[U-Boot] [PATCH v2 08/16] sandbox: Add a setjmp() implementation

[Heinrich Schuchardt]

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 at 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 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];

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
>