Re: [PATCH] mm, kasan: don't poison boot memory

Re: [PATCH] mm, kasan: don't poison boot memory

[George Kennedy]

On 2/28/2021 1:08 PM, Mike Rapoport wrote:
> On Fri, Feb 26, 2021 at 11:16:06AM -0500, George Kennedy wrote:
>> On 2/26/2021 6:17 AM, Mike Rapoport wrote:
>>> Hi George,
>>>
>>> On Thu, Feb 25, 2021 at 08:19:18PM -0500, George Kennedy wrote:
>>>> Not sure if it's the right thing to do, but added
>>>> "acpi_tb_find_table_address()" to return the physical address of a table to
>>>> use with memblock_reserve().
>>>>
>>>> virt_to_phys(table) does not seem to return the physical address for the
>>>> iBFT table (it would be nice if struct acpi_table_header also had a
>>>> "address" element for the physical address of the table).
>>> virt_to_phys() does not work that early because then it is mapped with
>>> early_memremap()  which uses different virtual to physical scheme.
>>>
>>> I'd say that acpi_tb_find_table_address() makes sense if we'd like to
>>> reserve ACPI tables outside of drivers/acpi.
>>>
>>> But probably we should simply reserve all the tables during
>>> acpi_table_init() so that any table that firmware put in the normal memory
>>> will be surely reserved.
>>>> Ran 10 successful boots with the above without failure.
>>> That's good news indeed :)
>> Wondering if we could do something like this instead (trying to keep changes
>> minimal). Just do the memblock_reserve() for all the standard tables.
> I think something like this should work, but I'm not an ACPI expert to say
> if this the best way to reserve the tables.
Adding ACPI maintainers to the CC list.
>   
>> diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
>> index 0bb15ad..830f82c 100644
>> --- a/drivers/acpi/acpica/tbinstal.c
>> +++ b/drivers/acpi/acpica/tbinstal.c
>> @@ -7,6 +7,7 @@
>>    *
>> *****************************************************************************/
>>
>> +#include <linux/memblock.h>
>>   #include <acpi/acpi.h>
>>   #include "accommon.h"
>>   #include "actables.h"
>> @@ -14,6 +15,23 @@
>>   #define _COMPONENT          ACPI_TABLES
>>   ACPI_MODULE_NAME("tbinstal")
>>
>> +void
>> +acpi_tb_reserve_standard_table(acpi_physical_address address,
>> +               struct acpi_table_header *header)
>> +{
>> +    struct acpi_table_header local_header;
>> +
>> +    if ((ACPI_COMPARE_NAMESEG(header->signature, ACPI_SIG_FACS)) ||
>> +        (ACPI_VALIDATE_RSDP_SIG(header->signature))) {
>> +        return;
>> +    }
>> +    /* Standard ACPI table with full common header */
>> +
>> +    memcpy(&local_header, header, sizeof(struct acpi_table_header));
>> +
>> +    memblock_reserve(address, PAGE_ALIGN(local_header.length));
>> +}
>> +
>>   /*******************************************************************************
>>    *
>>    * FUNCTION:    acpi_tb_install_table_with_override
>> @@ -58,6 +76,9 @@
>>                         new_table_desc->flags,
>>                         new_table_desc->pointer);
>>
>> +    acpi_tb_reserve_standard_table(new_table_desc->address,
>> +                   new_table_desc->pointer);
>> +
>>       acpi_tb_print_table_header(new_table_desc->address,
>>                      new_table_desc->pointer);
>>
>> There should be no harm in doing the memblock_reserve() for all the standard
>> tables, right?
> It should be ok to memblock_reserve() all the tables very early as long as
> we don't run out of static entries in memblock.reserved.
>
> We just need to make sure the tables are reserved before memblock
> allocations are possible, so we'd still need to move acpi_table_init() in
> x86::setup_arch() before e820__memblock_setup().
> Not sure how early ACPI is initialized on arm64.

Thanks Mike. Will try to move the memblock_reserves() before 
e820__memblock_setup().

George
>   
>> Ran 10 boots with the above without failure.
>>
>> George

Re: [PATCH] mm, kasan: don't poison boot memory

[George Kennedy]

On 3/1/2021 9:29 AM, George Kennedy wrote:
>
>
> On 2/28/2021 1:08 PM, Mike Rapoport wrote:
>> On Fri, Feb 26, 2021 at 11:16:06AM -0500, George Kennedy wrote:
>>> On 2/26/2021 6:17 AM, Mike Rapoport wrote:
>>>> Hi George,
>>>>
>>>> On Thu, Feb 25, 2021 at 08:19:18PM -0500, George Kennedy wrote:
>>>>> Not sure if it's the right thing to do, but added
>>>>> "acpi_tb_find_table_address()" to return the physical address of a 
>>>>> table to
>>>>> use with memblock_reserve().
>>>>>
>>>>> virt_to_phys(table) does not seem to return the physical address 
>>>>> for the
>>>>> iBFT table (it would be nice if struct acpi_table_header also had a
>>>>> "address" element for the physical address of the table).
>>>> virt_to_phys() does not work that early because then it is mapped with
>>>> early_memremap()  which uses different virtual to physical scheme.
>>>>
>>>> I'd say that acpi_tb_find_table_address() makes sense if we'd like to
>>>> reserve ACPI tables outside of drivers/acpi.
>>>>
>>>> But probably we should simply reserve all the tables during
>>>> acpi_table_init() so that any table that firmware put in the normal 
>>>> memory
>>>> will be surely reserved.
>>>>> Ran 10 successful boots with the above without failure.
>>>> That's good news indeed :)
>>> Wondering if we could do something like this instead (trying to keep 
>>> changes
>>> minimal). Just do the memblock_reserve() for all the standard tables.
>> I think something like this should work, but I'm not an ACPI expert 
>> to say
>> if this the best way to reserve the tables.
> Adding ACPI maintainers to the CC list.
>>> diff --git a/drivers/acpi/acpica/tbinstal.c 
>>> b/drivers/acpi/acpica/tbinstal.c
>>> index 0bb15ad..830f82c 100644
>>> --- a/drivers/acpi/acpica/tbinstal.c
>>> +++ b/drivers/acpi/acpica/tbinstal.c
>>> @@ -7,6 +7,7 @@
>>>    *
>>> *****************************************************************************/ 
>>>
>>>
>>> +#include <linux/memblock.h>
>>>   #include <acpi/acpi.h>
>>>   #include "accommon.h"
>>>   #include "actables.h"
>>> @@ -14,6 +15,23 @@
>>>   #define _COMPONENT          ACPI_TABLES
>>>   ACPI_MODULE_NAME("tbinstal")
>>>
>>> +void
>>> +acpi_tb_reserve_standard_table(acpi_physical_address address,
>>> +               struct acpi_table_header *header)
>>> +{
>>> +    struct acpi_table_header local_header;
>>> +
>>> +    if ((ACPI_COMPARE_NAMESEG(header->signature, ACPI_SIG_FACS)) ||
>>> +        (ACPI_VALIDATE_RSDP_SIG(header->signature))) {
>>> +        return;
>>> +    }
>>> +    /* Standard ACPI table with full common header */
>>> +
>>> +    memcpy(&local_header, header, sizeof(struct acpi_table_header));
>>> +
>>> +    memblock_reserve(address, PAGE_ALIGN(local_header.length));
>>> +}
>>> +
>>>   /******************************************************************************* 
>>>
>>>    *
>>>    * FUNCTION:    acpi_tb_install_table_with_override
>>> @@ -58,6 +76,9 @@
>>>                         new_table_desc->flags,
>>>                         new_table_desc->pointer);
>>>
>>> + acpi_tb_reserve_standard_table(new_table_desc->address,
>>> +                   new_table_desc->pointer);
>>> +
>>>       acpi_tb_print_table_header(new_table_desc->address,
>>>                      new_table_desc->pointer);
>>>
>>> There should be no harm in doing the memblock_reserve() for all the 
>>> standard
>>> tables, right?
>> It should be ok to memblock_reserve() all the tables very early as 
>> long as
>> we don't run out of static entries in memblock.reserved.
>>
>> We just need to make sure the tables are reserved before memblock
>> allocations are possible, so we'd still need to move 
>> acpi_table_init() in
>> x86::setup_arch() before e820__memblock_setup().
>> Not sure how early ACPI is initialized on arm64.
>
> Thanks Mike. Will try to move the memblock_reserves() before 
> e820__memblock_setup().

Hi Mike,

Moved acpi_table_init() in x86::setup_arch() before 
e820__memblock_setup() as you suggested.

Ran 10 boots with the following without error.

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 740f3bdb..3b1dd24 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1047,6 +1047,7 @@ void __init setup_arch(char **cmdline_p)
      cleanup_highmap();

      memblock_set_current_limit(ISA_END_ADDRESS);
+    acpi_boot_table_init();
      e820__memblock_setup();

      /*
@@ -1140,8 +1141,6 @@ void __init setup_arch(char **cmdline_p)
      /*
       * Parse the ACPI tables for possible boot-time SMP configuration.
       */
-    acpi_boot_table_init();
-
      early_acpi_boot_init();

      initmem_init();
diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
index 0bb15ad..7830109 100644
--- a/drivers/acpi/acpica/tbinstal.c
+++ b/drivers/acpi/acpica/tbinstal.c
@@ -7,6 +7,7 @@
   *
*****************************************************************************/

+#include <linux/memblock.h>
  #include <acpi/acpi.h>
  #include "accommon.h"
  #include "actables.h"
@@ -16,6 +17,33 @@

  /*******************************************************************************
   *
+ * FUNCTION:    acpi_tb_reserve_standard_table
+ *
+ * PARAMETERS:  address             - Table physical address
+ *              header              - Table header
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: To avoid an acpi table page from being "stolen" by the 
buddy
+ *              allocator run memblock_reserve() on all the standard 
acpi tables.
+ *
+ 
******************************************************************************/
+void
+acpi_tb_reserve_standard_table(acpi_physical_address address,
+               struct acpi_table_header *header)
+{
+    if ((ACPI_COMPARE_NAMESEG(header->signature, ACPI_SIG_FACS)) ||
+        (ACPI_VALIDATE_RSDP_SIG(header->signature)))
+        return;
+
+    if (header->length > PAGE_SIZE) /* same check as in acpi_map() */
+        return;
+
+    memblock_reserve(address, PAGE_ALIGN(header->length));
+}
+
+/*******************************************************************************
+ *
   * FUNCTION:    acpi_tb_install_table_with_override
   *
   * PARAMETERS:  new_table_desc          - New table descriptor to install
@@ -58,6 +86,9 @@
                        new_table_desc->flags,
                        new_table_desc->pointer);

+    acpi_tb_reserve_standard_table(new_table_desc->address,
+                   new_table_desc->pointer);
+
      acpi_tb_print_table_header(new_table_desc->address,
                     new_table_desc->pointer);

George

>
> George
>>> Ran 10 boots with the above without failure.
>>>
>>> George
>

Re: [PATCH] mm, kasan: don't poison boot memory

[Mike Rapoport]

Hi George,

On Mon, Mar 01, 2021 at 08:20:45PM -0500, George Kennedy wrote:
> > > > > 
> > > > There should be no harm in doing the memblock_reserve() for all
> > > > the standard
> > > > tables, right?
> > > It should be ok to memblock_reserve() all the tables very early as
> > > long as
> > > we don't run out of static entries in memblock.reserved.
> > > 
> > > We just need to make sure the tables are reserved before memblock
> > > allocations are possible, so we'd still need to move
> > > acpi_table_init() in
> > > x86::setup_arch() before e820__memblock_setup().
> > > Not sure how early ACPI is initialized on arm64.
> > 
> > Thanks Mike. Will try to move the memblock_reserves() before
> > e820__memblock_setup().
> 
> Hi Mike,
> 
> Moved acpi_table_init() in x86::setup_arch() before e820__memblock_setup()
> as you suggested.
> 
> Ran 10 boots with the following without error.

I'd suggest to send it as a formal patch to see what x86 and ACPI folks
have to say about this.
 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 740f3bdb..3b1dd24 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -1047,6 +1047,7 @@ void __init setup_arch(char **cmdline_p)
>      cleanup_highmap();
> 
>      memblock_set_current_limit(ISA_END_ADDRESS);
> +    acpi_boot_table_init();
>      e820__memblock_setup();
> 
>      /*
> @@ -1140,8 +1141,6 @@ void __init setup_arch(char **cmdline_p)
>      /*
>       * Parse the ACPI tables for possible boot-time SMP configuration.
>       */
> -    acpi_boot_table_init();
> -
>      early_acpi_boot_init();
> 
>      initmem_init();
> diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
> index 0bb15ad..7830109 100644
> --- a/drivers/acpi/acpica/tbinstal.c
> +++ b/drivers/acpi/acpica/tbinstal.c
> @@ -7,6 +7,7 @@
>   *
> *****************************************************************************/
> 
> +#include <linux/memblock.h>
>  #include <acpi/acpi.h>
>  #include "accommon.h"
>  #include "actables.h"
> @@ -16,6 +17,33 @@
> 
>  /*******************************************************************************
>   *
> + * FUNCTION:    acpi_tb_reserve_standard_table
> + *
> + * PARAMETERS:  address             - Table physical address
> + *              header              - Table header
> + *
> + * RETURN:      None
> + *
> + * DESCRIPTION: To avoid an acpi table page from being "stolen" by the
> buddy
> + *              allocator run memblock_reserve() on all the standard acpi
> tables.
> + *
> + ******************************************************************************/
> +void
> +acpi_tb_reserve_standard_table(acpi_physical_address address,
> +               struct acpi_table_header *header)
> +{
> +    if ((ACPI_COMPARE_NAMESEG(header->signature, ACPI_SIG_FACS)) ||
> +        (ACPI_VALIDATE_RSDP_SIG(header->signature)))
> +        return;
> +

Why these should be excluded?

> +    if (header->length > PAGE_SIZE) /* same check as in acpi_map() */
> +        return;

I don't think this is required, I believe acpi_map() has this check because
kmap() cannot handle multiple pages.

> +
> +    memblock_reserve(address, PAGE_ALIGN(header->length));
> +}
> +
> +/*******************************************************************************
> + *
>   * FUNCTION:    acpi_tb_install_table_with_override
>   *
>   * PARAMETERS:  new_table_desc          - New table descriptor to install
> @@ -58,6 +86,9 @@
>                        new_table_desc->flags,
>                        new_table_desc->pointer);
> 
> +    acpi_tb_reserve_standard_table(new_table_desc->address,
> +                   new_table_desc->pointer);
> +
>      acpi_tb_print_table_header(new_table_desc->address,
>                     new_table_desc->pointer);
> 
> George

-- 
Sincerely yours,
Mike.