From 1640c262dc63e2f8f43c0728dbe867c8fffe3e9d Mon Sep 17 00:00:00 2001
From: Waldemar Brodkorb <wbx@openadk.org>
Date: Sun, 24 Mar 2024 15:06:48 +0100
Subject: riscv64: implement Linuxthreads, from sorear

---
 libpthread/linuxthreads/manager.c                  |  2 +-
 .../linuxthreads/sysdeps/riscv64/pt-machine.h      | 61 ++++++++++++++++++++++
 2 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 libpthread/linuxthreads/sysdeps/riscv64/pt-machine.h

(limited to 'libpthread')

diff --git a/libpthread/linuxthreads/manager.c b/libpthread/linuxthreads/manager.c
index 122997b10..73fd1dcdb 100644
--- a/libpthread/linuxthreads/manager.c
+++ b/libpthread/linuxthreads/manager.c
@@ -455,7 +455,7 @@ static int pthread_allocate_stack(const pthread_attr_t *attr,
        * the kernel chokes on a non-aligned stack frame. Choose the lower
        * available word boundary.
        */
-      new_thread = ((pthread_descr) ((int)(new_thread_bottom + stacksize) & -sizeof(void*))) - 1;
+      new_thread = ((pthread_descr) ((long)(new_thread_bottom + stacksize) & -sizeof(void*))) - 1;
       guardaddr = NULL;
       guardsize = 0;
 
diff --git a/libpthread/linuxthreads/sysdeps/riscv64/pt-machine.h b/libpthread/linuxthreads/sysdeps/riscv64/pt-machine.h
new file mode 100644
index 000000000..d83057669
--- /dev/null
+++ b/libpthread/linuxthreads/sysdeps/riscv64/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.d      %1,%2\n\t"
+     "li        %0,0\n\t"
+     "bne       %1,%3,2f\n\t"
+     "li        %0,1\n\t"
+     "sc.d      %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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