Re: [PATCH 2/2] xen/arm: support compressed kernels

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 12/08/15 15:47, Stefano Stabellini wrote:
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> CC: julien.grall@citrix.com
> CC: ian.campbell@citrix.com
> ---
>  xen/arch/arm/kernel.c           |   36 ++++++++++++++++++++++++++++++++++++
>  xen/common/Makefile             |    2 +-
>  xen/include/asm-arm/byteorder.h |    2 ++
>  3 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
> index f641b12..ca50cdd 100644
> --- a/xen/arch/arm/kernel.c
> +++ b/xen/arch/arm/kernel.c
> @@ -13,6 +13,8 @@
>  #include <asm/byteorder.h>
>  #include <asm/setup.h>
>  #include <xen/libfdt/libfdt.h>
> +#include <xen/decompress.h>
> +#include <xen/vmap.h>
>  
>  #include "kernel.h"
>  
> @@ -310,6 +312,38 @@ static int kernel_zimage64_probe(struct kernel_info *info,
>  
>      return 0;
>  }
> +
> +static int kernel_zimage64_compressed_probe(struct kernel_info *info,
> +                                 paddr_t addr, paddr_t size)
> +{
> +    char *output, *input;
> +    unsigned char magic[2];
> +    int rc;
> +    unsigned kernel_order_in;
> +    unsigned kernel_order_out;
> +    paddr_t output_size;
> +    
> +    copy_from_paddr(magic, addr, sizeof(magic));

Need a size check before assuming sufficient length.  (All of the arm
probe functions suffer in a similar way.)

> +
> +    if (!((magic[0] == 0x1f) && ((magic[1] == 0x8b) || (magic[1] == 0x9e))))
> +        return -EINVAL;
> +
> +    kernel_order_in = get_order_from_bytes(size);
> +    input = (char *)ioremap_cache(addr, size);
> +
> +    output_size = output_length(input, size);
> +    kernel_order_out = get_order_from_bytes(output_size);
> +    output = (char *)alloc_xenheap_pages(kernel_order_out, 0);
> +
> +    rc = decompress(input, size, output);
> +    clean_dcache_va_range(output, output_size);
> +    iounmap(input);
> +
> +    if (rc != 0)

Xen style.

~Andrew