()) {
sys_set_tls(129 /*AMD64_SET_FSBASE*/, tib);
sys_set_tls(__tls_morphed ? AMD64_SET_GSBASE : AMD64_SET_FSBASE, tib);
} else if (IsLinux()) {
sys_set_tls(ARCH_SET_FS, tib);
sys_set_tls(__tls_morphed ? ARCH_SET_GS : ARCH_SET_FS, tib);
} else if (IsNetbsd()) {
// netbsd has sysarch(X86_SET_FSBASE) but we can't use that because
// signal handlers will cause it to be reset due to not setting the