sandbox: implement actual sandbox reset via exec(2)

On Linux, /proc/self/exe is a symlink to the originally exec(2)d
executable. We can exec that with the original argv to simulate
a reset. This is useful for shorter development cycles on sandbox
and in future, could be used to test barebox behavior around resets
(e.g. reset reason can be passed through via libc environment).

We leave the original hanging reset in place though, because:

 - Many boards have multiple reset providers and incoming patches
    will allow users to select a specific one. Having this on
    sandbox as well makes testing easier.

 - /proc/self/exe is Linux-specific and wouldn't work when being
   run on e.g. BSDs or macOS

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/sandbox/mach-sandbox/include/mach/linux.h b/arch/sandbox/mach-sandbox/include/mach/linux.h
index f0a3a7b510..1ab48e52a0 100644
--- a/arch/sandbox/mach-sandbox/include/mach/linux.h
+++ b/arch/sandbox/mach-sandbox/include/mach/linux.h
@@ -18,6 +18,7 @@ off_t linux_lseek(int fildes, off_t offset);
 int linux_tstc(int fd);
 void __attribute__((noreturn)) linux_exit(void);
 void linux_hang(void);
+void linux_reexec(void);
 
 int linux_execve(const char * filename, char *const argv[], char *const envp[]);