Pull x86 fixes from Thomas Gleixner:
"A set of fixes for x86:
- Ensure that direct mapping alias is always flushed when changing
page attributes. The optimization for small ranges failed to do so
when the virtual address was in the vmalloc or module space.
- Unbreak the trace event registration for syscalls without arguments
caused by the refactoring of the SYSCALL_DEFINE0() macro.
- Move the printk in the TSC deadline timer code to a place where it
is guaranteed to only be called once during boot and cannot be
rearmed by clearing warn_once after boot. If it's invoked post boot
then lockdep rightfully complains about a potential deadlock as the
calling context is different.
- A series of fixes for objtool and the ORC unwinder addressing
variety of small issues:
- Stack offset tracking for indirect CFAs in objtool ignored
subsequent pushs and pops
- Repair the unwind hints in the register clearing entry ASM code
- Make the unwinding in the low level exit to usermode code stop
after switching to the trampoline stack. The unwind hint is no
longer valid and the ORC unwinder emits a warning as it can't
find the registers anymore.
- Fix unwind hints in switch_to_asm() and rewind_stack_do_exit()
which caused objtool to generate bogus ORC data.
- Prevent unwinder warnings when dumping the stack of a
non-current task as there is no way to be sure about the
validity because the dumped stack can be a moving target.
- Make the ORC unwinder behave the same way as the frame pointer
unwinder when dumping an inactive tasks stack and do not skip
the first frame.
- Prevent ORC unwinding before ORC data has been initialized
- Immediately terminate unwinding when a unknown ORC entry type
is found.
- Prevent premature stop of the unwinder caused by IRET frames.
- Fix another infinite loop in objtool caused by a negative
offset which was not catched.
- Address a few build warnings in the ORC unwinder and add
missing static/ro_after_init annotations"
* tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/unwind/orc: Move ORC sorting variables under !CONFIG_MODULES
x86/apic: Move TSC deadline timer debug printk
ftrace/x86: Fix trace event registration for syscalls without arguments
x86/mm/cpa: Flush direct map alias during cpa
objtool: Fix infinite loop in for_offset_range()
x86/unwind/orc: Fix premature unwind stoppage due to IRET frames
x86/unwind/orc: Fix error path for bad ORC entry type
x86/unwind/orc: Prevent unwinding before ORC initialization
x86/unwind/orc: Don't skip the first frame for inactive tasks
x86/unwind: Prevent false warnings for non-current tasks
x86/unwind/orc: Convert global variables to static
x86/entry/64: Fix unwind hints in rewind_stack_do_exit()
x86/entry/64: Fix unwind hints in __switch_to_asm()
x86/entry/64: Fix unwind hints in kernel exit path
x86/entry/64: Fix unwind hints in register clearing code
objtool: Fix stack offset tracking for indirect CFAs
Kristen found a hang in objtool when building with -ffunction-sections.
It was caused by evergreen_pcie_gen2_enable.cold() being laid out
immediately before evergreen_pcie_gen2_enable(). Since their "pfunc" is
always the same, find_jump_table() got into an infinite loop because it
didn't recognize the boundary between the two functions.
Fix that with a new prev_insn_same_sym() helper, which doesn't cross
subfunction boundaries.
Reported-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/378b51c9d9c894dc3294bc460b4b0869e950b7c5.1588110291.git.jpoimboe@redhat.com
If a switch jump table's indirect branch is in a ".cold" subfunction in
.text.unlikely, objtool doesn't detect it, and instead prints a false
warning:
drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame
drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame
drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame
Fix it by comparing the function, instead of the section and offset.
Fixes: 13810435b9 ("objtool: Support GCC 8's cold subfunctions")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com
CONFIG_UBSAN_TRAP causes GCC to emit a UD2 whenever it encounters an
unreachable code path. This includes __builtin_unreachable(). Because
the BUG() macro uses __builtin_unreachable() after it emits its own UD2,
this results in a double UD2. In this case objtool rightfully detects
that the second UD2 is unreachable:
init/main.o: warning: objtool: repair_env_string()+0x1c8: unreachable instruction
We weren't able to figure out a way to get rid of the double UD2s, so
just silence the warning.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/6653ad73c6b59c049211bd7c11ed3809c20ee9f5.1585761021.git.jpoimboe@redhat.com
Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:
- Continued user-access cleanups in the futex code.
- percpu-rwsem rewrite that uses its own waitqueue and atomic_t
instead of an embedded rwsem. This addresses a couple of
weaknesses, but the primary motivation was complications on the -rt
kernel.
- Introduce raw lock nesting detection on lockdep
(CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal
lock differences. This too originates from -rt.
- Reuse lockdep zapped chain_hlocks entries, to conserve RAM
footprint on distro-ish kernels running into the "BUG:
MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep
chain-entries pool.
- Misc cleanups, smaller fixes and enhancements - see the changelog
for details"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t
thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t
Documentation/locking/locktypes: Minor copy editor fixes
Documentation/locking/locktypes: Further clarifications and wordsmithing
m68knommu: Remove mm.h include from uaccess_no.h
x86: get rid of user_atomic_cmpxchg_inatomic()
generic arch_futex_atomic_op_inuser() doesn't need access_ok()
x86: don't reload after cmpxchg in unsafe_atomic_op2() loop
x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end()
objtool: whitelist __sanitizer_cov_trace_switch()
[parisc, s390, sparc64] no need for access_ok() in futex handling
sh: no need of access_ok() in arch_futex_atomic_op_inuser()
futex: arch_futex_atomic_op_inuser() calling conventions change
completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all()
lockdep: Add posixtimer context tracing bits
lockdep: Annotate irq_work
lockdep: Add hrtimer context tracing bits
lockdep: Introduce wait-type checks
completion: Use simple wait queues
sched/swait: Prepare usage in completions
...
it's not really different from e.g. __sanitizer_cov_trace_cmp4();
as it is, the switches that generate an array of labels get
rejected by objtool, while slightly different set of cases
that gets compiled into a series of comparisons is accepted.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Perf showed that __hash_init() is a significant portion of
read_sections(), so instead of doing a per section rela_hash, use an
elf-wide rela_hash.
Statistics show us there are about 1.1 million relas, so size it
accordingly.
This reduces the objtool on vmlinux.o runtime to a third, from 15 to 5
seconds.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200324160924.739153726@infradead.org
There is func_for_each_insn() and func_for_each_insn_all(), the both
iterate the instructions, but the first uses symbol offset/length
while the second uses insn->func.
Rename func_for_each_insn() to sym_for_eac_insn() because it iterates
on symbol information.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200324160924.024341229@infradead.org
Clang has the ability to create a switch table which is not a jump
table, but is rather a table of string pointers. This confuses objtool,
because it sees the relocations for the string pointers and assumes
they're part of a jump table:
drivers/ata/sata_dwc_460ex.o: warning: objtool: sata_dwc_bmdma_start_by_tag()+0x3a2: can't find switch jump table
net/ceph/messenger.o: warning: objtool: ceph_con_workfn()+0x47c: can't find switch jump table
Make objtool's find_jump_table() smart enough to distinguish between a
switch jump table (which has relocations to text addresses in the same
function as the original instruction) and other anonymous rodata (which
may have relocations to elsewhere).
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/485
Link: https://lkml.kernel.org/r/263f6aae46d33da0b86d7030ced878cb5cab1788.1581997059.git.jpoimboe@redhat.com
Relocations in alternative code can be dangerous, because the code is
copy/pasted to the text section after relocations have been resolved,
which can corrupt PC-relative addresses.
However, relocations might be acceptable in some cases, depending on the
architecture. For example, the x86 alternatives code manually fixes up
the target addresses for PC-relative jumps and calls.
So disallow relocations in alternative code, except where the x86 arch
code allows it.
This code may need to be tweaked for other arches when objtool gets
support for them.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Julien Thierry <jthierry@redhat.com>
Link: https://lkml.kernel.org/r/7b90b68d093311e4e8f6b504a9e1c758fd7e0002.1581359535.git.jpoimboe@redhat.com
When objtool encounters a fatal error, it usually means the binary is
corrupt or otherwise broken in some way. Up until now, such errors were
just treated as warnings which didn't fail the kernel build.
However, objtool is now stable enough that if a fatal error is
discovered, it most likely means something is seriously wrong and it
should fail the kernel build.
Note that this doesn't apply to "normal" objtool warnings; only fatal
ones.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Julien Thierry <jthierry@redhat.com>
Link: https://lkml.kernel.org/r/f18c3743de0fef673d49dd35760f26bdef7f6fc3.1581359535.git.jpoimboe@redhat.com
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- Cross-arch changes to move the linker sections for NOTES and
EXCEPTION_TABLE into the RO_DATA area, where they belong on most
architectures. (Kees Cook)
- Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to
trap jumps into the middle of those padding areas instead of
sliding execution. (Kees Cook)
- A thorough cleanup of symbol definitions within x86 assembler code.
The rather randomly named macros got streamlined around a
(hopefully) straightforward naming scheme:
SYM_START(name, linkage, align...)
SYM_END(name, sym_type)
SYM_FUNC_START(name)
SYM_FUNC_END(name)
SYM_CODE_START(name)
SYM_CODE_END(name)
SYM_DATA_START(name)
SYM_DATA_END(name)
etc - with about three times of these basic primitives with some
label, local symbol or attribute variant, expressed via postfixes.
No change in functionality intended. (Jiri Slaby)
- Misc other changes, cleanups and smaller fixes"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
x86/entry/64: Remove pointless jump in paranoid_exit
x86/entry/32: Remove unused resume_userspace label
x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o
m68k: Convert missed RODATA to RO_DATA
x86/vmlinux: Use INT3 instead of NOP for linker fill bytes
x86/mm: Report actual image regions in /proc/iomem
x86/mm: Report which part of kernel image is freed
x86/mm: Remove redundant address-of operators on addresses
xtensa: Move EXCEPTION_TABLE to RO_DATA segment
powerpc: Move EXCEPTION_TABLE to RO_DATA segment
parisc: Move EXCEPTION_TABLE to RO_DATA segment
microblaze: Move EXCEPTION_TABLE to RO_DATA segment
ia64: Move EXCEPTION_TABLE to RO_DATA segment
h8300: Move EXCEPTION_TABLE to RO_DATA segment
c6x: Move EXCEPTION_TABLE to RO_DATA segment
arm64: Move EXCEPTION_TABLE to RO_DATA segment
alpha: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Actually use _etext for the end of the text segment
vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
...
Fix the following warning seen on GCC 7.3:
kunit/test-test.o: warning: objtool: kunit_test_unsuccessful_try() falls through to next function kunit_test_catch()
kunit_try_catch_throw is a function added in the following patch in this
series; it allows KUnit, a unit testing framework for the kernel, to
bail out of a broken test. As a consequence, it is a new __noreturn
function that objtool thinks is broken (as seen above). So fix this
warning by adding kunit_try_catch_throw to objtool's noreturn list.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://www.spinics.net/lists/linux-kbuild/msg21708.html
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Explicitly check kvm_rebooting in kvm_spurious_fault() prior to invoking
BUG(), as opposed to assuming the caller has already done so. Letting
kvm_spurious_fault() be called "directly" will allow VMX to better
optimize its low level assembly flows.
As a happy side effect, kvm_spurious_fault() no longer needs to be
marked as a dead end since it doesn't unconditionally BUG().
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A clang build reported an (obvious) double CLAC while a GCC build did not;
it turns out that objtool only re-visits instructions if the first visit
was with AC=0. If OTOH the first visit was with AC=1, it completely ignores
any subsequent visit, even when it has AC=0.
Fix this by using a visited mask instead of a boolean, and (explicitly)
mark the AC state.
$ ./objtool check -b --no-fp --retpoline --uaccess drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x22: redundant UACCESS disable
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: eb_copy_relocations.isra.34()+0xea: (alt)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0xffffffffffffffff: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: eb_copy_relocations.isra.34()+0xd9: (alt)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: eb_copy_relocations.isra.34()+0xb2: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: eb_copy_relocations.isra.34()+0x39: (branch)
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: eb_copy_relocations.isra.34()+0x0: <=== (func)
Reported-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/617
Link: https://lkml.kernel.org/r/5359166aad2d53f3145cd442d83d0e5115e0cd17.1564007838.git.jpoimboe@redhat.com
