[PATCH v3 11/13] arm64/efi: use plain memblock API for adding and removing reserved RAM

[Ard Biesheuvel]

On 20 November 2014 18:28, Mark Salter <msalter at redhat.com> wrote:
> On Tue, 2014-11-18 at 13:57 +0100, Ard Biesheuvel wrote:
>> diff --git a/drivers/firmware/efi/virtmap.c
>> b/drivers/firmware/efi/virtmap.c
>> index 98735fb43581..4b6a5c31629f 100644
>> --- a/drivers/firmware/efi/virtmap.c
>> +++ b/drivers/firmware/efi/virtmap.c
>> @@ -8,6 +8,7 @@
>>   */
>>
>>  #include <linux/efi.h>
>> +#include <linux/memblock.h>
>>  #include <linux/mm_types.h>
>>  #include <linux/rbtree.h>
>>  #include <linux/rwsem.h>
>> @@ -97,8 +98,15 @@ void __init efi_virtmap_init(void)
>>                 u64 paddr, npages, size;
>>                 pgprot_t prot;
>>
>> -               if (!efi_mem_is_usable_region(md))
>> +               paddr = md->phys_addr;
>> +               npages = md->num_pages;
>> +               memrange_efi_to_native(&paddr, &npages);
>> +               size = npages << PAGE_SHIFT;
>> +
>> +               if (!efi_mem_is_usable_region(md)) {
>>                         efi_register_mem_resource(md);
>> +                       memblock_remove(paddr, size);
>> +               }
>
> What exactly is the memblock_remove trying to accomplish? With it, I
> get:
>

The idea was pfn_valid() will then return false for those pfns,
allowing us to distinguish them from memory that the kernel may be
using, primarily for /dev/mem filtering. But apparently it is causing
problems for you, so I will have to figure out if there is a better
way of addressing this.


>  Unable to handle kernel NULL pointer dereference at virtual address 00000008
>  pgd = fffffe03d5890000
>  [00000008] *pgd=00000043d5ae0003, *pud=00000043d5ae0003, *pmd=00000043d5ae0003, *pte=0000000000000000
>  Internal error: Oops: 96000007 [#1] SMP
>  Modules linked in:
>  CPU: 0 PID: 107 Comm: modprobe Not tainted 3.18.0-rc5+ #8
>  Hardware name: APM X-Gene Mustang board (DT)
>  task: fffffe03d5770000 ti: fffffe03dd300000 task.ti: fffffe03dd300000
>  PC is at mem_cgroup_begin_page_stat+0x40/0x110
>  LR is at mem_cgroup_begin_page_stat+0x40/0x110
>  pc : [<fffffe00001ec34c>] lr : [<fffffe00001ec34c>] pstate: 60000145
>  sp : fffffe03dd303a80
>  x29: fffffe03dd303a80 x28: 000000000000ffe0
>  x27: fffffdfef0f56bc0 x26: 0000000000000000
>  x25: 000003ff89b80000 x24: 0000000000000000
>  x23: fffffe03dd303ae8 x22: fffffe03dd303ae7
>  x21: 0000000000000000 x20: fffffe03d58a0420
>  x19: fffffdfef0004500 x18: 0000000000000000
>  x17: 000003ff89ba40dc x16: 000003ff89bbff90
>  x15: 000003ff89ba3b44 x14: 31313030343d6e66
>  x13: 7020303035343030 x12: 0000000000000006
>  x11: 0000000000000000 x10: 0000000000000186
>  x9 : 0000000000000187 x8 : 3030306665666466
>  x7 : fffffe0001041c18 x6 : 00000000000000ff
>  x5 : fffffe00004aaf20 x4 : fffffe00004b209c
>  x3 : 0000000000000000 x2 : 0000000000000000
>  x1 : fffffe0000f6a5d0 x0 : 0000000000000000
>
>  Process modprobe (pid: 107, stack limit = 0xfffffe03dd300058)
>  Stack: (0xfffffe03dd303a80 to 0xfffffe03dd304000)
>  3a80: dd303ac0 fffffe03 001c3e20 fffffe00 f0004500 fffffdfe d58a0420 fffffe03
>  3aa0: f0004500 fffffdfe d58f4dc0 fffffe03 00000000 00000000 001b62d4 fffffe00
>  3ac0: dd303af0 fffffe03 001b9984 fffffe00 01140f53 00200040 d58a0420 fffffe03
>  3ae0: d5880000 fffffe03 d58a0420 fffffe03 dd303b40 fffffe03 001b9c4c fffffe00
>  3b00: d58a0420 fffffe03 89b80000 000003ff f0f56bf0 fffffdfe 00000000 00000000
>  ...
>  3fa0: 89b907b7 000003ff 89bbf000 000003ff 89bc16e8 000003ff eb753490 000003ff
>  3fc0: 89b91f9c 000003ff eb753490 000003ff 89b91fac 000003ff 20000000 00000000
>  3fe0: 00000000 00000000 ffffffff ffffffff aaaaaaaa aaaaaaaa aaaaaaaa aaaaaaaa
>  Call trace:
>  [<fffffe00001ec34c>] mem_cgroup_begin_page_stat+0x40/0x110
>  [<fffffe00001c3e1c>] page_add_file_rmap+0x24/0x80
>  [<fffffe00001b9980>] do_set_pte+0x108/0x19c
>  [<fffffe00001b9c48>] do_read_fault.isra.93+0x234/0x28c
>  [<fffffe00001ba57c>] handle_mm_fault+0x488/0xd64
>  [<fffffe00000a0ea0>] do_page_fault+0x224/0x358
>  [<fffffe0000090128>] do_mem_abort+0x4c/0xb0
>  Exception stack(0xfffffe03dd303e30 to 0xfffffe03dd303f50)
>  3e20:                                     00000000 00000000 89bbf000 000003ff
>  3e40: ffffffff ffffffff 89b91fac 000003ff 01043280 fffffe00 00000002 00000000
>  3e60: dd303e70 fffffe03 008ce3a0 fffffe00 dd303e90 fffffe03 001c0400 fffffe00
>  3e80: d5880000 fffffe03 000cbc60 fffffe00 eb753610 000003ff 00092fdc fffffe00
>  3ea0: 00000000 00000000 89bbf000 000003ff ffffffff ffffffff 89ba4654 000003ff
>  3ec0: 80000000 00000000 d5521480 fffffe03 89bc16e8 000003ff 89bc1a40 000003ff
>  3ee0: 00000004 00000000 89b80000 000003ff fefefeff fefefefe 00000000 00000000
>  3f00: 0000000f 00000000 89bc1028 000003ff 89ba7000 000003ff 0000079c 00000000
>  3f20: 00400000 00000000 ffff0000 ffffffff 004038a0 00000000 00010000 00000000
>  3f40: 89ba3c1c 000003ff 89ba3b44 000003ff
>  Code: b9405835 35000275 aa1303e0 9400065c (f9400413)
>
>