From 8f200b7fef0b9320b84e09b4c16df6c72daadd36 Mon Sep 17 00:00:00 2001
From: Waldemar Brodkorb <wbx@openadk.org>
Date: Fri, 29 Mar 2024 07:49:31 +0100
Subject: riscv32: implement linuxthreads, from sorear

---
 extra/Configs/Config.in                            |  1 -
 libc/sysdeps/linux/riscv32/jmpbuf-unwind.h         |  7 +--
 .../linuxthreads/sysdeps/riscv32/pt-machine.h      | 61 ++++++++++++++++++++++
 3 files changed, 63 insertions(+), 6 deletions(-)
 create mode 100644 libpthread/linuxthreads/sysdeps/riscv32/pt-machine.h

diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
index 2d1692ba5..122a7eb71 100644
--- a/extra/Configs/Config.in
+++ b/extra/Configs/Config.in
@@ -594,7 +594,6 @@ config UCLIBC_HAS_LINUXTHREADS
 	# linuxthreads need nanosleep()
 	select UCLIBC_HAS_REALTIME
 	depends on !TARGET_aarch64 && \
-		   !TARGET_riscv32 && \
 		   !TARGET_metag
 	help
 	  If you want to compile uClibc with Linuxthreads support, then answer Y.
diff --git a/libc/sysdeps/linux/riscv32/jmpbuf-unwind.h b/libc/sysdeps/linux/riscv32/jmpbuf-unwind.h
index 2e5f37f10..fb5d65ddd 100644
--- a/libc/sysdeps/linux/riscv32/jmpbuf-unwind.h
+++ b/libc/sysdeps/linux/riscv32/jmpbuf-unwind.h
@@ -23,8 +23,8 @@
 
 /* Test if longjmp to JMPBUF would unwind the frame
    containing a local variable at ADDRESS.  */
-#define _JMPBUF_UNWINDS(jmpbuf, address, demangle)		\
-  ((void *) (address) < (void *) demangle ((jmpbuf)[0].__sp))
+#define _JMPBUF_UNWINDS(jmpbuf, address)		\
+  ((void *) (address) < (void *) ((jmpbuf)[0].__sp))
 
 #define _JMPBUF_CFA_UNWINDS_ADJ(_jmpbuf, _context, _adj) \
   _JMPBUF_UNWINDS_ADJ (_jmpbuf, (void *) _Unwind_GetCFA (_context), _adj)
@@ -33,9 +33,6 @@ static inline uintptr_t __attribute__ ((unused))
 _jmpbuf_sp (__jmp_buf regs)
 {
   uintptr_t sp = regs[0].__sp;
-#ifdef PTR_DEMANGLE
-  PTR_DEMANGLE (sp);
-#endif
   return sp;
 }
 
diff --git a/libpthread/linuxthreads/sysdeps/riscv32/pt-machine.h b/libpthread/linuxthreads/sysdeps/riscv32/pt-machine.h
new file mode 100644
index 000000000..38f0d8eff
--- /dev/null
+++ b/libpthread/linuxthreads/sysdeps/riscv32/pt-machine.h
@@ -0,0 +1,61 @@
+/*
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#ifndef _PT_MACHINE_H
+#define _PT_MACHINE_H   1
+#include <features.h>
+
+#ifndef PT_EI
+# define PT_EI __extern_always_inline
+#endif
+
+#define HAS_COMPARE_AND_SWAP
+PT_EI int
+__compare_and_swap (long int *p, long int oldval, long int newval)
+{
+  long int ret, temp;
+
+  __asm__ __volatile__
+    ("/* Inline compare & swap */\n"
+     "1:\n\t"
+     "lr.w      %1,%2\n\t"
+     "li        %0,0\n\t"
+     "bne       %1,%3,2f\n\t"
+     "li        %0,1\n\t"
+     "sc.w      %1,%4,%2\n\t"
+     "bnez      %1,1b\n"
+     "2:\n\t"
+     "/* End compare & swap */"
+     : "=&r" (ret), "=&r" (temp), "+A" (*p)
+     : "r" (oldval), "r" (newval)
+     : "memory");
+
+  return ret;
+}
+
+extern long int testandset (int *spinlock);
+
+PT_EI long int
+testandset (int *spinlock)
+{
+        unsigned int old = 1;
+        int tmp = 1;
+
+        __asm__ __volatile__ (
+        "amoswap.w %0, %2, %1"
+        : "=r" (old), "+A" (*spinlock)
+        : "r" (tmp)
+        : "memory");
+
+        return old;
+}
+
+/* Get some notion of the current stack.  Need not be exactly the top
+   of the stack, just something somewhere in the current frame.  */
+#define CURRENT_STACK_FRAME  stack_pointer
+register char * stack_pointer __asm__ ("sp");
+
+#else
+#error PT_MACHINE already defined
+#endif /* pt-machine.h */
-- 
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