Commit 2f92447f9f96 ("powerpc/book3s64/hash: Use the pte_t address from the
caller") removed the local_irq_disable from hash_preload, but it was
required for more than just the page table walk: the hash pte busy bit is
effectively a lock which may be taken in interrupt context, and the local
update flag test must not be preempted before it's used.
This solves apparent lockups with perf interrupting __hash_page_64K. If
get_perf_callchain then also takes a hash fault on the same page while it
is already locked, it will loop forever taking hash faults, which looks like
this:
cpu 0x49e: Vector: 100 (System Reset) at [c00000001a4f7d70]
pc: c000000000072dc8: hash_page_mm+0x8/0x800
lr: c00000000000c5a4: do_hash_page+0x24/0x38
sp: c0002ac1cc69ac70
msr: 8000000000081033
current = 0xc0002ac1cc602e00
paca = 0xc00000001de1f280 irqmask: 0x03 irq_happened: 0x01
pid = 20118, comm = pread2_processe
Linux version 5.8.0-rc6-00345-g1fad14f18bc6
49e:mon> t
[c0002ac1cc69ac70] c00000000000c5a4 do_hash_page+0x24/0x38 (unreliable)
--- Exception: 300 (Data Access) at c00000000008fa60 __copy_tofrom_user_power7+0x20c/0x7ac
[link register ] c000000000335d10 copy_from_user_nofault+0xf0/0x150
[c0002ac1cc69af70] c00032bf9fa3c880 (unreliable)
[c0002ac1cc69afa0] c000000000109df0 read_user_stack_64+0x70/0xf0
[c0002ac1cc69afd0] c000000000109fcc perf_callchain_user_64+0x15c/0x410
[c0002ac1cc69b060] c000000000109c00 perf_callchain_user+0x20/0x40
[c0002ac1cc69b080] c00000000031c6cc get_perf_callchain+0x25c/0x360
[c0002ac1cc69b120] c000000000316b50 perf_callchain+0x70/0xa0
[c0002ac1cc69b140] c000000000316ddc perf_prepare_sample+0x25c/0x790
[c0002ac1cc69b1a0] c000000000317350 perf_event_output_forward+0x40/0xb0
[c0002ac1cc69b220] c000000000306138 __perf_event_overflow+0x88/0x1a0
[c0002ac1cc69b270] c00000000010cf70 record_and_restart+0x230/0x750
[c0002ac1cc69b620] c00000000010d69c perf_event_interrupt+0x20c/0x510
[c0002ac1cc69b730] c000000000027d9c performance_monitor_exception+0x4c/0x60
[c0002ac1cc69b750] c00000000000b2f8 performance_monitor_common_virt+0x1b8/0x1c0
--- Exception: f00 (Performance Monitor) at c0000000000cb5b0 pSeries_lpar_hpte_insert+0x0/0x160
[link register ] c0000000000846f0 __hash_page_64K+0x210/0x540
[c0002ac1cc69ba50] 0000000000000000 (unreliable)
[c0002ac1cc69bb00] c000000000073ae0 update_mmu_cache+0x390/0x3a0
[c0002ac1cc69bb70] c00000000037f024 wp_page_copy+0x364/0xce0
[c0002ac1cc69bc20] c00000000038272c do_wp_page+0xdc/0xa60
[c0002ac1cc69bc70] c0000000003857bc handle_mm_fault+0xb9c/0x1b60
[c0002ac1cc69bd50] c00000000006c434 __do_page_fault+0x314/0xc90
[c0002ac1cc69be20] c00000000000c5c8 handle_page_fault+0x10/0x2c
--- Exception: 300 (Data Access) at 00007fff8c861fe8
SP (7ffff6b19660) is in userspace
Fixes: 2f92447f9f96 ("powerpc/book3s64/hash: Use the pte_t address from the caller")
Reported-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reported-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200727060947.10060-1-npiggin@gmail.com
P9 DD2 NX workbook (Table 4-36) says DMA controller uses CC=5
internally for translation fault handling. NX reserves CC=250 for
OS to notify user space when NX encounters address translation
failure on the request buffer. Not an issue in earlier releases
as NX does not get faults on kernel addresses.
This patch defines CSB_CC_FAULT_ADDRESS(250) and updates CSB.CC with
this proper error code for user space.
Fixes: c96c4436aba4 ("powerpc/vas: Update CSB and notify process for fault CRBs")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
[mpe: Added Fixes tag and fix typo in comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/019fd53e7538c6f8f332d175df74b1815ef5aa8c.camel@linux.ibm.com
Early secure guest boot hits the below crash while booting with
vcpus numbers aligned with page boundary for PAGE size of 64k
and LPPACA size of 1k i.e 64, 128 etc.
Partition configured for 64 cpus.
CPU maps initialized for 1 thread per core
------------[ cut here ]------------
kernel BUG at arch/powerpc/kernel/paca.c:89!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
This is due to the BUG_ON() for shared_lppaca_total_size equal to
shared_lppaca_size. Instead the code should only BUG_ON() if we have
exceeded the total_size, which indicates we've overflowed the array.
Fixes: bd104e6db6f0 ("powerpc/pseries/svm: Use shared memory for LPPACA structures")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
[mpe: Reword change log to clarify we're fixing not removing the check]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200619070113.16696-1-sathnaga@linux.vnet.ibm.com
Even if the IAMR value denies execute access, the current code returns
true from pkey_access_permitted() for an execute permission check, if
the AMR read pkey bit is cleared.
This results in repeated page fault loop with a test like below:
#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <inttypes.h>
#include <assert.h>
#include <malloc.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/mman.h>
#ifdef SYS_pkey_mprotect
#undef SYS_pkey_mprotect
#endif
#ifdef SYS_pkey_alloc
#undef SYS_pkey_alloc
#endif
#ifdef SYS_pkey_free
#undef SYS_pkey_free
#endif
#undef PKEY_DISABLE_EXECUTE
#define PKEY_DISABLE_EXECUTE 0x4
#define SYS_pkey_mprotect 386
#define SYS_pkey_alloc 384
#define SYS_pkey_free 385
#define PPC_INST_NOP 0x60000000
#define PPC_INST_BLR 0x4e800020
#define PROT_RWX (PROT_READ | PROT_WRITE | PROT_EXEC)
static int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
{
return syscall(SYS_pkey_mprotect, addr, len, prot, pkey);
}
static int sys_pkey_alloc(unsigned long flags, unsigned long access_rights)
{
return syscall(SYS_pkey_alloc, flags, access_rights);
}
static int sys_pkey_free(int pkey)
{
return syscall(SYS_pkey_free, pkey);
}
static void do_execute(void *region)
{
/* jump to region */
asm volatile(
"mtctr %0;"
"bctrl"
: : "r"(region) : "ctr", "lr");
}
static void do_protect(void *region)
{
size_t pgsize;
int i, pkey;
pgsize = getpagesize();
pkey = sys_pkey_alloc(0, PKEY_DISABLE_EXECUTE);
assert (pkey > 0);
/* perform mprotect */
assert(!sys_pkey_mprotect(region, pgsize, PROT_RWX, pkey));
do_execute(region);
/* free pkey */
assert(!sys_pkey_free(pkey));
}
int main(int argc, char **argv)
{
size_t pgsize, numinsns;
unsigned int *region;
int i;
/* allocate memory region to protect */
pgsize = getpagesize();
region = memalign(pgsize, pgsize);
assert(region != NULL);
assert(!mprotect(region, pgsize, PROT_RWX));
/* fill page with NOPs with a BLR at the end */
numinsns = pgsize / sizeof(region[0]);
for (i = 0; i < numinsns - 1; i++)
region[i] = PPC_INST_NOP;
region[i] = PPC_INST_BLR;
do_protect(region);
return EXIT_SUCCESS;
}
The fix is to only check the IAMR for an execute check, the AMR value
is not relevant.
Fixes: f2407ef3ba22 ("powerpc: helper to validate key-access permissions of a pte")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Add detail to change log, tweak wording & formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200712132047.1038594-1-aneesh.kumar@linux.ibm.com
A typo caused the interrupt handler to branch immediately to the
common "unknown interrupt" handler and skip the special case test for
denormal cause.
This does not affect KVM softpatch handling (e.g., for POWER9 TM
assist) because the KVM test was moved to common code by commit
9600f261acaa ("powerpc/64s/exception: Move KVM test to common code")
just before this bug was introduced.
Fixes: 3f7fbd97d07d ("powerpc/64s/exception: Clean up SRR specifiers")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
[mpe: Split selftest into a separate patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200708074942.1713396-1-npiggin@gmail.com
Jan reported that LTP mmap03 was getting stuck in a page fault loop
after commit c46241a370a6 ("powerpc/pkeys: Check vma before returning
key fault error to the user"), as well as a minimised reproducer:
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
int main(int ac, char **av)
{
int page_sz = getpagesize();
int fildes;
char *addr;
fildes = open("tempfile", O_WRONLY | O_CREAT, 0666);
write(fildes, &fildes, sizeof(fildes));
close(fildes);
fildes = open("tempfile", O_RDONLY);
unlink("tempfile");
addr = mmap(0, page_sz, PROT_EXEC, MAP_FILE | MAP_PRIVATE, fildes, 0);
printf("%d\n", *addr);
return 0;
}
And noticed that access_pkey_error() in page fault handler now always
seem to return false:
__do_page_fault
access_pkey_error(is_pkey: 1, is_exec: 0, is_write: 0)
arch_vma_access_permitted
pkey_access_permitted
if (!is_pkey_enabled(pkey))
return true
return false
pkey_access_permitted() should not check if the pkey is available in
UAMOR (using is_pkey_enabled()). The kernel needs to do that check
only when allocating keys. This also makes sure the execute_only_key
which is marked as non-manageable via UAMOR is handled correctly in
pkey_access_permitted(), and fixes the bug.
Fixes: c46241a370a6 ("powerpc/pkeys: Check vma before returning key fault error to the user")
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Include bug report details etc. in the change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200627070147.297535-1-aneesh.kumar@linux.ibm.com
With CONFIG_DEBUG_VIRTUAL=y, __pa() checks for addr value and if it's
less than PAGE_OFFSET it leads to a BUG().
#define __pa(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);
(unsigned long)(x) & 0x0fffffffffffffffUL;
})
kernel BUG at arch/powerpc/kvm/book3s_64_mmu_radix.c:43!
cpu 0x70: Vector: 700 (Program Check) at [c0000018a2187360]
pc: c000000000161b30: __kvmhv_copy_tofrom_guest_radix+0x130/0x1f0
lr: c000000000161d5c: kvmhv_copy_from_guest_radix+0x3c/0x80
...
kvmhv_copy_from_guest_radix+0x3c/0x80
kvmhv_load_from_eaddr+0x48/0xc0
kvmppc_ld+0x98/0x1e0
kvmppc_load_last_inst+0x50/0x90
kvmppc_hv_emulate_mmio+0x288/0x2b0
kvmppc_book3s_radix_page_fault+0xd8/0x2b0
kvmppc_book3s_hv_page_fault+0x37c/0x1050
kvmppc_vcpu_run_hv+0xbb8/0x1080
kvmppc_vcpu_run+0x34/0x50
kvm_arch_vcpu_ioctl_run+0x2fc/0x410
kvm_vcpu_ioctl+0x2b4/0x8f0
ksys_ioctl+0xf4/0x150
sys_ioctl+0x28/0x80
system_call_exception+0x104/0x1d0
system_call_common+0xe8/0x214
kvmhv_copy_tofrom_guest_radix() uses a NULL value for to/from to
indicate direction of copy.
Avoid calling __pa() if the value is NULL to avoid the BUG().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Massage change log a bit to mention CONFIG_DEBUG_VIRTUAL]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611120159.680284-1-aneesh.kumar@linux.ibm.com
Building the current 5.8 kernel for an e500 machine with
CONFIG_RANDOMIZE_BASE=y and CONFIG_BLOCK=n yields the following
failure:
arch/powerpc/mm/nohash/kaslr_booke.c: In function 'kaslr_early_init':
arch/powerpc/mm/nohash/kaslr_booke.c:387:2: error: implicit
declaration of function 'flush_icache_range'; did you mean 'flush_tlb_range'?
Indeed, including asm/cacheflush.h into kaslr_booke.c fixes the build.
Fixes: 2b0e86cc5de6 ("powerpc/fsl_booke/32: implement KASLR infrastructure")
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Acked-by: Scott Wood <oss@buserror.net>
[mpe: Tweak change log to mention CONFIG_BLOCK=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200613162801.1946619-1-asolokha@kb.kras.ru
Pull powerpc fixes from Michael Ellerman: - One fix for the interrupt rework we did last release which broke KVM-PR - Three commits fixing some fallout from the READ_ONCE() changes interacting badly with our 8xx 16K pages support, which uses a pte_t that is a structure of 4 actual PTEs - A cleanup of the 8xx pte_update() to use the newly added pmd_off() - A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is enabled - A minor fix for the SPU syscall generation Thanks to Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike Rapoport, Nicholas Piggin. * tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/8xx: Provide ptep_get() with 16k pages mm: Allow arches to provide ptep_get() mm/gup: Use huge_ptep_get() in gup_hugepte() powerpc/syscalls: Use the number when building SPU syscall table powerpc/8xx: use pmd_off() to access a PMD entry in pte_update() powerpc/64s: Fix KVM interrupt using wrong save area powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL
Pull libnvdimm updates from Dan Williams:
"A feature (papr_scm health retrieval) and a fix (sysfs attribute
visibility) for v5.8.
Vaibhav explains in the merge commit below why missing v5.8 would be
painful and I agreed to try a -rc2 pull because only cosmetics kept
this out of -rc1 and his initial versions were posted in more than
enough time for v5.8 consideration:
'These patches are tied to specific features that were committed to
customers in upcoming distros releases (RHEL and SLES) whose
time-lines are tied to 5.8 kernel release.
Being able to track the health of an nvdimm is critical for our
customers that are running workloads leveraging papr-scm nvdimms.
Missing the 5.8 kernel would mean missing the distro timelines and
shifting forward the availability of this feature in distro kernels
by at least 6 months'
Summary:
- Fix the visibility of the region 'align' attribute.
The new unit tests for region alignment handling caught a corner
case where the alignment cannot be specified if the region is
converted from static to dynamic provisioning at runtime.
- Add support for device health retrieval for the persistent memory
supported by the papr_scm driver.
This includes both the standard sysfs "health flags" that the nfit
persistent memory driver publishes and a mechanism for the ndctl
tool to retrieve a health-command payload"
* tag 'libnvdimm-for-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nvdimm/region: always show the 'align' attribute
powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods
powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()
powerpc/papr_scm: Fetch nvdimm health information from PHYP
seq_buf: Export seq_buf_printf
powerpc: Document details on H_SCM_HEALTH hcall