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Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Update the DO_ERROR macro to take si_code and si_addr values for a siginfo,
removing the need for the fill_trap_info function.
Update do_trap to also take the sicode and si_addr values for a sigininfo
and modify the code to call force_sig when a sicode is not passed in
and to call force_sig_fault when all of the information is present.
Making this a more obvious, simpler and less error prone construction.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The function "force_sig(sig, tsk)" is equivalent to "
force_sig_info(sig, SEND_SIG_PRIV, tsk)". Using the siginfo variants can
be error prone so use the simpler old fashioned force_sig variant,
and with luck the force_sig_info variant can go away.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Instead of generating the siginfo in x86 specific code use the new
helper function force_sig_bnderr to separate the concerns of
collecting the information and generating a proper siginfo.
Making the code easier to understand and maintain.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The function do_trap_no_signal embodies almost all of the work of the
function do_trap. The exceptions are setting of thread.error_code and
thread.trap_nr in the case when the signal will be sent, and reporting
which signal will be sent with show_signal.
Filling in struct siginfo and then calling do_trap is problematic as
filling in struct siginfo is an fiddly process that can through
inattention has resulted in fields not initialized and the wrong
fields being filled in.
To avoid this error prone situation I am replacing force_sig_info with
a set of functions that take as arguments the information needed to
send a specific kind of signal.
The function do_trap is called in the context of several different
kinds of signals today. Having a solid do_trap_no_signal that
can be reused allows call sites that send different kinds of
signals to reuse all of the code in do_trap_no_signal.
Modify do_trap_no_signal to have a single exit there signals
where be sent (aka returning -1) to allow more of the signal
sending path to be moved to from do_trap to do_trap_no_signal.
Move setting thread.trap_nr and thread.error_code into do_trap_no_signal
so the code does not need to be duplicated.
Make the type of the string that is passed into do_trap_no_signal to
const. The only user of that str is die and it already takes a const
string, so this just makes it explicit that the string won't change.
All of this prepares the way for using do_trap_no_signal outside
of do_trap.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Clear the MCE struct which is used for collecting the injection details
after injection.
Also, populate it with more details from the machine.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20180905081954.10391-1-bp@alien8.de
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We met a kernel panic when enabling earlycon, which is due to the fixmap
address of earlycon is not statically setup.
Currently the static fixmap setup in head_64.S only covers 2M virtual
address space, while it actually could be in 4M space with different
kernel configurations, e.g. when VSYSCALL emulation is disabled.
So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2,
and add a build time check to ensure that the fixmap is covered by the
initial static page tables.
Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com> (Xen parts)
Cc: H Peter Anvin <hpa@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com
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All the cache maintainance is already stubbed out when not enabled,
but merging the two allows us to nicely handle the case where
cache maintainance is required for some devices, but not others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
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The code for conditionally printing unhanded signals is duplicated twice
in arch/x86/kernel/traps.c. Factor it out into it's own subroutine
called show_signal to make the code clearer and easier to maintain.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This separates the logic of generating the signal from the logic of
gathering the information about the bounds violation.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The function fill_sigtrap_info now only has one caller so remove
it and put it's contents in it's caller.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Replace user_single_step_siginfo with user_single_step_report
that allocates siginfo structure on the stack and sends it.
This allows tracehook_report_syscall_exit to become a simple
if statement that calls user_single_step_report or ptrace_report_syscall
depending on the value of step.
Update the default helper function now called user_single_step_report
to explicitly set si_code to SI_USER and to set si_uid and si_pid to 0.
The default helper has always been doing this (using memset) but it
was far from obvious.
The powerpc helper can now just call force_sig_fault.
The x86 helper can now just call send_sigtrap.
Unfortunately the default implementation of user_single_step_report
can not use force_sig_fault as it does not use a SIGTRAP si_code.
So it has to carefully setup the siginfo and use use force_sig_info.
The net result is code that is easier to understand and simpler
to maintain.
Ref: 85ec7fd9f8e5 ("ptrace: introduce user_single_step_siginfo() helper")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The first argument to WARN_ONCE() is a condition.
Fixes: 5800dc5c19f3 ("x86/paravirt: Fix spectre-v2 mitigations for paravirt guests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: virtualization@lists.linux-foundation.org
Cc: kernel-janitors@vger.kernel.org
Link: https://lkml.kernel.org/r/20180919103553.GD9238@mwanda
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In order to determine a sane default cache allocation for a new CAT/CDP
resource group, all resource groups are checked to determine which cache
portions are available to share. At this time all possible CLOSIDs
that can be supported by the resource is checked. This is problematic
if the resource supports more CLOSIDs than another CAT/CDP resource. In
this case, the number of CLOSIDs that could be allocated are fewer than
the number of CLOSIDs that can be supported by the resource.
Limit the check of closids to that what is supported by the system based
on the minimum across all resources.
Fixes: 95f0b77ef ("x86/intel_rdt: Initialize new resource group with sane defaults")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-10-git-send-email-fenghua.yu@intel.com
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It is possible for a resource group to consist out of MBA as well as
CAT/CDP resources. The "exclusive" resource mode only applies to the
CAT/CDP resources since MBA allocations cannot be specified to overlap
or not. When a user requests a resource group to become "exclusive" then it
can only be successful if there are CAT/CDP resources in the group
and none of their CBMs associated with the group's CLOSID overlaps with
any other resource group.
Fix the "exclusive" mode setting by failing if there isn't any CAT/CDP
resource in the group and ensuring that the CBM checking is only done on
CAT/CDP resources.
Fixes: 49f7b4efa ("x86/intel_rdt: Enable setting of exclusive mode")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-9-git-send-email-fenghua.yu@intel.com
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A loop is used to check if a CAT resource's CBM of one CLOSID
overlaps with the CBM of another CLOSID of the same resource. The loop
is run over all CLOSIDs supported by the resource.
The problem with running the loop over all CLOSIDs supported by the
resource is that its number of supported CLOSIDs may be more than the
number of supported CLOSIDs on the system, which is the minimum number of
CLOSIDs supported across all resources.
Fix the loop to only consider the number of system supported CLOSIDs,
not all that are supported by the resource.
Fixes: 49f7b4efa ("x86/intel_rdt: Enable setting of exclusive mode")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-8-git-send-email-fenghua.yu@intel.com
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A system supporting pseudo-locking may have MBA as well as CAT
resources of which only the CAT resources could support cache
pseudo-locking. When the schemata to be pseudo-locked is provided it
should be checked that that schemata does not attempt to pseudo-lock a
MBA resource.
Fixes: e0bdfe8e3 ("x86/intel_rdt: Support creation/removal of pseudo-locked region")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-7-git-send-email-fenghua.yu@intel.com
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When a new resource group is created, it is initialized with sane
defaults that currently assume the resource being initialized is a CAT
resource. This code path is also followed by a MBA resource that is not
allocated the same as a CAT resource and as a result we encounter the
following unchecked MSR access error:
unchecked MSR access error: WRMSR to 0xd51 (tried to write 0x0000
000000000064) at rIP: 0xffffffffae059994 (native_write_msr+0x4/0x20)
Call Trace:
mba_wrmsr+0x41/0x80
update_domains+0x125/0x130
rdtgroup_mkdir+0x270/0x500
Fix the above by ensuring the initial allocation is only attempted on a
CAT resource.
Fixes: 95f0b77ef ("x86/intel_rdt: Initialize new resource group with sane defaults")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-6-git-send-email-fenghua.yu@intel.com
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When multiple resources are managed by RDT, the number of CLOSIDs used
is the minimum of the CLOSIDs supported by each resource. In the function
rdt_bit_usage_show(), the annotated bitmask is created to depict how the
CAT supporting caches are being used. During this annotated bitmask
creation, each resource group is queried for its mode that is used as a
label in the annotated bitmask.
The maximum number of resource groups is currently assumed to be the
number of CLOSIDs supported by the resource for which the information is
being displayed. This is incorrect since the number of active CLOSIDs is
the minimum across all resources.
If information for a cache instance with more CLOSIDs than another is
being generated we thus encounter a warning like:
invalid mode for closid 8
WARNING: CPU: 88 PID: 1791 at [SNIP]/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
:827 rdt_bit_usage_show+0x221/0x2b0
Fix this by ensuring that only the number of supported CLOSIDs are
considered.
Fixes: e651901187ab8 ("x86/intel_rdt: Introduce "bit_usage" to display cache allocations details")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-5-git-send-email-fenghua.yu@intel.com
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The number of CLOSIDs supported by a system is the minimum number of
CLOSIDs supported by any of its resources. Care should be taken when
iterating over the CLOSIDs of a resource since it may be that the number
of CLOSIDs supported on the system is less than the number of CLOSIDs
supported by the resource.
Introduce a helper function that can be used to query the number of
CLOSIDs that is supported by all resources, irrespective of how many
CLOSIDs are supported by a particular resource.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-4-git-send-email-fenghua.yu@intel.com
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Chen Yu reported a divide-by-zero error when accessing the 'size'
resctrl file when a MBA resource is enabled.
divide error: 0000 [#1] SMP PTI
CPU: 93 PID: 1929 Comm: cat Not tainted 4.19.0-rc2-debug-rdt+ #25
RIP: 0010:rdtgroup_cbm_to_size+0x7e/0xa0
Call Trace:
rdtgroup_size_show+0x11a/0x1d0
seq_read+0xd8/0x3b0
Quoting Chen Yu's report: This is because for MB resource, the
r->cache.cbm_len is zero, thus calculating size in rdtgroup_cbm_to_size()
will trigger the exception.
Fix this issue in the 'size' file by getting correct memory bandwidth value
which is in MBps when MBA software controller is enabled or in percentage
when MBA software controller is disabled.
Fixes: d9b48c86eb38 ("x86/intel_rdt: Display resource groups' allocations in bytes")
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Link: https://lkml.kernel.org/r/20180904174614.26682-1-yu.c.chen@intel.com
Link: https://lkml.kernel.org/r/1537048707-76280-3-git-send-email-fenghua.yu@intel.com
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Each resource is associated with a parsing callback to parse the data
provided from user space when writing schemata file.
The 'data' parameter in the callbacks is defined as a void pointer which
is error prone due to lack of type check.
parse_bw() processes the 'data' parameter as a string while its caller
actually passes the parameter as a pointer to struct rdt_cbm_parse_data.
Thus, parse_bw() takes wrong data and causes failure of parsing MBA
throttle value.
To fix the issue, the 'data' parameter in all parsing callbacks is defined
and handled as a pointer to struct rdt_parse_data (renamed from struct
rdt_cbm_parse_data).
Fixes: 7604df6e16ae ("x86/intel_rdt: Support flexible data to parsing callbacks")
Fixes: 9ab9aa15c309 ("x86/intel_rdt: Ensure requested schemata respects mode")
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Chen Yu" <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/1537048707-76280-2-git-send-email-fenghua.yu@intel.com
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Linux spreads out the non managed interrupt across the possible target CPUs
to avoid vector space exhaustion.
Managed interrupts are treated differently, as for them the vectors are
reserved (with guarantee) when the interrupt descriptors are initialized.
When the interrupt is requested a real vector is assigned. The assignment
logic uses the first CPU in the affinity mask for assignment. If the
interrupt has more than one CPU in the affinity mask, which happens when a
multi queue device has less queues than CPUs, then doing the same search as
for non managed interrupts makes sense as it puts the interrupt on the
least interrupt plagued CPU. For single CPU affine vectors that's obviously
a NOOP.
Restructre the matrix allocation code so it does the 'best CPU' search, add
the sanity check for an empty affinity mask and adapt the call site in the
x86 vector management code.
[ tglx: Added the empty mask check to the core and improved change log ]
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180908175838.14450-2-dou_liyang@163.com
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The recent removal of the memblock dependency from kvmclock caused a SEV
guest regression because the wall_clock and hv_clock_boot variables are
no longer mapped decrypted when SEV is active.
Use the __bss_decrypted attribute to put the static wall_clock and
hv_clock_boot in the .bss..decrypted section so that they are mapped
decrypted during boot.
In the preparatory stage of CPU hotplug, the per-cpu pvclock data pointer
assigns either an element of the static array or dynamically allocated
memory for the pvclock data pointer. The static array are now mapped
decrypted but the dynamically allocated memory is not mapped decrypted.
However, when SEV is active this memory range must be mapped decrypted.
Add a function which is called after the page allocator is up, and
allocate memory for the pvclock data pointers for the all possible cpus.
Map this memory range as decrypted when SEV is active.
Fixes: 368a540e0232 ("x86/kvmclock: Remove memblock dependency")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/1536932759-12905-3-git-send-email-brijesh.singh@amd.com
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kvmclock defines few static variables which are shared with the
hypervisor during the kvmclock initialization.
When SEV is active, memory is encrypted with a guest-specific key, and
if the guest OS wants to share the memory region with the hypervisor
then it must clear the C-bit before sharing it.
Currently, we use kernel_physical_mapping_init() to split large pages
before clearing the C-bit on shared pages. But it fails when called from
the kvmclock initialization (mainly because the memblock allocator is
not ready that early during boot).
Add a __bss_decrypted section attribute which can be used when defining
such shared variable. The so-defined variables will be placed in the
.bss..decrypted section. This section will be mapped with C=0 early
during boot.
The .bss..decrypted section has a big chunk of memory that may be unused
when memory encryption is not active, free it when memory encryption is
not active.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Radim Krčmář<rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/1536932759-12905-2-git-send-email-brijesh.singh@amd.com
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Get rid of local @cpu variable which is unused in the
!CONFIG_IA32_EMULATION case.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/1536806985-24197-1-git-send-email-zhongjiang@huawei.com
[ Clean up commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
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Fix build warning in apm_32.c when CONFIG_PROC_FS is not enabled:
../arch/x86/kernel/apm_32.c:1643:12: warning: 'proc_apm_show' defined but not used [-Wunused-function]
static int proc_apm_show(struct seq_file *m, void *v)
Fixes: 3f3942aca6da ("proc: introduce proc_create_single{,_data}")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jiri Kosina <jikos@kernel.org>
Link: https://lkml.kernel.org/r/be39ac12-44c2-4715-247f-4dcc3c525b8b@infradead.org
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The SYSCALL64 trampoline has a couple of nice properties:
- The usual sequence of SWAPGS followed by two GS-relative accesses to
set up RSP is somewhat slow because the GS-relative accesses need
to wait for SWAPGS to finish. The trampoline approach allows
RIP-relative accesses to set up RSP, which avoids the stall.
- The trampoline avoids any percpu access before CR3 is set up,
which means that no percpu memory needs to be mapped in the user
page tables. This prevents using Meltdown to read any percpu memory
outside the cpu_entry_area and prevents using timing leaks
to directly locate the percpu areas.
The downsides of using a trampoline may outweigh the upsides, however.
It adds an extra non-contiguous I$ cache line to system calls, and it
forces an indirect jump to transfer control back to the normal kernel
text after CR3 is set up. The latter is because x86 lacks a 64-bit
direct jump instruction that could jump from the trampoline to the entry
text. With retpolines enabled, the indirect jump is extremely slow.
Change the code to map the percpu TSS into the user page tables to allow
the non-trampoline SYSCALL64 path to work under PTI. This does not add a
new direct information leak, since the TSS is readable by Meltdown from the
cpu_entry_area alias regardless. It does allow a timing attack to locate
the percpu area, but KASLR is more or less a lost cause against local
attack on CPUs vulnerable to Meltdown regardless. As far as I'm concerned,
on current hardware, KASLR is only useful to mitigate remote attacks that
try to attack the kernel without first gaining RCE against a vulnerable
user process.
On Skylake, with CONFIG_RETPOLINE=y and KPTI on, this reduces syscall
overhead from ~237ns to ~228ns.
There is a possible alternative approach: Move the trampoline within 2G of
the entry text and make a separate copy for each CPU. This would allow a
direct jump to rejoin the normal entry path. There are pro's and con's for
this approach:
+ It avoids a pipeline stall
- It executes from an extra page and read from another extra page during
the syscall. The latter is because it needs to use a relative
addressing mode to find sp1 -- it's the same *cacheline*, but accessed
using an alias, so it's an extra TLB entry.
- Slightly more memory. This would be one page per CPU for a simple
implementation and 64-ish bytes per CPU or one page per node for a more
complex implementation.
- More code complexity.
The current approach is chosen for simplicity and because the alternative
does not provide a significant benefit, which makes it worth.
[ tglx: Added the alternative discussion to the changelog ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/8c7c6e483612c3e4e10ca89495dc160b1aa66878.1536015544.git.luto@kernel.org
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Xen PV guests don't allow CPU0 hotplug, so disable it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20180912174122.24282-1-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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For unprivileged Xen PV guests this is normal memory and ioremap will
not be able to properly map it.
While at it, since ioremap may return NULL, add a test for pointer's
validity.
Reported-by: Andy Smith <andy@strugglers.net>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: xen-devel@lists.xenproject.org
Cc: jgross@suse.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180911195538.23289-1-boris.ostrovsky@oracle.com
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For userspace to tell the difference between an random signal
and an exception, the exception must include siginfo information.
Using SEND_SIG_FORCED for SIGSEGV is thus wrong, and it will result in
userspace seeing si_code == SI_USER (like a random signal) instead of
si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.
Therefore replace force_sig_info(SIGSEGV, SEND_SIG_FORCE, current)
with force_sig(SIG_SEGV, current) which gets this right and is shorter
and easier to type.
Fixes: 791eca10107f ("uretprobes/x86: Hijack return address")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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When CONFIG_PARAVIRT_SPINLOCKS=n, it generates a warning:
arch/x86/kernel/paravirt_patch_64.c: In function ‘native_patch’:
arch/x86/kernel/paravirt_patch_64.c:89:1: warning: label ‘patch_site’ defined but not used [-Wunused-label]
patch_site:
... but those labels can simply be removed by directly calling the
respective functions there.
Get rid of local variables too, while at it. Also, simplify function
flow for better readability.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/20180911091510.GA12094@zn.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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pr_*() is the preferred style.
Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: kstewart@linuxfoundation.org
Cc: pombredanne@nexb.com
Link: http://lkml.kernel.org/r/1534260823-87917-2-git-send-email-zhe.he@windriver.com
[ Moved all console output into a single line. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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option without value is provided
memory_corruption_check[{_period|_size}]()'s handlers do not check input
argument before passing it to kstrtoul() or simple_strtoull(). The argument
would be a NULL pointer if each of the kernel parameters, without its
value, is set in command line and thus cause the following panic.
PANIC: early exception 0xe3 IP 10:ffffffff73587c22 error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #2
[ 0.000000] RIP: 0010:kstrtoull+0x2/0x10
...
[ 0.000000] Call Trace
[ 0.000000] ? set_corruption_check+0x21/0x49
[ 0.000000] ? do_early_param+0x4d/0x82
[ 0.000000] ? parse_args+0x212/0x330
[ 0.000000] ? rdinit_setup+0x26/0x26
[ 0.000000] ? parse_early_options+0x20/0x23
[ 0.000000] ? rdinit_setup+0x26/0x26
[ 0.000000] ? parse_early_param+0x2d/0x39
[ 0.000000] ? setup_arch+0x2f7/0xbf4
[ 0.000000] ? start_kernel+0x5e/0x4c2
[ 0.000000] ? load_ucode_bsp+0x113/0x12f
[ 0.000000] ? secondary_startup_64+0xa5/0xb0
This patch adds checks to prevent the panic.
Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: kstewart@linuxfoundation.org
Cc: pombredanne@nexb.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1534260823-87917-1-git-send-email-zhe.he@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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activate_managed() returns EINVAL instead of -EINVAL in case of
error. While this is unlikely to happen, the positive return value would
cause further malfunction at the call site.
Fixes: 2db1f959d9dc ("x86/vector: Handle managed interrupts proper")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
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In the non-trampoline SYSCALL64 path, a percpu variable is used to
temporarily store the user RSP value.
Instead of a separate variable, use the otherwise unused sp2 slot in the
TSS. This will improve cache locality, as the sp1 slot is already used in
the same code to find the kernel stack. It will also simplify a future
change to make the non-trampoline path work in PTI mode.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/08e769a0023dbad4bac6f34f3631dbaf8ad59f4f.1536015544.git.luto@kernel.org
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The idtentry macro is complicated and magical. Document what it
does to help future readers and to allow future patches to adjust
the code and docs at the same time.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/6e56c3ad94879e41afe345750bc28ccc0e820ea8.1536015544.git.luto@kernel.org
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When the kernel.print-fatal-signals sysctl has been enabled, a simple
userspace crash will cause the kernel to write a crash dump that contains,
among other things, the kernel gsbase into dmesg.
As suggested by Andy, limit output to pt_regs, FS_BASE and KERNEL_GS_BASE
in this case.
This also moves the bitness-specific logic from show_regs() into
process_{32,64}.c.
Fixes: 45807a1df9f5 ("vdso: print fatal signals")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180831194151.123586-1-jannh@google.com
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Loops per jiffy is calculated by multiplying tsc_khz with 1e3 and then
dividing it by HZ.
Both tsc_khz and the temporary variable holding the multiplication result
are of type unsigned long, so on 32bit the result is truncated to the lower
32bit.
Use u64 as type for the temporary variable and cast tsc_khz to it before
multiplying.
[ tglx: Massaged changelog and removed pointless braces ]
Fixes: cf7a63ef4e02 ("x86/tsc: Calibrate tsc only once")
Signed-off-by: Chuanhua Lei <chuanhua.lei@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yixin.zhu@linux.intel.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@microsoft.com>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Link: https://lkml.kernel.org/r/1536228203-18701-1-git-send-email-chuanhua.lei@linux.intel.com
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Most of the paravirt ops defined in pv_mmu_ops are for Xen PV guests
only. Define them only if CONFIG_PARAVIRT_XXL is set.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-15-jgross@suse.com
|
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All of the paravirt ops defined in pv_irq_ops are for Xen PV guests
or VSMP only. Define them only if CONFIG_PARAVIRT_XXL is set.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-14-jgross@suse.com
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Most of the paravirt ops defined in pv_cpu_ops are for Xen PV guests
only. Define them only if CONFIG_PARAVIRT_XXL is set.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-13-jgross@suse.com
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All items but name in pv_info are needed by Xen PV only. Define them
with CONFIG_PARAVIRT_XXL set only.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-12-jgross@suse.com
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The macros ENABLE_INTERRUPTS_SYSEXIT, GET_CR0_INTO_EAX and
PARAVIRT_ADJUST_EXCEPTION_FRAME are used nowhere.
Remove their definitions.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-10-jgross@suse.com
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Instead of using six globally visible paravirt ops structures combine
them in a single structure, keeping the original structures as
sub-structures.
This avoids the need to assemble struct paravirt_patch_template at
runtime on the stack each time apply_paravirt() is being called (i.e.
when loading a module).
[ tglx: Made the struct and the initializer tabular for readability sake ]
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-9-jgross@suse.com
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The clobbers parameter from paravirt_patch_default() et al isn't used
any longer. Remove it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-7-jgross@suse.com
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paravirt_patch_call() and paravirt_patch_jmp() are used in paravirt.c
only. Convert them to static.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-6-jgross@suse.com
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This is preparation for looking at trap number and fault address in the
handlers for uaccess errors. No functional change.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org
Cc: dvyukov@google.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20180828201421.157735-6-jannh@google.com
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This removes the call into exception fixup that was added in commit
c28f896634f2 ("[PATCH] kprobes: fix broken fault handling for x86_64").
On X86, kprobe_fault_handler() is called from two places:
do_general_protection() (for #GP) and kprobes_fault() (for #PF). In both
paths, the fixup_exception() call in the kprobe fault handler is redundant.
In case of #GP, fixup_exception() is called immediately before
kprobe_fault_handler() is invoked, so no need to try that again. This
assumes that the kprobe's fault handler isn't going to do something crazy
like changing RIP so that it suddenly points to an instruction that does
userspace access.
For #PF on a kernel address from kernel space, after the kprobe fault
handler has run, no_context() is invoked, which calls fixup_exception().
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org
Cc: dvyukov@google.com
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20180828201421.157735-4-jannh@google.com
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The opaque plumbing of #GP from do_general_protection() through
notify_die() into kprobe_exceptions_notify() makes it hard to understand
what's going on.
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: dvyukov@google.com
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20180828201421.157735-3-jannh@google.com
|
