https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=e97c157432985faa5a26a900a8dfb7a388a74857
commit e97c157432985faa5a26a900a8dfb7a388a74857
Author: Radek Bartoň <radek.bar...@microsoft.com>
Date: Wed Jun 4 13:38:10 2025 +0200
Cygwin: obtain stack base on AArch64
Signed-off-by: Radek Bartoň <radek.bar...@microsoft.com>
Diff:
---
winsup/cygwin/include/cygwin/config.h | 7 ++++++-
winsup/testsuite/winsup.api/cygload.cc | 7 +++++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/winsup/cygwin/include/cygwin/config.h
b/winsup/cygwin/include/cygwin/config.h
index 2a7083278..d9f911d47 100644
--- a/winsup/cygwin/include/cygwin/config.h
+++ b/winsup/cygwin/include/cygwin/config.h
@@ -36,8 +36,13 @@ __attribute__((__gnu_inline__))
extern inline struct _reent *__getreent (void)
{
register char *ret;
-#ifdef __x86_64__
+#if defined(__x86_64__)
__asm __volatile__ ("movq %%gs:8,%0" : "=r" (ret));
+#elif defined(__aarch64__)
+ /* x18 register points to TEB, offset 0x8 points to stack base.
+ See _TEB structure definition in winsup\cygwin\local_includes\ntdll.h
+ for more details. */
+ __asm __volatile__ ("ldr %0, [x18, #0x8]" : "=r" (ret));
#else
#error unimplemented for this target
#endif
diff --git a/winsup/testsuite/winsup.api/cygload.cc
b/winsup/testsuite/winsup.api/cygload.cc
index afd3ee90f..08372a302 100644
--- a/winsup/testsuite/winsup.api/cygload.cc
+++ b/winsup/testsuite/winsup.api/cygload.cc
@@ -82,6 +82,13 @@ cygwin::padding::padding ()
"movl %%fs:4, %0"
:"=r"(stackbase)
);
+# elif __aarch64__
+ // x18 register points to TEB. See _TEB structure definition in
+ // winsup\cygwin\local_includes\ntdll.h
+ __asm__ volatile (
+ "ldr %0, [x18, #0x8]"
+ :"=r" (stackbase)
+ );
# else
# error Unknown architecture
# endif
