diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2021-03-26 12:37:55 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-03-26 22:19:39 +1100 |
| commit | 53f1d31708f6240e4615b0927df31f182e389e2f (patch) | |
| tree | 052387d1424f30af17052a9eebdc4a1f899ea940 /arch/powerpc/platforms/pseries/lpar.c | |
| parent | 274cb1ca2e7ce02cab56f5f4c61a74aeb566f931 (diff) | |
powerpc/mm/book3s64: Use the correct storage key value when calling H_PROTECT
H_PROTECT expects the flag value to include flags:
AVPN, pp0, pp1, pp2, key0-key4, Noexec, CMO Option flags
This patch updates hpte_updatepp() to fetch the storage key value from
the linux page table and use the same in H_PROTECT hcall.
native_hpte_updatepp() is not updated because the kernel doesn't clear
the existing storage key value there. The kernel also doesn't use
hpte_updatepp() callback for updating storage keys.
This fixes the below kernel crash observed with KUAP enabled.
BUG: Unable to handle kernel data access on write at 0xc009fffffc440000
Faulting instruction address: 0xc0000000000b7030
Key fault AMR: 0xfcffffffffffffff IAMR: 0xc0000077bc498100
Found HPTE: v = 0x40070adbb6fffc05 r = 0x1ffffffffff1194
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
...
CFAR: c000000000010100 DAR: c009fffffc440000 DSISR: 02200000 IRQMASK: 0
...
NIP memset+0x68/0x104
LR pcpu_alloc+0x54c/0xb50
Call Trace:
pcpu_alloc+0x55c/0xb50 (unreliable)
blk_stat_alloc_callback+0x94/0x150
blk_mq_init_allocated_queue+0x64/0x560
blk_mq_init_queue+0x54/0xb0
scsi_mq_alloc_queue+0x30/0xa0
scsi_alloc_sdev+0x1cc/0x300
scsi_probe_and_add_lun+0xb50/0x1020
__scsi_scan_target+0x17c/0x790
scsi_scan_channel+0x90/0xe0
scsi_scan_host_selected+0x148/0x1f0
do_scan_async+0x2c/0x2a0
async_run_entry_fn+0x78/0x220
process_one_work+0x264/0x540
worker_thread+0xa8/0x600
kthread+0x190/0x1a0
ret_from_kernel_thread+0x5c/0x6c
With KUAP enabled the kernel uses storage key 3 for all its
translations. But as shown by the debug print, in this specific case we
have the hash page table entry created with key value 0.
Found HPTE: v = 0x40070adbb6fffc05 r = 0x1ffffffffff1194
and DSISR indicates a key fault.
This can happen due to parallel fault on the same EA by different CPUs:
CPU 0 CPU 1
fault on X
H_PAGE_BUSY set
fault on X
finish fault handling and
clear H_PAGE_BUSY
check for H_PAGE_BUSY
continue with fault handling.
This implies CPU1 will end up calling hpte_updatepp for address X and
the kernel updated the hash pte entry with key 0
Fixes: d94b827e89dc ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation")
Reported-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Debugged-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326070755.304625-1-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc/platforms/pseries/lpar.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/lpar.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 764170fdb0f7..3805519a6469 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -887,7 +887,8 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot, want_v = hpte_encode_avpn(vpn, psize, ssize); - flags = (newpp & 7) | H_AVPN; + flags = (newpp & (HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_LO)) | H_AVPN; + flags |= (newpp & HPTE_R_KEY_HI) >> 48; if (mmu_has_feature(MMU_FTR_KERNEL_RO)) /* Move pp0 into bit 8 (IBM 55) */ flags |= (newpp & HPTE_R_PP0) >> 55; |