And allow instrumentation inside it because it does calls to other
facilities which will not be tagged noinstr.
Fixes
vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-8-bp@alien8.de
Mark all the MCE severity computation logic noinstr and allow
instrumentation when it "calls out".
Fixes
vmlinux.o: warning: objtool: do_machine_check()+0xc5d: call to mce_severity() leaves .noinstr.text section
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-7-bp@alien8.de
Instead, sandwitch around the call which is done in noinstr context and
mark the caller - mce_gather_info() - as noinstr.
Also, document what the whole instrumentation strategy with #MC is going
to be in the future and where it all is supposed to be going to.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-5-bp@alien8.de
== Problem ==
The amount of SGX memory on a system is determined by the BIOS and it
varies wildly between systems. It can be as small as dozens of MB's
and as large as many GB's on servers. Just like how applications need
to know how much regular RAM is available, enclave builders need to
know how much SGX memory an enclave can consume.
== Solution ==
Introduce a new sysfs file:
/sys/devices/system/node/nodeX/x86/sgx_total_bytes
to enumerate the amount of SGX memory available in each NUMA node.
This serves the same function for SGX as /proc/meminfo or
/sys/devices/system/node/nodeX/meminfo does for normal RAM.
'sgx_total_bytes' is needed today to help drive the SGX selftests.
SGX-specific swap code is exercised by creating overcommitted enclaves
which are larger than the physical SGX memory on the system. They
currently use a CPUID-based approach which can diverge from the actual
amount of SGX memory available. 'sgx_total_bytes' ensures that the
selftests can work efficiently and do not attempt stupid things like
creating a 100,000 MB enclave on a system with 128 MB of SGX memory.
== Implementation Details ==
Introduce CONFIG_HAVE_ARCH_NODE_DEV_GROUP opt-in flag to expose an
arch specific attribute group, and add an attribute for the amount of
SGX memory in bytes to each NUMA node:
== ABI Design Discussion ==
As opposed to the per-node ABI, a single, global ABI was considered.
However, this would prevent enclaves from being able to size
themselves so that they fit on a single NUMA node. Essentially, a
single value would rule out NUMA optimizations for enclaves.
Create a new "x86/" directory inside each "nodeX/" sysfs directory.
'sgx_total_bytes' is expected to be the first of at least a few
sgx-specific files to be placed in the new directory. Just scanning
/proc/meminfo, these are the no-brainers that we have for RAM, but we
need for SGX:
MemTotal: xxxx kB // sgx_total_bytes (implemented here)
MemFree: yyyy kB // sgx_free_bytes
SwapTotal: zzzz kB // sgx_swapped_bytes
So, at *least* three. I think we will eventually end up needing
something more along the lines of a dozen. A new directory (as
opposed to being in the nodeX/ "root") directory avoids cluttering the
root with several "sgx_*" files.
Place the new file in a new "nodeX/x86/" directory because SGX is
highly x86-specific. It is very unlikely that any other architecture
(or even non-Intel x86 vendor) will ever implement SGX. Using "sgx/"
as opposed to "x86/" was also considered. But, there is a real chance
this can get used for other arch-specific purposes.
[ dhansen: rewrite changelog ]
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211116162116.93081-2-jarkko@kernel.org
Currently, text_poke_bp() is very strict to only allow patching a
single instruction; however with straight-line-speculation it will be
required to patch: ret; int3, which is two instructions.
As such, relax the constraints a little to allow int3 padding for all
instructions that do not imply the execution of the next instruction,
ie: RET, JMP.d8 and JMP.d32.
While there, rename the text_poke_loc::rel32 field to ::disp.
Note: this fills up the text_poke_loc structure which is now a round
16 bytes big.
[ bp: Put comments ontop instead of on the side. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134908.082342723@infradead.org
INS/OUTS are not supported in TDX guests and cause #UD. Kernel has to
avoid them when running in TDX guest. To support existing usage, string
I/O operations are unrolled using IN/OUT instructions.
AMD SEV platform implements this support by adding unroll
logic in ins#bwl()/outs#bwl() macros with SEV-specific checks.
Since TDX VM guests will also need similar support, use
CC_ATTR_GUEST_UNROLL_STRING_IO and generic cc_platform_has() API to
implement it.
String I/O helpers were the last users of sev_key_active() interface and
sev_enable_key static key. Remove them.
[ bp: Move comment too and do not delete it. ]
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211206135505.75045-2-kirill.shutemov@linux.intel.com
Theoretically, when the hardware signature in FACS changes, the OS
is supposed to gracefully decline to attempt to resume from S4:
"If the signature has changed, OSPM will not restore the system
context and can boot from scratch"
In practice, Windows doesn't do this and many laptop vendors do allow
the signature to change especially when docking/undocking, so it would
be a bad idea to simply comply with the specification by default in the
general case.
However, there are use cases where we do want the compliant behaviour
and we know it's safe. Specifically, when resuming virtual machines where
we know the hypervisor has changed sufficiently that resume will fail.
We really want to be able to *tell* the guest kernel not to try, so it
boots cleanly and doesn't just crash. This patch provides a way to opt
in to the spec-compliant behaviour on the command line.
A follow-up patch may do this automatically for certain "known good"
machines based on a DMI match, or perhaps just for all hypervisor
guests since there's no good reason a hypervisor would change the
hardware_signature that it exposes to guests *unless* it wants them
to obey the ACPI specification.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Replace all ret/retq instructions with RET in preparation of making
RET a macro. Since AS is case insensitive it's a big no-op without
RET defined.
find arch/x86/ -name \*.S | while read file
do
sed -i 's/\<ret[q]*\>/RET/' $file
done
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134907.905503893@infradead.org
MCA handlers check the valid bit in each status register
(MCA_STATUS[Val]) and continue processing the error only if the valid
bit is set.
Set the valid bit unconditionally in the corresponding MCA_STATUS
register and correct any Val=0 injections made by the user as such
errors will get ignored and such injections will be largely pointless.
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211104215846.254012-3-Smita.KoralahalliChannabasappa@amd.com
The MCA_IPID register uniquely identifies a bank's type on Scalable MCA
(SMCA) systems. When an MCA bank is not populated, the MCA_IPID register
will read as zero and writes to it will be ignored.
On a hw-type error injection (injection which writes the actual MCA
registers in an attempt to cause a real MCE) check the value of this
register before trying to inject the error.
Do not impose any limitations on a sw injection and allow the user to
test out all the decoding paths without relying on the available hardware,
as its purpose is to just test the code.
[ bp: Heavily massage. ]
Link: https://lkml.kernel.org/r/20211019233641.140275-2-Smita.KoralahalliChannabasappa@amd.com
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211104215846.254012-2-Smita.KoralahalliChannabasappa@amd.com
Move the switching code into a function so that it can be re-used and
add a global TLB flush. This makes sure that usage of memory which is
not mapped in the trampoline page-table is reliably caught.
Also move the clearing of CR4.PCIDE before the CR3 switch because the
cr4_clear_bits() function will access data not mapped into the
trampoline page-table.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211202153226.22946-4-joro@8bytes.org
The AP bringup code uses the trampoline_pgd page-table which
establishes global mappings in the user range of the address space.
Flush the global TLB entries after the indentity mappings are removed so
no stale entries remain in the TLB.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211202153226.22946-3-joro@8bytes.org
Properly type the operands being passed to __put_user()/__get_user().
Otherwise, these routines truncate data for dependent instructions
(e.g., INSW) and only read/write one byte.
This has been tested by sending a string with REP OUTSW to a port and
then reading it back in with REP INSW on the same port.
Previous behavior was to only send and receive the first char of the
size. For example, word operations for "abcd" would only read/write
"ac". With change, the full string is now written and read back.
Fixes: f980f9c31a (x86/sev-es: Compile early handler code into kernel image)
Signed-off-by: Michael Sterritt <sterritt@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Peter Gonda <pgonda@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20211119232757.176201-1-sterritt@google.com
There are cases that the TSC clocksource is wrongly judged as unstable by
the clocksource watchdog mechanism which tries to validate the TSC against
HPET, PM_TIMER or jiffies. While there is hardly a general reliable way to
check the validity of a watchdog, Thomas Gleixner proposed [1]:
"I'm inclined to lift that requirement when the CPU has:
1) X86_FEATURE_CONSTANT_TSC
2) X86_FEATURE_NONSTOP_TSC
3) X86_FEATURE_NONSTOP_TSC_S3
4) X86_FEATURE_TSC_ADJUST
5) At max. 4 sockets
After two decades of horrors we're finally at a point where TSC seems
to be halfway reliable and less abused by BIOS tinkerers. TSC_ADJUST
was really key as we can now detect even small modifications reliably
and the important point is that we can cure them as well (not pretty
but better than all other options)."
As feature #3 X86_FEATURE_NONSTOP_TSC_S3 only exists on several generations
of Atom processorz, and is always coupled with X86_FEATURE_CONSTANT_TSC
and X86_FEATURE_NONSTOP_TSC, skip checking it, and also be more defensive
to use maximal 2 sockets.
The check is done inside tsc_init() before registering 'tsc-early' and
'tsc' clocksources, as there were cases that both of them had been
wrongly judged as unreliable.
For more background of tsc/watchdog, there is a good summary in [2]
[tglx} Update vs. jiffies:
On systems where the only remaining clocksource aside of TSC is jiffies
there is no way to make this work because that creates a circular
dependency. Jiffies accuracy depends on not missing a periodic timer
interrupt, which is not guaranteed. That could be detected by TSC, but as
TSC is not trusted this cannot be compensated. The consequence is a
circulus vitiosus which results in shutting down TSC and falling back to
the jiffies clocksource which is even more unreliable.
[1]. https://lore.kernel.org/lkml/87eekfk8bd.fsf@nanos.tec.linutronix.de/
[2]. https://lore.kernel.org/lkml/87a6pimt1f.ffs@nanos.tec.linutronix.de/
[ tglx: Refine comment and amend changelog ]
Fixes: 6e3cd95234 ("x86/hpet: Use another crystalball to evaluate HPET usability")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211117023751.24190-2-feng.tang@intel.com
Some thread flags can be set remotely, and so even when IRQs are disabled,
the flags can change under our feet. Generally this is unlikely to cause a
problem in practice, but it is somewhat unsound, and KCSAN will
legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20211129130653.2037928-12-mark.rutland@arm.com
Fix:
WARNING: modpost: vmlinux.o(.text.unlikely+0x64d0): Section mismatch in reference \
from the function prepare_command_line() to the variable .init.data:command_line
The function prepare_command_line() references
the variable __initdata command_line.
This is often because prepare_command_line lacks a __initdata
annotation or the annotation of command_line is wrong.
Apparently some toolchains do different inlining decisions.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YZySgpmBcNNM2qca@zn.tnic
Pull x86 fixes from Thomas Gleixner:
- Move the command line preparation and the early command line parsing
earlier so that the command line parameters which affect
early_reserve_memory(), e.g. efi=nosftreserve, are taken into
account. This was broken when the invocation of
early_reserve_memory() was moved recently.
- Use an atomic type for the SGX page accounting, which is read and
written locklessly, to plug various race conditions related to it.
* tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Fix free page accounting
x86/boot: Pull up cmdline preparation and early param parsing
Pull exit-vs-signal handling fixes from Eric Biederman:
"This is a small set of changes where debuggers were no longer able to
intercept synchronous SIGTRAP and SIGSEGV, introduced by the exit
cleanups.
This is essentially the change you suggested with all of i's dotted
and the t's crossed so that ptrace can intercept all of the cases it
has been able to intercept the past, and all of the cases that made it
to exit without giving ptrace a chance still don't give ptrace a
chance"
* 'SA_IMMUTABLE-fixes-for-v5.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
signal: Replace force_fatal_sig with force_exit_sig when in doubt
signal: Don't always set SA_IMMUTABLE for forced signals
Recently to prevent issues with SECCOMP_RET_KILL and similar signals
being changed before they are delivered SA_IMMUTABLE was added.
Unfortunately this broke debuggers[1][2] which reasonably expect
to be able to trap synchronous SIGTRAP and SIGSEGV even when
the target process is not configured to handle those signals.
Add force_exit_sig and use it instead of force_fatal_sig where
historically the code has directly called do_exit. This has the
implementation benefits of going through the signal exit path
(including generating core dumps) without the danger of allowing
userspace to ignore or change these signals.
This avoids userspace regressions as older kernels exited with do_exit
which debuggers also can not intercept.
In the future is should be possible to improve the quality of
implementation of the kernel by changing some of these force_exit_sig
calls to force_fatal_sig. That can be done where it matters on
a case-by-case basis with careful analysis.
Reported-by: Kyle Huey <me@kylehuey.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
[1] https://lkml.kernel.org/r/CAP045AoMY4xf8aC_4QU_-j7obuEPYgTcnQQP3Yxk=2X90jtpjw@mail.gmail.com
[2] https://lkml.kernel.org/r/20211117150258.GB5403@xsang-OptiPlex-9020
Fixes: 00b06da29c ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed")
Fixes: a3616a3c02 ("signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die")
Fixes: 83a1f27ad7 ("signal/powerpc: On swapcontext failure force SIGSEGV")
Fixes: 9bc508cf07 ("signal/s390: Use force_sigsegv in default_trap_handler")
Fixes: 086ec444f8 ("signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig")
Fixes: c317d306d5 ("signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails")
Fixes: 695dd0d634 ("signal/x86: In emulate_vsyscall force a signal instead of calling do_exit")
Fixes: 1fbd60df8a ("signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.")
Fixes: 941edc5bf1 ("exit/syscall_user_dispatch: Send ordinary signals on failure")
Link: https://lkml.kernel.org/r/871r3dqfv8.fsf_-_@email.froward.int.ebiederm.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The SGX driver maintains a single global free page counter,
sgx_nr_free_pages, that reflects the number of free pages available
across all NUMA nodes. Correspondingly, a list of free pages is
associated with each NUMA node and sgx_nr_free_pages is updated
every time a page is added or removed from any of the free page
lists. The main usage of sgx_nr_free_pages is by the reclaimer
that runs when it (sgx_nr_free_pages) goes below a watermark
to ensure that there are always some free pages available to, for
example, support efficient page faults.
With sgx_nr_free_pages accessed and modified from a few places
it is essential to ensure that these accesses are done safely but
this is not the case. sgx_nr_free_pages is read without any
protection and updated with inconsistent protection by any one
of the spin locks associated with the individual NUMA nodes.
For example:
CPU_A CPU_B
----- -----
spin_lock(&nodeA->lock); spin_lock(&nodeB->lock);
... ...
sgx_nr_free_pages--; /* NOT SAFE */ sgx_nr_free_pages--;
spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock);
Since sgx_nr_free_pages may be protected by different spin locks
while being modified from different CPUs, the following scenario
is possible:
CPU_A CPU_B
----- -----
{sgx_nr_free_pages = 100}
spin_lock(&nodeA->lock); spin_lock(&nodeB->lock);
sgx_nr_free_pages--; sgx_nr_free_pages--;
/* LOAD sgx_nr_free_pages = 100 */ /* LOAD sgx_nr_free_pages = 100 */
/* sgx_nr_free_pages-- */ /* sgx_nr_free_pages-- */
/* STORE sgx_nr_free_pages = 99 */ /* STORE sgx_nr_free_pages = 99 */
spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock);
In the above scenario, sgx_nr_free_pages is decremented from two CPUs
but instead of sgx_nr_free_pages ending with a value that is two less
than it started with, it was only decremented by one while the number
of free pages were actually reduced by two. The consequence of
sgx_nr_free_pages not being protected is that its value may not
accurately reflect the actual number of free pages on the system,
impacting the availability of free pages in support of many flows.
The problematic scenario is when the reclaimer does not run because it
believes there to be sufficient free pages while any attempt to allocate
a page fails because there are no free pages available. In the SGX driver
the reclaimer's watermark is only 32 pages so after encountering the
above example scenario 32 times a user space hang is possible when there
are no more free pages because of repeated page faults caused by no
free pages made available.
The following flow was encountered:
asm_exc_page_fault
...
sgx_vma_fault()
sgx_encl_load_page()
sgx_encl_eldu() // Encrypted page needs to be loaded from backing
// storage into newly allocated SGX memory page
sgx_alloc_epc_page() // Allocate a page of SGX memory
__sgx_alloc_epc_page() // Fails, no free SGX memory
...
if (sgx_should_reclaim(SGX_NR_LOW_PAGES)) // Wake reclaimer
wake_up(&ksgxd_waitq);
return -EBUSY; // Return -EBUSY giving reclaimer time to run
return -EBUSY;
return -EBUSY;
return VM_FAULT_NOPAGE;
The reclaimer is triggered in above flow with the following code:
static bool sgx_should_reclaim(unsigned long watermark)
{
return sgx_nr_free_pages < watermark &&
!list_empty(&sgx_active_page_list);
}
In the problematic scenario there were no free pages available yet the
value of sgx_nr_free_pages was above the watermark. The allocation of
SGX memory thus always failed because of a lack of free pages while no
free pages were made available because the reclaimer is never started
because of sgx_nr_free_pages' incorrect value. The consequence was that
user space kept encountering VM_FAULT_NOPAGE that caused the same
address to be accessed repeatedly with the same result.
Change the global free page counter to an atomic type that
ensures simultaneous updates are done safely. While doing so, move
the updating of the variable outside of the spin lock critical
section to which it does not belong.
Cc: stable@vger.kernel.org
Fixes: 901ddbb9ec ("x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()")
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/a95a40743bbd3f795b465f30922dde7f1ea9e0eb.1637004094.git.reinette.chatre@intel.com
Add a separate, local mask for tracking AVX512 usage which does not
include the opmask xfeature set. Opmask registers usage does not cause
frequency throttling so it is a completely unnecessary false positive.
While at it, carve it out into a separate function to keep that
abomination extracted out.
[ bp: Rediff and cleanup ontop of 5.16-rc1. ]
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20210920053951.4093668-1-goldstein.w.n@gmail.com
Provide a recovery function sgx_memory_failure(). If the poison was
consumed synchronously then send a SIGBUS. Note that the virtual
address of the access is not included with the SIGBUS as is the case
for poison outside of SGX enclaves. This doesn't matter as addresses
of code/data inside an enclave is of little to no use to code executing
outside the (now dead) enclave.
Poison found in a free page results in the page being moved from the
free list to the per-node poison page list.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-5-tony.luck@intel.com
A memory controller patrol scrubber can report poison in a page
that isn't currently being used.
Add "poison" field in the sgx_epc_page that can be set for an
sgx_epc_page. Check for it:
1) When sanitizing dirty pages
2) When freeing epc pages
Poison is a new field separated from flags to avoid having to make all
updates to flags atomic, or integrate poison state changes into some
other locking scheme to protect flags (Currently just sgx_reclaimer_lock
which protects the SGX_EPC_PAGE_RECLAIMER_TRACKED bit in page->flags).
In both cases place the poisoned page on a per-node list of poisoned
epc pages to make sure it will not be reallocated.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-4-tony.luck@intel.com
X86 machine check architecture reports a physical address when there
is a memory error. Handling that error requires a method to determine
whether the physical address reported is in any of the areas reserved
for EPC pages by BIOS.
SGX EPC pages do not have Linux "struct page" associated with them.
Keep track of the mapping from ranges of EPC pages to the sections
that contain them using an xarray. N.B. adds CONFIG_XARRAY_MULTI to
the SGX dependecies. So "select" that in arch/x86/Kconfig for X86/SGX.
Create a function arch_is_platform_page() that simply reports whether an
address is an EPC page for use elsewhere in the kernel. The ACPI error
injection code needs this function and is typically built as a module,
so export it.
Note that arch_is_platform_page() will be slower than other similar
"what type is this page" functions that can simply check bits in the
"struct page". If there is some future performance critical user of
this function it may need to be implemented in a more efficient way.
Note also that the current implementation of xarray allocates a few
hundred kilobytes for this usage on a system with 4GB of SGX EPC memory
configured. This isn't ideal, but worth it for the code simplicity.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-3-tony.luck@intel.com
