[U-Boot,v2,08/16] 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>
---

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

On 12/04/2017 10:28 PM, Simon Glass wrote:
> 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>
> ---
> 
> 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));

This produces a warning:
‘sizeof’ on array function parameter ‘jmp’ will return size of ‘struct
jmp_buf_data *’ [-Wsizeof-array-argument]

Did you mean sizeof(struct jmp_buf_data)?

> +}
> +
> +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 c524957b6c..e9200192c6 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>
> @@ -617,3 +618,19 @@ 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(struct jmp_buf_data));

Shouldn't this be 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@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];

Isn't this buffer is too short?

sizeof(jmp_buf)
===============
amd64: 200 bytes
arm64: 392 bytes
armhf: 392 bytes

Please, check the alignment. On Windows amd64 a jump buffer must be 16
byte aligned.

Best regards

Heinrich

> +};
> +
> +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 2bf4bdb1b8..ad1836ac9f 100644
> --- a/include/os.h
> +++ b/include/os.h
> @@ -310,4 +310,25 @@ 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
>