BMC/Intel-BMC/linux.git/arch/x86/entry, branch dev-4.17

x86/entry/64: Remove %ebx handling from error_entry/exit

2018-08-06T14:18:20+00:00

commit b3681dd548d06deb2e1573890829dff4b15abf46 upstream. error_entry and error_exit communicate the user vs. kernel status of the frame using %ebx. This is unnecessary -- the information is in regs->cs. Just use regs->cs. This makes error_entry simpler and makes error_exit more robust. It also fixes a nasty bug. Before all the Spectre nonsense, the xen_failsafe_callback entry point returned like this: ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS SAVE_EXTRA_REGS ENCODE_FRAME_POINTER jmp error_exit And it did not go through error_entry. This was bogus: RBX contained garbage, and error_exit expected a flag in RBX. Fortunately, it generally contained *nonzero* garbage, so the correct code path was used. As part of the Spectre fixes, code was added to clear RBX to mitigate certain speculation attacks. Now, depending on kernel configuration, RBX got zeroed and, when running some Wine workloads, the kernel crashes. This was introduced by: commit 3ac6d8c787b8 ("x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface") With this patch applied, RBX is no longer needed as a flag, and the problem goes away. I suspect that malicious userspace could use this bug to crash the kernel even without the offending patch applied, though. [ Historical note: I wrote this patch as a cleanup before I was aware of the bug it fixed. ] [ Note to stable maintainers: this should probably get applied to all kernels. If you're nervous about that, a more conservative fix to add xorl %ebx,%ebx; incl %ebx before the jump to error_exit should also fix the problem. ] Reported-and-tested-by: M. Vefa Bicakci Signed-off-by: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Dominik Brodowski Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: stable@vger.kernel.org Cc: xen-devel@lists.xenproject.org Fixes: 3ac6d8c787b8 ("x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface") Link: http://lkml.kernel.org/r/b5010a090d3586b2d6e06c7ad3ec5542d1241c45.1532282627.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/entry/64/compat: Fix "x86/entry/64/compat: Preserve r8-r11 in int $0x80"

2018-07-03T09:27:12+00:00

commit 22cd978e598618e82c3c3348d2069184f6884182 upstream. Commit: 8bb2610bc496 ("x86/entry/64/compat: Preserve r8-r11 in int $0x80") was busted: my original patch had a minor conflict with some of the nospec changes, but "git apply" is very clever and silently accepted the patch by making the same changes to a different function in the same file. There was obviously a huge offset, but "git apply" for some reason doesn't feel any need to say so. Move the changes to the correct function. Now the test_syscall_vdso_32 selftests passes. If anyone cares to observe the original problem, try applying the patch at: https://lore.kernel.org/lkml/d4c4d9985fbe64f8c9e19291886453914b48caee.1523975710.git.luto@kernel.org/raw to the kernel at 316d097c4cd4e7f2ef50c40cff2db266593c4ec4: - "git am" and "git apply" accept the patch without any complaints at all - "patch -p1" at least prints out a message about the huge offset. Reported-by: zhijianx.li@intel.com Signed-off-by: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: stable@vger.kernel.org #v4.17+ Fixes: 8bb2610bc496 ("x86/entry/64/compat: Preserve r8-r11 in int $0x80") Link: http://lkml.kernel.org/r/6012b922485401bc42676e804171ded262fc2ef2.1530078306.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/vdso: Remove unused file

2018-05-05T07:02:36+00:00

commit da861e18eccc ("x86, vdso: Get rid of the fake section mechanism") left this file behind; nothing is using it anymore. Signed-off-by: Jann Horn Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: luto@amacapital.net Link: http://lkml.kernel.org/r/20180504175935.104085-1-jannh@google.com Signed-off-by: Ingo Molnar

x86/entry/64/compat: Preserve r8-r11 in int $0x80

2018-04-27T15:07:58+00:00

32-bit user code that uses int $80 doesn't care about r8-r11. There is, however, some 64-bit user code that intentionally uses int $0x80 to invoke 32-bit system calls. From what I've seen, basically all such code assumes that r8-r15 are all preserved, but the kernel clobbers r8-r11. Since I doubt that there's any code that depends on int $0x80 zeroing r8-r11, change the kernel to preserve them. I suspect that very little user code is broken by the old clobber, since r8-r11 are only rarely allocated by gcc, and they're clobbered by function calls, so they only way we'd see a problem is if the same function that invokes int $0x80 also spills something important to one of these registers. The current behavior seems to date back to the historical commit "[PATCH] x86-64 merge for 2.6.4". Before that, all regs were preserved. I can't find any explanation of why this change was made. Update the test_syscall_vdso_32 testcase as well to verify the new behavior, and it strengthens the test to make sure that the kernel doesn't accidentally permute r8..r15. Suggested-by: Denys Vlasenko Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: Dominik Brodowski Link: https://lkml.kernel.org/r/d4c4d9985fbe64f8c9e19291886453914b48caee.1523975710.git.luto@kernel.org

Merge tag 'kbuild-v4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2018-04-16T00:21:30+00:00

Pull more Kbuild updates from Masahiro Yamada: - pass HOSTLDFLAGS when compiling single .c host programs - build genksyms lexer and parser files instead of using shipped versions - rename *-asn1.[ch] to *.asn1.[ch] for suffix consistency - let the top .gitignore globally ignore artifacts generated by flex, bison, and asn1_compiler - let the top Makefile globally clean artifacts generated by flex, bison, and asn1_compiler - use safer .SECONDARY marker instead of .PRECIOUS to prevent intermediate files from being removed - support -fmacro-prefix-map option to make __FILE__ a relative path - fix # escaping to prepare for the future GNU Make release - clean up deb-pkg by using debian tools instead of handrolled source/changes generation - improve rpm-pkg portability by supporting kernel-install as a fallback of new-kernel-pkg - extend Kconfig listnewconfig target to provide more information * tag 'kbuild-v4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kconfig: extend output of 'listnewconfig' kbuild: rpm-pkg: use kernel-install as a fallback for new-kernel-pkg Kbuild: fix # escaping in .cmd files for future Make kbuild: deb-pkg: split generating packaging and build kbuild: use -fmacro-prefix-map to make __FILE__ a relative path kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers kbuild: rename *-asn1.[ch] to *.asn1.[ch] kbuild: clean up *-asn1.[ch] patterns from top-level Makefile .gitignore: move *-asn1.[ch] patterns to the top-level .gitignore kbuild: add %.dtb.S and %.dtb to 'targets' automatically kbuild: add %.lex.c and %.tab.[ch] to 'targets' automatically genksyms: generate lexer and parser during build instead of shipping kbuild: clean up *.lex.c and *.tab.[ch] patterns from top-level Makefile .gitignore: move *.lex.c *.tab.[ch] patterns to the top-level .gitignore kbuild: use HOSTLDFLAGS for single .c executables

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

2018-04-15T23:12:35+00:00

Pull x86 fixes from Thomas Gleixner: "A set of fixes and updates for x86: - Address a swiotlb regression which was caused by the recent DMA rework and made driver fail because dma_direct_supported() returned false - Fix a signedness bug in the APIC ID validation which caused invalid APIC IDs to be detected as valid thereby bloating the CPU possible space. - Fix inconsisten config dependcy/select magic for the MFD_CS5535 driver. - Fix a corruption of the physical address space bits when encryption has reduced the address space and late cpuinfo updates overwrite the reduced bit information with the original value. - Dominiks syscall rework which consolidates the architecture specific syscall functions so all syscalls can be wrapped with the same macros. This allows to switch x86/64 to struct pt_regs based syscalls. Extend the clearing of user space controlled registers in the entry patch to the lower registers" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/apic: Fix signedness bug in APIC ID validity checks x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption x86/olpc: Fix inconsistent MFD_CS5535 configuration swiotlb: Use dma_direct_supported() for swiotlb_ops syscalls/x86: Adapt syscall_wrapper.h to the new syscall stub naming convention syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*() syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention syscalls/core, syscalls/x86: Clean up syscall stub naming convention syscalls/x86: Extend register clearing on syscall entry to lower registers syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64 syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32 syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls syscalls/x86: Use 'struct pt_regs' based syscall calling convention for 64-bit syscalls syscalls/core: Introduce CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y x86/syscalls: Don't pointlessly reload the system call number x86/mm: Fix documentation of module mapping range with 4-level paging x86/cpuid: Switch to 'static const' specifier

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

2018-04-15T20:35:29+00:00

Pull x86 pti updates from Thomas Gleixner: "Another series of PTI related changes: - Remove the manual stack switch for user entries from the idtentry code. This debloats entry by 5k+ bytes of text. - Use the proper types for the asm/bootparam.h defines to prevent user space compile errors. - Use PAGE_GLOBAL for !PCID systems to gain back performance - Prevent setting of huge PUD/PMD entries when the entries are not leaf entries otherwise the entries to which the PUD/PMD points to and are populated get lost" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/pgtable: Don't set huge PUD/PMD on non-leaf entries x86/pti: Leave kernel text global for !PCID x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image x86/pti: Enable global pages for shared areas x86/mm: Do not forbid _PAGE_RW before init for __ro_after_init x86/mm: Comment _PAGE_GLOBAL mystery x86/mm: Remove extra filtering in pageattr code x86/mm: Do not auto-massage page protections x86/espfix: Document use of _PAGE_GLOBAL x86/mm: Introduce "default" kernel PTE mask x86/mm: Undo double _PAGE_PSE clearing x86/mm: Factor out pageattr _PAGE_GLOBAL setting x86/entry/64: Drop idtentry's manual stack switch for user entries x86/uapi: Fix asm/bootparam.h userspace compilation errors

Merge branch 'linus' into x86/pti to pick up upstream changes

2018-04-09T16:24:58+00:00

Signed-off-by: Ingo Molnar

x86/entry/64: Drop idtentry's manual stack switch for user entries

2018-04-09T16:23:50+00:00

For non-paranoid entries, idtentry knows how to switch from the kernel stack to the user stack, as does error_entry. This results in pointless duplication and code bloat. Make idtentry stop thinking about stacks for non-paranoid entries. This reduces text size by 5377 bytes. This goes back to the following commit: 7f2590a110b8 ("x86/entry/64: Use a per-CPU trampoline stack for IDT entries") Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Dominik Brodowski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/90aab80c1f906e70742eaa4512e3c9b5e62d59d4.1522794757.git.luto@kernel.org Signed-off-by: Ingo Molnar

syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_() to __x64_sys_()

2018-04-09T14:47:28+00:00

This rename allows us to have a coherent syscall stub naming convention on 64-bit x86 (0xffffffff prefix removed): 810f0af0 t kernel_waitid # common (32/64) kernel helper __do_sys_waitid # inlined helper doing actual work 810f0be0 t __se_sys_waitid # C func calling inlined helper __do_compat_sys_waitid # inlined helper doing actual work 810f0d80 t __se_compat_sys_waitid # compat C func calling inlined helper 810f2080 T __x64_sys_waitid # x64 64-bit-ptregs -> C stub 810f20b0 T __ia32_sys_waitid # ia32 32-bit-ptregs -> C stub[*] 810f2470 T __ia32_compat_sys_waitid # ia32 32-bit-ptregs -> compat C stub 810f2490 T __x32_compat_sys_waitid # x32 64-bit-ptregs -> compat C stub [*] This stub is unused, as the syscall table links __ia32_compat_sys_waitid instead of __ia32_sys_waitid as we need a compat variant here. Suggested-by: Ingo Molnar Signed-off-by: Dominik Brodowski Cc: Al Viro Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180409105145.5364-4-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar