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

[George Kennedy <george.kennedy@oracle.com>]

Hi Mike,

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:
>> Mike,
>>
>> To get rid of the 0x00000000BE453000 hardcoding, I added the following patch
>> to your above patch to get the iBFT table "address" to use with
>> memblock_reserve():
>>
>> diff --git a/drivers/acpi/acpica/tbfind.c b/drivers/acpi/acpica/tbfind.c
>> index 56d81e4..4bc7bf3 100644
>> --- a/drivers/acpi/acpica/tbfind.c
>> +++ b/drivers/acpi/acpica/tbfind.c
>> @@ -120,3 +120,34 @@
>>       (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
>>       return_ACPI_STATUS(status);
>>   }
>> +
>> +acpi_physical_address
>> +acpi_tb_find_table_address(char *signature)
>> +{
>> +    acpi_physical_address address = 0;
>> +    struct acpi_table_desc *table_desc;
>> +    int i;
>> +
>> +    ACPI_FUNCTION_TRACE(tb_find_table_address);
>> +
>> +printk(KERN_ERR "XXX acpi_tb_find_table_address: signature=%s\n",
>> signature);
>> +
>> +    (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
>> +    for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
>> +        if (memcmp(&(acpi_gbl_root_table_list.tables[i].signature),
>> +               signature, ACPI_NAMESEG_SIZE)) {
>> +
>> +            /* Not the requested table */
>> +
>> +            continue;
>> +        }
>> +
>> +        /* Table with matching signature has been found */
>> +        table_desc = &acpi_gbl_root_table_list.tables[i];
>> +        address = table_desc->address;
>> +    }
>> +
>> +    (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
>> +printk(KERN_ERR "XXX acpi_tb_find_table_address(EXIT): address=%llx\n",
>> address);
>> +    return address;
>> +}
>> diff --git a/drivers/firmware/iscsi_ibft_find.c
>> b/drivers/firmware/iscsi_ibft_find.c
>> index 95fc1a6..0de70b4 100644
>> --- a/drivers/firmware/iscsi_ibft_find.c
>> +++ b/drivers/firmware/iscsi_ibft_find.c
>> @@ -28,6 +28,8 @@
>>
>>   #include <asm/mmzone.h>
>>
>> +extern acpi_physical_address acpi_tb_find_table_address(char *signature);
>> +
>>   /*
>>    * Physical location of iSCSI Boot Format Table.
>>    */
>> @@ -116,24 +118,32 @@ void __init reserve_ibft_region(void)
>>   {
>>       struct acpi_table_ibft *table;
>>       unsigned long size;
>> +    acpi_physical_address address;
>>
>>       table = find_ibft();
>>       if (!table)
>>           return;
>>
>>       size = PAGE_ALIGN(table->header.length);
>> +    address = acpi_tb_find_table_address(table->header.signature);
>>   #if 0
>>   printk(KERN_ERR "XXX reserve_ibft_region: table=%llx,
>> virt_to_phys(table)=%llx, size=%lx\n",
>>       (u64)table, virt_to_phys(table), size);
>>       memblock_reserve(virt_to_phys(table), size);
>>   #else
>> -printk(KERN_ERR "XXX reserve_ibft_region: table=%llx, 0x00000000BE453000,
>> size=%lx\n",
>> -    (u64)table, size);
>> -    memblock_reserve(0x00000000BE453000, size);
>> +printk(KERN_ERR "XXX reserve_ibft_region: table=%llx, address=%llx,
>> size=%lx\n",
>> +    (u64)table, address, size);
>> +    if (address)
>> +        memblock_reserve(address, size);
>> +    else
>> +        printk(KERN_ERR "%s: Can't find table address\n", __func__);
>>   #endif
>>
>> -    if (efi_enabled(EFI_BOOT))
>> +    if (efi_enabled(EFI_BOOT)) {
>> +printk(KERN_ERR "XXX reserve_ibft_region: calling acpi_put_table(%llx)\n",
>> (u64)&table->header);
>>           acpi_put_table(&table->header);
>> -    else
>> +    } else {
>>           ibft_addr = table;
>> +printk(KERN_ERR "XXX reserve_ibft_region: ibft_addr=%llx\n",
>> (u64)ibft_addr);
>> +    }
>>   }
>>
>> Debug from the above:
>> [    0.050646] ACPI: Early table checksum verification disabled
>> [    0.051778] ACPI: RSDP 0x00000000BFBFA014 000024 (v02 BOCHS )
>> [    0.052922] ACPI: XSDT 0x00000000BFBF90E8 00004C (v01 BOCHS BXPCFACP
>> 00000001      01000013)
>> [    0.054623] ACPI: FACP 0x00000000BFBF5000 000074 (v01 BOCHS BXPCFACP
>> 00000001 BXPC 00000001)
>> [    0.056326] ACPI: DSDT 0x00000000BFBF6000 00238D (v01 BOCHS BXPCDSDT
>> 00000001 BXPC 00000001)
>> [    0.058016] ACPI: FACS 0x00000000BFBFD000 000040
>> [    0.058940] ACPI: APIC 0x00000000BFBF4000 000090 (v01 BOCHS BXPCAPIC
>> 00000001 BXPC 00000001)
>> [    0.060627] ACPI: HPET 0x00000000BFBF3000 000038 (v01 BOCHS BXPCHPET
>> 00000001 BXPC 00000001)
>> [    0.062304] ACPI: BGRT 0x00000000BE49B000 000038 (v01 INTEL EDK2
>> 00000002      01000013)
>> [    0.063987] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS BXPCFACP
>> 00000000      00000000)
>> [    0.065683] XXX acpi_tb_find_table_address: signature=iBFT
>> [    0.066754] XXX acpi_tb_find_table_address(EXIT): address=be453000
>> [    0.067959] XXX reserve_ibft_region: table=ffffffffff240000,
>> address=be453000, size=1000
>> [    0.069534] XXX reserve_ibft_region: calling
>> acpi_put_table(ffffffffff240000)
>>
>> 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.

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?

Ran 10 boots with the above without failure.

George
>> George
>>>