[U-Boot] [PATCH v4 1/2] Reserve secure memory

[Joakim Tjernlund]

On Mon, 2015-11-16 at 08:34 -0800, York Sun wrote:
> Secure memory is at the end of memory, separated and reserved
> from OS, tracked by gd->secure_ram. Secure memory can host
> MMU tables, security monitor, etc.

Don't see the difference with pram here?
Also, do you really wan't to hide the memory from Linux or will
a resv map do? You get a lot of small TLB maps if memory is non power of 2

 Jocke

> 
> Signed-off-by: York Sun <yorksun at freescale.com>
> 
> ---
> 
> Changes in v4: None
> Changes in v3:
>   Put ifdef around secure_ram
>   Move defining CONFIG_SYS_MEM_RESERVE_SECURE to patch 2/2
> 
> Changes in v2:
>   Do not use CONFIG_SYS_MEM_TOP_HIDE mechanism
> 
> Changes in v1:
>   Initial patch.
>   Depends on http://patchwork.ozlabs.org/patch/540248/
> 
>  README                            |    8 ++++++++
>  common/board_f.c                  |    9 +++++++++
>  include/asm-generic/global_data.h |    4 ++++
>  3 files changed, 21 insertions(+)
> 
> diff --git a/README b/README
> index ef8d437..61cbc82 100644
> --- a/README
> +++ b/README
> @@ -3881,6 +3881,14 @@ Configuration Settings:
>  		Scratch address used by the alternate memory test
>  		You only need to set this if address zero isn't writeable
>  
> +- CONFIG_SYS_MEM_RESERVE_SECURE
> +		If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
> +		is substracted from total RAM and won't be reported to OS.
> +		This memory can be used as secure memory. A variable
> +		gd->secure_ram is used to track the location. In systems
> +		the RAM base is not zero, or RAM is divided into banks,
> +		this variable needs to be recalcuated to get the address.
> +
>  - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
>  		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
>  		this specified memory area will get subtracted from the top
> diff --git a/common/board_f.c b/common/board_f.c
> index 725eb18..8061105 100644
> --- a/common/board_f.c
> +++ b/common/board_f.c
> @@ -323,6 +323,15 @@ static int setup_dest_addr(void)
>  	 * Ram is setup, size stored in gd !!
>  	 */
>  	debug("Ram size: %08lX\n", (ulong)gd->ram_size);
> +#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
> +	/* Reserve memory for secure MMU tables, and/or security monitor */
> +	gd->ram_size -= CONFIG_SYS_MEM_RESERVE_SECURE;
> +	/*
> +	 * Record secure memory location. Need recalcuate if memory splits
> +	 * into banks, or the ram base is not zero.
> +	 */
> +	gd->secure_ram = gd->ram_size;
> +#endif
>  #if defined(CONFIG_SYS_MEM_TOP_HIDE)
>  	/*
>  	 * Subtract specified amount of memory to hide so that it won't
> diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
> index d0383f3..8cdafd6 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -58,6 +58,10 @@ typedef struct global_data {
>  
>  	unsigned long relocaddr;	/* Start address of U-Boot in RAM */
>  	phys_size_t ram_size;	/* RAM size */
> +#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
> +	/* Secure memory addr. LSB is a flag for "secured". */
> +	phys_addr_t secure_ram;
> +#endif
>  	unsigned long mon_len;	/* monitor len */
>  	unsigned long irq_sp;		/* irq stack pointer */
>  	unsigned long start_addr_sp;	/* start_addr_stackpointer */