[v5,2/2] efi: Free malloc regions on exit

Message ID 20170829192648.55830-3-agraf@suse.de
State New
Headers show
Series
  • efi: Free memory on exit
Related show

Commit Message

Alexander Graf Aug. 29, 2017, 7:26 p.m.
When we exit grub, we don't free all the memory that we allocated earlier
for our heap region. This can cause problems with setups where you try
to descend the boot order using "exit" entries, such as PXE -> HD boot
scenarios.

Signed-off-by: Alexander Graf <agraf@suse.de>


---

v2 -> v3:

  - add comment explaining the number of regions
  - move nr of regions into a define
  - add warning if we exceed the number of freeable regions
  - reset region counter to 0 on fini

v3 -> v4:

  - use dynamic list instead of static array at runtime
  - use allocate_pool for list, so we are not bound by heap or random numbers
  - remember all allocations, not just the heap

v4 -> v5:

  - free dynamic list entries on allocation removal
---
 grub-core/kern/efi/init.c |  1 +
 grub-core/kern/efi/mm.c   | 88 +++++++++++++++++++++++++++++++++++++++++++++++
 include/grub/efi/efi.h    |  1 +
 3 files changed, 90 insertions(+)

-- 
2.12.3


_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel

Comments

Daniel Kiper Aug. 30, 2017, 12:11 p.m. | #1
On Tue, Aug 29, 2017 at 09:26:48PM +0200, Alexander Graf wrote:
> When we exit grub, we don't free all the memory that we allocated earlier

> for our heap region. This can cause problems with setups where you try

> to descend the boot order using "exit" entries, such as PXE -> HD boot

> scenarios.

>

> Signed-off-by: Alexander Graf <agraf@suse.de>

>

> ---

>

> v2 -> v3:

>

>   - add comment explaining the number of regions

>   - move nr of regions into a define

>   - add warning if we exceed the number of freeable regions

>   - reset region counter to 0 on fini

>

> v3 -> v4:

>

>   - use dynamic list instead of static array at runtime

>   - use allocate_pool for list, so we are not bound by heap or random numbers

>   - remember all allocations, not just the heap

>

> v4 -> v5:

>

>   - free dynamic list entries on allocation removal

> ---

>  grub-core/kern/efi/init.c |  1 +

>  grub-core/kern/efi/mm.c   | 88 +++++++++++++++++++++++++++++++++++++++++++++++

>  include/grub/efi/efi.h    |  1 +

>  3 files changed, 90 insertions(+)

>

> diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c

> index 2c31847bf..3dfdf2d22 100644

> --- a/grub-core/kern/efi/init.c

> +++ b/grub-core/kern/efi/init.c

> @@ -80,4 +80,5 @@ grub_efi_fini (void)

>  {

>    grub_efidisk_fini ();

>    grub_console_fini ();

> +  grub_efi_memory_fini ();

>  }

> diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c

> index ac2a4c556..c9bd3568d 100644

> --- a/grub-core/kern/efi/mm.c

> +++ b/grub-core/kern/efi/mm.c

> @@ -49,6 +49,80 @@ static grub_efi_uintn_t finish_desc_size;

>  static grub_efi_uint32_t finish_desc_version;

>  int grub_efi_is_finished = 0;

>

> +/*

> + * We need to roll back EFI allocations on exit. Remember allocations that

> + * we'll free on exit.

> + */

> +struct efi_allocation;

> +struct efi_allocation {

> +	struct efi_allocation *next;


Please put this member as the last one.

> +	grub_efi_physical_address_t start_addr;


s/start_addr/address/

> +	grub_efi_uint64_t pages;

> +};

> +static struct efi_allocation *efi_allocated_memory;

> +

> +static void

> +grub_efi_unremember_pages (grub_efi_physical_address_t address,

> +                           grub_efi_uintn_t pages)


This function should be after grub_efi_remember_pages().

And maybe s/grub_efi_unremember_pages()/grub_efi_drop_alloc()/...

> +{

> +  struct efi_allocation **allocp;

> +  grub_efi_boot_services_t *b;

> +

> +  b = grub_efi_system_table->boot_services;

> +

> +  for (allocp = &efi_allocated_memory; *allocp;)

> +    {

> +      struct efi_allocation *alloc;

> +      struct efi_allocation *next;

> +

> +      alloc = *allocp;

> +

> +      if (alloc->start_addr != address ||

> +          alloc->pages != pages)

> +        {

> +          /* Move on to the next entry */

> +          allocp = &alloc->next;

> +

> +          continue;

> +        }

> +

> +      /* Remember the next entry */

> +      next = alloc->next;

> +

> +      /* Free the current list entry */

> +      efi_call_1 (b->free_pool, alloc);

> +

> +      /* Remove from list */

> +      *allocp = next;

> +

> +      /* Done */

> +      break;

> +    }


Hmmm... This looks a bit complicated. Could you try this:

struct efi_allocation *ea, *eap;

for (eap = NULL, ea = efi_allocated_memory; ea; eap = ea, ea = ea->next)
  {
    if (ea->start_addr != address || ea->pages != pages)
       continue;

    if (eap)
      efi_allocated_memory = ea->next;
    else
      eap->next = ea->next;

    efi_call_1 (b->free_pool, ea);

    return;
  }

> +}

> +

> +static void

> +grub_efi_remember_pages (grub_efi_physical_address_t address,

> +                         grub_efi_uintn_t pages)


This function should be before grub_efi_unremember_pages().

And maybe s/grub_efi_remember_pages()/grub_efi_store_alloc()/...

> +{

> +  grub_efi_boot_services_t *b;

> +  struct efi_allocation *alloc;

> +  grub_efi_status_t status;

> +

> +  b = grub_efi_system_table->boot_services;

> +  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

> +                           sizeof(*alloc), (void**)&alloc);

> +  if (status == GRUB_EFI_SUCCESS)

> +    {

> +      alloc->next = efi_allocated_memory;

> +      alloc->start_addr = address;

> +      alloc->pages = pages;

> +      efi_allocated_memory = alloc;

> +    }

> +  else

> +      grub_printf ("Could not malloc memory to remember EFI allocation. "

> +                   "Exiting grub2 won't free all memory.\n");


s/grub2/GRUB2/

> +}

> +

>  /* Allocate pages. Return the pointer to the first of allocated pages.  */

>  void *

>  grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

> @@ -79,6 +153,7 @@ grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

>  	return 0;

>      }

>

> +  grub_efi_remember_pages (address, pages);

>    return (void *) ((grub_addr_t) address);

>  }

>

> @@ -108,6 +183,7 @@ grub_efi_free_pages (grub_efi_physical_address_t address,

>

>    b = grub_efi_system_table->boot_services;

>    efi_call_2 (b->free_pages, address, pages);

> +  grub_efi_unremember_pages (address, pages);

>  }

>

>  #if defined (__i386__) || defined (__x86_64__)

> @@ -422,6 +498,18 @@ add_memory_regions (grub_efi_memory_descriptor_t *memory_map,

>      grub_fatal ("too little memory");

>  }

>

> +void

> +grub_efi_memory_fini (void)

> +{

> +  /* Free all stale allocations */

> +


Drop this empty line. And please improve the comment here. It took me
some time to understand why just "while (efi_allocated_memory)" works
here. grub_efi_free_pages() calls grub_efi_unremember_pages()
which advances the pointer.

> +  while (efi_allocated_memory)

> +      grub_efi_free_pages (efi_allocated_memory->start_addr,

> +                           efi_allocated_memory->pages);

> +

> +  efi_allocated_memory = NULL;


I have a feeling that you do not need this here.

Daniel

_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
Leif Lindholm Aug. 30, 2017, 1:03 p.m. | #2
On Wed, Aug 30, 2017 at 02:11:59PM +0200, Daniel Kiper wrote:
> On Tue, Aug 29, 2017 at 09:26:48PM +0200, Alexander Graf wrote:

> > +{

> > +  grub_efi_boot_services_t *b;

> > +  struct efi_allocation *alloc;

> > +  grub_efi_status_t status;

> > +

> > +  b = grub_efi_system_table->boot_services;

> > +  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

> > +                           sizeof(*alloc), (void**)&alloc);

> > +  if (status == GRUB_EFI_SUCCESS)

> > +    {

> > +      alloc->next = efi_allocated_memory;

> > +      alloc->start_addr = address;

> > +      alloc->pages = pages;

> > +      efi_allocated_memory = alloc;

> > +    }

> > +  else

> > +      grub_printf ("Could not malloc memory to remember EFI allocation. "

> > +                   "Exiting grub2 won't free all memory.\n");

> 

> s/grub2/GRUB2/


Well, GRUB. Grub2 is a distro-ism.
We shouldn't have to update individual message strings when we bump
revisions.

/
    Leif

_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
Alexander Graf Aug. 31, 2017, 12:10 p.m. | #3
On 08/30/2017 02:11 PM, Daniel Kiper wrote:
> On Tue, Aug 29, 2017 at 09:26:48PM +0200, Alexander Graf wrote:

>> When we exit grub, we don't free all the memory that we allocated earlier

>> for our heap region. This can cause problems with setups where you try

>> to descend the boot order using "exit" entries, such as PXE -> HD boot

>> scenarios.

>>

>> Signed-off-by: Alexander Graf <agraf@suse.de>

>>

>> ---

>>

>> v2 -> v3:

>>

>>    - add comment explaining the number of regions

>>    - move nr of regions into a define

>>    - add warning if we exceed the number of freeable regions

>>    - reset region counter to 0 on fini

>>

>> v3 -> v4:

>>

>>    - use dynamic list instead of static array at runtime

>>    - use allocate_pool for list, so we are not bound by heap or random numbers

>>    - remember all allocations, not just the heap

>>

>> v4 -> v5:

>>

>>    - free dynamic list entries on allocation removal

>> ---

>>   grub-core/kern/efi/init.c |  1 +

>>   grub-core/kern/efi/mm.c   | 88 +++++++++++++++++++++++++++++++++++++++++++++++

>>   include/grub/efi/efi.h    |  1 +

>>   3 files changed, 90 insertions(+)

>>

>> diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c

>> index 2c31847bf..3dfdf2d22 100644

>> --- a/grub-core/kern/efi/init.c

>> +++ b/grub-core/kern/efi/init.c

>> @@ -80,4 +80,5 @@ grub_efi_fini (void)

>>   {

>>     grub_efidisk_fini ();

>>     grub_console_fini ();

>> +  grub_efi_memory_fini ();

>>   }

>> diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c

>> index ac2a4c556..c9bd3568d 100644

>> --- a/grub-core/kern/efi/mm.c

>> +++ b/grub-core/kern/efi/mm.c

>> @@ -49,6 +49,80 @@ static grub_efi_uintn_t finish_desc_size;

>>   static grub_efi_uint32_t finish_desc_version;

>>   int grub_efi_is_finished = 0;

>>

>> +/*

>> + * We need to roll back EFI allocations on exit. Remember allocations that

>> + * we'll free on exit.

>> + */

>> +struct efi_allocation;

>> +struct efi_allocation {

>> +	struct efi_allocation *next;

> Please put this member as the last one.


Sure, but care to explain why? Having the list chaining at the beginning 
of the struct is a very natural thing to do in pretty much every other 
project I've worked on.

>

>> +	grub_efi_physical_address_t start_addr;

> s/start_addr/address/

>

>> +	grub_efi_uint64_t pages;

>> +};

>> +static struct efi_allocation *efi_allocated_memory;

>> +

>> +static void

>> +grub_efi_unremember_pages (grub_efi_physical_address_t address,

>> +                           grub_efi_uintn_t pages)

> This function should be after grub_efi_remember_pages().

>

> And maybe s/grub_efi_unremember_pages()/grub_efi_drop_alloc()/...

Sure...

>

>> +{

>> +  struct efi_allocation **allocp;

>> +  grub_efi_boot_services_t *b;

>> +

>> +  b = grub_efi_system_table->boot_services;

>> +

>> +  for (allocp = &efi_allocated_memory; *allocp;)

>> +    {

>> +      struct efi_allocation *alloc;

>> +      struct efi_allocation *next;

>> +

>> +      alloc = *allocp;

>> +

>> +      if (alloc->start_addr != address ||

>> +          alloc->pages != pages)

>> +        {

>> +          /* Move on to the next entry */

>> +          allocp = &alloc->next;

>> +

>> +          continue;

>> +        }

>> +

>> +      /* Remember the next entry */

>> +      next = alloc->next;

>> +

>> +      /* Free the current list entry */

>> +      efi_call_1 (b->free_pool, alloc);

>> +

>> +      /* Remove from list */

>> +      *allocp = next;

>> +

>> +      /* Done */

>> +      break;

>> +    }

> Hmmm... This looks a bit complicated. Could you try this:

>

> struct efi_allocation *ea, *eap;

>

> for (eap = NULL, ea = efi_allocated_memory; ea; eap = ea, ea = ea->next)

>    {

>      if (ea->start_addr != address || ea->pages != pages)

>         continue;

>

>      if (eap)


I suppose you mean !eap here

>        efi_allocated_memory = ea->next;

>      else

>        eap->next = ea->next;

>

>      efi_call_1 (b->free_pool, ea);

>

>      return;

>    }


I'm not sure the version above is actually more readable. Do you really 
want me to move to that? It basically does the same thing, just with an 
explicit branch in between.

>

>> +}

>> +

>> +static void

>> +grub_efi_remember_pages (grub_efi_physical_address_t address,

>> +                         grub_efi_uintn_t pages)

> This function should be before grub_efi_unremember_pages().

>

> And maybe s/grub_efi_remember_pages()/grub_efi_store_alloc()/...


works for me :)

>

>> +{

>> +  grub_efi_boot_services_t *b;

>> +  struct efi_allocation *alloc;

>> +  grub_efi_status_t status;

>> +

>> +  b = grub_efi_system_table->boot_services;

>> +  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

>> +                           sizeof(*alloc), (void**)&alloc);

>> +  if (status == GRUB_EFI_SUCCESS)

>> +    {

>> +      alloc->next = efi_allocated_memory;

>> +      alloc->start_addr = address;

>> +      alloc->pages = pages;

>> +      efi_allocated_memory = alloc;

>> +    }

>> +  else

>> +      grub_printf ("Could not malloc memory to remember EFI allocation. "

>> +                   "Exiting grub2 won't free all memory.\n");

> s/grub2/GRUB2/

>

>> +}

>> +

>>   /* Allocate pages. Return the pointer to the first of allocated pages.  */

>>   void *

>>   grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

>> @@ -79,6 +153,7 @@ grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

>>   	return 0;

>>       }

>>

>> +  grub_efi_remember_pages (address, pages);

>>     return (void *) ((grub_addr_t) address);

>>   }

>>

>> @@ -108,6 +183,7 @@ grub_efi_free_pages (grub_efi_physical_address_t address,

>>

>>     b = grub_efi_system_table->boot_services;

>>     efi_call_2 (b->free_pages, address, pages);

>> +  grub_efi_unremember_pages (address, pages);

>>   }

>>

>>   #if defined (__i386__) || defined (__x86_64__)

>> @@ -422,6 +498,18 @@ add_memory_regions (grub_efi_memory_descriptor_t *memory_map,

>>       grub_fatal ("too little memory");

>>   }

>>

>> +void

>> +grub_efi_memory_fini (void)

>> +{

>> +  /* Free all stale allocations */

>> +

> Drop this empty line. And please improve the comment here. It took me

> some time to understand why just "while (efi_allocated_memory)" works

> here. grub_efi_free_pages() calls grub_efi_unremember_pages()

> which advances the pointer.


Does this work for you?

void
grub_efi_memory_fini (void)
{
   /*
    * Free all stale allocations. grub_efi_free_pages() will remove
    * the found entry from the list and it will always find the first
    * list entry (efi_allocated_memory is the list start). Hence we
    * remove all entries from the list until none is left altogether.
    */
   while (efi_allocated_memory)
       grub_efi_free_pages (efi_allocated_memory->address,
                            efi_allocated_memory->pages);
}


>

>> +  while (efi_allocated_memory)

>> +      grub_efi_free_pages (efi_allocated_memory->start_addr,

>> +                           efi_allocated_memory->pages);

>> +

>> +  efi_allocated_memory = NULL;

> I have a feeling that you do not need this here.


You're right. It was only needed for the idx based, old version :)


Alex


_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
Daniel Kiper Aug. 31, 2017, 2:25 p.m. | #4
On Thu, Aug 31, 2017 at 02:10:48PM +0200, Alexander Graf wrote:
> On 08/30/2017 02:11 PM, Daniel Kiper wrote:

> >On Tue, Aug 29, 2017 at 09:26:48PM +0200, Alexander Graf wrote:

> >>When we exit grub, we don't free all the memory that we allocated earlier

> >>for our heap region. This can cause problems with setups where you try

> >>to descend the boot order using "exit" entries, such as PXE -> HD boot

> >>scenarios.

> >>

> >>Signed-off-by: Alexander Graf <agraf@suse.de>

> >>

> >>---

> >>

> >>v2 -> v3:

> >>

> >>   - add comment explaining the number of regions

> >>   - move nr of regions into a define

> >>   - add warning if we exceed the number of freeable regions

> >>   - reset region counter to 0 on fini

> >>

> >>v3 -> v4:

> >>

> >>   - use dynamic list instead of static array at runtime

> >>   - use allocate_pool for list, so we are not bound by heap or random

> >>   numbers

> >>   - remember all allocations, not just the heap

> >>

> >>v4 -> v5:

> >>

> >>   - free dynamic list entries on allocation removal

> >>---

> >>  grub-core/kern/efi/init.c |  1 +

> >>  grub-core/kern/efi/mm.c   | 88

> >>  +++++++++++++++++++++++++++++++++++++++++++++++

> >>  include/grub/efi/efi.h    |  1 +

> >>  3 files changed, 90 insertions(+)

> >>

> >>diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c

> >>index 2c31847bf..3dfdf2d22 100644

> >>--- a/grub-core/kern/efi/init.c

> >>+++ b/grub-core/kern/efi/init.c

> >>@@ -80,4 +80,5 @@ grub_efi_fini (void)

> >>  {

> >>    grub_efidisk_fini ();

> >>    grub_console_fini ();

> >>+  grub_efi_memory_fini ();

> >>  }

> >>diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c

> >>index ac2a4c556..c9bd3568d 100644

> >>--- a/grub-core/kern/efi/mm.c

> >>+++ b/grub-core/kern/efi/mm.c

> >>@@ -49,6 +49,80 @@ static grub_efi_uintn_t finish_desc_size;

> >>  static grub_efi_uint32_t finish_desc_version;

> >>  int grub_efi_is_finished = 0;

> >>

> >>+/*

> >>+ * We need to roll back EFI allocations on exit. Remember allocations

> >>that

> >>+ * we'll free on exit.

> >>+ */

> >>+struct efi_allocation;

> >>+struct efi_allocation {

> >>+	struct efi_allocation *next;

> >Please put this member as the last one.

>

> Sure, but care to explain why? Having the list chaining at the beginning

> of the struct is a very natural thing to do in pretty much every other

> project I've worked on.


OK, let's leave it then.

> >>+	grub_efi_physical_address_t start_addr;

> >s/start_addr/address/

> >

> >>+	grub_efi_uint64_t pages;

> >>+};

> >>+static struct efi_allocation *efi_allocated_memory;

> >>+

> >>+static void

> >>+grub_efi_unremember_pages (grub_efi_physical_address_t address,

> >>+                           grub_efi_uintn_t pages)

> >This function should be after grub_efi_remember_pages().

> >

> >And maybe s/grub_efi_unremember_pages()/grub_efi_drop_alloc()/...

> Sure...

>

> >

> >>+{

> >>+  struct efi_allocation **allocp;

> >>+  grub_efi_boot_services_t *b;

> >>+

> >>+  b = grub_efi_system_table->boot_services;

> >>+

> >>+  for (allocp = &efi_allocated_memory; *allocp;)

> >>+    {

> >>+      struct efi_allocation *alloc;

> >>+      struct efi_allocation *next;

> >>+

> >>+      alloc = *allocp;

> >>+

> >>+      if (alloc->start_addr != address ||

> >>+          alloc->pages != pages)

> >>+        {

> >>+          /* Move on to the next entry */

> >>+          allocp = &alloc->next;

> >>+

> >>+          continue;

> >>+        }

> >>+

> >>+      /* Remember the next entry */

> >>+      next = alloc->next;

> >>+

> >>+      /* Free the current list entry */

> >>+      efi_call_1 (b->free_pool, alloc);

> >>+

> >>+      /* Remove from list */

> >>+      *allocp = next;

> >>+

> >>+      /* Done */

> >>+      break;

> >>+    }

> >Hmmm... This looks a bit complicated. Could you try this:

> >

> >struct efi_allocation *ea, *eap;

> >

> >for (eap = NULL, ea = efi_allocated_memory; ea; eap = ea, ea = ea->next)

> >   {

> >     if (ea->start_addr != address || ea->pages != pages)

> >        continue;

> >

> >     if (eap)

>

> I suppose you mean !eap here


Yep, or even better:

if (eap)
  eap->next = ea->next;
else
  efi_allocated_memory = ea->next;

> >       efi_allocated_memory = ea->next;

> >     else

> >       eap->next = ea->next;

> >

> >     efi_call_1 (b->free_pool, ea);

> >

> >     return;

> >   }

>

> I'm not sure the version above is actually more readable. Do you really

> want me to move to that? It basically does the same thing, just with an


Yes, please.

> explicit branch in between.


...and lower number of pointers...

> >>+}

> >>+

> >>+static void

> >>+grub_efi_remember_pages (grub_efi_physical_address_t address,

> >>+                         grub_efi_uintn_t pages)

> >This function should be before grub_efi_unremember_pages().

> >

> >And maybe s/grub_efi_remember_pages()/grub_efi_store_alloc()/...

>

> works for me :)

>

> >

> >>+{

> >>+  grub_efi_boot_services_t *b;

> >>+  struct efi_allocation *alloc;

> >>+  grub_efi_status_t status;

> >>+

> >>+  b = grub_efi_system_table->boot_services;

> >>+  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

> >>+                           sizeof(*alloc), (void**)&alloc);

> >>+  if (status == GRUB_EFI_SUCCESS)

> >>+    {

> >>+      alloc->next = efi_allocated_memory;

> >>+      alloc->start_addr = address;

> >>+      alloc->pages = pages;

> >>+      efi_allocated_memory = alloc;

> >>+    }

> >>+  else

> >>+      grub_printf ("Could not malloc memory to remember EFI allocation. "

> >>+                   "Exiting grub2 won't free all memory.\n");

> >s/grub2/GRUB2/

> >

> >>+}

> >>+

> >>  /* Allocate pages. Return the pointer to the first of allocated pages.

> >>  */

> >>  void *

> >>  grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

> >>@@ -79,6 +153,7 @@ grub_efi_allocate_pages_real

> >>(grub_efi_physical_address_t address,

> >>  	return 0;

> >>      }

> >>

> >>+  grub_efi_remember_pages (address, pages);

> >>    return (void *) ((grub_addr_t) address);

> >>  }

> >>

> >>@@ -108,6 +183,7 @@ grub_efi_free_pages (grub_efi_physical_address_t

> >>address,

> >>

> >>    b = grub_efi_system_table->boot_services;

> >>    efi_call_2 (b->free_pages, address, pages);

> >>+  grub_efi_unremember_pages (address, pages);

> >>  }

> >>

> >>  #if defined (__i386__) || defined (__x86_64__)

> >>@@ -422,6 +498,18 @@ add_memory_regions (grub_efi_memory_descriptor_t

> >>*memory_map,

> >>      grub_fatal ("too little memory");

> >>  }

> >>

> >>+void

> >>+grub_efi_memory_fini (void)

> >>+{

> >>+  /* Free all stale allocations */

> >>+

> >Drop this empty line. And please improve the comment here. It took me

> >some time to understand why just "while (efi_allocated_memory)" works

> >here. grub_efi_free_pages() calls grub_efi_unremember_pages()

> >which advances the pointer.

>

> Does this work for you?

>

> void

> grub_efi_memory_fini (void)

> {

>   /*

>    * Free all stale allocations. grub_efi_free_pages() will remove

>    * the found entry from the list and it will always find the first

>    * list entry (efi_allocated_memory is the list start). Hence we

>    * remove all entries from the list until none is left altogether.

>    */

>   while (efi_allocated_memory)

>       grub_efi_free_pages (efi_allocated_memory->address,

>                            efi_allocated_memory->pages);

> }


I am OK with this.

Daniel

_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
Daniel Kiper Aug. 31, 2017, 2:26 p.m. | #5
On Wed, Aug 30, 2017 at 02:03:52PM +0100, Leif Lindholm wrote:
> On Wed, Aug 30, 2017 at 02:11:59PM +0200, Daniel Kiper wrote:

> > On Tue, Aug 29, 2017 at 09:26:48PM +0200, Alexander Graf wrote:

> > > +{

> > > +  grub_efi_boot_services_t *b;

> > > +  struct efi_allocation *alloc;

> > > +  grub_efi_status_t status;

> > > +

> > > +  b = grub_efi_system_table->boot_services;

> > > +  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

> > > +                           sizeof(*alloc), (void**)&alloc);

> > > +  if (status == GRUB_EFI_SUCCESS)

> > > +    {

> > > +      alloc->next = efi_allocated_memory;

> > > +      alloc->start_addr = address;

> > > +      alloc->pages = pages;

> > > +      efi_allocated_memory = alloc;

> > > +    }

> > > +  else

> > > +      grub_printf ("Could not malloc memory to remember EFI allocation. "

> > > +                   "Exiting grub2 won't free all memory.\n");

> >

> > s/grub2/GRUB2/

>

> Well, GRUB. Grub2 is a distro-ism.

> We shouldn't have to update individual message strings when we bump

> revisions.


I am OK with GRUB too.

Daniel

_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel

Patch

diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
index 2c31847bf..3dfdf2d22 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -80,4 +80,5 @@  grub_efi_fini (void)
 {
   grub_efidisk_fini ();
   grub_console_fini ();
+  grub_efi_memory_fini ();
 }
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index ac2a4c556..c9bd3568d 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -49,6 +49,80 @@  static grub_efi_uintn_t finish_desc_size;
 static grub_efi_uint32_t finish_desc_version;
 int grub_efi_is_finished = 0;
 
+/*
+ * We need to roll back EFI allocations on exit. Remember allocations that
+ * we'll free on exit.
+ */
+struct efi_allocation;
+struct efi_allocation {
+	struct efi_allocation *next;
+	grub_efi_physical_address_t start_addr;
+	grub_efi_uint64_t pages;
+};
+static struct efi_allocation *efi_allocated_memory;
+
+static void
+grub_efi_unremember_pages (grub_efi_physical_address_t address,
+                           grub_efi_uintn_t pages)
+{
+  struct efi_allocation **allocp;
+  grub_efi_boot_services_t *b;
+
+  b = grub_efi_system_table->boot_services;
+
+  for (allocp = &efi_allocated_memory; *allocp;)
+    {
+      struct efi_allocation *alloc;
+      struct efi_allocation *next;
+
+      alloc = *allocp;
+
+      if (alloc->start_addr != address ||
+          alloc->pages != pages)
+        {
+          /* Move on to the next entry */
+          allocp = &alloc->next;
+
+          continue;
+        }
+
+      /* Remember the next entry */
+      next = alloc->next;
+
+      /* Free the current list entry */
+      efi_call_1 (b->free_pool, alloc);
+
+      /* Remove from list */
+      *allocp = next;
+
+      /* Done */
+      break;
+    }
+}
+
+static void
+grub_efi_remember_pages (grub_efi_physical_address_t address,
+                         grub_efi_uintn_t pages)
+{
+  grub_efi_boot_services_t *b;
+  struct efi_allocation *alloc;
+  grub_efi_status_t status;
+
+  b = grub_efi_system_table->boot_services;
+  status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,
+                           sizeof(*alloc), (void**)&alloc);
+  if (status == GRUB_EFI_SUCCESS)
+    {
+      alloc->next = efi_allocated_memory;
+      alloc->start_addr = address;
+      alloc->pages = pages;
+      efi_allocated_memory = alloc;
+    }
+  else
+      grub_printf ("Could not malloc memory to remember EFI allocation. "
+                   "Exiting grub2 won't free all memory.\n");
+}
+
 /* Allocate pages. Return the pointer to the first of allocated pages.  */
 void *
 grub_efi_allocate_pages_real (grub_efi_physical_address_t address,
@@ -79,6 +153,7 @@  grub_efi_allocate_pages_real (grub_efi_physical_address_t address,
 	return 0;
     }
 
+  grub_efi_remember_pages (address, pages);
   return (void *) ((grub_addr_t) address);
 }
 
@@ -108,6 +183,7 @@  grub_efi_free_pages (grub_efi_physical_address_t address,
 
   b = grub_efi_system_table->boot_services;
   efi_call_2 (b->free_pages, address, pages);
+  grub_efi_unremember_pages (address, pages);
 }
 
 #if defined (__i386__) || defined (__x86_64__)
@@ -422,6 +498,18 @@  add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
     grub_fatal ("too little memory");
 }
 
+void
+grub_efi_memory_fini (void)
+{
+  /* Free all stale allocations */
+
+  while (efi_allocated_memory)
+      grub_efi_free_pages (efi_allocated_memory->start_addr,
+                           efi_allocated_memory->pages);
+
+  efi_allocated_memory = NULL;
+}
+
 #if 0
 /* Print the memory map.  */
 static void
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 3fa082816..c996913e5 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -55,6 +55,7 @@  EXPORT_FUNC(grub_efi_get_memory_map) (grub_efi_uintn_t *memory_map_size,
 				      grub_efi_uintn_t *map_key,
 				      grub_efi_uintn_t *descriptor_size,
 				      grub_efi_uint32_t *descriptor_version);
+void grub_efi_memory_fini (void);
 grub_efi_loaded_image_t *EXPORT_FUNC(grub_efi_get_loaded_image) (grub_efi_handle_t image_handle);
 void EXPORT_FUNC(grub_efi_print_device_path) (grub_efi_device_path_t *dp);
 char *EXPORT_FUNC(grub_efi_get_filename) (grub_efi_device_path_t *dp);