Operations which write to memory and special purpose registers should be
restricted on systems with integrity guarantees (such as Secure Boot)
and, optionally, to avoid self-destructive behaviors.
Add a config option, XMON_DEFAULT_RO_MODE, to set default xmon behavior.
The kernel cmdline options xmon=ro and xmon=rw override this default.
The following xmon operations are affected:
memops:
disable memmove
disable memset
disable memzcan
memex:
no-op'd mwrite
super_regs:
no-op'd write_spr
bpt_cmds:
disable
proc_call:
disable
Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
[mpe: Rebase since CURRENT_THREAD_INFO() removal]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
crypto node alias is needed by U-boot to identify the node and
perform fix-ups, like adding "fsl,sec-era" property.
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PROM_SCRATCH_SIZE is same as sizeof(prom_scratch)
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This can be helpful for debugging problems with the security feature
flags, especially on guests where the flags come from the hypervisor
via an hcall and so can't be observed in the device tree.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Implement code to walk all pages and warn if any are found to be both
writable and executable. Depends on STRICT_KERNEL_RWX enabled, and is
behind the DEBUG_WX config option.
This only runs on boot and has no runtime performance implications.
Very heavily influenced (and in some cases copied verbatim) from the
ARM64 code written by Laura Abbott (thanks!), since our ptdump
infrastructure is similar.
Signed-off-by: Russell Currey <ruscur@russell.cc>
[mpe: Fixup build error when disabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Lovingly borrowed from the arch/arm64 ptdump code.
This doesn't seem to be an issue in practice, but is necessary for my
upcoming commit.
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This export was added in this merge window, but without any actual
user, or justification for a modular user.
Fixes: a35a3c6f60 ("powerpc/mm/hash64: Add a variable to track the end of IO mapping")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use my @linux.ibm.com email to avoid a layer of redirection.
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
"Reconciling" in terms of interrupt handling, is to bring the soft irq
mask state in to synch with the hardware, after an interrupt causes
MSR[EE] to be cleared (while the soft mask may be enabled, and hard
irqs not marked disabled).
General kernel code should not be called while unreconciled, because
local_irq_disable, etc. manipulations can cause surprising irq traces,
and it's fragile because the soft irq code does not really expect to
be called in this situation.
When exiting from an interrupt, MSR[EE] is cleared to prevent races,
but soft irq state is enabled for the returned-to context, so this is
now an unreconciled state. restore_math is called in this state, and
that can be ftraced, and the ftrace subsystem disables local irqs.
Mark restore_math and its callees as notrace. Restore a sanity check
in the soft irq code that had to be disabled for this case, by commit
4da1f79227 ("powerpc/64: Disable irq restore warning for now").
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch drops__irq_offset_value which has not been used since
commit 9c4cb82515 ("powerpc: Remove use of CONFIG_PPC_MERGE")
This removes a sparse warning.
Fixes: 9c4cb82515 ("powerpc: Remove use of CONFIG_PPC_MERGE")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Compared to ifdefs, IS_ENABLED() provide a cleaner code and allows
to detect compilation failure regardless of the selected options.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use cpu_has_feature() instead of opencoding
Use IS_ENABLED() instead of #ifdef for CONFIG_TAU_AVERAGE
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
CPU_FTR_ALTIVEC is only set when CONFIG_ALTIVEC is selected, so
the ifdef is unnecessary.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
To avoid ifdefs, define a empty static inline mm_iommu_init() function
when CONFIG_SPAPR_TCE_IOMMU is not selected.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
To avoid #ifdefs, define an static inline fadump_cleanup() function
when CONFIG_FADUMP is not selected
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
No need to add dummy frames when calling trace_hardirqs_on or
trace_hardirqs_off. GCC properly handles empty stacks.
In addition, powerpc doesn't set CONFIG_FRAME_POINTER, therefore
__builtin_return_address(1..) returns NULL at all time. So the
dummy frames are definitely unneeded here.
In the meantime, avoid reading memory for loading r1 with a value
we already know.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
As syscalls are now handled via a fast entry path, syscall related
actions can be removed from the generic transfer_to_handler path.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch implements a fast entry for syscalls.
Syscalls don't have to preserve non volatile registers except LR.
This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.
As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off
It also assumes that the call is always from user, system calls are
unexpected from kernel.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch implements a fast entry for syscalls.
Syscalls don't have to preserve non volatile registers except LR.
This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.
As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off
It also assumes that the call is always from user, system calls are
unexpected from kernel.
The overall series improves null_syscall selftest by 12,5% on an 83xx
and by 17% on a 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[text mostly copied from benh's RFC/WIP]
ppc32 are still doing something rather gothic and wrong on 32-bit
which we stopped doing on 64-bit a while ago.
We have that thing where some handlers "copy" the EE value from the
original stack frame into the new MSR before transferring to the
handler.
Thus for a number of exceptions, we enter the handlers with interrupts
enabled.
This is rather fishy, some of the stuff that handlers might do early
on such as irq_enter/exit or user_exit, context tracking, etc...
should be run with interrupts off afaik.
Generally our handlers know when to re-enable interrupts if needed.
The problem we were having is that we assumed these interrupts would
return with interrupts enabled. However that isn't the case.
Instead, this patch changes things so that we always enter exception
handlers with interrupts *off* with the notable exception of syscalls
which are special (and get a fast path).
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
EXC_XFER_TEMPLATE() is not called with COPY_EE anymore so
we can get rid of copyee parameters and related COPY_EE and NOCOPY
macros.
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
All exceptions handlers know when to reenable interrupts, so
it is safer to enter all of them with MSR_EE unset, except
for syscalls.
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
syscalls are expected to be entered with MSR_EE set. Lets
make it inconditional by forcing MSR_EE on syscalls.
This patch adds EXC_XFER_SYS for that.
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
SPEFloatingPointException() is the only exception handler which 'forgets' to
re-enable interrupts. This patch makes sure it does.
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Refactor exception entry macros by using the ones defined in head_32.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch splits NORMAL_EXCEPTION_PROLOG in the same way as in
head_8xx.S and head_32.S and renames it EXCEPTION_PROLOG() as well
to match head_32.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Unlike said in the comment, r1 is not reused by the critical
exception handler, as it uses a dedicated critirq_ctx stack.
Decrementing r1 early is then unneeded.
Should the above be valid, the code is crap buggy anyway as
r1 gets some intermediate values that would jeopardise the
whole process (for instance after mfspr r1,SPRN_SPRG_THREAD)
Using SPRN_SPRG_SCRATCH2 to save r1 is then not needed, r11 can be
used instead. This avoids one mtspr and one mfspr and makes the
prolog closer to what's done on 6xx and 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
6xx/8xx EXC_XFER_TEMPLATE() macro adds a i##n symbol which is
unused and can be removed.
40x and booke EXC_XFER_TEMPLATE() macros takes msr from the caller
while the 6xx/8xx version uses only MSR_KERNEL as msr value.
This patch modifies the 6xx/8xx version to make it similar to the
40x and booke versions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
As preparation for using head_32.h for head_40x.S, move
LOAD_MSR_KERNEL() there and use it to load r10 with MSR_KERNEL value.
In the mean time, this patch modifies it so that it takes into account
the size of the passed value to determine if 'li' can be used or if
'lis/ori' is needed instead of using the size of MSR_KERNEL. This is
done by using gas macro.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
EXCEPTION_PROLOG is similar in head_8xx.S and head_32.S
This patch creates head_32.h and moves EXCEPTION_PROLOG macro
into it. It also converts it from a GCC macro to a GAS macro
in order to ease refactorisation with 40x later, since
GAS macros allows the use of #ifdef/#else/#endif inside it.
And it also has the advantage of not requiring the uggly "; \"
at the end of each line.
This patch also moves EXCEPTION() and EXC_XFER_XXXX() macros which
are also similar while adding START_EXCEPTION() out of EXCEPTION().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reduce #ifdef mess by defining a helper to print
hash info at startup.
In the meantime, remove the display of hash table address
to reduce leak of non necessary information.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Due to %p, (ptrval) is printed in lieu of the hash table address.
showing the hash table address isn't an operationnal need so just
don't print it.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For hash32, the zero shadow page gets mapped with PAGE_READONLY instead
of PAGE_KERNEL_RO, because the PP bits don't provide a RO kernel, so
PAGE_KERNEL_RO is equivalent to PAGE_KERNEL. By using PAGE_READONLY,
the page is RO for both kernel and user, but this is not a security issue
as it contains only zeroes.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
KASAN requires early activation of hash table, before memblock()
functions are available.
This patch implements an early hash_table statically defined in
__initdata.
During early boot, a single page table is used.
For hash32, when doing the final init, one page table is allocated
for each PGD entry because of the _PAGE_HASHPTE flag which can't be
common to several virt pages. This is done after memblock get
available but before switching to the final hash table, otherwise
there are issues with TLB flushing due to the shared entries.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For KASAN, hash table handling will be activated early for
accessing to KASAN shadow areas.
In order to avoid any modification of the hash functions while
they are still used with the early hash table, the code patching
is moved out of MMU_init_hw() and put close to the big-bang switch
to the final hash table.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch adds KASAN support for PPC32. The following patch
will add an early activation of hash table for book3s. Until
then, a warning will be raised if trying to use KASAN on an
hash 6xx.
To support KASAN, this patch initialises that MMU mapings for
accessing to the KASAN shadow area defined in a previous patch.
An early mapping is set as soon as the kernel code has been
relocated at its definitive place.
Then the definitive mapping is set once paging is initialised.
For modules, the shadow area is allocated at module_alloc().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
All files containing functions run before kasan_early_init() is called
must have KASAN instrumentation disabled.
For those file, branch profiling also have to be disabled otherwise
each if () generates a call to ftrace_likely_update().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch prepares a shadow area for KASAN.
The shadow area will be at the top of the kernel virtual
memory space above the fixmap area and will occupy one
eighth of the total kernel virtual memory space.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When we add KASAN shadow area, KVIRT_TOP can't be anymore fixed
at 0xfe000000.
This patch uses FIXADDR_START to define KVIRT_TOP.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since commit 400c47d81c ("powerpc32: memset: only use dcbz once cache is
enabled"), memset() can be used before activation of the cache,
so no need to use memset_io() for zeroing the BSS.
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In kernel/cputable.c, explicitly use memcpy() instead of *y = *x;
This will allow GCC to replace it with __memcpy() when KASAN is
selected.
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When KASAN is active, the string functions in lib/ are doing the
KASAN checks. This is too early for prom_init.
This patch implements dedicated string functions for prom_init,
which will be compiled in with KASAN disabled.
Size of prom_init before the patch:
text data bss dec hex filename
12060 488 6960 19508 4c34 arch/powerpc/kernel/prom_init.o
Size of prom_init after the patch:
text data bss dec hex filename
12460 488 6960 19908 4dc4 arch/powerpc/kernel/prom_init.o
This increases the size of prom_init a bit, but as prom_init is
in __init section, it is freed after boot anyway.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch makes CONFIG_CMDLINE defined at all time. It avoids
having to enclose related code inside #ifdef CONFIG_CMDLINE
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
CONFIG_KASAN implements wrappers for memcpy() memmove() and memset()
Those wrappers are doing the verification then call respectively
__memcpy() __memmove() and __memset(). The arches are therefore
expected to rename their optimised functions that way.
For files on which KASAN is inhibited, #defines are used to allow
them to directly call optimised versions of the functions without
going through the KASAN wrappers.
See commit 393f203f5f ("x86_64: kasan: add interceptors for
memset/memmove/memcpy functions") for details.
Other string / mem functions do not (yet) have kasan wrappers,
we therefore have to fallback to the generic versions when
KASAN is active, otherwise KASAN checks will be skipped.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fixups to keep selftests working]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In preparation of KASAN, move early_init() into a separate
file in order to allow deactivation of KASAN for that function.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Christopher M. Riedl