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2018-05-05x86/vdso: Remove unused fileJann Horn1-1/+0
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 <jannh@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Link: http://lkml.kernel.org/r/20180504175935.104085-1-jannh@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-27x86/entry/64/compat: Preserve r8-r11 in int $0x80Andy Lutomirski1-4/+4
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 <dvlasenk@redhat.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Link: https://lkml.kernel.org/r/d4c4d9985fbe64f8c9e19291886453914b48caee.1523975710.git.luto@kernel.org
2018-04-16Merge tag 'kbuild-v4.17-2' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild 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
2018-04-16Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds10-737/+782
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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
2018-04-15Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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
2018-04-09Merge branch 'linus' into x86/pti to pick up upstream changesIngo Molnar1-1/+6
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-09x86/entry/64: Drop idtentry's manual stack switch for user entriesAndy Lutomirski1-2/+2
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 <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/90aab80c1f906e70742eaa4512e3c9b5e62d59d4.1522794757.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-09syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to ↵Dominik Brodowski4-345/+359
__x64_sys_*() 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 <inline> __do_sys_waitid # inlined helper doing actual work 810f0be0 t __se_sys_waitid # C func calling inlined helper <inline> __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 <mingo@kernel.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180409105145.5364-4-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-09syscalls/core, syscalls/x86: Clean up compat syscall stub naming conventionDominik Brodowski2-162/+162
Tidy the naming convention for compat syscall subs. Hints which describe the purpose of the stub go in front and receive a double underscore to denote that they are generated on-the-fly by the COMPAT_SYSCALL_DEFINEx() macro. For the generic case, this means: t kernel_waitid # common C function (see kernel/exit.c) __do_compat_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) T __se_compat_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long, # casts them to unsigned long and then to # the declared type) T compat_sys_waitid # alias to __se_compat_sys_waitid() # (taking parameters as declared), to # be included in syscall table For x86, the naming is as follows: t kernel_waitid # common C function (see kernel/exit.c) __do_compat_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) t __se_compat_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long, # casts them to unsigned long and then to # the declared type) T __ia32_compat_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub, # calls __se_compat_sys_waitid(); to be # included in syscall table T __x32_compat_sys_waitid # x32 64-bit-ptregs -> C stub, calls # __se_compat_sys_waitid(); to be included # in syscall table If only one of IA32_EMULATION and x32 is enabled, __se_compat_sys_waitid() may be inlined into the stub __{ia32,x32}_compat_sys_waitid(). Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180409105145.5364-3-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-09syscalls/core, syscalls/x86: Clean up syscall stub naming conventionDominik Brodowski1-212/+212
Tidy the naming convention for compat syscall subs. Hints which describe the purpose of the stub go in front and receive a double underscore to denote that they are generated on-the-fly by the SYSCALL_DEFINEx() macro. For the generic case, this means (0xffffffff prefix removed): 810f08d0 t kernel_waitid # common C function (see kernel/exit.c) <inline> __do_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) 810f1aa0 T __se_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long; # casts them to the declared type) 810f1aa0 T sys_waitid # alias to __se_sys_waitid() (taking # parameters as declared), to be included # in syscall table For x86, the naming is as follows: 810efc70 t kernel_waitid # common C function (see kernel/exit.c) <inline> __do_sys_waitid # inlined helper doing the actual work # (takes original parameters as declared) 810efd60 t __se_sys_waitid # sign-extending C function calling inlined # helper (takes parameters of type long; # casts them to the declared type) 810f1140 T __ia32_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub, # calls __se_sys_waitid(); to be included # in syscall table 810f1110 T sys_waitid # x86 64-bit-ptregs -> C stub, calls # __se_sys_waitid(); to be included in # syscall table For x86, sys_waitid() will be re-named to __x64_sys_waitid in a follow-up patch. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180409105145.5364-2-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-07kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markersMasahiro Yamada1-3/+1
GNU Make automatically deletes intermediate files that are updated in a chain of pattern rules. Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts Example 2) %.o <- %.c <- %.c_shipped A couple of makefiles mark such targets as .PRECIOUS to prevent Make from deleting them, but the correct way is to use .SECONDARY. .SECONDARY Prerequisites of this special target are treated as intermediate files but are never automatically deleted. .PRECIOUS When make is interrupted during execution, it may delete the target file it is updating if the file was modified since make started. If you mark the file as precious, make will never delete the file if interrupted. Both can avoid deletion of intermediate files, but the difference is the behavior when Make is interrupted; .SECONDARY deletes the target, but .PRECIOUS does not. The use of .PRECIOUS is relatively rare since we do not want to keep partially constructed (possibly corrupted) targets. Another difference is that .PRECIOUS works with pattern rules whereas .SECONDARY does not. .PRECIOUS: $(obj)/%.lex.c works, but .SECONDARY: $(obj)/%.lex.c has no effect. However, for the reason above, I do not want to use .PRECIOUS which could cause obscure build breakage. The targets specified as .SECONDARY must be explicit. $(targets) contains all targets that need to include .*.cmd files. So, the intermediates you want to keep are mostly in there. Therefore, mark $(targets) as .SECONDARY. It means primary targets are also marked as .SECONDARY, but I do not see any drawback for this. I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This will make Kbuild search for non-existing .*.cmd files, but this is not a noticeable performance issue. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Ingo Molnar <mingo@kernel.org>
2018-04-05syscalls/x86: Extend register clearing on syscall entry to lower registersDominik Brodowski2-0/+8
To reduce the chance that random user space content leaks down the call chain in registers, also clear lower registers on syscall entry: For 64-bit syscalls, extend the register clearing in PUSH_AND_CLEAR_REGS to %dx and %cx. This should not hurt at all, also on the other callers of that macro. We do not need to clear %rdi and %rsi for syscall entry, as those registers are used to pass the parameters to do_syscall_64(). For the 32-bit compat syscalls, do_int80_syscall_32() and do_fast_syscall_32() each only take one parameter. Therefore, extend the register clearing to %dx, %cx, and %si in entry_SYSCALL_compat and entry_INT80_compat. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-8-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64Dominik Brodowski4-34/+5
Removing CONFIG_SYSCALL_PTREGS from arch/x86/Kconfig and simply selecting ARCH_HAS_SYSCALL_WRAPPER unconditionally on x86-64 allows us to simplify several codepaths. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-7-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION ↵Dominik Brodowski4-375/+395
and x32 Extend ARCH_HAS_SYSCALL_WRAPPER for i386 emulation and for x32 on 64-bit x86. For x32, all we need to do is to create an additional stub for each compat syscall which decodes the parameters in x86-64 ordering, e.g.: asmlinkage long __compat_sys_x32_xyzzy(struct pt_regs *regs) { return c_SyS_xyzzy(regs->di, regs->si, regs->dx); } For i386 emulation, we need to teach compat_sys_*() to take struct pt_regs as its only argument, e.g.: asmlinkage long __compat_sys_ia32_xyzzy(struct pt_regs *regs) { return c_SyS_xyzzy(regs->bx, regs->cx, regs->dx); } In addition, we need to create additional stubs for common syscalls (that is, for syscalls which have the same parameters on 32-bit and 64-bit), e.g.: asmlinkage long __sys_ia32_xyzzy(struct pt_regs *regs) { return c_sys_xyzzy(regs->bx, regs->cx, regs->dx); } This approach avoids leaking random user-provided register content down the call chain. This patch is based on an original proof-of-concept | From: Linus Torvalds <torvalds@linux-foundation.org> | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> and was split up and heavily modified by me, in particular to base it on ARCH_HAS_SYSCALL_WRAPPER. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-6-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05syscalls/x86: Use 'struct pt_regs' based syscall calling convention for ↵Dominik Brodowski3-2/+33
64-bit syscalls Let's make use of ARCH_HAS_SYSCALL_WRAPPER=y on pure 64-bit x86-64 systems: Each syscall defines a stub which takes struct pt_regs as its only argument. It decodes just those parameters it needs, e.g: asmlinkage long sys_xyzzy(const struct pt_regs *regs) { return SyS_xyzzy(regs->di, regs->si, regs->dx); } This approach avoids leaking random user-provided register content down the call chain. For example, for sys_recv() which is a 4-parameter syscall, the assembly now is (in slightly reordered fashion): <sys_recv>: callq <__fentry__> /* decode regs->di, ->si, ->dx and ->r10 */ mov 0x70(%rdi),%rdi mov 0x68(%rdi),%rsi mov 0x60(%rdi),%rdx mov 0x38(%rdi),%rcx [ SyS_recv() is automatically inlined by the compiler, as it is not [yet] used anywhere else ] /* clear %r9 and %r8, the 5th and 6th args */ xor %r9d,%r9d xor %r8d,%r8d /* do the actual work */ callq __sys_recvfrom /* cleanup and return */ cltq retq The only valid place in an x86-64 kernel which rightfully calls a syscall function on its own -- vsyscall -- needs to be modified to pass struct pt_regs onwards as well. To keep the syscall table generation working independent of SYSCALL_PTREGS being enabled, the stubs are named the same as the "original" syscall stubs, i.e. sys_*(). This patch is based on an original proof-of-concept | From: Linus Torvalds <torvalds@linux-foundation.org> | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> and was split up and heavily modified by me, in particular to base it on ARCH_HAS_SYSCALL_WRAPPER, to limit it to 64-bit-only for the time being, and to update the vsyscall to the new calling convention. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-4-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05x86/syscalls: Don't pointlessly reload the system call numberLinus Torvalds2-7/+8
We have it in a register in the low-level asm, just pass it in as an argument rather than have do_syscall_64() load it back in from the ptregs pointer. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-2-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05Merge tag 'char-misc-4.17-rc1' of ↵Linus Torvalds2-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc updates from Greg KH: "Here is the big set of char/misc driver patches for 4.17-rc1. There are a lot of little things in here, nothing huge, but all important to the different hardware types involved: - thunderbolt driver updates - parport updates (people still care...) - nvmem driver updates - mei updates (as always) - hwtracing driver updates - hyperv driver updates - extcon driver updates - ... and a handful of even smaller driver subsystem and individual driver updates All of these have been in linux-next with no reported issues" * tag 'char-misc-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (149 commits) hwtracing: Add HW tracing support menu intel_th: Add ACPI glue layer intel_th: Allow forcing host mode through drvdata intel_th: Pick up irq number from resources intel_th: Don't touch switch routing in host mode intel_th: Use correct method of finding hub intel_th: Add SPDX GPL-2.0 header to replace GPLv2 boilerplate stm class: Make dummy's master/channel ranges configurable stm class: Add SPDX GPL-2.0 header to replace GPLv2 boilerplate MAINTAINERS: Bestow upon myself the care for drivers/hwtracing hv: add SPDX license id to Kconfig hv: add SPDX license to trace Drivers: hv: vmbus: do not mark HV_PCIE as perf_device Drivers: hv: vmbus: respect what we get from hv_get_synint_state() /dev/mem: Avoid overwriting "err" in read_mem() eeprom: at24: use SPDX identifier instead of GPL boiler-plate eeprom: at24: simplify the i2c functionality checking eeprom: at24: fix a line break eeprom: at24: tweak newlines eeprom: at24: refactor at24_probe() ...
2018-04-03Merge branch 'syscalls-next' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux Pull removal of in-kernel calls to syscalls from Dominik Brodowski: "System calls are interaction points between userspace and the kernel. Therefore, system call functions such as sys_xyzzy() or compat_sys_xyzzy() should only be called from userspace via the syscall table, but not from elsewhere in the kernel. At least on 64-bit x86, it will likely be a hard requirement from v4.17 onwards to not call system call functions in the kernel: It is better to use use a different calling convention for system calls there, where struct pt_regs is decoded on-the-fly in a syscall wrapper which then hands processing over to the actual syscall function. This means that only those parameters which are actually needed for a specific syscall are passed on during syscall entry, instead of filling in six CPU registers with random user space content all the time (which may cause serious trouble down the call chain). Those x86-specific patches will be pushed through the x86 tree in the near future. Moreover, rules on how data may be accessed may differ between kernel data and user data. This is another reason why calling sys_xyzzy() is generally a bad idea, and -- at most -- acceptable in arch-specific code. This patchset removes all in-kernel calls to syscall functions in the kernel with the exception of arch/. On top of this, it cleans up the three places where many syscalls are referenced or prototyped, namely kernel/sys_ni.c, include/linux/syscalls.h and include/linux/compat.h" * 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: (109 commits) bpf: whitelist all syscalls for error injection kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions kernel/sys_ni: sort cond_syscall() entries syscalls/x86: auto-create compat_sys_*() prototypes syscalls: sort syscall prototypes in include/linux/compat.h net: remove compat_sys_*() prototypes from net/compat.h syscalls: sort syscall prototypes in include/linux/syscalls.h kexec: move sys_kexec_load() prototype to syscalls.h x86/sigreturn: use SYSCALL_DEFINE0 x86: fix sys_sigreturn() return type to be long, not unsigned long x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm() mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead() mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64() fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate() fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate() fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid() kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare() ...
2018-04-02fs/quota: use COMPAT_SYSCALL_DEFINE for sys32_quotactl()Dominik Brodowski1-1/+1
While sys32_quotactl() is only needed on x86, it can use the recommended COMPAT_SYSCALL_DEFINEx() machinery for its setup. Acked-by: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02x86: remove compat_sys_x86_waitpid()Dominik Brodowski1-1/+1
compat_sys_x86_waitpid() is not needed, as it takes the same parameters (int, *int, int) as the native syscall. Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: x86@kernel.org Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-03-28Merge 4.16-rc7 into char-misc-nextGreg Kroah-Hartman5-51/+25
We want the hyperv fix in here for merging and testing. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-27Merge tag 'v4.16-rc7' into x86/mm, to fix up conflictIngo Molnar3-4/+2
Conflicts: arch/x86/mm/init_64.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-25Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds3-4/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 and PTI fixes from Ingo Molnar: "Misc fixes: - fix EFI pagetables freeing - fix vsyscall pagetable setting on Xen PV guests - remove ancient CONFIG_X86_PPRO_FENCE=y - x86 is TSO again - fix two binutils (ld) development version related incompatibilities - clean up breakpoint handling - fix an x86 self-test" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/entry/64: Don't use IST entry for #BP stack x86/efi: Free efi_pgd with free_pages() x86/vsyscall/64: Use proper accessor to update P4D entry x86/cpu: Remove the CONFIG_X86_PPRO_FENCE=y quirk x86/boot/64: Verify alignment of the LOAD segment x86/build/64: Force the linker to use 2MB page size selftests/x86/ptrace_syscall: Fix for yet more glibc interference
2018-03-23x86/entry/64: Don't use IST entry for #BP stackAndy Lutomirski1-1/+1
There's nothing IST-worthy about #BP/int3. We don't allow kprobes in the small handful of places in the kernel that run at CPL0 with an invalid stack, and 32-bit kernels have used normal interrupt gates for #BP forever. Furthermore, we don't allow kprobes in places that have usergs while in kernel mode, so "paranoid" is also unnecessary. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
2018-03-20x86/vsyscall/64: Use proper accessor to update P4D entryBoris Ostrovsky1-1/+1
Writing to it directly does not work for Xen PV guests. Fixes: 49275fef986a ("x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable hierarchy") Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180319143154.3742-1-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-20x86/cpu: Remove the CONFIG_X86_PPRO_FENCE=y quirkChristoph Hellwig1-2/+0
There were only a few Pentium Pro multiprocessors systems where this errata applied. They are more than 20 years old now, and we've slowly dropped places which put the workarounds in and discouraged anyone from enabling the workaround. Get rid of it for good. Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Joerg Roedel <joro@8bytes.org> Cc: Jon Mason <jdmason@kudzu.us> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Muli Ben-Yehuda <mulix@mulix.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: iommu@lists.linux-foundation.org Link: http://lkml.kernel.org/r/20180319103826.12853-2-hch@lst.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-14Merge branch 'x86/urgent' into x86/mm to pick up dependenciesThomas Gleixner1-1/+1
2018-03-12Merge branch 'x86/pti' into x86/mm, to pick up dependenciesIngo Molnar6-152/+175
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds3-47/+23
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86/pti updates from Thomas Gleixner: "Yet another pile of melted spectrum related updates: - Drop native vsyscall support finally as it causes more trouble than benefit. - Make microcode loading more robust. There were a few issues especially related to late loading which are now surfacing because late loading of the IB* microcodes addressing spectre issues has become more widely used. - Simplify and robustify the syscall handling in the entry code - Prevent kprobes on the entry trampoline code which lead to kernel crashes when the probe hits before CR3 is updated - Don't check microcode versions when running on hypervisors as they are considered as lying anyway. - Fix the 32bit objtool build and a coment typo" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kprobes: Fix kernel crash when probing .entry_trampoline code x86/pti: Fix a comment typo x86/microcode: Synchronize late microcode loading x86/microcode: Request microcode on the BSP x86/microcode/intel: Look into the patch cache first x86/microcode: Do not upload microcode if CPUs are offline x86/microcode/intel: Writeback and invalidate caches before updating microcode x86/microcode/intel: Check microcode revision before updating sibling threads x86/microcode: Get rid of struct apply_microcode_ctx x86/spectre_v2: Don't check microcode versions when running under hypervisors x86/vsyscall/64: Drop "native" vsyscalls x86/entry/64/compat: Save one instruction in entry_INT80_compat() x86/entry: Do not special-case clone(2) in compat entry x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat syscalls x86/syscalls: Use proper syscall definition for sys_ioperm() x86/entry: Remove stale syscall prototype x86/syscalls/32: Simplify $entry == $compat entries objtool: Fix 32-bit build
2018-03-08x86/vsyscall/64: Drop "native" vsyscallsAndy Lutomirski1-13/+3
Since Linux v3.2, vsyscalls have been deprecated and slow. From v3.2 on, Linux had three vsyscall modes: "native", "emulate", and "none". "emulate" is the default. All known user programs work correctly in emulate mode, but vsyscalls turn into page faults and are emulated. This is very slow. In "native" mode, the vsyscall page is easily usable as an exploit gadget, but vsyscalls are a bit faster -- they turn into normal syscalls. (This is in contrast to vDSO functions, which can be much faster than syscalls.) In "none" mode, there are no vsyscalls. For all practical purposes, "native" was really just a chicken bit in case something went wrong with the emulation. It's been over six years, and nothing has gone wrong. Delete it. Signed-off-by: Andy Lutomirski <luto@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/519fee5268faea09ae550776ce969fa6e88668b0.1520449896.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-07x86/entry/64/compat: Save one instruction in entry_INT80_compat()Dominik Brodowski1-3/+1
As %rdi is never user except in the following push, there is no need to restore %rdi to the original value. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-07x86/entry: Do not special-case clone(2) in compat entryDominik Brodowski2-13/+1
With the CPU renaming registers on its own, and all the overhead of the syscall entry/exit, it is doubtful whether the compiled output of mov %r8, %rax mov %rcx, %r8 mov %rax, %rcx jmpq sys_clone is measurably slower than the hand-crafted version of xchg %r8, %rcx So get rid of this special case. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-07x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat syscallsDominik Brodowski1-15/+15
While at it, convert declarations of type "unsigned" to "unsigned int". Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-07x86/syscalls/32: Simplify $entry == $compat entriesDominik Brodowski1-3/+3
If the compat entry point is equivalent to the native entry point, it does not need to be specified explicitly. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-06Drivers: hv: vmbus: Implement Direct Mode for stimer0Michael Kelley2-0/+6
The 2016 version of Hyper-V offers the option to operate the guest VM per-vcpu stimer's in Direct Mode, which means the timer interupts on its own vector rather than queueing a VMbus message. Direct Mode reduces timer processing overhead in both the hypervisor and the guest, and avoids having timer interrupts pollute the VMbus interrupt stream for the synthetic NIC and storage. This patch enables Direct Mode by default on stimer0 when running on a version of Hyper-V that supports it. In prep for coming support of Hyper-V on ARM64, the arch independent portion of the code contains calls to routines that will be populated on ARM64 but are not needed and do nothing on x86. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-28x86/entry/64: Add instruction suffixJan Beulich1-1/+1
Omitting suffixes from instructions in AT&T mode is bad practice when operand size cannot be determined by the assembler from register operands, and is likely going to be warned about by upstream gas in the future (mine does already). Add the single missing suffix here. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/5A93F96902000078001ABAC8@prv-mh.provo.novell.com
2018-02-26Merge tag 'v4.16-rc3' into x86/mm, to pick up fixesIngo Molnar3-132/+97
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Simplify ENCODE_FRAME_POINTERJosh Poimboeuf1-6/+1
On 64-bit, the stack pointer is always aligned on interrupt, so instead of setting the LSB of the pt_regs address, we can just add 1 to it. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180221024214.lhl5jfgw33c4vz3m@treble Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Open-code switch_to_thread_stack()Dominik Brodowski2-38/+55
Open-code the two instances which called switch_to_thread_stack(). This allows us to remove the wrapper around DO_SWITCH_TO_THREAD_STACK. While at it, update the UNWIND hint to reflect where the IRET frame is, and update the commentary to reflect what we are actually doing here. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-7-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Move ASM_CLAC to interrupt_entry()Dominik Brodowski1-2/+1
Moving ASM_CLAC to interrupt_entry means two instructions (addq / pushq and call interrupt_entry) are not covered by it. However, it offers a noticeable size reduction (-.2k): text data bss dec hex filename 16882 0 0 16882 41f2 entry_64.o-orig 16623 0 0 16623 40ef entry_64.o Suggested-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-6-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Remove 'interrupt' macroDominik Brodowski1-10/+6
It is now trivial to call interrupt_entry() and then the actual worker. Therefore, remove the interrupt macro and open code it all. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-5-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry()Dominik Brodowski1-29/+37
We can also move the CLD, SWAPGS, and the switch_to_thread_stack() call to the interrupt_entry() helper function. As we do not want call depths of two, convert switch_to_thread_stack() to a macro. However, switch_to_thread_stack() has another user in entry_64_compat.S, which currently expects it to be a function. To keep the code changes in this patch minimal, create a wrapper function. The switch to a macro means that there is some binary code duplication if CONFIG_IA32_EMULATION=y is enabled. Therefore, the size reduction differs whether CONFIG_IA32_EMULATION is enabled or not: CONFIG_IA32_EMULATION=y (-0.13k): text data bss dec hex filename 17158 0 0 17158 4306 entry_64.o-orig 17028 0 0 17028 4284 entry_64.o CONFIG_IA32_EMULATION=n (-0.27k): text data bss dec hex filename 17158 0 0 17158 4306 entry_64.o-orig 16882 0 0 16882 41f2 entry_64.o Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-4-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Move ENTER_IRQ_STACK from interrupt macro to interrupt_entryDominik Brodowski1-18/+38
Moving the switch to IRQ stack from the interrupt macro to the helper function requires some trickery: All ENTER_IRQ_STACK really cares about is where the "original" stack -- meaning the GP registers etc. -- is stored. Therefore, we need to offset the stored RSP value by 8 whenever ENTER_IRQ_STACK is called from within a function. In such cases, and after switching to the IRQ stack, we need to push the "original" return address (i.e. the return address from the call to the interrupt entry function) to the IRQ stack. This trickery allows us to carve another .85k from the text size (it would be more except for the additional unwind hints): text data bss dec hex filename 18006 0 0 18006 4656 entry_64.o-orig 17158 0 0 17158 4306 entry_64.o Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-3-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper functionDominik Brodowski1-2/+9
The PUSH_AND_CLEAR_REGS macro is able to insert the GP registers "above" the original return address. This allows us to move a sizeable part of the interrupt entry macro to an interrupt entry helper function: text data bss dec hex filename 21088 0 0 21088 5260 entry_64.o-orig 18006 0 0 18006 4656 entry_64.o Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180220210113.6725-2-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21x86/mm: Optimize boot-time paging mode switching costKirill A. Shutemov1-9/+2
By this point we have functioning boot-time switching between 4- and 5-level paging mode. But naive approach comes with cost. Numbers below are for kernel build, allmodconfig, 5 times. CONFIG_X86_5LEVEL=n: Performance counter stats for 'sh -c make -j100 -B -k >/dev/null' (5 runs): 17308719.892691 task-clock:u (msec) # 26.772 CPUs utilized ( +- 0.11% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 331,993,164 page-faults:u # 0.019 M/sec ( +- 0.01% ) 43,614,978,867,455 cycles:u # 2.520 GHz ( +- 0.01% ) 39,371,534,575,126 stalled-cycles-frontend:u # 90.27% frontend cycles idle ( +- 0.09% ) 28,363,350,152,428 instructions:u # 0.65 insn per cycle # 1.39 stalled cycles per insn ( +- 0.00% ) 6,316,784,066,413 branches:u # 364.948 M/sec ( +- 0.00% ) 250,808,144,781 branch-misses:u # 3.97% of all branches ( +- 0.01% ) 646.531974142 seconds time elapsed ( +- 1.15% ) CONFIG_X86_5LEVEL=y: Performance counter stats for 'sh -c make -j100 -B -k >/dev/null' (5 runs): 17411536.780625 task-clock:u (msec) # 26.426 CPUs utilized ( +- 0.10% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 331,868,663 page-faults:u # 0.019 M/sec ( +- 0.01% ) 43,865,909,056,301 cycles:u # 2.519 GHz ( +- 0.01% ) 39,740,130,365,581 stalled-cycles-frontend:u # 90.59% frontend cycles idle ( +- 0.05% ) 28,363,358,997,959 instructions:u # 0.65 insn per cycle # 1.40 stalled cycles per insn ( +- 0.00% ) 6,316,784,937,460 branches:u # 362.793 M/sec ( +- 0.00% ) 251,531,919,485 branch-misses:u # 3.98% of all branches ( +- 0.00% ) 658.886307752 seconds time elapsed ( +- 0.92% ) The patch tries to fix the performance regression by using cpu_feature_enabled(X86_FEATURE_LA57) instead of pgtable_l5_enabled in all hot code paths. These will statically patch the target code for additional performance. CONFIG_X86_5LEVEL=y + the patch: Performance counter stats for 'sh -c make -j100 -B -k >/dev/null' (5 runs): 17381990.268506 task-clock:u (msec) # 26.907 CPUs utilized ( +- 0.19% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 331,862,625 page-faults:u # 0.019 M/sec ( +- 0.01% ) 43,697,726,320,051 cycles:u # 2.514 GHz ( +- 0.03% ) 39,480,408,690,401 stalled-cycles-frontend:u # 90.35% frontend cycles idle ( +- 0.05% ) 28,363,394,221,388 instructions:u # 0.65 insn per cycle # 1.39 stalled cycles per insn ( +- 0.00% ) 6,316,794,985,573 branches:u # 363.410 M/sec ( +- 0.00% ) 251,013,232,547 branch-misses:u # 3.97% of all branches ( +- 0.01% ) 645.991174661 seconds time elapsed ( +- 1.19% ) Unfortunately, this approach doesn't help with text size: vmlinux.before .text size: 8190319 vmlinux.after .text size: 8200623 The .text section is increased by about 4k. Not sure if we can do anything about this. Signed-off-by: Kirill A. Shuemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180216114948.68868-4-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-20Revert "x86/retpoline: Simplify vmexit_fill_RSB()"David Woodhouse2-4/+2
This reverts commit 1dde7415e99933bb7293d6b2843752cbdb43ec11. By putting the RSB filling out of line and calling it, we waste one RSB slot for returning from the function itself, which means one fewer actual function call we can make if we're doing the Skylake abomination of call-depth counting. It also changed the number of RSB stuffings we do on vmexit from 32, which was correct, to 16. Let's just stop with the bikeshedding; it didn't actually *fix* anything anyway. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: arjan.van.de.ven@intel.com Cc: bp@alien8.de Cc: dave.hansen@intel.com Cc: jmattson@google.com Cc: karahmed@amazon.de Cc: kvm@vger.kernel.org Cc: pbonzini@redhat.com Cc: rkrcmar@redhat.com Link: http://lkml.kernel.org/r/1519037457-7643-4-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-17x86/entry/64: Use 'xorl' for faster register clearingDominik Brodowski2-35/+35
On some x86 CPU microarchitectures using 'xorq' to clear general-purpose registers is slower than 'xorl'. As 'xorl' is sufficient to clear all 64 bits of these registers due to zero-extension [*], switch the x86 64-bit entry code to use 'xorl'. No change in functionality and no change in code size. [*] According to Intel 64 and IA-32 Architecture Software Developer's Manual, section 3.4.1.1, the result of 32-bit operands are "zero- extended to a 64-bit result in the destination general-purpose register." The AMD64 Architecture Programmer’s Manual Volume 3, Appendix B.1, describes the same behaviour. Suggested-by: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180214175924.23065-3-linux@dominikbrodowski.net [ Improved on the changelog a bit. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-17x86/entry: Reduce the code footprint of the 'idtentry' macroDominik Brodowski2-11/+18
Play a little trick in the generic PUSH_AND_CLEAR_REGS macro to insert the GP registers "above" the original return address. This allows us to (re-)insert the macro in error_entry() and paranoid_entry() and to remove it from the idtentry macro. This reduces the static footprint significantly: text data bss dec hex filename 24307 0 0 24307 5ef3 entry_64.o-orig 20987 0 0 20987 51fb entry_64.o Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180214175924.23065-2-linux@dominikbrodowski.net [ Small tweaks to comments. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-15Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds3-132/+97
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 PTI and Spectre related fixes and updates from Ingo Molnar: "Here's the latest set of Spectre and PTI related fixes and updates: Spectre: - Add entry code register clearing to reduce the Spectre attack surface - Update the Spectre microcode blacklist - Inline the KVM Spectre helpers to get close to v4.14 performance again. - Fix indirect_branch_prediction_barrier() - Fix/improve Spectre related kernel messages - Fix array_index_nospec_mask() asm constraint - KVM: fix two MSR handling bugs PTI: - Fix a paranoid entry PTI CR3 handling bug - Fix comments objtool: - Fix paranoid_entry() frame pointer warning - Annotate WARN()-related UD2 as reachable - Various fixes - Add Add Peter Zijlstra as objtool co-maintainer Misc: - Various x86 entry code self-test fixes - Improve/simplify entry code stack frame generation and handling after recent heavy-handed PTI and Spectre changes. (There's two more WIP improvements expected here.) - Type fix for cache entries There's also some low risk non-fix changes I've included in this branch to reduce backporting conflicts: - rename a confusing x86_cpu field name - de-obfuscate the naming of single-TLB flushing primitives" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) x86/entry/64: Fix CR3 restore in paranoid_exit() x86/cpu: Change type of x86_cache_size variable to unsigned int x86/spectre: Fix an error message x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping selftests/x86/mpx: Fix incorrect bounds with old _sigfault x86/mm: Rename flush_tlb_single() and flush_tlb_one() to __flush_tlb_one_[user|kernel]() x86/speculation: Add <asm/msr-index.h> dependency nospec: Move array_index_nospec() parameter checking into separate macro x86/speculation: Fix up array_index_nospec_mask() asm constraint x86/debug: Use UD2 for WARN() x86/debug, objtool: Annotate WARN()-related UD2 as reachable objtool: Fix segfault in ignore_unreachable_insn() selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c selftests/x86: Do not rely on "int $0x80" in test_mremap_vdso.c selftests/x86: Fix build bug caused by the 5lvl test which has been moved to the VM directory selftests/x86/pkeys: Remove unused functions selftests/x86: Clean up and document sscanf() usage selftests/x86: Fix vDSO selftest segfault for vsyscall=none x86/entry/64: Remove the unused 'icebp' macro ...
2018-02-15x86/entry/64: Fix CR3 restore in paranoid_exit()Ingo Molnar1-0/+1
Josh Poimboeuf noticed the following bug: "The paranoid exit code only restores the saved CR3 when it switches back to the user GS. However, even in the kernel GS case, it's possible that it needs to restore a user CR3, if for example, the paranoid exception occurred in the syscall exit path between SWITCH_TO_USER_CR3_STACK and SWAPGS." Josh also confirmed via targeted testing that it's possible to hit this bug. Fix the bug by also restoring CR3 in the paranoid_exit_no_swapgs branch. The reason we haven't seen this bug reported by users yet is probably because "paranoid" entry points are limited to the following cases: idtentry double_fault do_double_fault has_error_code=1 paranoid=2 idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK idtentry machine_check do_mce has_error_code=0 paranoid=1 Amongst those entry points only machine_check is one that will interrupt an IRQS-off critical section asynchronously - and machine check events are rare. The other main asynchronous entries are NMI entries, which can be very high-freq with perf profiling, but they are special: they don't use the 'idtentry' macro but are open coded and restore user CR3 unconditionally so don't have this bug. Reported-and-tested-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180214073910.boevmg65upbk3vqb@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-05 21:31:43 +0300