My recent patch to split pt_regs between user and kernel missed
the usage in struct sigcontext.
Because this is a user visible struct it should be using the user
visible definition, which when we're building for the kernel is called
struct user_pt_regs.
As far as I can see this hasn't actually caused a bug (yet), because
we don't use the sizeof() the sigcontext->regs anywhere. But we should
still fix it to avoid confusion and future bugs.
Fixes: 002af9391b ("powerpc: Split user/kernel definitions of struct pt_regs")
Reported-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch implements support for discovering storage class memory
devices at boot and for handling hotplug of new regions via RTAS
hotplug events.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Fix CONFIG_MEMORY_HOTPLUG=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Book3e defines both _PAGE_USER and _PAGE_PRIVILEGED, so the nohash
default pte_mkprivileged() and pte_mkuser() are not usable.
This patch redefines them for book3e.
In theorie, only pte_mkprivileged() needs to be redefined because
_PAGE_USER includes _PAGE_PRIVILEGED, but it is less confusing
to redefine both.
Fixes: a0da4bc166 ("powerpc/mm: Allow platforms to redefine some helpers")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Other archs do the same and instead of adding required pte bits (which
got masked out) in __ioremap_at(), make sure we filter only pfn bits
out.
Fixes: 26973fa5ac ("powerpc/mm: use pte helpers in generic code")
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently we limit the max addressable memory to 128TB. This patch increase the
limit to 2PB. We can have devices like nvdimm which adds memory above 512TB
limit.
We still don't support regular system ram above 512TB. One of the challenge with
that is the percpu allocator, that allocates per node memory and use the max
distance between them as the percpu offsets. This means with large gap in
address space ( system ram above 1PB) we will run out of vmalloc space to map
the percpu allocation.
In order to support addressable memory above 512TB, kernel should be able to
linear map this range. To do that with hash translation we now add 4 context
to kernel linear map region. Our per context addressable range is 512TB. We
still keep VMALLOC and VMEMMAP region to old size. SLB miss handlers is updated
to validate these limit.
We also limit this update to SPARSEMEM_VMEMMAP and SPARSEMEM_EXTREME
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We will be adding get_kernel_context later. Update function name to indicate
this handle context allocation user space address.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds CONFIG_DEBUG_VM checks to ensure:
- The kernel stack is in the SLB after it's flushed and bolted.
- We don't insert an SLB for an address that is aleady in the SLB.
- The kernel SLB miss handler does not take an SLB miss.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
slb_flush_and_rebolt() is misleading, it is called in virtual mode, so
it can not possibly change the stack, so it should not be touching the
shadow area. And since vmalloc is no longer bolted, it should not
change any bolted mappings at all.
Change the name to slb_flush_and_restore_bolted(), and have it just
load the kernel stack from what's currently in the shadow SLB area.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When switching processes, currently all user SLBEs are cleared, and a
few (exec_base, pc, and stack) are preloaded. In trivial testing with
small apps, this tends to miss the heap and low 256MB segments, and it
will also miss commonly accessed segments on large memory workloads.
Add a simple round-robin preload cache that just inserts the last SLB
miss into the head of the cache and preloads those at context switch
time. Every 256 context switches, the oldest entry is removed from the
cache to shrink the cache and require fewer slbmte if they are unused.
Much more could go into this, including into the SLB entry reclaim
side to track some LRU information etc, which would require a study of
large memory workloads. But this is a simple thing we can do now that
is an obvious win for common workloads.
With the full series, process switching speed on the context_switch
benchmark on POWER9/hash (with kernel speculation security masures
disabled) increases from 140K/s to 178K/s (27%).
POWER8 does not change much (within 1%), it's unclear why it does not
see a big gain like POWER9.
Booting to busybox init with 256MB segments has SLB misses go down
from 945 to 69, and with 1T segments 900 to 21. These could almost all
be eliminated by preloading a bit more carefully with ELF binary
loading.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This will be used by the SLB code in the next patch, but for now this
sets the slb_addr_limit to the correct size for 32-bit tasks.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add 32-entry bitmaps to track the allocation status of the first 32
SLB entries, and whether they are user or kernel entries. These are
used to allocate free SLB entries first, before resorting to the round
robin allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch moves SLB miss handlers completely to C, using the standard
exception handler macros to set up the stack and branch to C.
This can be done because the segment containing the kernel stack is
always bolted, so accessing it with relocation on will not cause an
SLB exception.
Arbitrary kernel memory must not be accessed when handling kernel
space SLB misses, so care should be taken there. However user SLB
misses can access any kernel memory, which can be used to move some
fields out of the paca (in later patches).
User SLB misses could quite easily reconcile IRQs and set up a first
class kernel environment and exit via ret_from_except, however that
doesn't seem to be necessary at the moment, so we only do that if a
bad fault is encountered.
[ Credit to Aneesh for bug fixes, error checks, and improvements to
bad address handling, etc ]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Disallow tracing for all of slb.c for now.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PPR is the odd register out when it comes to interrupt handling, it is
saved in current->thread.ppr while all others are saved on the stack.
The difficulty with this is that accessing thread.ppr can cause a SLB
fault, but the SLB fault handler implementation in C change had
assumed the normal exception entry handlers would not cause an SLB
fault.
Fix this by allocating room in the interrupt stack to save PPR.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We use a shared definition for struct pt_regs in uapi/asm/ptrace.h.
That means the layout of the structure is ABI, ie. we can't change it.
That would be fine if it was only used to describe the user-visible
register state of a process, but it's also the struct we use in the
kernel to describe the registers saved in an interrupt frame.
We'd like more flexibility in the content (and possibly layout) of the
kernel version of the struct, but currently that's not possible.
So split the definition into a user-visible definition which remains
unchanged, and a kernel internal one.
At the moment they're still identical, and we check that at build
time. That's because we have code (in ptrace etc.) that assumes that
they are the same. We will fix that code in future patches, and then
we can break the strict symmetry between the two structs.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In the same spirit as already done in pte query helpers,
this patch changes pte setting helpers to perform endian
conversions on the constants rather than on the pte value.
In the meantime, it changes pte_access_permitted() to use
pte helpers for the same reason.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
_PAGE_PRIVILEGED corresponds to the SH bit which doesn't protect
against user access but only disables ASID verification on kernel
accesses. User access is controlled with _PMD_USER flag.
Name it _PAGE_SH instead of _PAGE_PRIVILEGED
_PAGE_HUGE corresponds to the SPS bit which doesn't really tells
that's it is a huge page but only that it is not a 4k page.
Name it _PAGE_SPS instead of _PAGE_HUGE
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Do not include pte-common.h in nohash/32/pgtable.h
As that was the last includer, get rid of pte-common.h
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cache related flags like _PAGE_COHERENT and _PAGE_WRITETHRU
are defined on most platforms. The platforms not defining
them don't define any alternative. So we can give them a NUL
value directly for those platforms directly.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The 40xx defines _PAGE_HWWRITE while others don't.
The 8xx defines _PAGE_RO instead of _PAGE_RW.
The 8xx defines _PAGE_PRIVILEGED instead of _PAGE_USER.
The 8xx defines _PAGE_HUGE and _PAGE_NA while others don't.
Lets those platforms redefine pte_write(), pte_wrprotect() and
pte_mkwrite() and get _PAGE_RO and _PAGE_HWWRITE off the common
helpers.
Lets the 8xx redefine pte_user(), pte_mkprivileged() and pte_mkuser()
and get rid of _PAGE_PRIVILEGED and _PAGE_USER default values.
Lets the 8xx redefine pte_mkhuge() and get rid of
_PAGE_HUGE default value.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
nohash/64 only uses book3e PTE flags, so it doesn't need pte-common.h
This also allows to drop PAGE_SAO and H_PAGE_4K_PFN from pte_common.h
as they are only used by PPC64
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The base kernel PAGE_XXXX definition sets are more or less platform
specific. Lets distribute them close to platform _PAGE_XXX flags
definition, and customise them to their exact platform flags.
Also defines _PAGE_PSIZE and _PTE_NONE_MASK for each platform
allthough they are defined as 0.
Do the same with _PMD flags like _PMD_USER and _PMD_PRESENT_MASK
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Now the pte-common.h is only for nohash platforms, lets
move pte_user() helper out of pte-common.h to put it
together with other helpers.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
As done for book3s/64, add necessary flags/defines in
book3s/32/pgtable.h and do not include pte-common.h
It allows in the meantime to remove all related hash
definitions from pte-common.h and to also remove
_PAGE_EXEC default as _PAGE_EXEC is defined on all
platforms except book3s/32.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
__P and __S flags are the same for all platform and should remain
as is in the future, so avoid duplication.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The following page flags in pte-common.h can be dropped:
_PAGE_ENDIAN is only used in mm/fsl_booke_mmu.c and is defined in
asm/nohash/32/pte-fsl-booke.h
_PAGE_4K_PFN is nowhere defined nor used
_PAGE_READ, _PAGE_WRITE and _PAGE_PTE are only defined and used
in book3s/64
The following page flags in book3s/64/pgtable.h can be dropped as
they are not used on this platform nor by common code.
_PAGE_NA, _PAGE_RO, _PAGE_USER and _PAGE_PSIZE
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Get rid of platform specific _PAGE_XXXX in powerpc common code and
use helpers instead.
mm/dump_linuxpagetables.c will be handled separately
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In order to avoid using generic _PAGE_XXX flags in powerpc
core functions, define helpers for all needed flags:
- pte_mkuser() and pte_mkprivileged() to set/unset and/or
unset/set _PAGE_USER and/or _PAGE_PRIVILEGED
- pte_hashpte() to check if _PAGE_HASHPTE is set.
- pte_ci() check if cache is inhibited (already existing on book3s/64)
- pte_exprotect() to protect against execution
- pte_exec() and pte_mkexec() to query and set page execution
- pte_mkpte() to set _PAGE_PTE flag.
- pte_hw_valid() to check _PAGE_PRESENT since pte_present does
something different on book3s/64.
On book3s/32 there is no exec protection, so pte_mkexec() and
pte_exprotect() are nops and pte_exec() returns always true.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In order to allow their use in nohash/32/pgtable.h, we have to move the
following helpers in nohash/[32:64]/pgtable.h:
- pte_mkwrite()
- pte_mkdirty()
- pte_mkyoung()
- pte_wrprotect()
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
book3s/32 doesn't define _PAGE_EXEC, so no need to use it.
All other platforms define _PAGE_EXEC so no need to check
it is not NUL when not book3s/32.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In order to avoid multiple conversions, handover directly a
pgprot_t to map_kernel_page() as already done for radix.
Do the same for __ioremap_caller() and __ioremap_at().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Set PAGE_KERNEL directly in the caller and do not rely on a
hack adding PAGE_KERNEL flags when _PAGE_PRESENT is not set.
As already done for PPC64, use pgprot_cache() helpers instead of
_PAGE_XXX flags in PPC32 ioremap() derived functions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Other arches have ioremap_wt() to map IO areas write-through.
Implement it on PPC as well in order to avoid drivers using
__ioremap(_PAGE_WRITETHRU)
Also implement ioremap_coherent() to avoid drivers using
__ioremap(_PAGE_COHERENT)
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On IBM POWER9, the device tree exposes a property array identifed by
"ibm,thread-groups" which will indicate which groups of threads share
a particular set of resources.
As of today we only have one form of grouping identifying the group of
threads in the core that share the L1 cache, translation cache and
instruction data flow.
This patch adds helper functions to parse the contents of
"ibm,thread-groups" and populate a per-cpu variable to cache
information about siblings of each CPU that share the L1, traslation
cache and instruction data-flow.
It also defines a new global variable named "has_big_cores" which
indicates if the cores on this configuration have multiple groups of
threads that share L1 cache.
For each online CPU, it maintains a cpu_smallcore_mask, which
indicates the online siblings which share the L1-cache with it.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The wait_state member of eeh_ops does not need to be platform
dependent; it's just logic around eeh_ops.get_state(). Therefore,
merge the two (slightly different!) platform versions into a new
function, eeh_wait_state() and remove the eeh_ops member.
While doing this, also correct:
* The wait logic, so that it never waits longer than max_wait.
* The wait logic, so that it never waits less than
EEH_STATE_MIN_WAIT_TIME.
* One call site where the result is treated like a bit field before
it's checked for negative error values.
* In pseries_eeh_get_state(), rename the "state" parameter to "delay"
because that's what it is.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently, eeh_pe_state_mark() marks a PE (and it's children) with a
state and then performs additional processing if that state included
EEH_PE_ISOLATED.
The state parameter is always a constant at the call site, so
rearrange eeh_pe_state_mark() into two functions and just call the
appropriate one at each site.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Instances of struct eeh_pe are placed in a tree structure using the
fields "child_list" and "child", so place these next to each other
in the definition.
The field "child" is a list entry, so remove the unnecessary and
misleading use of the list initializer, LIST_HEAD(), on it.
The eeh_dev struct contains two list entry fields, called "list" and
"rmv_list". Rename them to "entry" and "rmv_entry" and, as above, stop
initializing them with LIST_HEAD().
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The 'bus' member of struct eeh_dev is assigned to once but never used,
so remove it.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently a flag, EEH_POSTPONED_PROBE, is used to prevent an incorrect
message "EEH: No capable adapters found" from being displayed during
the boot of powernv systems.
It is necessary because, on powernv, the call to eeh_probe_devices()
made from eeh_init() is too early and EEH can't yet be enabled. A
second call is made later from eeh_pnv_post_init(), which succeeds.
(On pseries, the first call succeeds because PCI devices are set up
early enough and no second call is made.)
This can be simplified by moving the early call to eeh_probe_devices()
from eeh_init() (where it's seen by both platforms) to
pSeries_final_fixup(), so that each platform only calls
eeh_probe_devices() once, at a point where it can succeed.
This is slightly later in the boot sequence, but but still early
enough and it is now in the same place in the sequence for both
platforms (the pcibios_fixup hook).
The display of the message can be cleaned up as well, by moving it
into eeh_probe_devices().
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.
This function is not necessary, since MSR_TM_ACTIVE() just do the same and
could be used, removing the dualism and simplifying the code.
This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This is a patch that adds support for PTRACE_SYSEMU ptrace request in
PowerPC architecture.
When ptrace(PTRACE_SYSEMU, ...) request is called, it will be handled by
the arch independent function ptrace_resume(), which will tag the task with
the TIF_SYSCALL_EMU flag. This flag needs to be handled from a platform
dependent point of view, which is what this patch does.
This patch adds this task's flag as part of the _TIF_SYSCALL_DOTRACE, which
is the MACRO that is used to trace syscalls at entrance/exit.
Since TIF_SYSCALL_EMU is now part of _TIF_SYSCALL_DOTRACE, if the task has
_TIF_SYSCALL_DOTRACE set, it will hit do_syscall_trace_enter() at syscall
entrance and do_syscall_trace_leave() at syscall leave.
do_syscall_trace_enter() needs to handle the TIF_SYSCALL_EMU flag properly,
which will interrupt the syscall executing if TIF_SYSCALL_EMU is set. The
output values should not be changed, i.e. the return value (r3) should
contain the original syscall argument on exit.
With this flag set, the syscall is not executed fundamentally, because
do_syscall_trace_enter() is returning -1 which is bigger than NR_syscall,
thus, skipping the syscall execution and exiting userspace.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Moving TIF_32BIT to use bit 20 instead of 4 in the task flag field.
This change is making room for an upcoming new task macro
(_TIF_SYSCALL_EMU) which is preferred to set a bit in the lower 16-bits
part of the word.
This upcoming flag macro will take part in a composed macro
(_TIF_SYSCALL_DOTRACE) which will contain other flags as well, and it is
preferred that the whole _TIF_SYSCALL_DOTRACE macro only sets the lower 16
bits of a word, so, it could be handled using immediate operations (as load
immediate, add immediate, ...) where the immediate operand (SI) is limited
to 16-bits.
Another possible solution would be using the LOAD_REG_IMMEDIATE() macro
to load a full 64-bits word immediate, but it takes 5 operations instead of
one.
Having TIF_32BITS being redefined to use an upper bit is not a problem
since there is only one place in the assembly code where TIF_32BIT is being
used, and it could be replaced with an operation with right shift (addis),
since it is used alone, i.e. not being part of a composed macro, which has
different bits set, and would require LOAD_REG_IMMEDIATE().
Tested on a 64 bits Big Endian machine running a 32 bits task.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On PPC64, as register r13 points to the paca_struct at all time,
this patch adds a copy of the canary there, which is copied at
task_switch.
That new canary is then used by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r13
-mstack-protector-guard-offset=offsetof(struct paca_struct, canary))
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This functionality was tentatively added in the past
(commit 6533b7c16e ("powerpc: Initial stack protector
(-fstack-protector) support")) but had to be reverted
(commit f2574030b0 ("powerpc: Revert the initial stack
protector support") because of GCC implementing it differently
whether it had been built with libc support or not.
Now, GCC offers the possibility to manually set the
stack-protector mode (global or tls) regardless of libc support.
This time, the patch selects HAVE_STACKPROTECTOR only if
-mstack-protector-guard=tls is supported by GCC.
On PPC32, as register r2 points to current task_struct at
all time, the stack_canary located inside task_struct can be
used directly by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r2
-mstack-protector-guard-offset=offsetof(struct task_struct, stack_canary))
The protector is disabled for prom_init and bootx_init as
it is too early to handle it properly.
$ echo CORRUPT_STACK > /sys/kernel/debug/provoke-crash/DIRECT
[ 134.943666] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: lkdtm_CORRUPT_STACK+0x64/0x64
[ 134.943666]
[ 134.955414] CPU: 0 PID: 283 Comm: sh Not tainted 4.18.0-s3k-dev-12143-ga3272be41209 #835
[ 134.963380] Call Trace:
[ 134.965860] [c6615d60] [c001f76c] panic+0x118/0x260 (unreliable)
[ 134.971775] [c6615dc0] [c001f654] panic+0x0/0x260
[ 134.976435] [c6615dd0] [c032c368] lkdtm_CORRUPT_STACK_STRONG+0x0/0x64
[ 134.982769] [c6615e00] [ffffffff] 0xffffffff
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PPC32 uses nonrecoverable_exception() while PPC64 uses
unrecoverable_exception().
Both functions are doing almost the same thing.
This patch removes nonrecoverable_exception()
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We need to make sure pmd_trans_huge returns false for a pmd migration entry.
We mark the migration entry by clearing the _PAGE_PRESENT bit. We keep the
_PAGE_PTE bit set to indicate a leaf page table entry. Hence we need to make
sure we check for pmd_present() so that pmd_trans_huge won't return true on
pmd migration entry.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This make hugetlb directory pointer similar to other page able entries. A hugepd
entry is identified by lack of _PAGE_PTE bit set and directory size stored in
HUGEPD_SHIFT_MASK. We update that to also look at _PAGE_PRESENT
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
