With the new interrupt exit code, context tracking can be managed
more precisely, so remove the last of the 64e workarounds and switch
to the new context tracking code already used by 64s.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-8-npiggin@gmail.com
64e non-maskable interrupts save the state of the irq soft-mask in
asm. This can be done in C in interrupt wrappers as 64s does.
I haven't been able to test this with qemu because it doesn't seem
to cause FSL bookE WDT interrupts.
This makes WatchdogException an NMI interrupt, which affects 32-bit
as well (okay, or create a new handler?)
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-6-npiggin@gmail.com
Update the new C and asm interrupt return code to account for 64e
specifics, switch over to use it.
The now-unused old ret_from_except code, that was moved to 64e after the
64s conversion, is removed.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-5-npiggin@gmail.com
This makes adjustments to 64-bit asm and common C interrupt return
code to be usable by the 64e subarchitecture.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-4-npiggin@gmail.com
user_exit_irqoff() -> __context_tracking_exit -> vtime_user_exit
warns in __seqprop_assert due to lockdep thinking preemption is enabled
because trace_hardirqs_off() has not yet been called.
Switch the order of these two calls, which matches their ordering in
interrupt_enter_prepare.
Fixes: 5f0b6ac390 ("powerpc/64/syscall: Reconcile interrupts")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-2-npiggin@gmail.com
Many architectures duplicate similar shell scripts.
This commit converts powerpc to use scripts/syscallhdr.sh.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301153019.362742-2-masahiroy@kernel.org
Many architectures duplicate similar shell scripts.
This commit converts powerpc to use scripts/syscalltbl.sh. This also
unifies syscall_table_32.h and syscall_table_c32.h.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301153019.362742-1-masahiroy@kernel.org
RTAS_RMOBUF_MAX doesn't actually describe a "maximum" value in any
sense. It represents the size of an area of memory set aside for user
space to use as work areas for certain RTAS calls.
Rename it to RTAS_USER_REGION_SIZE.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408140630.205502-6-nathanl@linux.ibm.com
Reduce conditionally compiled sections within rtas_initialize() by
moving the filter table initialization into its own function already
guarded by CONFIG_PPC_RTAS_FILTER. No behavior change intended.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408140630.205502-5-nathanl@linux.ibm.com
There's not a compelling reason to cache the value of the token for
the ibm,suspend-me function. Just look it up when needed in the RTAS
syscall's special case for it.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408140630.205502-4-nathanl@linux.ibm.com
Add kerneldoc for ppc_rtas_rmo_buf_show(), the callback for
/proc/powerpc/rtas/rmo_buffer, explaining its expected use.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408140630.205502-2-nathanl@linux.ibm.com
During the EEH MMIO error checking, the current implementation fails to map
the (virtual) MMIO address back to the pci device on radix with hugepage
mappings for I/O. This results into failure to dispatch EEH event with no
recovery even when EEH capability has been enabled on the device.
eeh_check_failure(token) # token = virtual MMIO address
addr = eeh_token_to_phys(token);
edev = eeh_addr_cache_get_dev(addr);
if (!edev)
return 0;
eeh_dev_check_failure(edev); <= Dispatch the EEH event
In case of hugepage mappings, eeh_token_to_phys() has a bug in virt -> phys
translation that results in wrong physical address, which is then passed to
eeh_addr_cache_get_dev() to match it against cached pci I/O address ranges
to get to a PCI device. Hence, it fails to find a match and the EEH event
never gets dispatched leaving the device in failed state.
The commit 3343962068 ("powerpc/eeh: Handle hugepages in ioremap space")
introduced following logic to translate virt to phys for hugepage mappings:
eeh_token_to_phys():
+ pa = pte_pfn(*ptep);
+
+ /* On radix we can do hugepage mappings for io, so handle that */
+ if (hugepage_shift) {
+ pa <<= hugepage_shift; <= This is wrong
+ pa |= token & ((1ul << hugepage_shift) - 1);
+ }
This patch fixes the virt -> phys translation in eeh_token_to_phys()
function.
$ cat /sys/kernel/debug/powerpc/eeh_address_cache
mem addr range [0x0000040080000000-0x00000400807fffff]: 0030:01:00.1
mem addr range [0x0000040080800000-0x0000040080ffffff]: 0030:01:00.1
mem addr range [0x0000040081000000-0x00000400817fffff]: 0030:01:00.0
mem addr range [0x0000040081800000-0x0000040081ffffff]: 0030:01:00.0
mem addr range [0x0000040082000000-0x000004008207ffff]: 0030:01:00.1
mem addr range [0x0000040082080000-0x00000400820fffff]: 0030:01:00.0
mem addr range [0x0000040082100000-0x000004008210ffff]: 0030:01:00.1
mem addr range [0x0000040082110000-0x000004008211ffff]: 0030:01:00.0
Above is the list of cached io address ranges of pci 0030:01:00.<fn>.
Before this patch:
Tracing 'arg1' of function eeh_addr_cache_get_dev() during error injection
clearly shows that 'addr=' contains wrong physical address:
kworker/u16:0-7 [001] .... 108.883775: eeh_addr_cache_get_dev:
(eeh_addr_cache_get_dev+0xc/0xf0) addr=0x80103000a510
dmesg shows no EEH recovery messages:
[ 108.563768] bnx2x: [bnx2x_timer:5801(eth2)]MFW seems hanged: drv_pulse (0x9ae) != mcp_pulse (0x7fff)
[ 108.563788] bnx2x: [bnx2x_hw_stats_update:870(eth2)]NIG timer max (4294967295)
[ 108.883788] bnx2x: [bnx2x_acquire_hw_lock:2013(eth1)]lock_status 0xffffffff resource_bit 0x1
[ 108.884407] bnx2x 0030:01:00.0 eth1: MDC/MDIO access timeout
[ 108.884976] bnx2x 0030:01:00.0 eth1: MDC/MDIO access timeout
<..>
After this patch:
eeh_addr_cache_get_dev() trace shows correct physical address:
<idle>-0 [001] ..s. 1043.123828: eeh_addr_cache_get_dev:
(eeh_addr_cache_get_dev+0xc/0xf0) addr=0x40080bc7cd8
dmesg logs shows EEH recovery getting triggerred:
[ 964.323980] bnx2x: [bnx2x_timer:5801(eth2)]MFW seems hanged: drv_pulse (0x746f) != mcp_pulse (0x7fff)
[ 964.323991] EEH: Recovering PHB#30-PE#10000
[ 964.324002] EEH: PE location: N/A, PHB location: N/A
[ 964.324006] EEH: Frozen PHB#30-PE#10000 detected
<..>
Fixes: 3343962068 ("powerpc/eeh: Handle hugepages in ioremap space")
Cc: stable@vger.kernel.org # v5.3+
Reported-by: Dominic DeMarco <ddemarc@us.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-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/161821396263.48361.2796709239866588652.stgit@jupiter
The sparse tool complains as follows:
arch/powerpc/kernel/smp.c:86:1: warning:
symbol '__pcpu_scope_cpu_coregroup_map' was not declared. Should it be static?
arch/powerpc/kernel/smp.c:125:1: warning:
symbol '__pcpu_scope_thread_group_l1_cache_map' was not declared. Should it be static?
arch/powerpc/kernel/smp.c:132:1: warning:
symbol '__pcpu_scope_thread_group_l2_cache_map' was not declared. Should it be static?
These symbols are not used outside of smp.c, so this
commit marks them static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210407125903.4139663-1-yukuai3@huawei.com
The sparse tool complains as follows:
arch/powerpc/kernel/mce.c:43:1: warning:
symbol 'mce_ue_event_work' was not declared. Should it be static?
This symbol is not used outside of mce.c, so this commit marks it
static.
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408035802.31853-1-lihuafei1@huawei.com
The sparse tool complains as follows:
arch/powerpc/kernel/security.c:253:6: warning:
symbol 'stf_barrier' was not declared. Should it be static?
This symbol is not used outside of security.c, so this commit marks it
static.
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210408033951.28369-1-lihuafei1@huawei.com
On book3s/32, when STRICT_KERNEL_RWX is selected, modules are
allocated on the segment just before kernel text, ie on the
0xb0000000-0xbfffffff when PAGE_OFFSET is 0xc0000000.
On the 8xx, TASK_SIZE is 0x80000000. The space between TASK_SIZE and
PAGE_OFFSET is not used and could be used for modules.
The idea comes from ARM architecture.
Having modules just below PAGE_OFFSET offers an opportunity to
minimise the distance between kernel text and modules and avoid
trampolines in modules to access kernel functions or other module
functions.
When MODULES_VADDR is defined, powerpc has it's own module_alloc()
function. In that function, first try to allocate the module
above the limit defined by '_etext - 32M'. Then if the allocation
fails, fallback to the entire MODULES area.
DEBUG logs in module_32.c without the patch:
[ 1572.588822] module_32: Applying ADD relocate section 13 to 12
[ 1572.588891] module_32: Doing plt for call to 0xc00671a4 at 0xcae04024
[ 1572.588964] module_32: Initialized plt for 0xc00671a4 at cae04000
[ 1572.589037] module_32: REL24 value = CAE04000. location = CAE04024
[ 1572.589110] module_32: Location before: 48000001.
[ 1572.589171] module_32: Location after: 4BFFFFDD.
[ 1572.589231] module_32: ie. jump to 03FFFFDC+CAE04024 = CEE04000
[ 1572.589317] module_32: Applying ADD relocate section 15 to 14
[ 1572.589386] module_32: Doing plt for call to 0xc00671a4 at 0xcadfc018
[ 1572.589457] module_32: Initialized plt for 0xc00671a4 at cadfc000
[ 1572.589529] module_32: REL24 value = CADFC000. location = CADFC018
[ 1572.589601] module_32: Location before: 48000000.
[ 1572.589661] module_32: Location after: 4BFFFFE8.
[ 1572.589723] module_32: ie. jump to 03FFFFE8+CADFC018 = CEDFC000
With the patch:
[ 279.404671] module_32: Applying ADD relocate section 13 to 12
[ 279.404741] module_32: REL24 value = C00671B4. location = BF808024
[ 279.404814] module_32: Location before: 48000001.
[ 279.404874] module_32: Location after: 4885F191.
[ 279.404933] module_32: ie. jump to 0085F190+BF808024 = C00671B4
[ 279.405016] module_32: Applying ADD relocate section 15 to 14
[ 279.405085] module_32: REL24 value = C00671B4. location = BF800018
[ 279.405156] module_32: Location before: 48000000.
[ 279.405215] module_32: Location after: 4886719C.
[ 279.405275] module_32: ie. jump to 0086719C+BF800018 = C00671B4
We see that with the patch, no plt entries are set.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0c3d5cb8a4dfdf6ca1b8aeb385c01470d6628d55.1617283827.git.christophe.leroy@csgroup.eu
Add missing fault exit label in unsafe_copy_from_user() in order to
avoid following build failure with CONFIG_SPE
CC arch/powerpc/kernel/signal_32.o
arch/powerpc/kernel/signal_32.c: In function 'restore_user_regs':
arch/powerpc/kernel/signal_32.c:565:36: error: macro "unsafe_copy_from_user" requires 4 arguments, but only 3 given
565 | ELF_NEVRREG * sizeof(u32));
| ^
In file included from ./include/linux/uaccess.h:11,
from ./include/linux/sched/task.h:11,
from ./include/linux/sched/signal.h:9,
from ./include/linux/rcuwait.h:6,
from ./include/linux/percpu-rwsem.h:7,
from ./include/linux/fs.h:33,
from ./include/linux/huge_mm.h:8,
from ./include/linux/mm.h:707,
from arch/powerpc/kernel/signal_32.c:17:
./arch/powerpc/include/asm/uaccess.h:428: note: macro "unsafe_copy_from_user" defined here
428 | #define unsafe_copy_from_user(d, s, l, e) \
|
arch/powerpc/kernel/signal_32.c:564:3: error: 'unsafe_copy_from_user' undeclared (first use in this function); did you mean 'raw_copy_from_user'?
564 | unsafe_copy_from_user(current->thread.evr, &sr->mc_vregs,
| ^~~~~~~~~~~~~~~~~~~~~
| raw_copy_from_user
arch/powerpc/kernel/signal_32.c:564:3: note: each undeclared identifier is reported only once for each function it appears in
make[3]: *** [arch/powerpc/kernel/signal_32.o] Error 1
Fixes: 627b72bee8 ("powerpc/signal32: Convert restore_[tm]_user_regs() to user access block")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/aad2cb1801a3cc99bc27081022925b9fc18a0dfb.1618159169.git.christophe.leroy@csgroup.eu
The code being executed in KVM_GUEST_MODE_SKIP is hypervisor code with
MSR[IR]=0, so the faults of concern are the d-side ones caused by access
to guest context by the hypervisor.
Instruction breakpoint interrupts are not a concern here. It's unlikely
any good would come of causing breaks in this code, but skipping the
instruction that caused it won't help matters (e.g., skip the mtmsr that
sets MSR[DR]=0 or clears KVM_GUEST_MODE_SKIP).
[Paul notes: "the 0x1300 interrupt was dropped from the architecture a
long time ago and is not generated by P7, P8, P9 or P10." So add a
comment about this in the handler code while we're here. ]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210412014845.1517916-11-npiggin@gmail.com
Cell does not support KVM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210412014845.1517916-10-npiggin@gmail.com
There is no need for this to be in asm, use the new intrrupt entry wrapper.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210406025508.821718-1-npiggin@gmail.com
When the original spectre/meltdown mitigations were merged we put them
in setup_64.c for lack of a better place.
Since then we created security.c for some of the other mitigation
related code. But it should all be in there.
This sort of code movement can cause trouble for backports, but
hopefully this code is relatively stable these days (famous last words).
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326101201.1973552-1-mpe@ellerman.id.au
Various spelling/typo fixes.
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Convert powerpc to relative jump labels.
Before the patch, pseries_defconfig vmlinux.o has:
9074 __jump_table 0003f2a0 0000000000000000 0000000000000000 01321fa8 2**0
With the patch, the same config gets:
9074 __jump_table 0002a0e0 0000000000000000 0000000000000000 01321fb4 2**0
Size is 258720 without the patch, 172256 with the patch.
That's a 33% size reduction.
Largely copied from commit c296146c05 ("arm64/kernel: jump_label:
Switch to relative references")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/828348da7868eda953ce023994404dfc49603b64.1616514473.git.christophe.leroy@csgroup.eu
In preparation of using user_access_begin/end in restore_user_regs(),
move the access_ok() inside the function.
It makes no difference as the behaviour on a failed access_ok() is
the same as on failed restore_user_regs().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c106eb2f37c3040f1fd38b40e50c670feb7cb835.1616151715.git.christophe.leroy@csgroup.eu
In the same spirit as commit f1cf4f93de ("powerpc/signal32: Remove
ifdefery in middle of if/else")
MSR_TM_ACTIVE() is always defined and returns always 0 when
CONFIG_PPC_TRANSACTIONAL_MEM is not selected, so the awful
ifdefery in the middle of an if/else can be removed.
Make 'msr_hi' a 'long long' to avoid build failure on PPC32
due to the 32 bits left shift.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a4b48b2f0be1ef13fc8e57452b7f8350da28d521.1616151715.git.christophe.leroy@csgroup.eu
Convention is to prefix functions with __unsafe_ instead of
suffixing it with _unsafe.
Rename save_user_regs_unsafe() and save_general_regs_unsafe()
accordingly, that is respectively __unsafe_save_general_regs() and
__unsafe_save_user_regs().
Suggested-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8cef43607e5b35a7fd0829dec812d88beb570df2.1616151715.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
Commit bce74491c3 ("powerpc/vdso: fix unnecessary rebuilds of
vgettimeofday.o") moved vdso32_wrapper.o and vdso64_wrapper.o out
of arch/powerpc/kernel/vdso[32/64]/ and removed the dependencies in
the Makefile. This leads to the wrappers not being re-build hence the
kernel embedding the old vdso library.
Add back missing dependencies to ensure vdso32_wrapper.o and vdso64_wrapper.o
are rebuilt when vdso32.so.dbg and vdso64.so.dbg are changed.
Fixes: bce74491c3 ("powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8bb015bc98c51d8ced581415b7e3d157e18da7c9.1617181918.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
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
Section mismatch in reference from the function .smp_setup_pacas() to
the function .init.text:.allocate_paca()
The only caller of smp_setup_pacas() is setup_arch() which is __init,
so mark smp_setup_pacas() __init.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210314093333.132657-1-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
Commit aac6a91fea ("powerpc/asm: Remove unused symbols in
asm-offsets.c") removed GPR15 to GPR31 but kept GPR14,
probably because it pops up in a couple of comments when doing
a grep.
However, it was never used either, so remove it as well.
Fixes: aac6a91fea ("powerpc/asm: Remove unused symbols in asm-offsets.c")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9881c68fbca004f9ea18fc9473f630e11ccd6417.1615806071.git.christophe.leroy@csgroup.eu
Sparse reports the following problems:
arch/powerpc/math-emu/math.c:228:21: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:31: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:41: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:228:51: warning: Using plain integer as NULL pointer
arch/powerpc/math-emu/math.c:237:13: warning: incorrect type in initializer (different address spaces)
arch/powerpc/math-emu/math.c:237:13: expected unsigned int [noderef] __user *_gu_addr
arch/powerpc/math-emu/math.c:237:13: got unsigned int [usertype] *
arch/powerpc/math-emu/math.c:226:1: warning: symbol 'do_mathemu' was not declared. Should it be static?
Add missing __user qualifier when casting pointer used in get_user()
Use NULL instead of 0 to initialise opX local variables.
Add a prototype for do_mathemu() (Added in processor.h like sparc)
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e4d1aae7604d89c98a52dfd8ce8443462e595670.1615809591.git.christophe.leroy@csgroup.eu
In preparation of porting powerpc32 to C syscall entry/exit,
rename kuap_check_amr() and kuap_get_and_check_amr() as
kuap_assert_locked() and kuap_get_and_assert_locked(), and move in the
generic asm/kup.h the stub for when CONFIG_PPC_KUAP is not selected.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f82614d9b17b83abd739aa18fc08811815d0c2e3.1615552867.git.christophe.leroy@csgroup.eu
Save non volatile registers, XER, CTR, MSR and NIP in exception prolog.
Also assign proper value to r2 and r3 there.
For now, recalculate thread pointer in prepare_transfer_to_handler.
It will disappear once KUAP is ported to C.
And remove the comment which is now completely wrong.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/56f0cde9dd0362edf2ddba4d887552013eee7329.1615552867.git.christophe.leroy@csgroup.eu
Exception prologs all do the same at the end:
- Save trapno in stack
- Mark stack with exception marker
- Save r0
- Save r3 to r8
Refactor that into a COMMON_EXCEPTION_PROLOG_END macro.
At the same time use r1 instead of r11.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e1c45d2e895e0693c42d2a6840df1105a148efea.1615552867.git.christophe.leroy@csgroup.eu
In order to get more control in exception prolog, dismantle
all non standard exception macros, finishing with EXC_XFER_STD
and EXC_XFER_LITE and EXC_XFER_TEMPLATE.
Also remove transfer_to_handler_full and ret_from_except and
ret_from_except_full as they are not used anymore.
Last parameter of EXCEPTION() is now ignored, will be removed
in a later patch to avoid too much churn.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ca5795d04a220586b7037dbbbe6951dfa9e768eb.1615552867.git.christophe.leroy@csgroup.eu
Until now, non volatile registers were restored everytime they
were saved, ie using EXC_XFER_STD meant saving and restoring
them while EXC_XFER_LITE meant neither saving not restoring them.
Now that they are always saved, EXC_XFER_STD means to restore
them and EXC_XFER_LITE means to not restore them.
Most of the users of EXC_XFER_STD only need to retrieve the
non volatile registers. For them there is no need to restore
the non volatile registers as they have not been modified.
Only very few exceptions require non volatile registers restore.
Opencode the few places which require saving of non volatile
registers.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d1cb12d8023cc6afc1f07150565571373c04945c.1615552867.git.christophe.leroy@csgroup.eu
In order to increase flexibility, add a macro that will for now
call transfer_to_handler.
As transfer_to_handler doesn't do the actual transfer anymore,
also name it prepare_transfer_to_handler. The following patches
will progressively remove the use of transfer_to_handler label.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7f757c52518ab1d7b27ad5113b10f860e803f467.1615552867.git.christophe.leroy@csgroup.eu
Since commit 06d67d5474 ("powerpc: make process.c suitable for both
32-bit and 64-bit"), thread.regs is set on task creation, no need to
set it again and again at each interrupt entry as it never change.
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20d52c627303d63e461797df13e6890fc04017d0.1615552867.git.christophe.leroy@csgroup.eu
Now that the MMU is re-enabled before calling the transfer function,
we don't need anymore that hack with the address of the handler and
the return function sitting just after the 'bl' to the transfer
fonction, that function is retrieving via a read relative to 'lr'.
Do a regular call to the transfer function, then to the handler,
then branch to the return function.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/73c00f3361ca280ef8fd7814c291bd1f5b6e2081.1615552867.git.christophe.leroy@csgroup.eu
Refactor booke critical registers saving into a few macros
and move it into the exception prolog directly.
Keep the dedicated transfert_to_handler entry point for the
moment allthough they are empty. They will be removed in a
later patch to reduce churn.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/269171496f1f5f22afa621695bded22976c9d48d.1615552867.git.christophe.leroy@csgroup.eu
The space in the head section is rather constrained by the fact that
exception vectors are spread every 0x100 bytes and sometimes we
need to have "out of line" code because it doesn't fit.
Now that we are enabling MMU early in the prolog, take that opportunity
to jump somewhere else in the .text section where we don't have any
space constraint.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/38b31ca4bc782a4985bc7952a675404d7ff27c24.1615552867.git.christophe.leroy@csgroup.eu
For consistency, add in the macro the label used by exception prolog
to branch to stack overflow processing.
While at it, enclose the macro in #ifdef CONFIG_VMAP_STACK on the 8xx
as already done on book3s/32.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cf80056f5b946572ad98aea9d915dd25b23beda6.1615552867.git.christophe.leroy@csgroup.eu
The check of the emergency context initialisation in
vmap_stack_overflow is buggy for the SMP case, as it
compares r1 with 0 while in the SMP case r1 is offseted
by the CPU id.
Instead of fixing it, just perform static initialisation
of the first emergency context.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4a67ba422be75713286dca0c86ee0d3df2eb6dfa.1615552867.git.christophe.leroy@csgroup.eu
On 40x and 8xx, kernel text is pinned.
On book3s/32, kernel text is mapped by BATs.
Enable instruction translation at the same time as data translation, it
makes things simpler.
In syscall handler, MSR_RI can also be set at the same time because
srr0/srr1 are already saved and r1 is set properly.
On booke, translation is always on, so at the end all PPC32
have translation on early. Just update msr.
Also update comment in power_save_ppc32_restore().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5269c7e5f5d2117358af3a89744d75a116be27b0.1615552867.git.christophe.leroy@csgroup.eu
8xx requires to tag the DAR with a magic value in order to
fixup DAR on faults generated by 'dcbX', as the 8xx
forgets to update the DAR for those faults.
Do the tagging as early as possible, that is before enabling MMU.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/853a2e28ca7c5fc85617037030f99fe6070c9536.1615552867.git.christophe.leroy@csgroup.eu
If the code can use a stack in vm area, it can also use a
stack in linear space.
Simplify code by removing old non VMAP stack code on PPC32.
That means the data translation is now re-enabled early in
exception prolog in all cases, not only when using VMAP stacks.
While we are touching EXCEPTION_PROLOG macros, remove the
unused for_rtas parameter in EXCEPTION_PROLOG_1.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7cd6440c60a7e8f4f035b245c57720f51e225aae.1615552866.git.christophe.leroy@csgroup.eu
ksp_limit is there to help detect stack overflows.
That is specific to ppc32 as it was removed from ppc64 in
commit cbc9565ee8 ("powerpc: Remove ksp_limit on ppc64").
There are other means for detecting stack overflows.
As ppc64 has proven to not need it, ppc32 should be able to do
without it too.
Lets remove it and simplify exception handling.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d789c3385b22e07bedc997613c0d26074cb513e7.1615552866.git.christophe.leroy@csgroup.eu
Ensure normal exception handler are able to manage stuff with
MMU enabled. For that we use CONFIG_VMAP_STACK related code
allthough there is no intention to really activate CONFIG_VMAP_STACK
on powerpc 40x for the moment.
40x uses SPRN_DEAR instead of SPRN_DAR and SPRN_ESR instead of
SPRN_DSISR. Take it into account in common macros.
40x MSR value doesn't fit on 15 bits, use LOAD_REG_IMMEDIATE() in
common macros that will be used also with 40x.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/01963af2b83037bca270d7bf1336ffcf35da8282.1615552866.git.christophe.leroy@csgroup.eu
In order the enable MMU early in exception prolog, implement
CONFIG_VMAP_STACK principles in critical exception prolog.
There is no intention to use CONFIG_VMAP_STACK on 40x,
but related code will be used to enable MMU early in exception
in a later patch.
Also address (critirq_ctx - PAGE_OFFSET) directly instead of
using tophys() in order to win one instruction.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3fd75ee54c48307119acdbf66cfea966c1463bbd.1615552866.git.christophe.leroy@csgroup.eu
SPRN_SPRG_SCRATCH5 is used to save SPRN_PID.
SPRN_SPRG_SCRATCH6 is already available.
SPRN_PID is only 8 bits. We have r12 that contains CR.
We only need to preserve CR0, so we have space available in r12
to save PID.
Keep PID in r12 and free up SPRN_SPRG_SCRATCH5.
Then In TLB miss handlers, instead of using SPRN_SPRG_SCRATCH0 and
SPRN_SPRG_SCRATCH1, use SPRN_SPRG_SCRATCH5 and SPRN_SPRG_SCRATCH6
to avoid future conflicts with normal exception prologs.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4cdaa85d38e14d594ba902424060ec55babf2c42.1615552866.git.christophe.leroy@csgroup.eu
As per ISA 3.1, prefixed instruction should not cross 64-byte
boundary. So don't allow Uprobe on such prefixed instruction.
There are two ways probed instruction is changed in mapped pages.
First, when Uprobe is activated, it searches for all the relevant
pages and replace instruction in them. In this case, if that probe
is on the 64-byte unaligned prefixed instruction, error out
directly. Second, when Uprobe is already active and user maps a
relevant page via mmap(), instruction is replaced via mmap() code
path. But because Uprobe is invalid, entire mmap() operation can
not be stopped. In this case just print an error and continue.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210311091538.368590-1-ravi.bangoria@linux.ibm.com
Usually sigset_t is exactly 8B which is a "trivial" size and does not
warrant using __copy_from_user(). Use __get_user() directly in
anticipation of future work to remove the trivial size optimizations
from __copy_from_user().
The ppc32 implementation of get_sigset_t() previously called
copy_from_user() which, unlike __copy_from_user(), calls access_ok().
Replacing this w/ __get_user() (no access_ok()) is fine here since both
callsites in signal_32.c are preceded by an earlier access_ok().
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-11-cmr@codefail.de
Add uaccess blocks and use the 'unsafe' versions of functions doing user
access where possible to reduce the number of times uaccess has to be
opened/closed.
Co-developed-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-10-cmr@codefail.de
Add uaccess blocks and use the 'unsafe' versions of functions doing user
access where possible to reduce the number of times uaccess has to be
opened/closed.
There is no 'unsafe' version of copy_siginfo_to_user, so move it
slightly to allow for a "longer" uaccess block.
Co-developed-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-9-cmr@codefail.de
Previously restore_sigcontext() performed a costly KUAP switch on every
uaccess operation. These repeated uaccess switches cause a significant
drop in signal handling performance.
Rewrite restore_sigcontext() to assume that a userspace read access
window is open by replacing all uaccess functions with their 'unsafe'
versions. Modify the callers to first open, call
unsafe_restore_sigcontext(), and then close the uaccess window.
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-8-cmr@codefail.de
Previously setup_sigcontext() performed a costly KUAP switch on every
uaccess operation. These repeated uaccess switches cause a significant
drop in signal handling performance.
Rewrite setup_sigcontext() to assume that a userspace write access window
is open by replacing all uaccess functions with their 'unsafe' versions.
Modify the callers to first open, call unsafe_setup_sigcontext() and
then close the uaccess window.
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-7-cmr@codefail.de
Both rt_sigreturn() and handle_rt_signal_64() contain TM-related ifdefs
which break-up an if/else block. Provide stubs for the ifdef-guarded TM
functions and remove the need for an ifdef in rt_sigreturn().
Rework the remaining TM ifdef in handle_rt_signal64() similar to
commit f1cf4f93de ("powerpc/signal32: Remove ifdefery in middle of if/else").
Unlike in the commit for ppc32, the ifdef can't be removed entirely
since uc_transact in sigframe depends on CONFIG_PPC_TRANSACTIONAL_MEM.
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-6-cmr@codefail.de
The majority of setup_sigcontext() can be refactored to execute in an
"unsafe" context assuming an open uaccess window except for some
non-inline function calls. Move these out into a separate
prepare_setup_sigcontext() function which must be called first and
before opening up a uaccess window. Non-inline function calls should be
avoided during a uaccess window for a few reasons:
- KUAP should be enabled for as much kernel code as possible.
Opening a uaccess window disables KUAP which means any code
executed during this time contributes to a potential attack
surface.
- Non-inline functions default to traceable which means they are
instrumented for ftrace. This adds more code which could run
with KUAP disabled.
- Powerpc does not currently support the objtool UACCESS checks.
All code running with uaccess must be audited manually which
means: less code -> less work -> fewer problems (in theory).
A follow-up commit converts setup_sigcontext() to be "unsafe".
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-4-cmr@codefail.de
