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[ Upstream commit c07e45553da1808aa802e9f0ffa8108cfeaf7a17 ]
Commit
18ec54fdd6d18 ("x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations")
added FENCE_SWAPGS_{KERNEL|USER}_ENTRY for conditional SWAPGS. In
paranoid_entry(), it uses only FENCE_SWAPGS_KERNEL_ENTRY for both
branches. This is because the fence is required for both cases since the
CR3 write is conditional even when PTI is enabled.
But
96b2371413e8f ("x86/entry/64: Switch CR3 before SWAPGS in paranoid entry")
changed the order of SWAPGS and the CR3 write. And it missed the needed
FENCE_SWAPGS_KERNEL_ENTRY for the user gsbase case.
Add it back by changing the branches so that FENCE_SWAPGS_KERNEL_ENTRY
can cover both branches.
[ bp: Massage, fix typos, remove obsolete comment while at it. ]
Fixes: 96b2371413e8f ("x86/entry/64: Switch CR3 before SWAPGS in paranoid entry")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211126101209.8613-2-jiangshanlai@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 53c9d9240944088274aadbbbafc6138ca462db4f ]
SWAPGS is used only for interrupts coming from user mode or for
returning to user mode. So there is no reason to use the PARAVIRT
framework, as it can easily be replaced by an ALTERNATIVE depending
on X86_FEATURE_XENPV.
There are several instances using the PV-aware SWAPGS macro in paths
which are never executed in a Xen PV guest. Replace those with the
plain swapgs instruction. For SWAPGS_UNSAFE_STACK the same applies.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210120135555.32594-5-jgross@suse.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 5c8f6a2e316efebb3ba93d8c1af258155dcf5632 ]
In the native case, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is the
trampoline stack. But XEN pv doesn't use trampoline stack, so
PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is also the kernel stack.
In that case, source and destination stacks are identical, which means
that reusing swapgs_restore_regs_and_return_to_usermode() in XEN pv
would cause %rsp to move up to the top of the kernel stack and leave the
IRET frame below %rsp.
This is dangerous as it can be corrupted if #NMI / #MC hit as either of
these events occurring in the middle of the stack pushing would clobber
data on the (original) stack.
And, with XEN pv, swapgs_restore_regs_and_return_to_usermode() pushing
the IRET frame on to the original address is useless and error-prone
when there is any future attempt to modify the code.
[ bp: Massage commit message. ]
Fixes: 7f2590a110b8 ("x86/entry/64: Use a per-CPU trampoline stack for IDT entries")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lkml.kernel.org/r/20211126101209.8613-4-jiangshanlai@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 1367afaa2ee90d1c956dfc224e199fcb3ff3f8cc ]
The commit
c75890700455 ("x86/entry/64: Remove unneeded kernel CR3 switching")
removed a CR3 write in the faulting path of load_gs_index().
But the path's FENCE_SWAPGS_USER_ENTRY has no fence operation if PTI is
enabled, see spectre_v1_select_mitigation().
Rather, it depended on the serializing CR3 write of SWITCH_TO_KERNEL_CR3
and since it got removed, add a FENCE_SWAPGS_KERNEL_ENTRY call to make
sure speculation is blocked.
[ bp: Massage commit message and comment. ]
Fixes: c75890700455 ("x86/entry/64: Remove unneeded kernel CR3 switching")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211126101209.8613-3-jiangshanlai@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit be1a5408868af341f61f93c191b5e346ee88c82a ]
Split up the #VC handler code into a from-user and a from-kernel part.
This allows clean and correct state tracking, as the #VC handler needs
to enter NMI-state when raised from kernel mode and plain IRQ state when
raised from user-mode.
Fixes: 62441a1fb532 ("x86/sev-es: Correctly track IRQ states in runtime #VC handler")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210618115409.22735-3-joro@8bytes.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 240001d4e3041832e8a2654adc3ccf1683132b92 ]
Fix:
vmlinux.o: warning: objtool: __do_fast_syscall_32()+0xf5: call to trace_hardirqs_off() leaves .noinstr.text section
Fixes: 5d5675df792f ("x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210621120120.467898710@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 5d5675df792ff67e74a500c4c94db0f99e6a10ef upstream.
On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work. This confuses audit and ptrace. For example:
$ ./tools/testing/selftests/x86/syscall_arg_fault_32
...
strace: pid 264258: entering, ptrace_syscall_info.op == 2
...
This is a minimal fix intended for ease of backporting. A more
complete cleanup is coming.
Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b6be002bcd1dd1dedb926abf3c90c794eacb77dc upstream.
Lockdep state handling on NMI enter and exit is nothing specific to X86. It's
not any different on other architectures. Also the extra state type is not
necessary, irqentry_state_t can carry the necessary information as well.
Move it to common code and extend irqentry_state_t to carry lockdep state.
[ Ira: Make exit_rcu and lockdep a union as they are mutually exclusive
between the IRQ and NMI exceptions, and add kernel documentation for
struct irqentry_state_t ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201102205320.1458656-7-ira.weiny@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 78a81d88f60ba773cbe890205e1ee67f00502948 upstream.
Introduce a helper to check whether an exception came from the syscall
gap and use it in the SEV-ES code. Extend the check to also cover the
compatibility SYSCALL entry path.
Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org # 5.10+
Link: https://lkml.kernel.org/r/20210303141716.29223-2-joro@8bytes.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 15f720aabe71a5662c4198b22532d95bbeec80ef upstream.
Embracing a callout into instrumentation_begin() / instrumentation_begin()
does not really make sense. Make the latter instrumentation_end().
Fixes: 2f6474e4636b ("x86/entry: Switch XEN/PV hypercall entry to IDTENTRY")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210210002512.106502464@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5e6dca82bcaa49348f9e5fcb48df4881f6d6c4ae upstream.
Arnd found a randconfig that produces the warning:
arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at
offset 0x3e
when building with LLVM_IAS=1 (Clang's integrated assembler). Josh
notes:
With the LLVM assembler not generating section symbols, objtool has no
way to reference this code when it generates ORC unwinder entries,
because this code is outside of any ELF function.
The limitation now being imposed by objtool is that all code must be
contained in an ELF symbol. And .L symbols don't create such symbols.
So basically, you can use an .L symbol *inside* a function or a code
segment, you just can't use the .L symbol to contain the code using a
SYM_*_START/END annotation pair.
Fangrui notes that this optimization is helpful for reducing image size
when compiling with -ffunction-sections and -fdata-sections. I have
observed on the order of tens of thousands of symbols for the kernel
images built with those flags.
A patch has been authored against GNU binutils to match this behavior
of not generating unused section symbols ([1]), so this will
also become a problem for users of GNU binutils once they upgrade to 2.36.
Omit the .L prefix on a label so that the assembler will emit an entry
into the symbol table for the label, with STB_LOCAL binding. This
enables objtool to generate proper unwind info here with LLVM_IAS=1 or
GNU binutils 2.36+.
[ bp: Massage commit message. ]
Reported-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20210112194625.4181814-1-ndesaulniers@google.com
Link: https://github.com/ClangBuiltLinux/linux/issues/1209
Link: https://reviews.llvm.org/D93783
Link: https://sourceware.org/binutils/docs/as/Symbol-Names.html
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1408485ce69f844dcd7ded093a8 [1]
Cc: Chris Clayton <chris2553@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9caa7ff509add50959a793b811cc7c9339e281cd upstream.
vmlinux.o: warning: objtool: __do_fast_syscall_32()+0x47: call to syscall_enter_from_user_mode_work() leaves .noinstr.text section
Fixes: 4facb95b7ada ("x86/entry: Unbreak 32bit fast syscall")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.472696632@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"A couple of x86 fixes which missed rc1 due to my stupidity:
- Drop lazy TLB mode before switching to the temporary address space
for text patching.
text_poke() switches to the temporary mm which clears the lazy mode
and restores the original mm afterwards. Due to clearing lazy mode
this might restore a already dead mm if exit_mmap() runs in
parallel on another CPU.
- Document the x32 syscall design fail vs. syscall numbers 512-547
properly.
- Fix the ORC unwinder to handle the inactive task frame correctly.
This was unearthed due to the slightly different code generation of
gcc-10.
- Use an up to date screen_info for the boot params of kexec instead
of the possibly stale and invalid version which happened to be
valid when the kexec kernel was loaded"
* tag 'x86-urgent-2020-10-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/alternative: Don't call text_poke() in lazy TLB mode
x86/syscalls: Document the fact that syscalls 512-547 are a legacy mistake
x86/unwind/orc: Fix inactive tasks with stack pointer in %sp on GCC 10 compiled kernels
hyperv_fb: Update screen_info after removing old framebuffer
x86/kexec: Use up-to-dated screen_info copy to fill boot params
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Support 'make compile_commands.json' to generate the compilation
database more easily, avoiding stale entries
- Support 'make clang-analyzer' and 'make clang-tidy' for static checks
using clang-tidy
- Preprocess scripts/modules.lds.S to allow CONFIG options in the
module linker script
- Drop cc-option tests from compiler flags supported by our minimal
GCC/Clang versions
- Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y
- Use sha1 build id for both BFD linker and LLD
- Improve deb-pkg for reproducible builds and rootless builds
- Remove stale, useless scripts/namespace.pl
- Turn -Wreturn-type warning into error
- Fix build error of deb-pkg when CONFIG_MODULES=n
- Replace 'hostname' command with more portable 'uname -n'
- Various Makefile cleanups
* tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
kbuild: Use uname for LINUX_COMPILE_HOST detection
kbuild: Only add -fno-var-tracking-assignments for old GCC versions
kbuild: remove leftover comment for filechk utility
treewide: remove DISABLE_LTO
kbuild: deb-pkg: clean up package name variables
kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n
kbuild: enforce -Werror=return-type
scripts: remove namespace.pl
builddeb: Add support for all required debian/rules targets
builddeb: Enable rootless builds
builddeb: Pass -n to gzip for reproducible packages
kbuild: split the build log of kallsyms
kbuild: explicitly specify the build id style
scripts/setlocalversion: make git describe output more reliable
kbuild: remove cc-option test of -Werror=date-time
kbuild: remove cc-option test of -fno-stack-check
kbuild: remove cc-option test of -fno-strict-overflow
kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles
kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan
kbuild: do not create built-in objects for external module builds
...
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This change removes all instances of DISABLE_LTO from
Makefiles, as they are currently unused, and the preferred
method of disabling LTO is to filter out the flags instead.
Note added by Masahiro Yamada:
DISABLE_LTO was added as preparation for GCC LTO, but GCC LTO was
not pulled into the mainline. (https://lkml.org/lkml/2014/4/8/272)
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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There is usecase that System Management Software(SMS) want to give a
memory hint like MADV_[COLD|PAGEEOUT] to other processes and in the
case of Android, it is the ActivityManagerService.
The information required to make the reclaim decision is not known to the
app. Instead, it is known to the centralized userspace
daemon(ActivityManagerService), and that daemon must be able to initiate
reclaim on its own without any app involvement.
To solve the issue, this patch introduces a new syscall
process_madvise(2). It uses pidfd of an external process to give the
hint. It also supports vector address range because Android app has
thousands of vmas due to zygote so it's totally waste of CPU and power if
we should call the syscall one by one for each vma.(With testing 2000-vma
syscall vs 1-vector syscall, it showed 15% performance improvement. I
think it would be bigger in real practice because the testing ran very
cache friendly environment).
Another potential use case for the vector range is to amortize the cost
ofTLB shootdowns for multiple ranges when using MADV_DONTNEED; this could
benefit users like TCP receive zerocopy and malloc implementations. In
future, we could find more usecases for other advises so let's make it
happens as API since we introduce a new syscall at this moment. With
that, existing madvise(2) user could replace it with process_madvise(2)
with their own pid if they want to have batch address ranges support
feature.
ince it could affect other process's address range, only privileged
process(PTRACE_MODE_ATTACH_FSCREDS) or something else(e.g., being the same
UID) gives it the right to ptrace the process could use it successfully.
The flag argument is reserved for future use if we need to extend the API.
I think supporting all hints madvise has/will supported/support to
process_madvise is rather risky. Because we are not sure all hints make
sense from external process and implementation for the hint may rely on
the caller being in the current context so it could be error-prone. Thus,
I just limited hints as MADV_[COLD|PAGEOUT] in this patch.
If someone want to add other hints, we could hear the usecase and review
it for each hint. It's safer for maintenance rather than introducing a
buggy syscall but hard to fix it later.
So finally, the API is as follows,
ssize_t process_madvise(int pidfd, const struct iovec *iovec,
unsigned long vlen, int advice, unsigned int flags);
DESCRIPTION
The process_madvise() system call is used to give advice or directions
to the kernel about the address ranges from external process as well as
local process. It provides the advice to address ranges of process
described by iovec and vlen. The goal of such advice is to improve
system or application performance.
The pidfd selects the process referred to by the PID file descriptor
specified in pidfd. (See pidofd_open(2) for further information)
The pointer iovec points to an array of iovec structures, defined in
<sys/uio.h> as:
struct iovec {
void *iov_base; /* starting address */
size_t iov_len; /* number of bytes to be advised */
};
The iovec describes address ranges beginning at address(iov_base)
and with size length of bytes(iov_len).
The vlen represents the number of elements in iovec.
The advice is indicated in the advice argument, which is one of the
following at this moment if the target process specified by pidfd is
external.
MADV_COLD
MADV_PAGEOUT
Permission to provide a hint to external process is governed by a
ptrace access mode PTRACE_MODE_ATTACH_FSCREDS check; see ptrace(2).
The process_madvise supports every advice madvise(2) has if target
process is in same thread group with calling process so user could
use process_madvise(2) to extend existing madvise(2) to support
vector address ranges.
RETURN VALUE
On success, process_madvise() returns the number of bytes advised.
This return value may be less than the total number of requested
bytes, if an error occurred. The caller should check return value
to determine whether a partial advice occurred.
FAQ:
Q.1 - Why does any external entity have better knowledge?
Quote from Sandeep
"For Android, every application (including the special SystemServer)
are forked from Zygote. The reason of course is to share as many
libraries and classes between the two as possible to benefit from the
preloading during boot.
After applications start, (almost) all of the APIs end up calling into
this SystemServer process over IPC (binder) and back to the
application.
In a fully running system, the SystemServer monitors every single
process periodically to calculate their PSS / RSS and also decides
which process is "important" to the user for interactivity.
So, because of how these processes start _and_ the fact that the
SystemServer is looping to monitor each process, it does tend to *know*
which address range of the application is not used / useful.
Besides, we can never rely on applications to clean things up
themselves. We've had the "hey app1, the system is low on memory,
please trim your memory usage down" notifications for a long time[1].
They rely on applications honoring the broadcasts and very few do.
So, if we want to avoid the inevitable killing of the application and
restarting it, some way to be able to tell the OS about unimportant
memory in these applications will be useful.
- ssp
Q.2 - How to guarantee the race(i.e., object validation) between when
giving a hint from an external process and get the hint from the target
process?
process_madvise operates on the target process's address space as it
exists at the instant that process_madvise is called. If the space
target process can run between the time the process_madvise process
inspects the target process address space and the time that
process_madvise is actually called, process_madvise may operate on
memory regions that the calling process does not expect. It's the
responsibility of the process calling process_madvise to close this
race condition. For example, the calling process can suspend the
target process with ptrace, SIGSTOP, or the freezer cgroup so that it
doesn't have an opportunity to change its own address space before
process_madvise is called. Another option is to operate on memory
regions that the caller knows a priori will be unchanged in the target
process. Yet another option is to accept the race for certain
process_madvise calls after reasoning that mistargeting will do no
harm. The suggested API itself does not provide synchronization. It
also apply other APIs like move_pages, process_vm_write.
The race isn't really a problem though. Why is it so wrong to require
that callers do their own synchronization in some manner? Nobody
objects to write(2) merely because it's possible for two processes to
open the same file and clobber each other's writes --- instead, we tell
people to use flock or something. Think about mmap. It never
guarantees newly allocated address space is still valid when the user
tries to access it because other threads could unmap the memory right
before. That's where we need synchronization by using other API or
design from userside. It shouldn't be part of API itself. If someone
needs more fine-grained synchronization rather than process level,
there were two ideas suggested - cookie[2] and anon-fd[3]. Both are
applicable via using last reserved argument of the API but I don't
think it's necessary right now since we have already ways to prevent
the race so don't want to add additional complexity with more
fine-grained optimization model.
To make the API extend, it reserved an unsigned long as last argument
so we could support it in future if someone really needs it.
Q.3 - Why doesn't ptrace work?
Injecting an madvise in the target process using ptrace would not work
for us because such injected madvise would have to be executed by the
target process, which means that process would have to be runnable and
that creates the risk of the abovementioned race and hinting a wrong
VMA. Furthermore, we want to act the hint in caller's context, not the
callee's, because the callee is usually limited in cpuset/cgroups or
even freezed state so they can't act by themselves quick enough, which
causes more thrashing/kill. It doesn't work if the target process are
ptraced(e.g., strace, debugger, minidump) because a process can have at
most one ptracer.
[1] https://developer.android.com/topic/performance/memory"
[2] process_getinfo for getting the cookie which is updated whenever
vma of process address layout are changed - Daniel Colascione -
https://lore.kernel.org/lkml/20190520035254.57579-1-minchan@kernel.org/T/#m7694416fd179b2066a2c62b5b139b14e3894e224
[3] anonymous fd which is used for the object(i.e., address range)
validation - Michal Hocko -
https://lore.kernel.org/lkml/20200120112722.GY18451@dhcp22.suse.cz/
[minchan@kernel.org: fix process_madvise build break for arm64]
Link: http://lkml.kernel.org/r/20200303145756.GA219683@google.com
[minchan@kernel.org: fix build error for mips of process_madvise]
Link: http://lkml.kernel.org/r/20200508052517.GA197378@google.com
[akpm@linux-foundation.org: fix patch ordering issue]
[akpm@linux-foundation.org: fix arm64 whoops]
[minchan@kernel.org: make process_madvise() vlen arg have type size_t, per Florian]
[akpm@linux-foundation.org: fix i386 build]
[sfr@canb.auug.org.au: fix syscall numbering]
Link: https://lkml.kernel.org/r/20200905142639.49fc3f1a@canb.auug.org.au
[sfr@canb.auug.org.au: madvise.c needs compat.h]
Link: https://lkml.kernel.org/r/20200908204547.285646b4@canb.auug.org.au
[minchan@kernel.org: fix mips build]
Link: https://lkml.kernel.org/r/20200909173655.GC2435453@google.com
[yuehaibing@huawei.com: remove duplicate header which is included twice]
Link: https://lkml.kernel.org/r/20200915121550.30584-1-yuehaibing@huawei.com
[minchan@kernel.org: do not use helper functions for process_madvise]
Link: https://lkml.kernel.org/r/20200921175539.GB387368@google.com
[akpm@linux-foundation.org: pidfd_get_pid() gained an argument]
[sfr@canb.auug.org.au: fix up for "iov_iter: transparently handle compat iovecs in import_iovec"]
Link: https://lkml.kernel.org/r/20200928212542.468e1fef@canb.auug.org.au
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Daniel Colascione <dancol@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Dias <joaodias@google.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: <linux-man@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200302193630.68771-3-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200508183320.GA125527@google.com
Link: http://lkml.kernel.org/r/20200622192900.22757-4-minchan@kernel.org
Link: https://lkml.kernel.org/r/20200901000633.1920247-4-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since this commit:
6365b842aae4 ("x86/syscalls: Split the x32 syscalls into their own table")
there is no need for special x32-specific syscall numbers. I forgot to
update the comments in syscall_64.tbl. Add comments to make it clear to
future contributors that this range is a legacy wart.
Reported-by: Jessica Clarke <jrtc27@jrtc27.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/6c56fb4ddd18fc60a238eb4d867e4b3d97c6351e.1602471055.git.luto@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV-ES support from Borislav Petkov:
"SEV-ES enhances the current guest memory encryption support called SEV
by also encrypting the guest register state, making the registers
inaccessible to the hypervisor by en-/decrypting them on world
switches. Thus, it adds additional protection to Linux guests against
exfiltration, control flow and rollback attacks.
With SEV-ES, the guest is in full control of what registers the
hypervisor can access. This is provided by a guest-host exchange
mechanism based on a new exception vector called VMM Communication
Exception (#VC), a new instruction called VMGEXIT and a shared
Guest-Host Communication Block which is a decrypted page shared
between the guest and the hypervisor.
Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest
so in order for that exception mechanism to work, the early x86 init
code needed to be made able to handle exceptions, which, in itself,
brings a bunch of very nice cleanups and improvements to the early
boot code like an early page fault handler, allowing for on-demand
building of the identity mapping. With that, !KASLR configurations do
not use the EFI page table anymore but switch to a kernel-controlled
one.
The main part of this series adds the support for that new exchange
mechanism. The goal has been to keep this as much as possibly separate
from the core x86 code by concentrating the machinery in two
SEV-ES-specific files:
arch/x86/kernel/sev-es-shared.c
arch/x86/kernel/sev-es.c
Other interaction with core x86 code has been kept at minimum and
behind static keys to minimize the performance impact on !SEV-ES
setups.
Work by Joerg Roedel and Thomas Lendacky and others"
* tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer
x86/sev-es: Check required CPU features for SEV-ES
x86/efi: Add GHCB mappings when SEV-ES is active
x86/sev-es: Handle NMI State
x86/sev-es: Support CPU offline/online
x86/head/64: Don't call verify_cpu() on starting APs
x86/smpboot: Load TSS and getcpu GDT entry before loading IDT
x86/realmode: Setup AP jump table
x86/realmode: Add SEV-ES specific trampoline entry point
x86/vmware: Add VMware-specific handling for VMMCALL under SEV-ES
x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES
x86/paravirt: Allow hypervisor-specific VMMCALL handling under SEV-ES
x86/sev-es: Handle #DB Events
x86/sev-es: Handle #AC Events
x86/sev-es: Handle VMMCALL Events
x86/sev-es: Handle MWAIT/MWAITX Events
x86/sev-es: Handle MONITOR/MONITORX Events
x86/sev-es: Handle INVD Events
x86/sev-es: Handle RDPMC Events
x86/sev-es: Handle RDTSC(P) Events
...
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat mount cleanups from Al Viro:
"The last remnants of mount(2) compat buried by Christoph.
Buried into NFS, that is.
Generally I'm less enthusiastic about "let's use in_compat_syscall()
deep in call chain" kind of approach than Christoph seems to be, but
in this case it's warranted - that had been an NFS-specific wart,
hopefully not to be repeated in any other filesystems (read: any new
filesystem introducing non-text mount options will get NAKed even if
it doesn't mess the layout up).
IOW, not worth trying to grow an infrastructure that would avoid that
use of in_compat_syscall()..."
* 'compat.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: remove compat_sys_mount
fs,nfs: lift compat nfs4 mount data handling into the nfs code
nfs: simplify nfs4_parse_monolithic
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat quotactl cleanups from Al Viro:
"More Christoph's compat cleanups: quotactl(2)"
* 'work.quota-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
quota: simplify the quotactl compat handling
compat: add a compat_need_64bit_alignment_fixup() helper
compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat iovec cleanups from Al Viro:
"Christoph's series around import_iovec() and compat variant thereof"
* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
security/keys: remove compat_keyctl_instantiate_key_iov
mm: remove compat_process_vm_{readv,writev}
fs: remove compat_sys_vmsplice
fs: remove the compat readv/writev syscalls
fs: remove various compat readv/writev helpers
iov_iter: transparently handle compat iovecs in import_iovec
iov_iter: refactor rw_copy_check_uvector and import_iovec
iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
compat.h: fix a spelling error in <linux/compat.h>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 paravirt cleanup from Ingo Molnar:
"Clean up the paravirt code after the removal of 32-bit Xen PV support"
* tag 'x86-paravirt-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/paravirt: Avoid needless paravirt step clearing page table entries
x86/paravirt: Remove set_pte_at() pv-op
x86/entry/32: Simplify CONFIG_XEN_PV build dependency
x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT
x86/paravirt: Clean up paravirt macros
x86/paravirt: Remove 32-bit support from CONFIG_PARAVIRT_XXL
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Borislav Petkov:
"Misc minor cleanups"
* tag 'x86_cleanups_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Fix typo in comments for syscall_enter_from_user_mode()
x86/resctrl: Fix spelling in user-visible warning messages
x86/entry/64: Do not include inst.h in calling.h
x86/mpparse: Remove duplicate io_apic.h include
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fsgsbase updates from Borislav Petkov:
"Misc minor cleanups and corrections to the fsgsbase code and
respective selftests"
* tag 'x86_fsgsbase_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS
selftests/x86/fsgsbase: Reap a forgotten child
x86/fsgsbase: Replace static_cpu_has() with boot_cpu_has()
x86/entry/64: Correct the comment over SAVE_AND_SET_GSBASE
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ld's --build-id defaults to "sha1" style, while lld defaults to "fast".
The build IDs are very different between the two, which may confuse
programs that reference them.
Signed-off-by: Bill Wendling <morbo@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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Now that import_iovec handles compat iovecs, the native syscalls
can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Now that import_iovec handles compat iovecs, the native vmsplice syscall
can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Now that import_iovec handles compat iovecs, the native readv and writev
syscalls can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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compat_sys_mount is identical to the regular sys_mount now, so remove it
and use the native version everywhere.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Sami reported that run_on_irqstack_cond() requires the caller to cast
functions to mismatching types, which trips indirect call Control-Flow
Integrity (CFI) in Clang.
Instead of disabling CFI on that function, provide proper helpers for
the three call variants. The actual ASM code stays the same as that is
out of reach.
[ bp: Fix __run_on_irqstack() prototype to match. ]
Fixes: 931b94145981 ("x86/entry: Provide helpers for executing on the irqstack")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/1052
Link: https://lkml.kernel.org/r/87pn6eb5tv.fsf@nanos.tec.linutronix.de
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Fold the misaligned u64 workarounds into the main quotactl flow instead
of implementing a separate compat syscall handler.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The #VC handler needs special entry code because:
1. It runs on an IST stack
2. It needs to be able to handle nested #VC exceptions
To make this work, the entry code is implemented to pretend it doesn't
use an IST stack. When entered from user-mode or early SYSCALL entry
path it switches to the task stack. If entered from kernel-mode it tries
to switch back to the previous stack in the IRET frame.
The stack found in the IRET frame is validated first, and if it is not
safe to use it for the #VC handler, the code will switch to a
fall-back stack (the #VC2 IST stack). From there, it can cause nested
exceptions again.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-46-joro@8bytes.org
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Andy reported that the syscall treacing for 32bit fast syscall fails:
# ./tools/testing/selftests/x86/ptrace_syscall_32
...
[RUN] SYSEMU
[FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732)
...
[RUN] SYSCALL
[FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732)
The eason is that the conversion to generic entry code moved the retrieval
of the sixth argument (EBP) after the point where the syscall entry work
runs, i.e. ptrace, seccomp, audit...
Unbreak it by providing a split up version of syscall_enter_from_user_mode().
- syscall_enter_from_user_mode_prepare() establishes state and enables
interrupts
- syscall_enter_from_user_mode_work() runs the entry work
Replace the call to syscall_enter_from_user_mode() in the 32bit fast
syscall C-entry with the split functions and stick the EBP retrieval
between them.
Fixes: 27d6b4d14f5c ("x86/entry: Use generic syscall entry function")
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/87k0xdjbtt.fsf@nanos.tec.linutronix.de
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inst.h was included in calling.h solely to instantiate the RDPID macro.
The usage of RDPID was removed in
6a3ea3e68b8a ("x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM")
so remove the include.
Fixes: 6a3ea3e68b8a ("x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200827171735.93825-1-ubizjak@gmail.com
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Unused remnants
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.487040689@infradead.org
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Add the proper explanation why an LFENCE is not needed in the FSGSBASE
case.
Fixes: c82965f9e530 ("x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit")
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200821090710.GE12181@zn.tnic
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KVM has an optmization to avoid expensive MRS read/writes on
VMENTER/EXIT. It caches the MSR values and restores them either when
leaving the run loop, on preemption or when going out to user space.
The affected MSRs are not required for kernel context operations. This
changed with the recently introduced mechanism to handle FSGSBASE in the
paranoid entry code which has to retrieve the kernel GSBASE value by
accessing per CPU memory. The mechanism needs to retrieve the CPU number
and uses either LSL or RDPID if the processor supports it.
Unfortunately RDPID uses MSR_TSC_AUX which is in the list of cached and
lazily restored MSRs, which means between the point where the guest value
is written and the point of restore, MSR_TSC_AUX contains a random number.
If an NMI or any other exception which uses the paranoid entry path happens
in such a context, then RDPID returns the random guest MSR_TSC_AUX value.
As a consequence this reads from the wrong memory location to retrieve the
kernel GSBASE value. Kernel GS is used to for all regular this_cpu_*()
operations. If the GSBASE in the exception handler points to the per CPU
memory of a different CPU then this has the obvious consequences of data
corruption and crashes.
As the paranoid entry path is the only place which accesses MSR_TSX_AUX
(via RDPID) and the fallback via LSL is not significantly slower, remove
the RDPID alternative from the entry path and always use LSL.
The alternative would be to write MSR_TSC_AUX on every VMENTER and VMEXIT
which would be inflicting massive overhead on that code path.
[ tglx: Rewrote changelog ]
Fixes: eaad981291ee3 ("x86/entry/64: Introduce the FIND_PERCPU_BASE macro")
Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Debugged-by: Tom Lendacky <thomas.lendacky@amd.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200821105229.18938-1-pbonzini@redhat.com
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There are some code parts using CONFIG_PARAVIRT for Xen pvops related
issues instead of the more stringent CONFIG_PARAVIRT_XXL.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200815100641.26362-4-jgross@suse.com
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The last 32-bit user of stuff under CONFIG_PARAVIRT_XXL is gone.
Remove 32-bit specific parts.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200815100641.26362-2-jgross@suse.com
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