kernel/linux.git/arch/x86/Kconfig.debug, branch linux-5.9.y

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-04T17:09:05+00:00

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Acked-by: Michael Ellerman Cc: Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman

Revert "x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()"

2020-11-04T17:08:28+00:00

This reverts commit a85748ed9eb70108f9605558f2754ca94ee91401 which is commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. We had a mistake when merging a later patch in this series due to some file movements, so revert this change for now, as we will add it back in a later commit. Signed-off-by: Greg Kroah-Hartman

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-01T11:47:03+00:00

locking/lockdep: Fix TRACE_IRQFLAGS vs. NMIs

2020-07-27T13:13:29+00:00

Prior to commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ state tracking") IRQ state tracking was disabled in NMIs due to nmi_enter() doing lockdep_off() -- with the obvious requirement that NMI entry call nmi_enter() before trace_hardirqs_off(). [ AFAICT, PowerPC and SH violate this order on their NMI entry ] However, that commit explicitly changed lockdep_hardirqs_*() to ignore lockdep_off() and breaks every architecture that has irq-tracing in it's NMI entry that hasn't been fixed up (x86 being the only fixed one at this point). The reason for this change is that by ignoring lockdep_off() we can: - get rid of 'current->lockdep_recursion' in lockdep_assert_irqs*() which was going to to give header-recursion issues with the seqlock rework. - allow these lockdep_assert_*() macros to function in NMI context. Restore the previous state of things and allow an architecture to opt-in to the NMI IRQ tracking support, however instead of relying on lockdep_off(), rely on in_nmi(), both are part of nmi_enter() and so over-all entry ordering doesn't need to change. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200727124852.GK119549@hirez.programming.kicks-ass.net

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21+00:00

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada

x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined

2020-06-04T03:09:50+00:00

Extract DEBUG_WX to mm/Kconfig.debug for shared use. Change to use ARCH_HAS_DEBUG_WX instead of DEBUG_WX defined by arch port. Signed-off-by: Zong Li Signed-off-by: Andrew Morton Cc: Borislav Petkov Cc: Catalin Marinas Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Thomas Gleixner Cc: Will Deacon Link: http://lkml.kernel.org/r/430736828d149df3f5b462d291e845ec690e0141.1587455584.git.zong.li@sifive.com Signed-off-by: Linus Torvalds

x86/32: Remove CONFIG_DOUBLEFAULT

2020-04-14T12:24:05+00:00

Make the doublefault exception handler unconditional on 32-bit. Yes, it is important to be able to catch #DF exceptions instead of silent reboots. Yes, the code size increase is worth every byte. And one less CONFIG symbol is just the cherry on top. No functional changes. Signed-off-by: Borislav Petkov Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200404083646.8897-1-bp@alien8.de

x86: mm: convert dump_pagetables to use walk_page_range

2020-02-04T03:05:25+00:00

Make use of the new functionality in walk_page_range to remove the arch page walking code and use the generic code to walk the page tables. The effective permissions are passed down the chain using new fields in struct pg_state. The KASAN optimisation is implemented by setting action=CONTINUE in the callbacks to skip an entire tree of entries. Link: http://lkml.kernel.org/r/20191218162402.45610-21-steven.price@arm.com Signed-off-by: Steven Price Cc: Albert Ou Cc: Alexandre Ghiti Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Dave Hansen Cc: David S. Miller Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Hogan Cc: James Morse Cc: Jerome Glisse Cc: "Liang, Kan" Cc: Mark Rutland Cc: Michael Ellerman Cc: Paul Burton Cc: Paul Mackerras Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Russell King Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vineet Gupta Cc: Will Deacon Cc: Zong Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86/traps: Disentangle the 32-bit and 64-bit doublefault code

2019-11-26T20:53:34+00:00

The 64-bit doublefault handler is much nicer than the 32-bit one. As a first step toward unifying them, make the 64-bit handler self-contained. This should have no effect no functional effect except in the odd case of x86_64 with CONFIG_DOUBLEFAULT=n in which case it will change the logging a bit. This also gets rid of CONFIG_DOUBLEFAULT configurability on 64-bit kernels. It didn't do anything useful -- CONFIG_DOUBLEFAULT=n didn't actually disable doublefault handling on x86_64. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Linus Torvalds Signed-off-by: Ingo Molnar

x86/stacktrace: update kconfig help text for reliable unwinders

2019-11-07T14:48:18+00:00

commit 6415b38bae26 ("x86/stacktrace: Enable HAVE_RELIABLE_STACKTRACE for the ORC unwinder") added the ORC unwinder as a "reliable" unwinder. Update the help text to reflect that change: the frame pointer unwinder is no longer the only one that can provide HAVE_RELIABLE_STACKTRACE. Link: http://lkml.kernel.org/r/20191107032958.14034-1-joe.lawrence@redhat.com To: linux-kernel@vger.kernel.org To: live-patching@vger.kernel.org Signed-off-by: Joe Lawrence Acked-by: Josh Poimboeuf Acked-by: Miroslav Benes Reviewed-by: Kamalesh Babulal Signed-off-by: Petr Mladek