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2022-10-11treewide: use prandom_u32_max() when possible, part 1Jason A. Donenfeld1-1/+1
Rather than incurring a division or requesting too many random bytes for the given range, use the prandom_u32_max() function, which only takes the minimum required bytes from the RNG and avoids divisions. This was done mechanically with this coccinelle script: @basic@ expression E; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u64; @@ ( - ((T)get_random_u32() % (E)) + prandom_u32_max(E) | - ((T)get_random_u32() & ((E) - 1)) + prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2) | - ((u64)(E) * get_random_u32() >> 32) + prandom_u32_max(E) | - ((T)get_random_u32() & ~PAGE_MASK) + prandom_u32_max(PAGE_SIZE) ) @multi_line@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; identifier RAND; expression E; @@ - RAND = get_random_u32(); ... when != RAND - RAND %= (E); + RAND = prandom_u32_max(E); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Add one to the literal. @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1: print("Skipping 0x%x for cleanup elsewhere" % (value)) cocci.include_match(False) elif value & (value + 1) != 0: print("Skipping 0x%x because it's not a power of two minus one" % (value)) cocci.include_match(False) elif literal.startswith('0x'): coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1)) else: coccinelle.RESULT = cocci.make_expr("%d" % (value + 1)) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; expression add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + prandom_u32_max(RESULT) @collapse_ret@ type T; identifier VAR; expression E; @@ { - T VAR; - VAR = (E); - return VAR; + return E; } @drop_var@ type T; identifier VAR; @@ { - T VAR; ... when != VAR } Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Yury Norov <yury.norov@gmail.com> Reviewed-by: KP Singh <kpsingh@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390 Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-10Merge tag 'mm-stable-2022-10-08' of ↵Linus Torvalds2-4/+8
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...
2022-10-03x86: kmsan: disable instrumentation of unsupported codeAlexander Potapenko1-0/+3
Instrumenting some files with KMSAN will result in kernel being unable to link, boot or crashing at runtime for various reasons (e.g. infinite recursion caused by instrumentation hooks calling instrumented code again). Completely omit KMSAN instrumentation in the following places: - arch/x86/boot and arch/x86/realmode/rm, as KMSAN doesn't work for i386; - arch/x86/entry/vdso, which isn't linked with KMSAN runtime; - three files in arch/x86/kernel - boot problems; - arch/x86/mm/cpu_entry_area.c - recursion. Link: https://lkml.kernel.org/r/20220915150417.722975-33-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26x86: remove vma linked list walksMatthew Wilcox (Oracle)1-4/+5
Use the VMA iterator instead. Link: https://lkml.kernel.org/r/20220906194824.2110408-36-Liam.Howlett@oracle.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26treewide: Filter out CC_FLAGS_CFISami Tolvanen1-1/+2
In preparation for removing CC_FLAGS_CFI from CC_FLAGS_LTO, explicitly filter out CC_FLAGS_CFI in all the makefiles where we currently filter out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220908215504.3686827-2-samitolvanen@google.com
2022-08-16x86/entry: Fix entry_INT80_compat for Xen PV guestsJuergen Gross1-1/+1
Commit c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS") missed one use case of SWAPGS in entry_INT80_compat(). Removing of the SWAPGS macro led to asm just using "swapgs", as it is accepting instructions in capital letters, too. This in turn leads to splats in Xen PV guests like: [ 36.145223] general protection fault, maybe for address 0x2d: 0000 [#1] PREEMPT SMP NOPTI [ 36.145794] CPU: 2 PID: 1847 Comm: ld-linux.so.2 Not tainted 5.19.1-1-default #1 \ openSUSE Tumbleweed f3b44bfb672cdb9f235aff53b57724eba8b9411b [ 36.146608] Hardware name: HP ProLiant ML350p Gen8, BIOS P72 11/14/2013 [ 36.148126] RIP: e030:entry_INT80_compat+0x3/0xa3 Fix that by open coding this single instance of the SWAPGS macro. Fixes: c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS") Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jan Beulich <jbeulich@suse.com> Cc: <stable@vger.kernel.org> # 5.19 Link: https://lore.kernel.org/r/20220816071137.4893-1-jgross@suse.com
2022-08-10x86: link vdso and boot with -z noexecstack --no-warn-rwx-segmentsNick Desaulniers1-1/+1
Users of GNU ld (BFD) from binutils 2.39+ will observe multiple instances of a new warning when linking kernels in the form: ld: warning: arch/x86/boot/pmjump.o: missing .note.GNU-stack section implies executable stack ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker ld: warning: arch/x86/boot/compressed/vmlinux has a LOAD segment with RWX permissions Generally, we would like to avoid the stack being executable. Because there could be a need for the stack to be executable, assembler sources have to opt-in to this security feature via explicit creation of the .note.GNU-stack feature (which compilers create by default) or command line flag --noexecstack. Or we can simply tell the linker the production of such sections is irrelevant and to link the stack as --noexecstack. LLVM's LLD linker defaults to -z noexecstack, so this flag isn't strictly necessary when linking with LLD, only BFD, but it doesn't hurt to be explicit here for all linkers IMO. --no-warn-rwx-segments is currently BFD specific and only available in the current latest release, so it's wrapped in an ld-option check. While the kernel makes extensive usage of ELF sections, it doesn't use permissions from ELF segments. Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@kernel.dk/ Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107 Link: https://github.com/llvm/llvm-project/issues/57009 Reported-and-tested-by: Jens Axboe <axboe@kernel.dk> Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-06Merge tag 'x86-urgent-2022-08-06' of ↵Linus Torvalds3-7/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: - build fix for old(er) binutils - build fix for new GCC - kexec boot environment fix * tag 'x86-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y x86/numa: Use cpumask_available instead of hardcoded NULL check x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero
2022-08-04Merge tag 'spdx-6.0-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX updates from Greg KH: "Here is the set of SPDX comment updates for 6.0-rc1. Nothing huge here, just a number of updated SPDX license tags and cleanups based on the review of a number of common patterns in GPLv2 boilerplate text. Also included in here are a few other minor updates, two USB files, and one Documentation file update to get the SPDX lines correct. All of these have been in the linux-next tree for a very long time" * tag 'spdx-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (28 commits) Documentation: samsung-s3c24xx: Add blank line after SPDX directive x86/crypto: Remove stray comment terminator treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_406.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_398.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_391.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_390.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_320.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_319.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_318.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_298.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_292.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_179.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_168.RULE (part 2) treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_168.RULE (part 1) treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_160.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_152.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_149.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_147.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_133.RULE ...
2022-08-04x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=yAndrea Righi3-7/+2
With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_$(BITS).o becomes an empty object file. With some old versions of binutils (i.e., 2.35.90.20210113-1ubuntu1) the GNU assembler doesn't generate a symbol table for empty object files and objtool fails with the following error when a valid symbol table cannot be found: arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table To prevent this from happening, build thunk_$(BITS).o only if CONFIG_PREEMPTION is enabled. BugLink: https://bugs.launchpad.net/bugs/1911359 Fixes: 320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft") Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/Ys/Ke7EWjcX+ZlXO@arighi-desktop
2022-07-14x86/entry: Remove UNTRAIN_RET from native_irq_return_ldtAlexandre Chartre1-1/+0
UNTRAIN_RET is not needed in native_irq_return_ldt because RET untraining has already been done at this point. In addition, when the RETBleed mitigation is IBPB, UNTRAIN_RET clobbers several registers (AX, CX, DX) so here it trashes user values which are in these registers. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/35b0d50f-12d1-10c3-f5e8-d6c140486d4a@oracle.com
2022-07-07x86/entry: Move PUSH_AND_CLEAR_REGS() back into error_entryPeter Zijlstra1-3/+6
Commit ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()") moved PUSH_AND_CLEAR_REGS out of error_entry, into its own function, in part to avoid calling error_entry() for XenPV. However, commit 7c81c0c9210c ("x86/entry: Avoid very early RET") had to change that because the 'ret' was too early and moved it into idtentry, bloating the text size, since idtentry is expanded for every exception vector. However, with the advent of xen_error_entry() in commit d147553b64bad ("x86/xen: Add UNTRAIN_RET") it became possible to remove PUSH_AND_CLEAR_REGS from idtentry, back into *error_entry(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-29x86/retbleed: Add fine grained Kconfig knobsPeter Zijlstra1-0/+4
Do fine-grained Kconfig for all the various retbleed parts. NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=nJosh Poimboeuf2-4/+0
If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be silently disabled. There's nothing retpoline-specific about RSB buffer filling. Remove the CONFIG_RETPOLINE guards around it. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27objtool: Add entry UNRET validationPeter Zijlstra2-4/+5
Since entry asm is tricky, add a validation pass that ensures the retbleed mitigation has been done before the first actual RET instruction. Entry points are those that either have UNWIND_HINT_ENTRY, which acts as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or those that have UWIND_HINT_IRET_REGS at +0. This is basically a variant of validate_branch() that is intra-function and it will simply follow all branches from marked entry points and ensures that all paths lead to ANNOTATE_UNRET_END. If a path hits RET or an indirection the path is a fail and will be reported. There are 3 ANNOTATE_UNRET_END instances: - UNTRAIN_RET itself - exception from-kernel; this path doesn't need UNTRAIN_RET - all early exceptions; these also don't need UNTRAIN_RET Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/bugs: Add retbleed=ibpbPeter Zijlstra2-1/+23
jmp2ret mitigates the easy-to-attack case at relatively low overhead. It mitigates the long speculation windows after a mispredicted RET, but it does not mitigate the short speculation window from arbitrary instruction boundaries. On Zen2, there is a chicken bit which needs setting, which mitigates "arbitrary instruction boundaries" down to just "basic block boundaries". But there is no fix for the short speculation window on basic block boundaries, other than to flush the entire BTB to evict all attacker predictions. On the spectrum of "fast & blurry" -> "safe", there is (on top of STIBP or no-SMT): 1) Nothing System wide open 2) jmp2ret May stop a script kiddy 3) jmp2ret+chickenbit Raises the bar rather further 4) IBPB Only thing which can count as "safe". Tentative numbers put IBPB-on-entry at a 2.5x hit on Zen2, and a 10x hit on Zen1 according to lmbench. [ bp: Fixup feature bit comments, document option, 32-bit build fix. ] Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/xen: Add UNTRAIN_RETPeter Zijlstra1-1/+7
Ensure the Xen entry also passes through UNTRAIN_RET. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/entry: Add kernel IBRS implementationPeter Zijlstra3-9/+110
Implement Kernel IBRS - currently the only known option to mitigate RSB underflow speculation issues on Skylake hardware. Note: since IBRS_ENTER requires fuller context established than UNTRAIN_RET, it must be placed after it. However, since UNTRAIN_RET itself implies a RET, it must come after IBRS_ENTER. This means IBRS_ENTER needs to also move UNTRAIN_RET. Note 2: KERNEL_IBRS is sub-optimal for XenPV. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86: Add magic AMD return-thunkPeter Zijlstra2-0/+10
Note: needs to be in a section distinct from Retpolines such that the Retpoline RET substitution cannot possibly use immediate jumps. ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a little tricky but works due to the fact that zen_untrain_ret() doesn't have any stack ops and as such will emit a single ORC entry at the start (+0x3f). Meanwhile, unwinding an IP, including the __x86_return_thunk() one (+0x40) will search for the largest ORC entry smaller or equal to the IP, these will find the one ORC entry (+0x3f) and all works. [ Alexandre: SVM part. ] [ bp: Build fix, massages. ] Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/entry: Avoid very early RETPeter Zijlstra1-10/+2
Commit ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()") manages to introduce a CALL/RET pair that is before SWITCH_TO_KERNEL_CR3, which means it is before RETBleed can be mitigated. Revert to an earlier version of the commit in Fixes. Down side is that this will bloat .text size somewhat. The alternative is fully reverting it. The purpose of this patch was to allow migrating error_entry() to C, including the whole of kPTI. Much care needs to be taken moving that forward to not re-introduce this problem of early RETs. Fixes: ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86: Use return-thunk in asm codePeter Zijlstra1-0/+1
Use the return thunk in asm code. If the thunk isn't needed, it will get patched into a RET instruction during boot by apply_returns(). Since alternatives can't handle relocations outside of the first instruction, putting a 'jmp __x86_return_thunk' in one is not valid, therefore carve out the memmove ERMS path into a separate label and jump to it. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27x86/vsyscall_emu/64: Don't use RET in vsyscall emulationPeter Zijlstra1-3/+6
This is userspace code and doesn't play by the normal kernel rules. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-10treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULEThomas Gleixner1-1/+1
Based on the normalized pattern: licensed under the gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference. Reviewed-by: Allison Randal <allison@lohutok.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-24Merge tag 'kernel-hardening-v5.19-rc1' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull kernel hardening updates from Kees Cook: - usercopy hardening expanded to check other allocation types (Matthew Wilcox, Yuanzheng Song) - arm64 stackleak behavioral improvements (Mark Rutland) - arm64 CFI code gen improvement (Sami Tolvanen) - LoadPin LSM block dev API adjustment (Christoph Hellwig) - Clang randstruct support (Bill Wendling, Kees Cook) * tag 'kernel-hardening-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (34 commits) loadpin: stop using bdevname mm: usercopy: move the virt_addr_valid() below the is_vmalloc_addr() gcc-plugins: randstruct: Remove cast exception handling af_unix: Silence randstruct GCC plugin warning niu: Silence randstruct warnings big_keys: Use struct for internal payload gcc-plugins: Change all version strings match kernel randomize_kstack: Improve docs on requirements/rationale lkdtm/stackleak: fix CONFIG_GCC_PLUGIN_STACKLEAK=n arm64: entry: use stackleak_erase_on_task_stack() stackleak: add on/off stack variants lkdtm/stackleak: check stack boundaries lkdtm/stackleak: prevent unexpected stack usage lkdtm/stackleak: rework boundary management lkdtm/stackleak: avoid spurious failure stackleak: rework poison scanning stackleak: rework stack high bound handling stackleak: clarify variable names stackleak: rework stack low bound handling stackleak: remove redundant check ...
2022-05-23Merge tag 'x86_vdso_for_v5.19_rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 vdso update from Borislav Petkov: - Get rid of CONFIG_LEGACY_VSYSCALL_EMULATE as nothing should be using it anymore * tag 'x86_vdso_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATE
2022-05-23Merge tag 'x86_misc_for_v5.19_rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull misc x86 updates from Borislav Petkov: "A variety of fixes which don't fit any other tip bucket: - Remove unnecessary function export - Correct asm constraint - Fix __setup handlers retval" * tag 'x86_misc_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Cleanup the control_va_addr_alignment() __setup handler x86: Fix return value of __setup handlers x86/delay: Fix the wrong asm constraint in delay_loop() x86/amd_nb: Unexport amd_cache_northbridges()
2022-05-23Merge tag 'x86_asm_for_v5.19_rc1' of ↵Linus Torvalds3-126/+55
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm updates from Borislav Petkov: - A bunch of changes towards streamlining low level asm helpers' calling conventions so that former can be converted to C eventually - Simplify PUSH_AND_CLEAR_REGS so that it can be used at the system call entry paths instead of having opencoded, slightly different variants of it everywhere - Misc other fixes * tag 'x86_asm_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/entry: Fix register corruption in compat syscall objtool: Fix STACK_FRAME_NON_STANDARD reloc type linkage: Fix issue with missing symbol size x86/entry: Remove skip_r11rcx x86/entry: Use PUSH_AND_CLEAR_REGS for compat x86/entry: Simplify entry_INT80_compat() x86/mm: Simplify RESERVE_BRK() x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS x86/entry: Don't call error_entry() for XENPV x86/entry: Move CLD to the start of the idtentry macro x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry() x86/entry: Switch the stack after error_entry() returns x86/traps: Use pt_regs directly in fixup_bad_iret()
2022-05-23Merge tag 'x86_sev_for_v5.19_rc1' of ↵Linus Torvalds2-0/+11
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull AMD SEV-SNP support from Borislav Petkov: "The third AMD confidential computing feature called Secure Nested Paging. Add to confidential guests the necessary memory integrity protection against malicious hypervisor-based attacks like data replay, memory remapping and others, thus achieving a stronger isolation from the hypervisor. At the core of the functionality is a new structure called a reverse map table (RMP) with which the guest has a say in which pages get assigned to it and gets notified when a page which it owns, gets accessed/modified under the covers so that the guest can take an appropriate action. In addition, add support for the whole machinery needed to launch a SNP guest, details of which is properly explained in each patch. And last but not least, the series refactors and improves parts of the previous SEV support so that the new code is accomodated properly and not just bolted on" * tag 'x86_sev_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits) x86/entry: Fixup objtool/ibt validation x86/sev: Mark the code returning to user space as syscall gap x86/sev: Annotate stack change in the #VC handler x86/sev: Remove duplicated assignment to variable info x86/sev: Fix address space sparse warning x86/sev: Get the AP jump table address from secrets page x86/sev: Add missing __init annotations to SEV init routines virt: sevguest: Rename the sevguest dir and files to sev-guest virt: sevguest: Change driver name to reflect generic SEV support x86/boot: Put globals that are accessed early into the .data section x86/boot: Add an efi.h header for the decompressor virt: sevguest: Fix bool function returning negative value virt: sevguest: Fix return value check in alloc_shared_pages() x86/sev-es: Replace open-coded hlt-loop with sev_es_terminate() virt: sevguest: Add documentation for SEV-SNP CPUID Enforcement virt: sevguest: Add support to get extended report virt: sevguest: Add support to derive key virt: Add SEV-SNP guest driver x86/sev: Register SEV-SNP guest request platform device x86/sev: Provide support for SNP guest request NAEs ...
2022-05-20x86/entry: Fixup objtool/ibt validationPeter Zijlstra2-0/+6
Commit 47f33de4aafb ("x86/sev: Mark the code returning to user space as syscall gap") added a bunch of text references without annotating them, resulting in a spree of objtool complaints: vmlinux.o: warning: objtool: vc_switch_off_ist+0x77: relocation to !ENDBR: entry_SYSCALL_64+0x15c vmlinux.o: warning: objtool: vc_switch_off_ist+0x8f: relocation to !ENDBR: entry_SYSCALL_compat+0xa5 vmlinux.o: warning: objtool: vc_switch_off_ist+0x97: relocation to !ENDBR: .entry.text+0x21ea vmlinux.o: warning: objtool: vc_switch_off_ist+0xef: relocation to !ENDBR: .entry.text+0x162 vmlinux.o: warning: objtool: __sev_es_ist_enter+0x60: relocation to !ENDBR: entry_SYSCALL_64+0x15c vmlinux.o: warning: objtool: __sev_es_ist_enter+0x6c: relocation to !ENDBR: .entry.text+0x162 vmlinux.o: warning: objtool: __sev_es_ist_enter+0x8a: relocation to !ENDBR: entry_SYSCALL_compat+0xa5 vmlinux.o: warning: objtool: __sev_es_ist_enter+0xc1: relocation to !ENDBR: .entry.text+0x21ea Since these text references are used to compare against IP, and are not an indirect call target, they don't need ENDBR so annotate them away. Fixes: 47f33de4aafb ("x86/sev: Mark the code returning to user space as syscall gap") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220520082604.GQ2578@worktop.programming.kicks-ass.net
2022-05-19x86/entry: Fix register corruption in compat syscallJosh Poimboeuf2-5/+5
A panic was reported in the init process on AMD: Run /sbin/init as init process init[1]: segfault at f7fd5ca0 ip 00000000f7f5bbc7 sp 00000000ffa06aa0 error 7 in libc.so[f7f51000+4e000] Code: 8a 44 24 10 88 41 ff 8b 44 24 10 83 c4 2c 5b 5e 5f 5d c3 53 83 ec 08 8b 5c 24 10 81 fb 00 f0 ff ff 76 0c e8 ba dc ff ff f7 db <89> 18 83 cb ff 83 c4 08 89 d8 5b c3 e8 81 60 ff ff 05 28 84 07 00 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b CPU: 1 PID: 1 Comm: init Tainted: G W 5.18.0-rc7-next-20220519 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x57/0x7d panic+0x10f/0x28d do_exit.cold+0x18/0x48 do_group_exit+0x2e/0xb0 get_signal+0xb6d/0xb80 arch_do_signal_or_restart+0x31/0x760 ? show_opcodes.cold+0x1c/0x21 ? force_sig_fault+0x49/0x70 exit_to_user_mode_prepare+0x131/0x1a0 irqentry_exit_to_user_mode+0x5/0x30 asm_exc_page_fault+0x27/0x30 RIP: 0023:0xf7f5bbc7 Code: 8a 44 24 10 88 41 ff 8b 44 24 10 83 c4 2c 5b 5e 5f 5d c3 53 83 ec 08 8b 5c 24 10 81 fb 00 f0 ff ff 76 0c e8 ba dc ff ff f7 db <89> 18 83 cb ff 83 c4 08 89 d8 5b c3 e8 81 60 ff ff 05 28 84 07 00 RSP: 002b:00000000ffa06aa0 EFLAGS: 00000217 RAX: 00000000f7fd5ca0 RBX: 000000000000000c RCX: 0000000000001000 RDX: 0000000000000001 RSI: 00000000f7fd5b60 RDI: 00000000f7fd5b60 RBP: 00000000f7fd1c1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> The task's CX register got corrupted by commit 8c42819b61b8 ("x86/entry: Use PUSH_AND_CLEAR_REGS for compat"), which overlooked the fact that compat SYSCALL apparently stores the user's CX value in BP. Before that commit, CX was saved from its stashed value in BP: pushq %rbp /* pt_regs->cx (stashed in bp) */ But then it got changed to: pushq %rcx /* pt_regs->cx */ So the wrong value got saved and later restored back to the user. Fix it by pushing the correct value again (BP) for regs->cx. Fixes: 8c42819b61b8 ("x86/entry: Use PUSH_AND_CLEAR_REGS for compat") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Link: https://lkml.kernel.org/r/b5a26592c9dd60bbacdf97974a7433fd802a5593.1652985970.git.jpoimboe@kernel.org
2022-05-19x86/sev: Mark the code returning to user space as syscall gapLai Jiangshan2-0/+4
When returning to user space, %rsp is user-controlled value. If it is a SNP-guest and the hypervisor decides to mess with the code-page for this path while a CPU is executing it, a potential #VC could hit in the syscall return path and mislead the #VC handler. So make ip_within_syscall_gap() return true in this case. Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Joerg Roedel <jroedel@suse.de> Link: https://lore.kernel.org/r/20220412124909.10467-1-jiangshanlai@gmail.com
2022-05-18x86/sev: Annotate stack change in the #VC handlerLai Jiangshan1-0/+1
In idtentry_vc(), vc_switch_off_ist() determines a safe stack to switch to, off of the IST stack. Annotate the new stack switch with ENCODE_FRAME_POINTER in case UNWINDER_FRAME_POINTER is used. A stack walk before looks like this: CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl dump_stack kernel_exc_vmm_communication asm_exc_vmm_communication ? native_read_msr ? __x2apic_disable.part.0 ? x2apic_setup ? cpu_init ? trap_init ? start_kernel ? x86_64_start_reservations ? x86_64_start_kernel ? secondary_startup_64_no_verify </TASK> and with the fix, the stack dump is exact: CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #3 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl dump_stack kernel_exc_vmm_communication asm_exc_vmm_communication RIP: 0010:native_read_msr Code: ... < snipped regs > ? __x2apic_disable.part.0 x2apic_setup cpu_init trap_init start_kernel x86_64_start_reservations x86_64_start_kernel secondary_startup_64_no_verify </TASK> [ bp: Test in a SEV-ES guest and rewrite the commit message to explain what exactly this does. ] Fixes: a13644f3a53d ("x86/entry/64: Add entry code for #VC handler") Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220316041612.71357-1-jiangshanlai@gmail.com
2022-05-11x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATEAndy Lutomirski1-1/+1
CONFIG_LEGACY_VSYSCALL_EMULATE is, as far as I know, only needed for the combined use of exotic and outdated debugging mechanisms with outdated binaries. At this point, no one should be using it. Eventually, dynamic switching of vsyscalls will be implemented, but this is much more complicated to support in EMULATE mode than XONLY mode. So let's force all the distros off of EMULATE mode. If anyone actually needs it, they can set vsyscall=emulate, and the kernel can then get away with refusing to support newer security models if that option is set. [ bp: Remove "we"s. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Florian Weimer <fweimer@redhat.com> Link: https://lore.kernel.org/r/898932fe61db6a9d61bc2458fa2f6049f1ca9f5c.1652290558.git.luto@kernel.org
2022-05-08randstruct: Split randstruct Makefile and CFLAGSKees Cook1-1/+2
To enable the new Clang randstruct implementation[1], move randstruct into its own Makefile and split the CFLAGS from GCC_PLUGINS_CFLAGS into RANDSTRUCT_CFLAGS. [1] https://reviews.llvm.org/D121556 Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-5-keescook@chromium.org
2022-05-06x86/entry: Remove skip_r11rcxPeter Zijlstra2-11/+2
Yes, r11 and rcx have been restored previously, but since they're being popped anyway (into rsi) might as well pop them into their own regs -- setting them to the value they already are. Less magical code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220506121631.365070674@infradead.org
2022-05-06x86/entry: Use PUSH_AND_CLEAR_REGS for compatPeter Zijlstra2-84/+4
Since the upper regs don't exist for ia32 code, preserving them doesn't hurt and it simplifies the code. This doesn't add any attack surface that would not already be available through INT80. Notably: - 32bit SYSENTER: didn't clear si, dx, cx. - 32bit SYSCALL, INT80: *do* clear si since the C functions don't take a second argument. - 64bit: didn't clear si since the C functions take a second argument; except the error_entry path might have only one argument, so clearing si was missing here. 32b SYSENTER should be clearing all those 3 registers, nothing uses them and selftests pass. Unconditionally clear rsi since it simplifies code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220506121631.293889636@infradead.org
2022-05-06x86/entry: Simplify entry_INT80_compat()Linus Torvalds1-10/+9
Instead of playing silly games with rdi, use rax for simpler and more consistent code. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220506121631.221072885@infradead.org
2022-05-04x86: Fix return value of __setup handlersRandy Dunlap1-1/+1
__setup() handlers should return 1 to obsolete_checksetup() in init/main.c to indicate that the boot option has been handled. A return of 0 causes the boot option/value to be listed as an Unknown kernel parameter and added to init's (limited) argument (no '=') or environment (with '=') strings. So return 1 from these x86 __setup handlers. Examples: Unknown kernel command line parameters "apicpmtimer BOOT_IMAGE=/boot/bzImage-517rc8 vdso=1 ring3mwait=disable", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init apicpmtimer with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc8 vdso=1 ring3mwait=disable Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu") Fixes: 77b52b4c5c66 ("x86: add "debugpat" boot option") Fixes: e16fd002afe2 ("x86/cpufeature: Enable RING3MWAIT for Knights Landing") Fixes: b8ce33590687 ("x86_64: convert to clock events") Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Link: https://lore.kernel.org/r/20220314012725.26661-1-rdunlap@infradead.org
2022-05-03x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGSLai Jiangshan2-4/+4
XENPV doesn't use swapgs_restore_regs_and_return_to_usermode(), error_entry() and the code between entry_SYSENTER_compat() and entry_SYSENTER_compat_after_hwframe. Change the PV-compatible SWAPGS to the ASM instruction swapgs in these places. Also remove the definition of SWAPGS since no more users. Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220503032107.680190-7-jiangshanlai@gmail.com
2022-05-03x86/entry: Don't call error_entry() for XENPVLai Jiangshan1-2/+11
XENPV guests enter already on the task stack and they can't fault for native_iret() nor native_load_gs_index() since they use their own pvop for IRET and load_gs_index(). A CR3 switch is not needed either. So there is no reason to call error_entry() in XENPV. [ bp: Massage commit message. ] Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220503032107.680190-6-jiangshanlai@gmail.com
2022-05-03x86/entry: Move CLD to the start of the idtentry macroLai Jiangshan1-3/+5
Move it after CLAC. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220503032107.680190-5-jiangshanlai@gmail.com
2022-05-03x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()Lai Jiangshan1-3/+12
The macro idtentry() (through idtentry_body()) calls error_entry() unconditionally even on XENPV. But XENPV needs to only push and clear regs. PUSH_AND_CLEAR_REGS in error_entry() makes the stack not return to its original place when the function returns, which means it is not possible to convert it to a C function. Carve out PUSH_AND_CLEAR_REGS out of error_entry() and into a separate function and call it before error_entry() in order to avoid calling error_entry() on XENPV. It will also allow for error_entry() to be converted to C code that can use inlined sync_regs() and save a function call. [ bp: Massage commit message. ] Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220503032107.680190-4-jiangshanlai@gmail.com
2022-05-03x86/entry: Switch the stack after error_entry() returnsLai Jiangshan1-10/+6
error_entry() calls fixup_bad_iret() before sync_regs() if it is a fault from a bad IRET, to copy pt_regs to the kernel stack. It switches to the kernel stack directly after sync_regs(). But error_entry() itself is also a function call, so it has to stash the address it is going to return to, in %r12 which is unnecessarily complicated. Move the stack switching after error_entry() and get rid of the need to handle the return address. [ bp: Massage commit message. ] Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220503032107.680190-3-jiangshanlai@gmail.com
2022-05-03x86/traps: Use pt_regs directly in fixup_bad_iret()Lai Jiangshan1-1/+4
Always stash the address error_entry() is going to return to, in %r12 and get rid of the void *error_entry_ret; slot in struct bad_iret_stack which was supposed to account for it and pt_regs pushed on the stack. After this, both fixup_bad_iret() and sync_regs() can work on a struct pt_regs pointer directly. [ bp: Rewrite commit message, touch ups. ] Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220503032107.680190-2-jiangshanlai@gmail.com
2022-04-19x86,objtool: Explicitly mark idtentry_body()s tail REACHABLEPeter Zijlstra1-0/+3
Objtool can figure out that some \cfunc()s are noreturn and then complains about certain instances having unreachable tails: vmlinux.o: warning: objtool: asm_exc_xen_unknown_trap()+0x16: unreachable instruction Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220408094718.441854969@infradead.org
2022-03-31Merge tag 'kbuild-v5.18-v2' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add new environment variables, USERCFLAGS and USERLDFLAGS to allow additional flags to be passed to user-space programs. - Fix missing fflush() bugs in Kconfig and fixdep - Fix a minor bug in the comment format of the .config file - Make kallsyms ignore llvm's local labels, .L* - Fix UAPI compile-test for cross-compiling with Clang - Extend the LLVM= syntax to support LLVM=<suffix> form for using a particular version of LLVm, and LLVM=<prefix> form for using custom LLVM in a particular directory path. - Clean up Makefiles * tag 'kbuild-v5.18-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: Make $(LLVM) more flexible kbuild: add --target to correctly cross-compile UAPI headers with Clang fixdep: use fflush() and ferror() to ensure successful write to files arch: syscalls: simplify uapi/kapi directory creation usr/include: replace extra-y with always-y certs: simplify empty certs creation in certs/Makefile certs: include certs/signing_key.x509 unconditionally kallsyms: ignore all local labels prefixed by '.L' kconfig: fix missing '# end of' for empty menu kconfig: add fflush() before ferror() check kbuild: replace $(if A,A,B) with $(or A,B) kbuild: Add environment variables for userprogs flags kbuild: unify cmd_copy and cmd_shipped
2022-03-31arch: syscalls: simplify uapi/kapi directory creationMasahiro Yamada1-2/+1
$(shell ...) expands to empty. There is no need to assign it to _dummy. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2022-03-15x86: Remove toolchain check for X32 ABI capabilityMasahiro Yamada1-1/+1
Commit 0bf6276392e9 ("x32: Warn and disable rather than error if binutils too old") added a small test in arch/x86/Makefile because binutils 2.22 or newer is needed to properly support elf32-x86-64. This check is no longer necessary, as the minimum supported version of binutils is 2.23, which is enforced at configuration time with scripts/min-tool-version.sh. Remove this check and replace all uses of CONFIG_X86_X32 with CONFIG_X86_X32_ABI, as two symbols are no longer necessary. [nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still used, and simplify commit message to satisfy -tip requirements] Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org
2022-03-15x86: Annotate idtentry_df()Peter Zijlstra1-0/+3
Without CONFIG_X86_ESPFIX64 exc_double_fault() is noreturn and objtool is clever enough to figure that out. vmlinux.o: warning: objtool: asm_exc_double_fault()+0x22: unreachable instruction 0000000000001260 <asm_exc_double_fault>: 1260: f3 0f 1e fa endbr64 1264: 90 nop 1265: 90 nop 1266: 90 nop 1267: e8 84 03 00 00 call 15f0 <paranoid_entry> 126c: 48 89 e7 mov %rsp,%rdi 126f: 48 8b 74 24 78 mov 0x78(%rsp),%rsi 1274: 48 c7 44 24 78 ff ff ff ff movq $0xffffffffffffffff,0x78(%rsp) 127d: e8 00 00 00 00 call 1282 <asm_exc_double_fault+0x22> 127e: R_X86_64_PLT32 exc_double_fault-0x4 1282: e9 09 04 00 00 jmp 1690 <paranoid_exit> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/Yi9gOW9f1GGwwUD6@hirez.programming.kicks-ass.net
2022-03-15x86/ibt,sev: AnnotationsPeter Zijlstra2-0/+2
No IBT on AMD so far.. probably correct, who knows. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154318.995109889@infradead.org
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