Re: [bootwrapper PATCH v2 11/13] Announce locations of memory objects

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 14 Jan 2022 10:56:51 +0000
Mark Rutland <mark.rutland@arm.com> wrote:

Hi Mark,

> To make it easier to debug boot failures, log the location of memory
> objects at boot time.
> 
> This is logged to the serial console as:
> 
> | Boot-wrapper v0.2
> | Entered at EL3
> | Memory layout:
> | [0000000080000000..0000000080001f90] => boot-wrapper
> | [000000008000fff8..0000000080010000] => mbox
> | [0000000080200000..00000000822af200] => kernel
> | [0000000088000000..0000000088002857] => dtb

That looks indeed very useful!

> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> ---
>  common/init.c      | 27 +++++++++++++++++++++++++++
>  common/platform.c  | 13 +++++++++++++
>  include/platform.h |  2 ++
>  model.lds.S        | 20 ++++++++++++++------
>  4 files changed, 56 insertions(+), 6 deletions(-)
> 
> diff --git a/common/init.c b/common/init.c
> index 2600f73..fc74b9e 100644
> --- a/common/init.c
> +++ b/common/init.c
> @@ -14,6 +14,32 @@ static void announce_bootwrapper(void)
>  	print_string("Boot-wrapper v0.2\r\n");
>  }
>  
> +#define announce_object(object, desc)				\
> +do {								\
> +	extern char object##__start[];				\
> +	extern char object##__end[];				\
> +	print_string("[");					\
> +	print_ulong_hex((unsigned long)object##__start);	\
> +	print_string("..");					\
> +	print_ulong_hex((unsigned long)object##__end);		\
> +	print_string("] => " desc "\r\n");			\
> +} while (0)
> +
> +static void announce_objects(void)
> +{
> +	print_string("Memory layout:\r\n");
> +	announce_object(text, "boot-wrapper");
> +	announce_object(mbox, "mbox");
> +	announce_object(kernel, "kernel");
> +#ifdef XEN
> +	announce_object(xen, "xen");
> +#endif
> +	announce_object(dtb, "dtb");
> +#ifdef USE_INITRD
> +	announce_object(filesystem, "initrd");
> +#endif
> +}
> +
>  void announce_arch(void);
>  
>  void cpu_init_bootwrapper(void)
> @@ -22,6 +48,7 @@ void cpu_init_bootwrapper(void)
>  		init_uart();
>  		announce_bootwrapper();
>  		announce_arch();
> +		announce_objects();
>  		print_string("\r\n");
>  		init_platform();
>  	}
> diff --git a/common/platform.c b/common/platform.c
> index 80d0562..26e5944 100644
> --- a/common/platform.c
> +++ b/common/platform.c
> @@ -52,6 +52,19 @@ void print_string(const char *str)
>  		print_char(*str++);
>  }
>  
> +#define HEX_CHARS_PER_LONG (2 * sizeof(long))
> +
> +void print_ulong_hex(unsigned long val)
> +{
> +	const char hex_chars[16] = "0123456789abcdef";
> +	int i;
> +
> +	for (i = HEX_CHARS_PER_LONG - 1; i >= 0; i--) {
> +		int v = (val >> (4 * i)) & 0xf;
> +		print_char(hex_chars[v]);
> +	}
> +}
> +
>  void init_uart(void)
>  {
>  	/*
> diff --git a/include/platform.h b/include/platform.h
> index 237b481..c88e124 100644
> --- a/include/platform.h
> +++ b/include/platform.h
> @@ -11,6 +11,8 @@
>  
>  void print_char(char c);
>  void print_string(const char *str);
> +void print_ulong_hex(unsigned long val);
> +
>  void init_uart(void);
>  
>  void init_platform(void);
> diff --git a/model.lds.S b/model.lds.S
> index d4e7e13..dacaa25 100644
> --- a/model.lds.S
> +++ b/model.lds.S
> @@ -35,46 +35,54 @@ SECTIONS
>  	 * the boot section's *(.data)
>  	 */
>  	.kernel (PHYS_OFFSET + KERNEL_OFFSET): {
> -		kernel = .;
> +		kernel__start = .;
>  		KERNEL
> +		kernel__end = .;
>  	}
>  
>  #ifdef XEN
>  	.xen (PHYS_OFFSET + XEN_OFFSET): {
> -		xen = .;
> +		xen__start = .;
>  		XEN
> +		xen__end = .;
>  	}
>  
> -	entrypoint = xen;
> +	entrypoint = xen__start;
>  #else
> -	entrypoint = kernel;
> +	entrypoint = kernel__start;
>  #endif
>  
>  	.dtb (PHYS_OFFSET + FDT_OFFSET): {
> +		dtb__start = .;
>  		dtb = .;
>  		./fdt.dtb
> +		dtb__end = .;
>  	}
>  
>  #ifdef USE_INITRD
>  	.filesystem (PHYS_OFFSET + FS_OFFSET): {
> -		filesystem = .;
> +		filesystem__start = .;
>  		FILESYSTEM
> -		fs_size = . - filesystem;
> +		filesystem__end = .;
>  	}
>  #endif
>  
>  	.boot PHYS_OFFSET: {
> +		text__start = .;
>  		*(.init)
>  		*(.text*)
>  		*(.data* .rodata* .bss* COMMON)
>  		*(.vectors)
>  		*(.stack)
>  		PROVIDE(etext = .);
> +		text__end = .;
>  	}
>  
>  	.mbox (PHYS_OFFSET + MBOX_OFFSET): {
> +		mbox__start = .;
>  		mbox = .;
>  		QUAD(0x0)
> +		mbox__end = .;
>  	}
>  
>  	ASSERT(etext <= (PHYS_OFFSET + TEXT_LIMIT), ".text overflow!")


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