Re: [PATCH 1/1] of: of_reserved_mem: Ensure cma reserved region not cross the low/high memory

[Jason Liu]

2016-11-23 19:37 GMT+08:00 Jason Liu <jason.hui.liu@xxxxxxx>:
> Need ensure the cma reserved region not cross the low/high memory boundary
> when using the dynamic allocation methond through device-tree, otherwise,
> kernel will fail to boot up when cma reserved region cross how/high mem.
>
> Signed-off-by: Jason Liu <jason.hui.liu@xxxxxxx>
> Cc: Laura Abbott <labbott@xxxxxxxxxx>
> Cc: Frank Rowand <frowand.list@xxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
>  drivers/of/of_reserved_mem.c    | 42 +++++++++++++++++++++++++++++++----------
>  include/linux/of_reserved_mem.h |  3 ++-
>  2 files changed, 34 insertions(+), 11 deletions(-)


Rob, any comments about this patch?


Jason Liu

>
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 366d8c3..852345a 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -31,11 +31,15 @@
>
>  #if defined(CONFIG_HAVE_MEMBLOCK)
>  #include <linux/memblock.h>
> -int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> -       phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
> -       phys_addr_t *res_base)
> +int __init __weak early_init_dt_alloc_reserved_memory_arch(unsigned long node,
> +       phys_addr_t size, phys_addr_t align, phys_addr_t start, phys_addr_t end,
> +       bool nomap, phys_addr_t *res_base)
>  {
>         phys_addr_t base;
> +       phys_addr_t highmem_start;
> +
> +       highmem_start = __pa(high_memory - 1) + 1;
> +
>         /*
>          * We use __memblock_alloc_base() because memblock_alloc_base()
>          * panic()s on allocation failure.
> @@ -53,15 +57,33 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
>                 return -ENOMEM;
>         }
>
> +       /*
> +        * Sanity check for the cma reserved region:If the reserved region
> +        * crosses the low/high memory boundary, try to fix it up and then
> +        * fall back to allocate the cma region from the low mememory space.
> +        */
> +
> +       if (IS_ENABLED(CONFIG_CMA)
> +           && of_flat_dt_is_compatible(node, "shared-dma-pool")
> +           && of_get_flat_dt_prop(node, "reusable", NULL) && !nomap) {
> +               if (base < highmem_start && (base + size) > highmem_start) {
> +                       memblock_free(base, size);
> +                       base = memblock_alloc_range(size, align, start,
> +                                               highmem_start, MEMBLOCK_NONE);
> +                       if (!base)
> +                               return -ENOMEM;
> +               }
> +       }
> +
>         *res_base = base;
>         if (nomap)
>                 return memblock_remove(base, size);
>         return 0;
>  }
>  #else
> -int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> -       phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
> -       phys_addr_t *res_base)
> +int __init __weak early_init_dt_alloc_reserved_memory_arch(unsigned long node,
> +       phys_addr_t size, phys_addr_t align, phys_addr_t start, phys_addr_t end,
> +       bool nomap, phys_addr_t *res_base)
>  {
>         pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
>                   size, nomap ? " (nomap)" : "");
> @@ -155,8 +177,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
>                         end = start + dt_mem_next_cell(dt_root_size_cells,
>                                                        &prop);
>
> -                       ret = early_init_dt_alloc_reserved_memory_arch(size,
> -                                       align, start, end, nomap, &base);
> +                       ret = early_init_dt_alloc_reserved_memory_arch(node,
> +                                       size, align, start, end, nomap, &base);
>                         if (ret == 0) {
>                                 pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
>                                         uname, &base,
> @@ -167,8 +189,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
>                 }
>
>         } else {
> -               ret = early_init_dt_alloc_reserved_memory_arch(size, align,
> -                                                       0, 0, nomap, &base);
> +               ret = early_init_dt_alloc_reserved_memory_arch(node,
> +                                       size, align, 0, 0, nomap, &base);
>                 if (ret == 0)
>                         pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
>                                 uname, &base, (unsigned long)size / SZ_1M);
> diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
> index f8e1992..a6ee451 100644
> --- a/include/linux/of_reserved_mem.h
> +++ b/include/linux/of_reserved_mem.h
> @@ -34,7 +34,8 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
>                                        struct device_node *np, int idx);
>  void of_reserved_mem_device_release(struct device *dev);
>
> -int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> +int early_init_dt_alloc_reserved_memory_arch(unsigned long node,
> +                                            phys_addr_t size,
>                                              phys_addr_t align,
>                                              phys_addr_t start,
>                                              phys_addr_t end,
> --
> 1.8.3.2
>