sandbox: Add a setjmp() implementation

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@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index d4ad020012e7835e365fcb62ea4f771f5c3ef958..cde0b055a673a2f5c897d9832cb6ead33d79d9ad 100644 (file)
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -9,6 +9,7 @@
 #include <linux/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 d76d0211a2d58063bfa8db233fe24040d0858ac1..5839932b00571538d3e8291694f3e6a692e14dae 100644 (file)
--- 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 +629,25 @@ 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)
+{
+       jmp_buf dummy;
+
+       /*
+        * We cannot rely on the struct name that jmp_buf uses, so use a
+        * local variable here
+        */
+       if (size < sizeof(dummy)) {
+               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 (file)
index 0000000..0fb1a11
--- /dev/null
+++ b/arch/sandbox/include/asm/setjmp.h
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) 2018 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef _SETJMP_H_
+#define _SETJMP_H_
+
+struct jmp_buf_data {
+       /*
+        * We're not sure how long this should be:
+        *
+        *   amd64: 200 bytes
+        *   arm64: 392 bytes
+        *   armhf: 392 bytes
+        *
+        * So allow space for all of those, plus some extra.
+        * We don't need to worry about 16-byte alignment, since this does not
+        * run on Windows.
+        */
+       ulong data[128];
+};
+
+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 64e89a06c9498e24d84a00e734ce9f339ee657e8..c8e0f52d306345ac91d2a57d3dffe913e98e3764 100644 (file)
--- 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