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* Merge tag 'docs-6.4-2' of git://git.lwn.net/linuxLinus Torvalds2023-05-0512-24/+652
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull more documentation updates from Jonathan Corbet: "A handful of late-arriving documentation fixes, plus one Spanish translation that has been ready for some time but got applied late" * tag 'docs-6.4-2' of git://git.lwn.net/linux: docs/sp_SP: Add translation of process/adding-syscalls CREDITS: Update email address for Mat Martineau Documentation: update kernel stack for x86_64 docs: Remove unnecessary unicode character docs: fix "Reviewd" typo Documentation: timers: hrtimers: Make hybrid union historical docs/admin-guide/mm/ksm.rst fix intraface -> interface typo doc:it_IT: fix some typos
| * docs/sp_SP: Add translation of process/adding-syscallsCarlos Bilbao2023-05-022-0/+633
| | | | | | | | | | | | | | | | | | Translate Documentation/process/adding-syscalls.rst into Spanish. Co-developed-by: Mauricio Fuentes <mauriciofb@gmail.com> Signed-off-by: Mauricio Fuentes <mauriciofb@gmail.com> Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com> Link: https://lore.kernel.org/r/20230315143526.1213813-1-carlos.bilbao@amd.com
| * CREDITS: Update email address for Mat MartineauMat Martineau2023-05-021-2/+2
| | | | | | | | | | | | | | | | | | | | Changing my email address in CREDITS to be consistent with what's in use in MAINTAINERS and mailmap. Also removed extra date information from the CREDITS entry since I'm a maintainer for MPTCP again. Signed-off-by: Mat Martineau <martineau@kernel.org> Link: https://lore.kernel.org/r/20230502000545.2899055-1-martineau@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * Documentation: update kernel stack for x86_64晏艳(采苓)2023-05-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | Commit 6538b8ea886e ("x86_64: expand kernel stack to 16K") expanded kernel stack for x86_64 but left the wrong documentation, update it. Signed-off-by: Yan Yan <yanyan.yan@antgroup.com> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Link: https://lore.kernel.org/r/20230328072537.20188-1-yanyan.yan@antgroup.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * docs: Remove unnecessary unicode characterTao Liu2023-05-022-2/+2
| | | | | | | | | | | | | | | | | | | | | | There is a non-printable unicode char '\u202a' or "0xe2 0x80 0xaa" in hex in the translation doc. It is unnecessary and should be removed for better text formatting when using editors like vi. Signed-off-by: Tao Liu <ltao@redhat.com> Reviewed-by: Yanteng Si <siyanteng@loongson.cn> Link: https://lore.kernel.org/r/20230426021452.9745-1-ltao@redhat.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * docs: fix "Reviewd" typoDeming Wang2023-05-021-1/+1
| | | | | | | | | | | | | | | | | | Spell "Reviewed" properly in Documentation/Translations/jp/SubmittingPatches Signed-off-by: Deming Wang <wangdeming@inspur.com> Reviewed-by: Akira Yokosawa <akiyks@gmail.com> Link: https://lore.kernel.org/r/20230502010157.1655-1-wangdeming@inspur.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * Documentation: timers: hrtimers: Make hybrid union historicalGeert Uytterhoeven2023-05-021-12/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Non-scalar time was removed from the ktime hybrid union in v3.17, and the union itself followed suit in v4.10. Make it clear that ktime_t is always a 64bit scalar type, to avoid confusing the casual reader. While at it, fix a spelling mistake. Fixes: 24e4a8c3e8868874 ("ktime: Kill non-scalar ktime_t implementation for 2038") Fixes: 2456e855354415bf ("ktime: Get rid of the union") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/59250a3d1c2c827b5c1833169a6e652ca6a784e6.1683021785.git.geert+renesas@glider.be Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * docs/admin-guide/mm/ksm.rst fix intraface -> interface typoDonald Hunter2023-04-261-1/+1
| | | | | | | | | | | | | | | | Fix typo from 'intraface' to 'interface' in admin guide for KSM. Signed-off-by: Donald Hunter <donald.hunter@gmail.com> Link: https://lore.kernel.org/r/20230424080305.2985-1-donald.hunter@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * doc:it_IT: fix some typosFabio Fantoni2023-04-263-5/+5
| | | | | | | | | | | | | | | | | | | | Fix of some typos spotted reading documentation in italian and latest changes for 6.4 Signed-off-by: Fabio Fantoni <fantonifabio@tiscali.it> Reviewed-by: Federico Vaga <federico.vaga@vaga.pv.it> Link: https://lore.kernel.org/r/20230425110158.9755-1-fantonifabio@tiscali.it Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | Merge tag 'trace-v6.4-rc1' of ↵Linus Torvalds2023-05-054-5/+38
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull more tracing updates from Steven Rostedt: - Make buffer_percent read/write. The buffer_percent file is how users can state how long to block on the tracing buffer depending on how much is in the buffer. When it hits the "buffer_percent" it will wake the task waiting on the buffer. For some reason it was set to read-only. This was not noticed because testing was done as root without SELinux, but with SELinux it will prevent even root to write to it without having CAP_DAC_OVERRIDE. - The "touched_functions" was added this merge window, but one of the reasons for adding it was not implemented. That was to show what functions were not only touched, but had either a direct trampoline attached to it, or a kprobe or live kernel patching that can "hijack" the function to run a different function. The point is to know if there's functions in the kernel that may not be behaving as the kernel code shows. This can be used for debugging. TODO: Add this information to kernel oops too. * tag 'trace-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attached tracing: Fix permissions for the buffer_percent file
| * | ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attachedSteven Rostedt (Google)2023-05-053-4/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a function had ever had IPMODIFY or DIRECT attached to it, where this is how live kernel patching and BPF overrides work, mark them and display an "M" in the enabled_functions and touched_functions files. This can be used for debugging. If a function had been modified and later there's a bug in the code related to that function, this can be used to know if the cause is possibly from a live kernel patch or a BPF program that changed the behavior of the code. Also update the documentation on the enabled_functions and touched_functions output, as it was missing direct callers and CALL_OPS. And include this new modify attribute. Link: https://lore.kernel.org/linux-trace-kernel/20230502213233.004e3ae4@gandalf.local.home Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| * | tracing: Fix permissions for the buffer_percent fileOndrej Mosnacek2023-05-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This file defines both read and write operations, yet it is being created as read-only. This means that it can't be written to without the CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write to it without the need to override DAC perms. Link: https://lore.kernel.org/linux-trace-kernel/20230503140114.3280002-1-omosnace@redhat.com Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
* | | Merge tag 'locking-core-2023-05-05' of ↵Linus Torvalds2023-05-0533-111/+209
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: - Introduce local{,64}_try_cmpxchg() - a slightly more optimal primitive, which will be used in perf events ring-buffer code - Simplify/modify rwsems on PREEMPT_RT, to address writer starvation - Misc cleanups/fixes * tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/atomic: Correct (cmp)xchg() instrumentation locking/x86: Define arch_try_cmpxchg_local() locking/arch: Wire up local_try_cmpxchg() locking/generic: Wire up local{,64}_try_cmpxchg() locking/atomic: Add generic try_cmpxchg{,64}_local() support locking/rwbase: Mitigate indefinite writer starvation locking/arch: Rename all internal __xchg() names to __arch_xchg()
| * | | locking/atomic: Correct (cmp)xchg() instrumentationMark Rutland2023-04-292-41/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All xchg() and cmpxchg() ops are atomic RMWs, but currently we instrument these with instrument_atomic_write() rather than instrument_atomic_read_write(), missing the read aspect. Similarly, all try_cmpxchg() ops are non-atomic RMWs on *oldp, but we instrument these accesses with instrument_atomic_write() rather than instrument_read_write(), missing the read aspect and erroneously marking these as atomic. Fix the instrumentation for both points. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20230413160644.490976-1-mark.rutland@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/x86: Define arch_try_cmpxchg_local()Uros Bizjak2023-04-291-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define target specific arch_try_cmpxchg_local(). This definition overrides the generic arch_try_cmpxchg_local() fallback definition and enables target-specific implementation of try_cmpxchg_local(). Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230405141710.3551-5-ubizjak@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/arch: Wire up local_try_cmpxchg()Uros Bizjak2023-04-295-8/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement target specific support for local_try_cmpxchg() and local_cmpxchg() using typed C wrappers that call their _local counterpart and provide additional checking of their input arguments. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230405141710.3551-4-ubizjak@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/generic: Wire up local{,64}_try_cmpxchg()Uros Bizjak2023-04-292-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement generic support for local{,64}_try_cmpxchg(). Redirect to the atomic_ family of functions when the target does not provide its own local.h definitions. For 64-bit targets, implement local64_try_cmpxchg and local64_cmpxchg using typed C wrappers that call local_ family of functions and provide additional checking of their input arguments. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20230405141710.3551-3-ubizjak@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/atomic: Add generic try_cmpxchg{,64}_local() supportUros Bizjak2023-04-294-3/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add generic support for try_cmpxchg{,64}_local() and their falbacks. These provides the generic try_cmpxchg_local family of functions from the arch_ prefixed version, also adding explicit instrumentation. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20230405141710.3551-2-ubizjak@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/rwbase: Mitigate indefinite writer starvationSebastian Andrzej Siewior2023-04-291-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On PREEMPT_RT, rw_semaphore and rwlock_t locks are unfair to writers. Readers can indefinitely acquire the lock unless the writer fully acquired the lock, which might never happen if there is always a reader in the critical section owning the lock. Mel Gorman reported that since LTP-20220121 the dio_truncate test case went from having 1 reader to having 16 readers and that number of readers is sufficient to prevent the down_write ever succeeding while readers exist. Eventually the test is killed after 30 minutes as a failure. Mel proposed a timeout to limit how long a writer can be blocked until the reader is forced into the slowpath. Thomas argued that there is no added value by providing this timeout. From a PREEMPT_RT point of view, there are no critical rw_semaphore or rwlock_t locks left where the reader must be preferred. Mitigate indefinite writer starvation by forcing the READER into the slowpath once the WRITER attempts to acquire the lock. Reported-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/877cwbq4cq.ffs@tglx Link: https://lore.kernel.org/r/20230321161140.HMcQEhHb@linutronix.de Cc: Linus Torvalds <torvalds@linux-foundation.org>
| * | | locking/arch: Rename all internal __xchg() names to __arch_xchg()Andrzej Hajda2023-04-2920-54/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Decrease the probability of this internal facility to be used by driver code. Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Palmer Dabbelt <palmer@rivosinc.com> [riscv] Link: https://lore.kernel.org/r/20230118154450.73842-1-andrzej.hajda@intel.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Merge branch 'x86-uaccess-cleanup': x86 uaccess header cleanupsLinus Torvalds2023-05-055-94/+124
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge my x86 uaccess updates branch. The LAM ("Linear Address Masking") updates in this release made me unhappy about how "access_ok()" was done, and it actually turned out to have a couple of small bugs in it too. This is my cleanup of the code: - use the sign bit of the __user pointer rather than masking the address and checking it against the TASK_SIZE range. We already did this part for the get/put_user() side, but 'access_ok()' did the naïve "mask and range check" thing, which not only generates nasty code, but also ended up meaning that __access_ok itself didn't do a good job, and so copy_from_user_nmi() didn't get the check right. - move all the code that is 64-bit only into the 64-bit version of the header file, so that we don't unnecessarily pollute the shared x86 code and make it look like LAM might work in 32-bit too. - fix a bug in the address masking (that doesn't end up mattering: in this case the fix was to just remove the buggy code entirely). - a couple of trivial cleanups and added commentary about the access_ok() rules. * x86-uaccess-cleanup: x86-64: mm: clarify the 'positive addresses' user address rules x86: mm: remove 'sign' games from LAM untagged_addr*() macros x86: uaccess: move 32-bit and 64-bit parts into proper <asm/uaccess_N.h> header x86: mm: remove architecture-specific 'access_ok()' define x86-64: make access_ok() independent of LAM
| * | | | x86-64: mm: clarify the 'positive addresses' user address rulesLinus Torvalds2023-05-032-15/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dave Hansen found the "(long) addr >= 0" code in the x86-64 access_ok checks somewhat confusing, and suggested using a helper to clarify what the code is doing. So this does exactly that: clarifying what the sign bit check is all about, by adding a helper macro that makes it clear what it is testing. This also adds some explicit comments talking about how even with LAM enabled, any addresses with the sign bit will still GP-fault in the non-canonical region just above the sign bit. This is all what allows us to do the user address checks with just the sign bit, and furthermore be a bit cavalier about accesses that might be done with an additional offset even past that point. (And yes, this talks about 'positive' even though zero is also a valid user address and so technically we should call them 'non-negative'. But I don't think using 'non-negative' ends up being more understandable). Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | x86: mm: remove 'sign' games from LAM untagged_addr*() macrosLinus Torvalds2023-05-031-15/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The intent of the sign games was to not modify kernel addresses when untagging them. However, that had two issues: (a) it didn't actually work as intended, since the mask was calculated as 'addr >> 63' on an _unsigned_ address. So instead of getting a mask of all ones for kernel addresses, you just got '1'. (b) untagging a kernel address isn't actually a valid operation anyway. Now, (a) had originally been true for both 'untagged_addr()' and the remote version of it, but had accidentally been fixed for the regular version of untagged_addr() by commit e0bddc19ba95 ("x86/mm: Reduce untagged_addr() overhead for systems without LAM"). That one rewrote the shift to be part of the alternative asm code, and in the process changed the unsigned shift into a signed 'sar' instruction. And while it is true that we don't want to turn what looks like a kernel address into a user address by masking off the high bit, that doesn't need these sign masking games - all it needs is that the mm context 'untag_mask' value has the high bit set. Which it always does. So simplify the code by just removing the superfluous (and in the case of untagged_addr_remote(), still buggy) sign bit games in the address masking. Acked-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | x86: uaccess: move 32-bit and 64-bit parts into proper <asm/uaccess_N.h> headerLinus Torvalds2023-05-033-85/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The x86 <asm/uaccess.h> file has grown features that are specific to x86-64 like LAM support and the related access_ok() changes. They really should be in the <asm/uaccess_64.h> file and not pollute the generic x86 header. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | x86: mm: remove architecture-specific 'access_ok()' defineLinus Torvalds2023-05-031-34/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's already a generic definition of 'access_ok()' in the asm-generic/access_ok.h header file, and the only difference bwteen that and the x86-specific one is the added check for WARN_ON_IN_IRQ(). And it turns out that the reason for that check is long gone: it used to use a "user_addr_max()" inline function that depended on the current thread, and caused problems in non-thread contexts. For details, see commits 7c4788950ba5 ("x86/uaccess, sched/preempt: Verify access_ok() context") and in particular commit ae31fe51a3cc ("perf/x86: Restore TASK_SIZE check on frame pointer") about how and why this came to be. But that "current task" issue was removed in the big set_fs() removal by Christoph Hellwig in commit 47058bb54b57 ("x86: remove address space overrides using set_fs()"). So the reason for the test and the architecture-specific access_ok() define no longer exists, and is actually harmful these days. For example, it led various 'copy_from_user_nmi()' games (eg using __range_not_ok() instead, and then later converted to __access_ok() when that became ok). And that in turn meant that LAM was broken for the frame following before this series, because __access_ok() used to not do the address untagging. Accessing user state still needs care in many contexts, but access_ok() is not the place for this test. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Linus Torvalds torvalds@linux-foundation.org>
| * | | | x86-64: make access_ok() independent of LAMLinus Torvalds2023-05-033-10/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The linear address masking (LAM) code made access_ok() more complicated, in that it now needs to untag the address in order to verify the access range. See commit 74c228d20a51 ("x86/uaccess: Provide untagged_addr() and remove tags before address check"). We were able to avoid that overhead in the get_user/put_user code paths by simply using the sign bit for the address check, and depending on the GP fault if the address was non-canonical, which made it all independent of LAM. And we can do the same thing for access_ok(): simply check that the user pointer range has the high bit clear. No need to bother with any address bit masking. In fact, we can go a bit further, and just check the starting address for known small accesses ranges: any accesses that overflow will still be in the non-canonical area and will still GP fault. To still make syzkaller catch any potentially unchecked user addresses, we'll continue to warn about GP faults that are caused by accesses in the non-canonical range. But we'll limit that to purely "high bit set and past the one-page 'slop' area". We could probably just do that "check only starting address" for any arbitrary range size: realistically all kernel accesses to user space will be done starting at the low address. But let's leave that kind of optimization for later. As it is, this already allows us to generate simpler code and not worry about any tag bits in the address. The one thing to look out for is the GUP address check: instead of actually copying data in the virtual address range (and thus bad addresses being caught by the GP fault), GUP will look up the page tables manually. As a result, the page table limits need to be checked, and that was previously implicitly done by the access_ok(). With the relaxed access_ok() check, we need to just do an explicit check for TASK_SIZE_MAX in the GUP code instead. The GUP code already needs to do the tag bit unmasking anyway, so there this is all very straightforward, and there are no LAM issues. Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | Merge tag 'riscv-for-linus-6.4-mw2' of ↵Linus Torvalds2023-05-0522-68/+682
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull more RISC-V updates from Palmer Dabbelt: - Support for hibernation - The .rela.dyn section has been moved to the init area - A fix for the SBI probing to allow for implementation-defined behavior - Various other fixes and cleanups throughout the tree * tag 'riscv-for-linus-6.4-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: include cpufeature.h in cpufeature.c riscv: Move .rela.dyn to the init sections dt-bindings: riscv: explicitly mention assumption of Zicsr & Zifencei support riscv: compat_syscall_table: Fixup compile warning RISC-V: fixup in-flight collision with ARCH_WANT_OPTIMIZE_VMEMMAP rename RISC-V: fix sifive and thead section mismatches in errata RISC-V: Align SBI probe implementation with spec riscv: mm: remove redundant parameter of create_fdt_early_page_table riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selection RISC-V: Add arch functions to support hibernation/suspend-to-disk RISC-V: mm: Enable huge page support to kernel_page_present() function RISC-V: Factor out common code of __cpu_resume_enter() RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public function
| * | | | | RISC-V: include cpufeature.h in cpufeature.cConor Dooley2023-05-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Automation complains: warning: symbol '__pcpu_scope_misaligned_access_speed' was not declared. Should it be static? cpufeature.c doesn't actually include the header of the same name, as it had not previously used anything from it. The per-cpu variable is declared there, so include it to silence the complaints. Fixes: 62a31d6e38bd ("RISC-V: hwprobe: Support probing of misaligned access performance") Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Evan Green <evan@rivosinc.com> Link: https://lore.kernel.org/r/20230420-wound-gizzard-2b2b589d9bea@spud Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | riscv: Move .rela.dyn to the init sectionsAlexandre Ghiti2023-05-021-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The recent introduction of relocatable kernels prepared the move of .rela.dyn to the init section, but actually forgot to do so, so do it here. Before this patch: "Freeing unused kernel image (initmem) memory: 2592K" After this patch: "Freeing unused kernel image (initmem) memory: 6288K" The difference corresponds to the size of the .rela.dyn section: "[42] .rela.dyn RELA ffffffff8197e798 0127f798 000000000039c660 0000000000000018 A 47 0 8" Fixes: 559d1e45a16d ("riscv: Use --emit-relocs in order to move .rela.dyn in init") Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20230428120932.22735-1-alexghiti@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | dt-bindings: riscv: explicitly mention assumption of Zicsr & Zifencei supportConor Dooley2023-05-021-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dt-binding was defined before the extraction of csr access and fence.i into their own extensions, and thus the presence of the I base extension implies Zicsr and Zifencei. There's no harm in adding them obviously, but for backwards compatibility with DTs that existed prior to that extraction, software is unable to differentiate between "i" and "i_zicsr_zifencei" without any further information. Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Acked-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20230427-fence-blurred-c92fb69d4137@wendy Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | riscv: compat_syscall_table: Fixup compile warningGuo Ren2023-05-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ../arch/riscv/kernel/compat_syscall_table.c:12:41: warning: initialized field overwritten [-Woverride-init] 12 | #define __SYSCALL(nr, call) [nr] = (call), | ^ ../include/uapi/asm-generic/unistd.h:567:1: note: in expansion of macro '__SYSCALL' 567 | __SYSCALL(__NR_semget, sys_semget) Fixes: 59c10c52f573 ("riscv: compat: syscall: Add compat_sys_call_table implementation") Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reported-by: kernel test robot <lkp@intel.com> Tested-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Signed-off-by: Drew Fustini <dfustini@baylibre.com> Link: https://lore.kernel.org/r/20230501223353.2833899-1-dfustini@baylibre.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | RISC-V: fixup in-flight collision with ARCH_WANT_OPTIMIZE_VMEMMAP renameConor Dooley2023-04-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lukas warned that ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP had been renamed in the mm tree & that RISC-V would need a fixup as part of the merge. The warning was missed however, and RISC-V is selecting the orphaned Kconfig option. Fixes: 89d77f71f493 ("Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux") Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>. Link: https://lore.kernel.org/linux-riscv/CAKXUXMyVeg2kQK_edKHtMD3eADrDK_PKhCSVkMrLDdYgTQQ5rg@mail.gmail.com/ Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20230429-trilogy-jolly-12bf5c53d62d@spud Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | RISC-V: fix sifive and thead section mismatches in errataRandy Dunlap2023-04-292-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_MODULES is set, __init_or_module becomes <empty>, but when CONFIG_MODULES is not set, __init_or_module becomes __init. In the latter case, it causes section mismatch warnings: WARNING: modpost: vmlinux.o: section mismatch in reference: riscv_fill_cpu_mfr_info (section: .text) -> sifive_errata_patch_func (section: .init.text) WARNING: modpost: vmlinux.o: section mismatch in reference: riscv_fill_cpu_mfr_info (section: .text) -> thead_errata_patch_func (section: .init.text) Fixes: bb3f89487fd9 ("RISC-V: hwprobe: Remove __init on probe_vendor_features()") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Evan Green <evan@rivosinc.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230429155247.12131-1-rdunlap@infradead.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | RISC-V: Align SBI probe implementation with specAndrew Jones2023-04-296-14/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sbi_probe_extension() is specified with "Returns 0 if the given SBI extension ID (EID) is not available, or 1 if it is available unless defined as any other non-zero value by the implementation." Additionally, sbiret.value is a long. Fix the implementation to ensure any nonzero long value is considered a success, rather than only positive int values. Fixes: b9dcd9e41587 ("RISC-V: Add basic support for SBI v0.2") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230427163626.101042-1-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | riscv: mm: remove redundant parameter of create_fdt_early_page_tableSong Shuai2023-04-291-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | create_fdt_early_page_table() explicitly uses early_pg_dir for 32-bit fdt mapping and the pgdir parameter is redundant here. So remove it and its caller. Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Song Shuai <suagrfillet@gmail.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Fixes: ef69d2559fe9 ("riscv: Move early dtb mapping into the fixmap region") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230426100009.685435-1-suagrfillet@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | Merge patch series "RISC-V Hibernation Support"Palmer Dabbelt2023-04-2910-34/+634
| |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sia Jee Heng <jeeheng.sia@starfivetech.com> says: This series adds RISC-V Hibernation/suspend to disk support. Low level Arch functions were created to support hibernation. swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write cpu state onto the stack, then calling swsusp_save() to save the memory image. Arch specific hibernation header is implemented and is utilized by the arch_hibernation_header_restore() and arch_hibernation_header_save() functions. The arch specific hibernation header consists of satp, hartid, and the cpu_resume address. The kernel built version is also need to be saved into the hibernation image header to making sure only the same kernel is restore when resume. swsusp_arch_resume() creates a temporary page table that covering only the linear map. It copies the restore code to a 'safe' page, then start to restore the memory image. Once completed, it restores the original kernel's page table. It then calls into __hibernate_cpu_resume() to restore the CPU context. Finally, it follows the normal hibernation path back to the hibernation core. To enable hibernation/suspend to disk into RISCV, the below config need to be enabled: - CONFIG_HIBERNATION - CONFIG_ARCH_HIBERNATION_HEADER - CONFIG_ARCH_HIBERNATION_POSSIBLE At high-level, this series includes the following changes: 1) Change suspend_save_csrs() and suspend_restore_csrs() to public function as these functions are common to suspend/hibernation. (patch 1) 2) Refactor the common code in the __cpu_resume_enter() function and __hibernate_cpu_resume() function. The common code are used by hibernation and suspend. (patch 2) 3) Enhance kernel_page_present() function to support huge page. (patch 3) 4) Add arch/riscv low level functions to support hibernation/suspend to disk. (patch 4) * b4-shazam-merge: RISC-V: Add arch functions to support hibernation/suspend-to-disk RISC-V: mm: Enable huge page support to kernel_page_present() function RISC-V: Factor out common code of __cpu_resume_enter() RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public function Link: https://lore.kernel.org/r/20230330064321.1008373-1-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| | * | | | | RISC-V: Add arch functions to support hibernation/suspend-to-diskSia Jee Heng2023-04-297-1/+556
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Low level Arch functions were created to support hibernation. swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write cpu state onto the stack, then calling swsusp_save() to save the memory image. Arch specific hibernation header is implemented and is utilized by the arch_hibernation_header_restore() and arch_hibernation_header_save() functions. The arch specific hibernation header consists of satp, hartid, and the cpu_resume address. The kernel built version is also need to be saved into the hibernation image header to making sure only the same kernel is restore when resume. swsusp_arch_resume() creates a temporary page table that covering only the linear map. It copies the restore code to a 'safe' page, then start to restore the memory image. Once completed, it restores the original kernel's page table. It then calls into __hibernate_cpu_resume() to restore the CPU context. Finally, it follows the normal hibernation path back to the hibernation core. To enable hibernation/suspend to disk into RISCV, the below config need to be enabled: - CONFIG_HIBERNATION - CONFIG_ARCH_HIBERNATION_HEADER - CONFIG_ARCH_HIBERNATION_POSSIBLE Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com> Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com> Reviewed-by: Mason Huo <mason.huo@starfivetech.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230330064321.1008373-5-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| | * | | | | RISC-V: mm: Enable huge page support to kernel_page_present() functionSia Jee Heng2023-04-291-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently kernel_page_present() function doesn't support huge page detection causes the function to mistakenly return false to the hibernation core. Add huge page detection to the function to solve the problem. Fixes: 9e953cda5cdf ("riscv: Introduce huge page support for 32/64bit kernel") Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com> Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com> Reviewed-by: Mason Huo <mason.huo@starfivetech.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20230330064321.1008373-4-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| | * | | | | RISC-V: Factor out common code of __cpu_resume_enter()Sia Jee Heng2023-04-292-31/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The cpu_resume() function is very similar for the suspend to disk and suspend to ram cases. Factor out the common code into suspend_restore_csrs macro and suspend_restore_regs macro. Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230330064321.1008373-3-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| | * | | | | RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public functionSia Jee Heng2023-04-292-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently suspend_save_csrs() and suspend_restore_csrs() functions are statically defined in the suspend.c. Change the function's attribute to public so that the functions can be used by hibernation as well. Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com> Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com> Reviewed-by: Mason Huo <mason.huo@starfivetech.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230330064321.1008373-2-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| * | | | | | riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selectionNathan Chancellor2023-04-291-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When building allmodconfig with clang and its integrated assembler and linking with a version of GNU ld prior to 2.36, the following link error occurs: riscv64-linux-gnu-ld: .init.data has both ordered [`__patchable_function_entries' in init/main.o] and unordered [`.init_array.0' in kernel/trace/trace_benchmark.o] sections riscv64-linux-gnu-ld: final link failed: bad value This is the same error addressed by commit 45bd8951806e ("arm64: Improve HAVE_DYNAMIC_FTRACE_WITH_REGS selection for clang") for arm64. See that changelog for a full description of why this error occurs with this combination of tools. In a similar manner as that change, restrict the CONFIG_HAVE_DYNAMIC_FTRACE selection to combinations of tools known to work so that there are no errors. Link: https://github.com/ClangBuiltLinux/linux/issues/1817 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230404-riscv-dynamic-ftrace-checks-clang-v1-1-0ce296b7d423@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
* | | | | | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2023-05-0523-177/+1208
|\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull more kvm updates from Paolo Bonzini: "This includes the 6.4 changes for RISC-V, and a few bugfix patches for other architectures. For x86, this closes a longstanding performance issue in the newer and (usually) more scalable page table management code. RISC-V: - ONE_REG interface to enable/disable SBI extensions - Zbb extension for Guest/VM - AIA CSR virtualization x86: - Fix a long-standing TDP MMU flaw, where unloading roots on a vCPU can result in the root being freed even though the root is completely valid and can be reused as-is (with a TLB flush). s390: - A couple of bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: s390: fix race in gmap_make_secure() KVM: s390: pv: fix asynchronous teardown for small VMs KVM: x86: Preserve TDP MMU roots until they are explicitly invalidated RISC-V: KVM: Virtualize per-HART AIA CSRs RISC-V: KVM: Use bitmap for irqs_pending and irqs_pending_mask RISC-V: KVM: Add ONE_REG interface for AIA CSRs RISC-V: KVM: Implement subtype for CSR ONE_REG interface RISC-V: KVM: Initial skeletal support for AIA RISC-V: KVM: Drop the _MASK suffix from hgatp.VMID mask defines RISC-V: Detect AIA CSRs from ISA string RISC-V: Add AIA related CSR defines RISC-V: KVM: Allow Zbb extension for Guest/VM RISC-V: KVM: Add ONE_REG interface to enable/disable SBI extensions RISC-V: KVM: Alphabetize selects KVM: RISC-V: Retry fault if vma_lookup() results become invalid
| * \ \ \ \ \ \ Merge tag 'kvm-s390-next-6.4-2' of ↵Paolo Bonzini2023-05-053-21/+23
| |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD For 6.4
| | * | | | | | | KVM: s390: fix race in gmap_make_secure()Claudio Imbrenda2023-05-041-21/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix a potential race in gmap_make_secure() and remove the last user of follow_page() without FOLL_GET. The old code is locking something it doesn't have a reference to, and as explained by Jason and David in this discussion: https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/ it can lead to all kind of bad things, including the page getting unmapped (MADV_DONTNEED), freed, reallocated as a larger folio and the unlock_page() would target the wrong bit. There is also another race with the FOLL_WRITE, which could race between the follow_page() and the get_locked_pte(). The main point is to remove the last use of follow_page() without FOLL_GET or FOLL_PIN, removing the races can be considered a nice bonus. Link: https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/ Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Fixes: 214d9bbcd3a6 ("s390/mm: provide memory management functions for protected KVM guests") Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Message-Id: <20230428092753.27913-2-imbrenda@linux.ibm.com>
| | * | | | | | | KVM: s390: pv: fix asynchronous teardown for small VMsClaudio Imbrenda2023-05-042-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On machines without the Destroy Secure Configuration Fast UVC, the topmost level of page tables is set aside and freed asynchronously as last step of the asynchronous teardown. Each gmap has a host_to_guest radix tree mapping host (userspace) addresses (with 1M granularity) to gmap segment table entries (pmds). If a guest is smaller than 2GB, the topmost level of page tables is the segment table (i.e. there are only 2 levels). Replacing it means that the pointers in the host_to_guest mapping would become stale and cause all kinds of nasty issues. This patch fixes the issue by disallowing asynchronous teardown for guests with only 2 levels of page tables. Userspace should (and already does) try using the normal destroy if the asynchronous one fails. Update s390_replace_asce so it refuses to replace segment type ASCEs. This is still needed in case the normal destroy VM fails. Fixes: fb491d5500a7 ("KVM: s390: pv: asynchronous destroy for reboot") Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Message-Id: <20230421085036.52511-2-imbrenda@linux.ibm.com>
| * | | | | | | | Merge tag 'kvm-x86-mmu-6.4-2' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini2023-05-051-65/+56
| |\ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix a long-standing flaw in x86's TDP MMU where unloading roots on a vCPU can result in the root being freed even though the root is completely valid and can be reused as-is (with a TLB flush).
| | * | | | | | | | KVM: x86: Preserve TDP MMU roots until they are explicitly invalidatedSean Christopherson2023-04-271-65/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Preserve TDP MMU roots until they are explicitly invalidated by gifting the TDP MMU itself a reference to a root when it is allocated. Keeping a reference in the TDP MMU fixes a flaw where the TDP MMU exhibits terrible performance, and can potentially even soft-hang a vCPU, if a vCPU frequently unloads its roots, e.g. when KVM is emulating SMI+RSM. When KVM emulates something that invalidates _all_ TLB entries, e.g. SMI and RSM, KVM unloads all of the vCPUs roots (KVM keeps a small per-vCPU cache of previous roots). Unloading roots is a simple way to ensure KVM flushes and synchronizes all roots for the vCPU, as KVM flushes and syncs when allocating a "new" root (from the vCPU's perspective). In the shadow MMU, KVM keeps track of all shadow pages, roots included, in a per-VM hash table. Unloading a shadow MMU root just wipes it from the per-vCPU cache; the root is still tracked in the per-VM hash table. When KVM loads a "new" root for the vCPU, KVM will find the old, unloaded root in the per-VM hash table. Unlike the shadow MMU, the TDP MMU doesn't track "inactive" roots in a per-VM structure, where "active" in this case means a root is either in-use or cached as a previous root by at least one vCPU. When a TDP MMU root becomes inactive, i.e. the last vCPU reference to the root is put, KVM immediately frees the root (asterisk on "immediately" as the actual freeing may be done by a worker, but for all intents and purposes the root is gone). The TDP MMU behavior is especially problematic for 1-vCPU setups, as unloading all roots effectively frees all roots. The issue is mitigated to some degree in multi-vCPU setups as a different vCPU usually holds a reference to an unloaded root and thus keeps the root alive, allowing the vCPU to reuse its old root after unloading (with a flush+sync). The TDP MMU flaw has been known for some time, as until very recently, KVM's handling of CR0.WP also triggered unloading of all roots. The CR0.WP toggling scenario was eventually addressed by not unloading roots when _only_ CR0.WP is toggled, but such an approach doesn't Just Work for emulating SMM as KVM must emulate a full TLB flush on entry and exit to/from SMM. Given that the shadow MMU plays nice with unloading roots at will, teaching the TDP MMU to do the same is far less complex than modifying KVM to track which roots need to be flushed before reuse. Note, preserving all possible TDP MMU roots is not a concern with respect to memory consumption. Now that the role for direct MMUs doesn't include information about the guest, e.g. CR0.PG, CR0.WP, CR4.SMEP, etc., there are _at most_ six possible roots (where "guest_mode" here means L2): 1. 4-level !SMM !guest_mode 2. 4-level SMM !guest_mode 3. 5-level !SMM !guest_mode 4. 5-level SMM !guest_mode 5. 4-level !SMM guest_mode 6. 5-level !SMM guest_mode And because each vCPU can track 4 valid roots, a VM can already have all 6 root combinations live at any given time. Not to mention that, in practice, no sane VMM will advertise different guest.MAXPHYADDR values across vCPUs, i.e. KVM won't ever use both 4-level and 5-level roots for a single VM. Furthermore, the vast majority of modern hypervisors will utilize EPT/NPT when available, thus the guest_mode=%true cases are also unlikely to be utilized. Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com> Link: https://lore.kernel.org/all/959c5bce-beb5-b463-7158-33fc4a4f910c@linux.microsoft.com Link: https://lkml.kernel.org/r/20220209170020.1775368-1-pbonzini%40redhat.com Link: https://lore.kernel.org/all/20230322013731.102955-1-minipli@grsecurity.net Link: https://lore.kernel.org/all/000000000000a0bc2b05f9dd7fab@google.com Link: https://lore.kernel.org/all/000000000000eca0b905fa0f7756@google.com Cc: Ben Gardon <bgardon@google.com> Cc: David Matlack <dmatlack@google.com> Cc: stable@vger.kernel.org Tested-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com> Link: https://lore.kernel.org/r/20230426220323.3079789-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
| * | | | | | | | | Merge tag 'kvm-riscv-6.4-1' of https://github.com/kvm-riscv/linux into HEADPaolo Bonzini2023-05-0519-91/+1129
| |\ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM/riscv changes for 6.4 - ONE_REG interface to enable/disable SBI extensions - Zbb extension for Guest/VM - AIA CSR virtualization
| | * | | | | | | | | RISC-V: KVM: Virtualize per-HART AIA CSRsAnup Patel2023-04-213-35/+382
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The AIA specification introduce per-HART AIA CSRs which primarily support: * 64 local interrupts on both RV64 and RV32 * priority for each of the 64 local interrupts * interrupt filtering for local interrupts This patch virtualize above mentioned AIA CSRs and also extend ONE_REG interface to allow user-space save/restore Guest/VM view of these CSRs. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
| | * | | | | | | | | RISC-V: KVM: Use bitmap for irqs_pending and irqs_pending_maskAnup Patel2023-04-212-22/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To support 64 VCPU local interrupts on RV32 host, we should use bitmap for irqs_pending and irqs_pending_mask in struct kvm_vcpu_arch. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>