[U-Boot] [PATCH 1/1] efi_loader: create handles from normal memory

[U-Boot] [PATCH 1/1] efi_loader: create handles from normal memory

[Heinrich Schuchardt]

Handles are not used at runtime. They are freed by the firmware when the
last protocol interface is uninstalled. So there is no reason to use EFI
memory when creating handles.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 lib/efi_loader/efi_boottime.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index b7ab2e8208e..50d311548e2 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -431,16 +431,15 @@ void efi_add_handle(struct efi_object *obj)
 efi_status_t efi_create_handle(efi_handle_t *handle)
 {
 	struct efi_object *obj;
-	efi_status_t r;
 
-	r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES,
-			      sizeof(struct efi_object),
-			      (void **)&obj);
-	if (r != EFI_SUCCESS)
-		return r;
+	obj = calloc(1, sizeof(struct efi_object));
+	if (!obj)
+		return EFI_OUT_OF_RESOURCES;
+
 	efi_add_handle(obj);
 	*handle = obj->handle;
-	return r;
+
+	return EFI_SUCCESS;
 }
 
 /**
-- 
2.17.0

[U-Boot] [PATCH 1/1] efi_loader: create handles from normal memory

[Alexander Graf]

On 27.05.18 16:47, Heinrich Schuchardt wrote:
> Handles are not used at runtime. They are freed by the firmware when the
> last protocol interface is uninstalled. So there is no reason to use EFI
> memory when creating handles.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

I agree that efi object structs are supposed to be opaque and thus we
can use any allocation mechanism we like.

What I also see is that efi_delete_handle() even calls free() on
objects, so spawning them from efi memory rather than malloc memory is
also just wrong.

In short, I think your patch is completely correct :).


Alex

[U-Boot] [PATCH 1/1] efi_loader: create handles from normal memory

[Heinrich Schuchardt]

On 06/03/2018 03:23 PM, Alexander Graf wrote:
> 
> 
> On 27.05.18 16:47, Heinrich Schuchardt wrote:
>> Handles are not used at runtime. They are freed by the firmware when the
>> last protocol interface is uninstalled. So there is no reason to use EFI
>> memory when creating handles.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> 
> I agree that efi object structs are supposed to be opaque and thus we
> can use any allocation mechanism we like.
> 
> What I also see is that efi_delete_handle() even calls free() on
> objects, so spawning them from efi memory rather than malloc memory is
> also just wrong.

The bit that is missing is to call efi_delete_handle() when the last
protocol interface is uninstalled. Before doing so we must ensure that
no static memory is used and the first element of the handles is an
efi_obj. I did not yet check if we reached that point.

Best regards

Heinrich

> 
> In short, I think your patch is completely correct :).
> 
> 
> Alex
> 
>