Commit d02f6b7dab ("powerpc/uaccess: Evaluate macro arguments once,
before user access is allowed") changed the __chk_user_ptr()
argument from the passed ptr pointer to the locally
declared __gu_addr. But __gu_addr is locally defined as __user
so the check is pointless.
During kernel build __chk_user_ptr() voids and is only evaluated
during sparse checks so it should have been armless to leave the
original pointer check there.
Nevertheless, this check is indeed redundant with the assignment
above which casts the ptr pointer to the local __user __gu_addr.
In case of mismatch, sparse will detect it there, so the
__check_user_ptr() is not needed anywhere else than in access_ok().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/69f17d75046733b891ab2e668dbf464787cdf598.1615398265.git.christophe.leroy@csgroup.eu
Commit 6bfd93c32a ("powerpc: Fix incorrect might_sleep in
__get_user/__put_user on kernel addresses") added a check to not call
might_sleep() on kernel addresses. This was to enable the use of
__get_user() in the alignment exception handler for any address.
Then commit 95156f0051 ("lockdep, mm: fix might_fault() annotation")
added a check of the address space in might_fault(), based on
set_fs() logic. But this didn't solve the powerpc alignment exception
case as it didn't call set_fs(KERNEL_DS).
Nowadays, set_fs() is gone, previous patch fixed the alignment
exception handler and __get_user/__put_user are not supposed to be
used anymore to read kernel memory.
Therefore the is_kernel_addr() check has become useless and can be
removed.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e0a980a4dc7a2551183dd5cb30f46eafdbee390c.1615398265.git.christophe.leroy@csgroup.eu
In the old days, when we didn't have kernel userspace access
protection and had set_fs(), it was wise to use __get_user()
and friends to read kernel memory.
Nowadays, get_user() is granting userspace access and is exclusively
for userspace access.
In alignment exception handler, use probe_kernel_read_inst()
instead of __get_user_instr() for reading instructions in kernel.
This will allow to remove the is_kernel_addr() check in
__get/put_user() in a following patch.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d9ecbce00178484e66ca7adec2ff210058037704.1615398265.git.christophe.leroy@csgroup.eu
Powerpc is the only architecture having _inatomic variants of
__get_user() and __put_user() accessors. They were introduced
by commit e68c825bb0 ("[POWERPC] Add inatomic versions of __get_user
and __put_user").
Those variants expand to the _nosleep macros instead of expanding
to the _nocheck macros. The only difference between the _nocheck
and the _nosleep macros is the call to might_fault().
Since commit 662bbcb274 ("mm, sched: Allow uaccess in atomic with
pagefault_disable()"), __get/put_user() can be used in atomic parts
of the code, therefore __get/put_user_inatomic() have become useless.
Remove __get_user_inatomic() and __put_user_inatomic().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1e5c895669e8d54a7810b62dc61eb111f33c2c37.1615398265.git.christophe.leroy@csgroup.eu
This patch converts emulate_spe() to using user_access_begin
logic.
Since commit 662bbcb274 ("mm, sched: Allow uaccess in atomic with
pagefault_disable()"), might_fault() doesn't fire when called from
sections where pagefaults are disabled, which must be the case
when using _inatomic variants of __get_user and __put_user. So
the might_fault() in user_access_begin() is not a problem.
There was a verification of user_mode() together with the access_ok(),
but there is a second verification of user_mode() just after, that
leads to immediate return. The access_ok() is now part of the
user_access_begin which is called after that other user_mode()
verification, so no need to check user_mode() again.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c95a648fdf75992c9d88f3c73cc23e7537fcf2ad.1615555354.git.christophe.leroy@csgroup.eu
PPC32 encounters a KUAP fault when trying to handle a signal with
VDSO unmapped.
Kernel attempted to read user page (7fc07ec0) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel data access on read at 0x7fc07ec0
Faulting instruction address: 0xc00111d4
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=16K PREEMPT CMPC885
CPU: 0 PID: 353 Comm: sigreturn_vdso Not tainted 5.12.0-rc4-s3k-dev-01553-gb30c310ea220 #4814
NIP: c00111d4 LR: c0005a28 CTR: 00000000
REGS: cadb3dd0 TRAP: 0300 Not tainted (5.12.0-rc4-s3k-dev-01553-gb30c310ea220)
MSR: 00009032 <EE,ME,IR,DR,RI> CR: 48000884 XER: 20000000
DAR: 7fc07ec0 DSISR: 88000000
GPR00: c0007788 cadb3e90 c28d4a40 7fc07ec0 7fc07ed0 000004e0 7fc07ce0 00000000
GPR08: 00000001 00000001 7fc07ec0 00000000 28000282 1001b828 100a0920 00000000
GPR16: 100cac0c 100b0000 105c43a4 105c5685 100d0000 100d0000 100d0000 100b2e9e
GPR24: ffffffff 105c43c8 00000000 7fc07ec8 cadb3f40 cadb3ec8 c28d4a40 00000000
NIP [c00111d4] flush_icache_range+0x90/0xb4
LR [c0005a28] handle_signal32+0x1bc/0x1c4
Call Trace:
[cadb3e90] [100d0000] 0x100d0000 (unreliable)
[cadb3ec0] [c0007788] do_notify_resume+0x260/0x314
[cadb3f20] [c000c764] syscall_exit_prepare+0x120/0x184
[cadb3f30] [c00100b4] ret_from_syscall+0xc/0x28
--- interrupt: c00 at 0xfe807f8
NIP: 0fe807f8 LR: 10001060 CTR: c0139378
REGS: cadb3f40 TRAP: 0c00 Not tainted (5.12.0-rc4-s3k-dev-01553-gb30c310ea220)
MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28000482 XER: 20000000
GPR00: 00000025 7fc081c0 77bb1690 00000000 0000000a 28000482 00000001 0ff03a38
GPR08: 0000d032 00006de5 c28d4a40 00000009 88000482 1001b828 100a0920 00000000
GPR16: 100cac0c 100b0000 105c43a4 105c5685 100d0000 100d0000 100d0000 100b2e9e
GPR24: ffffffff 105c43c8 00000000 77ba7628 10002398 10010000 10002124 00024000
NIP [0fe807f8] 0xfe807f8
LR [10001060] 0x10001060
--- interrupt: c00
Instruction dump:
38630010 7c001fac 38630010 4200fff0 7c0004ac 4c00012c 4e800020 7c001fac
2c0a0000 38630010 4082ffcc 4bffffe4 <7c00186c> 2c070000 39430010 4082ff8c
---[ end trace 3973fb72b049cb06 ]---
This is because flush_icache_range() is called on user addresses.
The same problem was detected some time ago on PPC64. It was fixed by
enabling KUAP in commit 59bee45b97 ("powerpc/mm: Fix missing KUAP
disable in flush_coherent_icache()").
PPC32 doesn't use flush_coherent_icache() and fallbacks on
clean_dcache_range() and invalidate_icache_range().
We could fix it similarly by enabling user access in those functions,
but this is overkill for just flushing two instructions.
The two instructions are 8 bytes aligned, so a single dcbst/icbi is
enough to flush them. Do like __patch_instruction() and inline
a dcbst followed by an icbi just after the write of the instructions,
while user access is still allowed. The isync is not required because
rfi will be used to return to user.
icbi() is handled as a read so read-write user access is needed.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bde9154e5351a5ac7bca3d59cdb5a5e8edacbb79.1617199569.git.christophe.leroy@csgroup.eu
The vio bus is a fake bus, which we use on pseries LPARs (guests) to
discover devices provided by the hypervisor. There's no need or sense
in creating the vio bus on bare metal systems.
Which is why commit 4336b93378 ("powerpc/pseries: Make vio and
ibmebus initcalls pseries specific") made the initialisation of the
vio bus only happen in LPARs.
However as a result of that commit we now see errors at boot on bare
metal systems:
Driver 'hvc_console' was unable to register with bus_type 'vio' because the bus was not initialized.
Driver 'tpm_ibmvtpm' was unable to register with bus_type 'vio' because the bus was not initialized.
This happens because those drivers are built-in, and are calling
vio_register_driver(). It in turn calls driver_register() with a
reference to vio_bus_type, but we haven't registered vio_bus_type with
the driver core.
Fix it by also guarding vio_register_driver() with a check to see if
we are on pseries.
Fixes: 4336b93378 ("powerpc/pseries: Make vio and ibmebus initcalls pseries specific")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Link: https://lore.kernel.org/r/20210316010938.525657-1-mpe@ellerman.id.au
When compiling the powerpc with the SMP disabled, it shows the issue:
arch/powerpc/kernel/watchdog.c: In function ‘watchdog_smp_panic’:
arch/powerpc/kernel/watchdog.c:177:4: error: implicit declaration of function ‘smp_send_nmi_ipi’; did you mean ‘smp_send_stop’? [-Werror=implicit-function-declaration]
177 | smp_send_nmi_ipi(c, wd_lockup_ipi, 1000000);
| ^~~~~~~~~~~~~~~~
| smp_send_stop
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:273: arch/powerpc/kernel/watchdog.o] Error 1
make[1]: *** [scripts/Makefile.build:534: arch/powerpc/kernel] Error 2
make: *** [Makefile:1980: arch/powerpc] Error 2
make: *** Waiting for unfinished jobs....
We found that powerpc used ipi to implement hardlockup watchdog, so the
HAVE_HARDLOCKUP_DETECTOR_ARCH should depend on the SMP.
Fixes: 2104180a53 ("powerpc/64s: implement arch-specific hardlockup watchdog")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Chen Huang <chenhuang5@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210327094900.938555-1-chenhuang5@huawei.com
One of the reasons that dlpar_cpu_offline can fail is when attempting to
offline the last online CPU of the kernel. This can be observed in a
pseries QEMU guest that has hotplugged CPUs. If the user offlines all
other CPUs of the guest, and a hotplugged CPU is now the last online
CPU, trying to reclaim it will fail.
The current error message in this situation returns rc with -EBUSY and a
generic explanation, e.g.:
pseries-hotplug-cpu: Failed to offline CPU PowerPC,POWER9, rc: -16
EBUSY can be caused by other conditions, such as cpu_hotplug_disable
being true. Throwing a more specific error message for this case,
instead of just "Failed to offline CPU", makes it clearer that the error
is in fact a known error situation instead of other generic/unknown
cause.
This patch adds a 'last online' check in dlpar_cpu_offline() to catch
the 'last online CPU' offline error, eturning a more informative error
message:
pseries-hotplug-cpu: Unable to remove last online CPU PowerPC,POWER9
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210323205056.52768-2-danielhb413@gmail.com
call_do_irq() and call_do_softirq() are simple enough to be
worth inlining.
Inlining them avoids an mflr/mtlr pair plus a save/reload on stack.
This is inspired from S390 arch. Several other arches do more or
less the same. The way sparc arch does seems odd thought.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210320122227.345427-1-mpe@ellerman.id.au
Sparse warns:
warning: symbol 'rfi_flush' was not declared.
warning: symbol 'entry_flush' was not declared.
warning: symbol 'uaccess_flush' was not declared.
Define 'entry_flush' and 'uaccess_flush' as static because they are
not referenced outside the file. Include asm/security_features.h in
which 'rfi_flush' is declared.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: He Ying <heying24@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316041148.29694-1-heying24@huawei.com
arch/powerpc/kernel/iommu.c:76:2-16: WARNING: NULL check before some freeing functions is not needed.
NULL check before some freeing functions is not needed.
Based on checkpatch warning
"kfree(NULL) is safe this check is probably not required"
and kfreeaddr.cocci by Julia Lawall.
Generated by: scripts/coccinelle/free/ifnullfree.cocci
Fixes: 691602aab9 ("powerpc/iommu/debug: Add debugfs entries for IOMMU tables")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210318234441.GA63469@f8e20a472e81
Hash faults use the trap vector to decide whether this is an
instruction or data fault. This should use the TRAP accessor
rather than open access regs->trap.
This won't cause a problem at the moment because 64s only uses
trap flags for system call interrupts (the norestart flag), but
that could change if any other trap flags get used in future.
Fixes: a4922f5442 ("powerpc/64s: move the hash fault handling logic to C")
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316105205.407767-1-npiggin@gmail.com
Section mismatch in reference from the function .fsl_add_bridge() to
the function .init.text:.setup_pci_cmd()
fsl_add_bridge() is not __init, and can't be, and is the only caller
of setup_pci_cmd(). Fix it by making setup_pci_cmd() non-init.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210314093341.132986-1-mpe@ellerman.id.au
lkp reported warnings in some configuration due to
update_current_thread_amr() being unused:
arch/powerpc/mm/book3s64/pkeys.c:284:20: error: unused function 'update_current_thread_amr'
static inline void update_current_thread_amr(u64 value)
Which is because it's only use is inside an ifdef. We could move it
inside the ifdef, but it's a single line function and only has one
caller, so just fold it in.
Similarly update_current_thread_iamr() is small and only called once,
so fold it in also.
Fixes: 48a8ab4eeb ("powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210314093320.132331-1-mpe@ellerman.id.au
The build fails with CONFIG_PROC_FS=n:
arch/powerpc/kernel/eeh.c:1571:12: error: ‘proc_eeh_show’ defined but not used
1571 | static int proc_eeh_show(struct seq_file *m, void *v)
Wrap proc_eeh_show() in an ifdef to avoid it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210314093300.131998-1-mpe@ellerman.id.au
