Similarly as the static regions defined in bootinfo.reserved_mem,
the bootmodule regions defined in bootinfo.modules should also not
be overlapping with memory regions in either bootinfo.reserved_mem
or bootinfo.modules.

Therefore, this commit introduces a helper `bootmodules_overlap_check()`
and uses this helper to extend the check in function
`check_reserved_regions_overlap()` so that memory regions in
bootinfo.modules are included. Use `check_reserved_regions_overlap()`
in `add_boot_module()` to return early if any error occurs.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
---
v2 -> v3:
1. Use "[start, end]" format in printk error message.
2. Change the return type of helper functions to bool.
3. Use 'start' and 'size' in helper functions to describe a region.
v1 -> v2:
1. Split original `overlap_check()` to `bootmodules_overlap_check()`.
2. Rework commit message.
---
 xen/arch/arm/setup.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 636604aafa..98df0baffa 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -287,6 +287,32 @@ static bool __init meminfo_overlap_check(struct meminfo *meminfo,
     return false;
 }
 
+static bool __init bootmodules_overlap_check(struct bootmodules *bootmodules,
+                                             paddr_t region_start,
+                                             paddr_t region_size)
+{
+    paddr_t mod_start = INVALID_PADDR, mod_end = 0;
+    paddr_t region_end = region_start + region_size;
+    unsigned int i, mod_num = bootmodules->nr_mods;
+
+    for ( i = 0; i < mod_num; i++ )
+    {
+        mod_start = bootmodules->module[i].start;
+        mod_end = mod_start + bootmodules->module[i].size;
+
+        if ( region_end <= mod_start || region_start >= mod_end )
+            continue;
+        else
+        {
+            printk("Region: [%#"PRIpaddr", %#"PRIpaddr"] overlapping with mod[%u]: [%#"PRIpaddr", %#"PRIpaddr"]\n",
+                   region_start, region_end, i, mod_start, mod_end);
+            return true;
+        }
+    }
+
+    return false;
+}
+
 void __init fw_unreserved_regions(paddr_t s, paddr_t e,
                                   void (*cb)(paddr_t, paddr_t),
                                   unsigned int first)
@@ -311,6 +337,11 @@ bool __init check_reserved_regions_overlap(paddr_t region_start,
                                region_start, region_size) )
         return true;
 
+    /* Check if input region is overlapping with bootmodules */
+    if ( bootmodules_overlap_check(&bootinfo.modules,
+                                   region_start, region_size) )
+        return true;
+
     return false;
 }
 
@@ -328,6 +359,10 @@ struct bootmodule __init *add_boot_module(bootmodule_kind kind,
                boot_module_kind_as_string(kind), start, start + size);
         return NULL;
     }
+
+    if ( check_reserved_regions_overlap(start, size) )
+        return NULL;
+
     for ( i = 0 ; i < mods->nr_mods ; i++ )
     {
         mod = &mods->module[i];
-- 
2.25.1

On Mon, 30 Jan 2023, Henry Wang wrote:
> Similarly as the static regions defined in bootinfo.reserved_mem,
> the bootmodule regions defined in bootinfo.modules should also not
> be overlapping with memory regions in either bootinfo.reserved_mem
> or bootinfo.modules.
> 
> Therefore, this commit introduces a helper `bootmodules_overlap_check()`
> and uses this helper to extend the check in function
> `check_reserved_regions_overlap()` so that memory regions in
> bootinfo.modules are included. Use `check_reserved_regions_overlap()`
> in `add_boot_module()` to return early if any error occurs.
> 
> Signed-off-by: Henry Wang <Henry.Wang@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> v2 -> v3:
> 1. Use "[start, end]" format in printk error message.
> 2. Change the return type of helper functions to bool.
> 3. Use 'start' and 'size' in helper functions to describe a region.
> v1 -> v2:
> 1. Split original `overlap_check()` to `bootmodules_overlap_check()`.
> 2. Rework commit message.
> ---
>  xen/arch/arm/setup.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 636604aafa..98df0baffa 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -287,6 +287,32 @@ static bool __init meminfo_overlap_check(struct meminfo *meminfo,
>      return false;
>  }
>  
> +static bool __init bootmodules_overlap_check(struct bootmodules *bootmodules,
> +                                             paddr_t region_start,
> +                                             paddr_t region_size)
> +{
> +    paddr_t mod_start = INVALID_PADDR, mod_end = 0;
> +    paddr_t region_end = region_start + region_size;
> +    unsigned int i, mod_num = bootmodules->nr_mods;
> +
> +    for ( i = 0; i < mod_num; i++ )
> +    {
> +        mod_start = bootmodules->module[i].start;
> +        mod_end = mod_start + bootmodules->module[i].size;
> +
> +        if ( region_end <= mod_start || region_start >= mod_end )
> +            continue;
> +        else
> +        {
> +            printk("Region: [%#"PRIpaddr", %#"PRIpaddr"] overlapping with mod[%u]: [%#"PRIpaddr", %#"PRIpaddr"]\n",
> +                   region_start, region_end, i, mod_start, mod_end);
> +            return true;
> +        }
> +    }
> +
> +    return false;
> +}
> +
>  void __init fw_unreserved_regions(paddr_t s, paddr_t e,
>                                    void (*cb)(paddr_t, paddr_t),
>                                    unsigned int first)
> @@ -311,6 +337,11 @@ bool __init check_reserved_regions_overlap(paddr_t region_start,
>                                 region_start, region_size) )
>          return true;
>  
> +    /* Check if input region is overlapping with bootmodules */
> +    if ( bootmodules_overlap_check(&bootinfo.modules,
> +                                   region_start, region_size) )
> +        return true;
> +
>      return false;
>  }
>  
> @@ -328,6 +359,10 @@ struct bootmodule __init *add_boot_module(bootmodule_kind kind,
>                 boot_module_kind_as_string(kind), start, start + size);
>          return NULL;
>      }
> +
> +    if ( check_reserved_regions_overlap(start, size) )
> +        return NULL;
> +
>      for ( i = 0 ; i < mods->nr_mods ; i++ )
>      {
>          mod = &mods->module[i];
> -- 
> 2.25.1
>