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windows.cygwin: add TLS fix patch

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This commit is contained in:
David McFarland
2025-09-18 14:41:42 -03:00
parent a56ff336a7
commit 50399c0115
2 changed files with 252 additions and 0 deletions
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6
pkgs/os-specific/cygwin/newlib-cygwin/default.nix
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@@ -41,6 +41,12 @@
# declared. Backport of https://cygwin.com/cgit/newlib-cygwin/commit/?id=73600d68227e125af24b7de7c3fccbd4eb66ee03
./fix-winsize.patch
]
++ lib.optional (!headersOnly) [
# https://cygwin.com/pipermail/cygwin-developers/2020-September/011970.html
# This is required for boost coroutines to work. After we get to the point
# where nix runs on cygwin, we can attempt to upstream this again.
./store-tls-pointer-in-win32-tls.patch
]
# After cygwin hosted builds are working, we should upstream this
++ lib.optional (
!headersOnly && stdenvNoLibc.hostPlatform != stdenvNoLibc.buildPlatform

246
pkgs/os-specific/cygwin/newlib-cygwin/store-tls-pointer-in-win32-tls.patch Normal file
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@@ -0,0 +1,246 @@
From f74059ffbcf53d8ff4db59ca9e7b07d58bd3e3c6 Mon Sep 17 00:00:00 2001
From: David McFarland <corngood@gmail.com>
Date: Fri, 4 Sep 2020 10:15:57 -0300
Subject: [PATCH] Cygwin: store tls pointer in win32 tls
Use WIN32 TLS instead of stack-relative pointers for TLS. This allows windows
fibers and boost coroutines to be used without crashing whenever a syscall is
made from a fiber.
NOTE: This should be submitted upstream, but there is a blocker first. In the
main branch there are conflicts with new ARM64 support. In addition to fixing
the conflicts, we should actually test whether ARM64 builds work too, first.
---
winsup/cygwin/create_posix_thread.cc | 2 ++
winsup/cygwin/cygtls.cc | 15 +++++++++++++++
winsup/cygwin/dcrt0.cc | 1 +
winsup/cygwin/fork.cc | 1 +
winsup/cygwin/include/cygwin/config.h | 2 +-
winsup/cygwin/init.cc | 12 ++++++++----
winsup/cygwin/local_includes/cygtls.h | 7 +++++--
winsup/cygwin/scripts/gendef | 15 ++++++++++-----
8 files changed, 43 insertions(+), 12 deletions(-)
diff --git a/winsup/cygwin/create_posix_thread.cc b/winsup/cygwin/create_posix_thread.cc
index 3fcd61707..85c1a8af3 100644
--- a/winsup/cygwin/create_posix_thread.cc
+++ b/winsup/cygwin/create_posix_thread.cc
@@ -52,6 +52,7 @@ pthread_wrapper (PVOID arg)
/* Set stack values in TEB */
PTEB teb = NtCurrentTeb ();
teb->Tib.StackBase = wrapper_arg.stackbase;
+ _set_tls();
teb->Tib.StackLimit = wrapper_arg.stacklimit ?: wrapper_arg.stackaddr;
/* Set DeallocationStack value. If we have an application-provided stack,
we set DeallocationStack to NULL, so NtTerminateThread does not deallocate
@@ -250,6 +251,7 @@ create_new_main_thread_stack (PVOID &allocationbase)
return NULL;
NtCurrentTeb()->Tib.StackBase = ((PBYTE) allocationbase + stacksize);
NtCurrentTeb()->Tib.StackLimit = stacklimit;
+ _set_tls();
return ((PBYTE) allocationbase + stacksize - 16);
}
diff --git a/winsup/cygwin/cygtls.cc b/winsup/cygwin/cygtls.cc
index 13d133f47..d23f9b42a 100644
--- a/winsup/cygwin/cygtls.cc
+++ b/winsup/cygwin/cygtls.cc
@@ -17,6 +17,20 @@ details. */
#include "sigproc.h"
#include "exception.h"
+extern DWORD cygtls_slot;
+
+void _set_tls(TEB *teb)
+{
+ TlsSetValue(cygtls_slot, teb->Tib.StackBase);
+}
+
+_cygtls* _current_tls()
+{
+ register void *ret;
+ __asm __volatile__ ("movl cygtls_slot(%%rip),%%r10d\nmovq %%gs:0x1480(,%%r10d,8),%0" : "=r" (ret) : : "r10");
+ return (_cygtls *) ((PBYTE) ret - __CYGTLS_PADSIZE__);
+}
+
/* Two calls to get the stack right... */
void
_cygtls::call (DWORD (*func) (void *, void *), void *arg)
@@ -25,6 +39,7 @@ _cygtls::call (DWORD (*func) (void *, void *), void *arg)
/* Initialize this thread's ability to respond to things like
SIGSEGV or SIGFPE. */
exception protect;
+ _set_tls();
_my_tls.call2 (func, arg, buf);
}
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index f4c09befd..e6ba488f2 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -462,6 +462,7 @@ child_info_fork::alloc_stack ()
StackBase in the child to be the same as in the parent, so that the
computation of _my_tls is correct. */
teb->Tib.StackBase = (PVOID) stackbase;
+ _set_tls(teb);
}
}
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index f88acdbbf..582f1a454 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -141,6 +141,7 @@ frok::child (volatile char * volatile here)
myself->pid, myself->ppid, __builtin_frame_address (0));
sigproc_printf ("hParent %p, load_dlls %d", hParent, load_dlls);
+ _set_tls();
/* Make sure threadinfo information is properly set up. */
if (&_my_tls != _main_tls)
{
diff --git a/winsup/cygwin/include/cygwin/config.h b/winsup/cygwin/include/cygwin/config.h
index 2a7083278..21ce484cf 100644
--- a/winsup/cygwin/include/cygwin/config.h
+++ b/winsup/cygwin/include/cygwin/config.h
@@ -37,7 +37,7 @@ extern inline struct _reent *__getreent (void)
{
register char *ret;
#ifdef __x86_64__
- __asm __volatile__ ("movq %%gs:8,%0" : "=r" (ret));
+ __asm __volatile__ ("movl cygtls_slot(%%rip),%%r10d\nmovq %%gs:0x1480(,%%r10d,8),%0" : "=r" (ret) : : "r10");
#else
#error unimplemented for this target
#endif
diff --git a/winsup/cygwin/init.cc b/winsup/cygwin/init.cc
index ce6484aff..392ac8600 100644
--- a/winsup/cygwin/init.cc
+++ b/winsup/cygwin/init.cc
@@ -11,7 +11,7 @@ details. */
#include "ntdll.h"
#include "shared_info.h"
-static DWORD _my_oldfunc;
+DWORD NO_COPY cygtls_slot;
static char *search_for = (char *) cygthread::stub;
unsigned threadfunc_ix[8];
@@ -22,7 +22,9 @@ static bool dll_finished_loading;
static void
threadfunc_fe (VOID *arg)
{
- _cygtls::call ((DWORD (*) (void *, void *)) TlsGetValue (_my_oldfunc), arg);
+ PVOID f = TlsGetValue (cygtls_slot);
+ _set_tls();
+ _cygtls::call ((DWORD (*) (void *, void *)) f, arg);
}
/* If possible, redirect the thread entry point to a cygwin routine which
@@ -59,7 +61,7 @@ munge_threadfunc ()
for (i = 0; threadfunc_ix[i]; i++)
if (!threadfunc || ebp[threadfunc_ix[i]] == threadfunc)
ebp[threadfunc_ix[i]] = (char *) threadfunc_fe;
- TlsSetValue (_my_oldfunc, threadfunc);
+ TlsSetValue (cygtls_slot, threadfunc);
}
}
}
@@ -78,6 +80,8 @@ dll_entry (HANDLE h, DWORD reason, void *static_load)
switch (reason)
{
case DLL_PROCESS_ATTACH:
+ cygtls_slot = TlsAlloc ();
+ _set_tls();
init_console_handler (false);
cygwin_hmodule = (HMODULE) h;
@@ -94,7 +98,6 @@ dll_entry (HANDLE h, DWORD reason, void *static_load)
memcpy (_REENT, _GLOBAL_REENT, sizeof (struct _reent));
dll_crt0_0 ();
- _my_oldfunc = TlsAlloc ();
dll_finished_loading = true;
break;
case DLL_PROCESS_DETACH:
@@ -102,6 +105,7 @@ dll_entry (HANDLE h, DWORD reason, void *static_load)
shared_destroy ();
break;
case DLL_THREAD_ATTACH:
+ _set_tls();
if (dll_finished_loading)
munge_threadfunc ();
break;
diff --git a/winsup/cygwin/local_includes/cygtls.h b/winsup/cygwin/local_includes/cygtls.h
index 306497a33..e3a216280 100644
--- a/winsup/cygwin/local_includes/cygtls.h
+++ b/winsup/cygwin/local_includes/cygtls.h
@@ -301,8 +301,11 @@ private:
#include "cygerrno.h"
#include "ntdll.h"
-#define _my_tls (*((_cygtls *) ((PBYTE) NtCurrentTeb()->Tib.StackBase \
- - __CYGTLS_PADSIZE__)))
+void _set_tls(TEB*);
+inline void _set_tls() { _set_tls(NtCurrentTeb()); }
+_cygtls* _current_tls();
+
+#define _my_tls (*_current_tls())
extern _cygtls *_main_tls;
extern _cygtls *_sig_tls;
diff --git a/winsup/cygwin/scripts/gendef b/winsup/cygwin/scripts/gendef
index 861a2405b..9a4479bd8 100755
--- a/winsup/cygwin/scripts/gendef
+++ b/winsup/cygwin/scripts/gendef
@@ -118,7 +118,8 @@ EOF
.seh_proc _sigfe_maybe
_sigfe_maybe: # stack is aligned on entry!
.seh_endprologue
- movq %gs:8,%r10 # location of bottom of stack
+ movl cygtls_slot(%rip),%r10d
+ movq %gs:0x1480(,%r10d,8),%r10 # location of bottom of stack
leaq _cygtls.initialized(%r10),%r11 # where we will be looking
cmpq %r11,%rsp # stack loc > than tls
jge 0f # yep. we don't have a tls.
@@ -131,7 +132,8 @@ _sigfe_maybe: # stack is aligned on entry!
.seh_proc _sigfe
_sigfe: # stack is aligned on entry!
.seh_endprologue
- movq %gs:8,%r10 # location of bottom of stack
+ movl cygtls_slot(%rip),%r10d
+ movq %gs:0x1480(,%r10d,8),%r10 # location of bottom of stack
1: movl \$1,%r11d
xchgl %r11d,_cygtls.stacklock(%r10) # try to acquire lock
testl %r11d,%r11d # it will be zero
@@ -154,7 +156,8 @@ _sigfe: # stack is aligned on entry!
_sigbe: # return here after cygwin syscall
# stack is aligned on entry!
.seh_endprologue
- movq %gs:8,%r10 # address of bottom of tls
+ movl cygtls_slot(%rip),%r10d
+ movq %gs:0x1480(,%r10d,8),%r10 # address of bottom of tls
1: movl \$1,%r11d
xchgl %r11d,_cygtls.stacklock(%r10) # try to acquire lock
testl %r11d,%r11d # it will be zero
@@ -249,7 +252,8 @@ sigdelayed:
2:
.seh_endprologue
- movq %gs:8,%r12 # get tls
+ movl cygtls_slot(%rip),%r12d
+ movq %gs:0x1480(,%r12d,8),%r12 # get tls
movl _cygtls.saved_errno(%r12),%r15d # temporarily save saved_errno
movq \$_cygtls.start_offset,%rcx # point to beginning of tls block
addq %r12,%rcx # and store as first arg to method
@@ -316,7 +320,8 @@ stabilize_sig_stack:
subq \$0x20,%rsp
.seh_stackalloc 32
.seh_endprologue
- movq %gs:8,%r12
+ movl cygtls_slot(%rip),%r12d
+ movq %gs:0x1480(,%r12d,8),%r12
1: movl \$1,%r10d
xchgl %r10d,_cygtls.stacklock(%r12) # try to acquire lock
testl %r10d,%r10d
--
2.50.1