[U-Boot] [PATCH v3 09/21] sandbox: Add a setjmp() implementation

[Simon Glass]

Add an implementation of setjmp() and longjmp() which rely on the
underlying host C library. Since we cannot know how large the jump buffer
needs to be, pick something that should be suitable and check it at
runtime. At present we need access to the underlying struct as well.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

Changes in v3: None
Changes in v2: None

 arch/sandbox/cpu/cpu.c            | 13 +++++++++++++
 arch/sandbox/cpu/os.c             | 17 +++++++++++++++++
 arch/sandbox/include/asm/setjmp.h | 21 +++++++++++++++++++++
 include/os.h                      | 21 +++++++++++++++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 arch/sandbox/include/asm/setjmp.h

diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index 66c3a6a88a..8b397c7168 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -9,6 +9,7 @@
 #include <libfdt.h>
 #include <os.h>
 #include <asm/io.h>
+#include <asm/setjmp.h>
 #include <asm/state.h>
 #include <dm/root.h>
 
@@ -164,3 +165,15 @@ ulong timer_get_boot_us(void)
 
 	return (count - base_count) / 1000;
 }
+
+int setjmp(jmp_buf jmp)
+{
+	return os_setjmp((ulong *)jmp, sizeof(jmp));
+}
+
+void longjmp(jmp_buf jmp, int ret)
+{
+	os_longjmp((ulong *)jmp, ret);
+	while (1)
+		;
+}
diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index 9dd90a1b30..f29fa184b8 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -7,6 +7,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
+#include <setjmp.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -628,3 +629,19 @@ void os_localtime(struct rtc_time *rt)
 	rt->tm_yday = tm->tm_yday;
 	rt->tm_isdst = tm->tm_isdst;
 }
+
+int os_setjmp(ulong *jmp, int size)
+{
+	if (size < sizeof(jmp_buf)) {
+		printf("setjmp: jmpbuf is too small (%d bytes, need %d)\n",
+		       size, sizeof(jmp_buf));
+		return -ENOSPC;
+	}
+
+	return setjmp((struct __jmp_buf_tag *)jmp);
+}
+
+void os_longjmp(ulong *jmp, int ret)
+{
+	longjmp((struct __jmp_buf_tag *)jmp, ret);
+}
diff --git a/arch/sandbox/include/asm/setjmp.h b/arch/sandbox/include/asm/setjmp.h
new file mode 100644
index 0000000000..e25f50107c
--- /dev/null
+++ b/arch/sandbox/include/asm/setjmp.h
@@ -0,0 +1,21 @@
+/*
+ * (C) Copyright 2016
+ * Alexander Graf <agraf at suse.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _SETJMP_H_
+#define _SETJMP_H_	1
+
+struct jmp_buf_data {
+	/* We're not sure how long this should be */
+	ulong data[32];
+};
+
+typedef struct jmp_buf_data jmp_buf[1];
+
+int setjmp(jmp_buf jmp);
+__noreturn void longjmp(jmp_buf jmp, int ret);
+
+#endif /* _SETJMP_H_ */
diff --git a/include/os.h b/include/os.h
index 049b248c5b..80fca6e85e 100644
--- a/include/os.h
+++ b/include/os.h
@@ -330,4 +330,25 @@ int os_spl_to_uboot(const char *fname);
  */
 void os_localtime(struct rtc_time *rt);
 
+/**
+ * os_setjmp() - Call setjmp()
+ *
+ * Call the host system's setjmp() function.
+ *
+ * @jmp: Buffer to store current execution state
+ * @size: Size of buffer
+ * @return normal setjmp() value if OK, -ENOSPC if @size is too small
+ */
+int os_setjmp(ulong *jmp, int size);
+
+/**
+ * os_longjmp() - Call longjmp()
+ *
+ * Call the host system's longjmp() function.
+ *
+ * @jmp: Buffer where previous execution state was stored
+ * @ret: Value to pass to longjmp()
+ */
+void os_longjmp(ulong *jmp, int ret);
+
 #endif
-- 
2.16.1.291.g4437f3f132-goog