linux-stable.git/arch/x86/entry, branch linux-5.11.y

x86/vdso: Use proper modifier for len's format specifier in extract()

2021-05-14T08:49:33+00:00

[ Upstream commit 70c9d959226b7c5c48c119e2c1cfc1424f87b023 ]

Commit

  8382c668ce4f ("x86/vdso: Add support for exception fixup in vDSO functions")

prints length "len" which is size_t.

Compilers now complain when building on a 32-bit host:

  HOSTCC  arch/x86/entry/vdso/vdso2c
  ...
  In file included from arch/x86/entry/vdso/vdso2c.c:162:
  arch/x86/entry/vdso/vdso2c.h: In function 'extract64':
  arch/x86/entry/vdso/vdso2c.h:38:52: warning: format '%lu' expects argument of \
	type 'long unsigned int', but argument 4 has type 'size_t' {aka 'unsigned int'}

So use proper modifier (%zu) for size_t.

 [ bp: Massage commit message. ]

Fixes: 8382c668ce4f ("x86/vdso: Add support for exception fixup in vDSO functions")
Signed-off-by: Jiri Slaby 
Signed-off-by: Borislav Petkov 
Acked-by: Jarkko Sakkinen 
Link: https://lkml.kernel.org/r/20210303064357.17056-1-jslaby@suse.cz
Signed-off-by: Sasha Levin

x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls

2021-03-17T16:11:46+00:00

commit 5d5675df792ff67e74a500c4c94db0f99e6a10ef upstream.

On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work.  This confuses audit and ptrace.  For example:

    $ ./tools/testing/selftests/x86/syscall_arg_fault_32
    ...
    strace: pid 264258: entering, ptrace_syscall_info.op == 2
    ...

This is a minimal fix intended for ease of backporting.  A more
complete cleanup is coming.

Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org
Signed-off-by: Greg Kroah-Hartman

x86/sev-es: Introduce ip_within_syscall_gap() helper

2021-03-17T16:11:45+00:00

commit 78a81d88f60ba773cbe890205e1ee67f00502948 upstream.

Introduce a helper to check whether an exception came from the syscall
gap and use it in the SEV-ES code. Extend the check to also cover the
compatibility SYSCALL entry path.

Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Signed-off-by: Joerg Roedel 
Signed-off-by: Borislav Petkov 
Cc: stable@vger.kernel.org # 5.10+
Link: https://lkml.kernel.org/r/20210303141716.29223-2-joro@8bytes.org
Signed-off-by: Greg Kroah-Hartman

x86/entry: Fix instrumentation annotation

2021-03-04T11:15:30+00:00

commit 15f720aabe71a5662c4198b22532d95bbeec80ef upstream.

Embracing a callout into instrumentation_begin() / instrumentation_begin()
does not really make sense. Make the latter instrumentation_end().

Fixes: 2f6474e4636b ("x86/entry: Switch XEN/PV hypercall entry to IDTENTRY")
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210210002512.106502464@linutronix.de
Signed-off-by: Greg Kroah-Hartman

Merge tag 'x86_entry_for_v5.11_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-01-31T19:48:12+00:00

Pull x86 fix from Borislav Petkov:
 "A single fix for objtool to generate proper unwind info for newer
  toolchains which do not generate section symbols anymore. And a
  cleanup ontop.

  This was originally going to go during the next merge window but
  people can already trigger a build error with binutils-2.36 which
  doesn't emit section symbols - something which objtool relies on - so
  let's expedite it"

* tag 'x86_entry_for_v5.11_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Remove put_ret_addr_in_rdi THUNK macro argument
  x86/entry: Emit a symbol for register restoring thunk

x86/entry: Remove put_ret_addr_in_rdi THUNK macro argument

2021-01-19T10:06:14+00:00

That logic is unused since

  320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft")

Remove it.

Suggested-by: Peter Zijlstra (Intel) 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/YAAszZJ2GcIYZmB5@hirez.programming.kicks-ass.net

x86/entry: Emit a symbol for register restoring thunk

2021-01-14T16:18:25+00:00

Arnd found a randconfig that produces the warning:

arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at
offset 0x3e

when building with LLVM_IAS=1 (Clang's integrated assembler). Josh
notes:

With the LLVM assembler not generating section symbols, objtool has no
way to reference this code when it generates ORC unwinder entries,
because this code is outside of any ELF function.

The limitation now being imposed by objtool is that all code must be
contained in an ELF symbol. And .L symbols don't create such symbols.

So basically, you can use an .L symbol *inside* a function or a code
segment, you just can't use the .L symbol to contain the code using a
SYM_*_START/END annotation pair.

Fangrui notes that this optimization is helpful for reducing image size
when compiling with -ffunction-sections and -fdata-sections. I have
observed on the order of tens of thousands of symbols for the kernel
images built with those flags.

A patch has been authored against GNU binutils to match this behavior
of not generating unused section symbols ([1]), so this will
also become a problem for users of GNU binutils once they upgrade to 2.36.

Omit the .L prefix on a label so that the assembler will emit an entry
into the symbol table for the label, with STB_LOCAL binding. This
enables objtool to generate proper unwind info here with LLVM_IAS=1 or
GNU binutils 2.36+.

[ bp: Massage commit message. ]

Reported-by: Arnd Bergmann
Suggested-by: Josh Poimboeuf
Suggested-by: Borislav Petkov
Suggested-by: Mark Brown
Signed-off-by: Nick Desaulniers
Signed-off-by: Borislav Petkov
Acked-by: Peter Zijlstra (Intel)
Acked-by: Josh Poimboeuf
Link: https://lkml.kernel.org/r/20210112194625.4181814-1-ndesaulniers@google.com
Link: https://github.com/ClangBuiltLinux/linux/issues/1209
Link: https://reviews.llvm.org/D93783
Link: https://sourceware.org/binutils/docs/as/Symbol-Names.html
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1408485ce69f844dcd7ded093a8 [1]

x86/entry: Fix noinstr fail

2021-01-12T20:10:58+00:00

  vmlinux.o: warning: objtool: __do_fast_syscall_32()+0x47: call to syscall_enter_from_user_mode_work() leaves .noinstr.text section

Fixes: 4facb95b7ada ("x86/entry: Unbreak 32bit fast syscall")
Reported-by: Randy Dunlap 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20210106144017.472696632@infradead.org

epoll: wire up syscall epoll_pwait2

2020-12-19T19:18:38+00:00

Split off from prev patch in the series that implements the syscall.

Link: https://lkml.kernel.org/r/20201121144401.3727659-4-willemdebruijn.kernel@gmail.com
Signed-off-by: Willem de Bruijn 
Cc: Al Viro 
Cc: Arnd Bergmann 
Cc: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2020-12-15T20:53:37+00:00

Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton : (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...