kernel/git/stable/linux.git/arch/x86/entry, branch linux-5.7.y

x86/unwind/orc: Fix premature unwind stoppage due to IRET frames

2020-04-25T10:22:29+00:00

The following execution path is possible: fsnotify() [ realign the stack and store previous SP in R10 ] [ only IRET regs saved ] common_interrupt() interrupt_entry() [ full pt_regs saved ] ... [ unwind stack ] When the unwinder goes through the NMI and the IRQ on the stack, and then sees fsnotify(), it doesn't have access to the value of R10, because it only has the five IRET registers. So the unwind stops prematurely. However, because the interrupt_entry() code is careful not to clobber R10 before saving the full regs, the unwinder should be able to read R10 from the previously saved full pt_regs associated with the NMI. Handle this case properly. When encountering an IRET regs frame immediately after a full pt_regs frame, use the pt_regs as a backup which can be used to get the C register values. Also, note that a call frame resets the 'prev_regs' value, because a function is free to clobber the registers. For this fix to work, the IRET and full regs frames must be adjacent, with no FUNC frames in between. So replace the FUNC hint in interrupt_entry() with an IRET_REGS hint. Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/97a408167cc09f1cfa0de31a7b70dd88868d743f.1587808742.git.jpoimboe@redhat.com

x86/entry/64: Fix unwind hints in rewind_stack_do_exit()

2020-04-25T10:22:28+00:00

The LEAQ instruction in rewind_stack_do_exit() moves the stack pointer directly below the pt_regs at the top of the task stack before calling do_exit(). Tell the unwinder to expect pt_regs. Fixes: 8c1f75587a18 ("x86/entry/64: Add unwind hint annotations") Reviewed-by: Miroslav Benes Signed-off-by: Jann Horn Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/68c33e17ae5963854916a46f522624f8e1d264f2.1587808742.git.jpoimboe@redhat.com

x86/entry/64: Fix unwind hints in __switch_to_asm()

2020-04-25T10:22:28+00:00

UNWIND_HINT_FUNC has some limitations: specifically, it doesn't reset all the registers to undefined. This causes objtool to get confused about the RBP push in __switch_to_asm(), resulting in bad ORC data. While __switch_to_asm() does do some stack magic, it's otherwise a normal callable-from-C function, so just annotate it as a function, which makes objtool happy and allows it to produces the correct hints automatically. Fixes: 8c1f75587a18 ("x86/entry/64: Add unwind hint annotations") Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/03d0411920d10f7418f2e909210d8e9a3b2ab081.1587808742.git.jpoimboe@redhat.com

x86/entry/64: Fix unwind hints in kernel exit path

2020-04-25T10:22:27+00:00

In swapgs_restore_regs_and_return_to_usermode, after the stack is switched to the trampoline stack, the existing UNWIND_HINT_REGS hint is no longer valid, which can result in the following ORC unwinder warning: WARNING: can't dereference registers at 000000003aeb0cdd for ip swapgs_restore_regs_and_return_to_usermode+0x93/0xa0 For full correctness, we could try to add complicated unwind hints so the unwinder could continue to find the registers, but when when it's this close to kernel exit, unwind hints aren't really needed anymore and it's fine to just use an empty hint which tells the unwinder to stop. For consistency, also move the UNWIND_HINT_EMPTY in entry_SYSCALL_64_after_hwframe to a similar location. Fixes: 3e3b9293d392 ("x86/entry/64: Return to userspace from the trampoline stack") Reported-by: Vince Weaver Reported-by: Dave Jones Reported-by: Dr. David Alan Gilbert Reported-by: Joe Mario Reported-by: Jann Horn Reported-by: Linus Torvalds Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lore.kernel.org/r/60ea8f562987ed2d9ace2977502fe481c0d7c9a0.1587808742.git.jpoimboe@redhat.com

x86/entry/64: Fix unwind hints in register clearing code

2020-04-25T10:22:27+00:00

The PUSH_AND_CLEAR_REGS macro zeroes each register immediately after pushing it. If an NMI or exception hits after a register is cleared, but before the UNWIND_HINT_REGS annotation, the ORC unwinder will wrongly think the previous value of the register was zero. This can confuse the unwinding process and cause it to exit early. Because ORC is simpler than DWARF, there are a limited number of unwind annotation states, so it's not possible to add an individual unwind hint after each push/clear combination. Instead, the register clearing instructions need to be consolidated and moved to after the UNWIND_HINT_REGS annotation. Fixes: 3f01daecd545 ("x86/entry/64: Introduce the PUSH_AND_CLEAN_REGS macro") Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/68fd3d0bc92ae2d62ff7879d15d3684217d51f08.1587808742.git.jpoimboe@redhat.com

sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING

2020-04-07T17:43:42+00:00

The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected because is parsed before vclock_gettime.c since 28128c61e08e ("kconfig.h: Include compiler types to avoid missed struct attributes"). Since then, is included really early by using the '-include' option. So, you cannot negate the decision of in this way. You can confirm it by checking the pre-processed code, like this: $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE. It is about two years since 28128c61e08e. Nobody has reported a problem (or, nobody has even noticed the fact that this code is not working). It is ugly and unreliable to attempt to undefine a CONFIG option from C files, and anyway the inlining heuristic is up to the compiler. Just remove the broken code. Signed-off-by: Masahiro Yamada Signed-off-by: Andrew Morton Reviewed-by: Nathan Chancellor Acked-by: Miguel Ojeda Cc: Arnd Bergmann Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Masahiro Yamada Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: David Miller Link: http://lkml.kernel.org/r/20200220110807.32534-1-masahiroy@kernel.org Signed-off-by: Linus Torvalds

Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

2020-04-03T20:12:26+00:00

Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments

Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-03-31T18:04:05+00:00

Pull x86 cleanups from Ingo Molnar: "This topic tree contains more commits than usual: - most of it are uaccess cleanups/reorganization by Al - there's a bunch of prototype declaration (--Wmissing-prototypes) cleanups - misc other cleanups all around the map" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/mm/set_memory: Fix -Wmissing-prototypes warnings x86/efi: Add a prototype for efi_arch_mem_reserve() x86/mm: Mark setup_emu2phys_nid() static x86/jump_label: Move 'inline' keyword placement x86/platform/uv: Add a missing prototype for uv_bau_message_interrupt() kill uaccess_try() x86: unsafe_put-style macro for sigmask x86: x32_setup_rt_frame(): consolidate uaccess areas x86: __setup_rt_frame(): consolidate uaccess areas x86: __setup_frame(): consolidate uaccess areas x86: setup_sigcontext(): list user_access_{begin,end}() into callers x86: get rid of put_user_try in __setup_rt_frame() (both 32bit and 64bit) x86: ia32_setup_rt_frame(): consolidate uaccess areas x86: ia32_setup_frame(): consolidate uaccess areas x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers x86/alternatives: Mark text_poke_loc_init() static x86/cpu: Fix a -Wmissing-prototypes warning for init_ia32_feat_ctl() x86/mm: Drop pud_mknotpresent() x86: Replace setup_irq() by request_irq() x86/configs: Slightly reduce defconfigs ...

Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-03-31T17:51:12+00:00

Pull x86 build updates from Ingo Molnar: "A handful of updates: two linker script cleanups and a stock defconfig+allmodconfig bootability fix" * 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vdso: Discard .note.gnu.property sections in vDSO x86, vmlinux.lds: Add RUNTIME_DISCARD_EXIT to generic DISCARDS x86/Kconfig: Make CMDLINE_OVERRIDE depend on non-empty CMDLINE

Merge tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-03-31T02:14:28+00:00

Pull x86 entry code updates from Thomas Gleixner: - Convert the 32bit syscalls to be pt_regs based which removes the requirement to push all 6 potential arguments onto the stack and consolidates the interface with the 64bit variant - The first small portion of the exception and syscall related entry code consolidation which aims to address the recently discovered issues vs. RCU, int3, NMI and some other exceptions which can interrupt any context. The bulk of the changes is still work in progress and aimed for 5.8. - A few lockdep namespace cleanups which have been applied into this branch to keep the prerequisites for the ongoing work confined. * tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits) x86/entry: Fix build error x86 with !CONFIG_POSIX_TIMERS lockdep: Rename trace_{hard,soft}{irq_context,irqs_enabled}() lockdep: Rename trace_softirqs_{on,off}() lockdep: Rename trace_hardirq_{enter,exit}() x86/entry: Rename ___preempt_schedule x86: Remove unneeded includes x86/entry: Drop asmlinkage from syscalls x86/entry/32: Enable pt_regs based syscalls x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments x86/entry/32: Rename 32-bit specific syscalls x86/entry/32: Clean up syscall_32.tbl x86/entry: Remove ABI prefixes from functions in syscall tables x86/entry/64: Add __SYSCALL_COMMON() x86/entry: Remove syscall qualifier support x86/entry/64: Remove ptregs qualifier from syscall table x86/entry: Move max syscall number calculation to syscallhdr.sh x86/entry/64: Split X32 syscall table into its own file x86/entry/64: Move sys_ni_syscall stub to common.c x86/entry/64: Use syscall wrappers for x32_rt_sigreturn x86/entry: Refactor SYS_NI macros ...