tmp_suning_uos_patched/arch
Fangrui Song b3d0f1c3a6 x86/build: Treat R_386_PLT32 relocation as R_386_PC32
commit bb73d07148c405c293e576b40af37737faf23a6a upstream.

This is similar to commit

  b21ebf2fb4 ("x86: Treat R_X86_64_PLT32 as R_X86_64_PC32")

but for i386. As far as the kernel is concerned, R_386_PLT32 can be
treated the same as R_386_PC32.

R_386_PLT32/R_X86_64_PLT32 are PC-relative relocation types which
can only be used by branches. If the referenced symbol is defined
externally, a PLT will be used.

R_386_PC32/R_X86_64_PC32 are PC-relative relocation types which can be
used by address taking operations and branches. If the referenced symbol
is defined externally, a copy relocation/canonical PLT entry will be
created in the executable.

On x86-64, there is no PIC vs non-PIC PLT distinction and an
R_X86_64_PLT32 relocation is produced for both `call/jmp foo` and
`call/jmp foo@PLT` with newer (2018) GNU as/LLVM integrated assembler.
This avoids canonical PLT entries (st_shndx=0, st_value!=0).

On i386, there are 2 types of PLTs, PIC and non-PIC. Currently,
the GCC/GNU as convention is to use R_386_PC32 for non-PIC PLT and
R_386_PLT32 for PIC PLT. Copy relocations/canonical PLT entries
are possible ABI issues but GCC/GNU as will likely keep the status
quo because (1) the ABI is legacy (2) the change will drop a GNU
ld diagnostic for non-default visibility ifunc in shared objects.

clang-12 -fno-pic (since [1]) can emit R_386_PLT32 for compiler
generated function declarations, because preventing canonical PLT
entries is weighed over the rare ifunc diagnostic.

Further info for the more interested:

  https://github.com/ClangBuiltLinux/linux/issues/1210
  https://sourceware.org/bugzilla/show_bug.cgi?id=27169
  a084c0388e [1]

 [ bp: Massage commit message. ]

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://lkml.kernel.org/r/20210127205600.1227437-1-maskray@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-07 12:34:04 +01:00
..
alpha local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
arc arch/arc: add copy_user_page() to <asm/page.h> to fix build error on ARC 2021-01-19 18:27:26 +01:00
arm ARM: dts: aspeed: Add LCLK to lpc-snoop 2021-03-04 11:38:47 +01:00
arm64 arm64: spectre: Prevent lockdep splat on v4 mitigation enable path 2021-03-04 11:38:36 +01:00
c6x arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
csky csky: Fix a size determination in gpr_get() 2021-03-04 11:38:21 +01:00
h8300 h8300: fix PREEMPTION build, TI_PRE_COUNT undefined 2021-02-17 11:02:28 +01:00
hexagon local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
ia64 local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
m68k local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
microblaze local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
mips Revert "MIPS: Octeon: Remove special handling of CONFIG_MIPS_ELF_APPENDED_DTB=y" 2021-03-04 11:38:26 +01:00
nds32 local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
nios2 nios2: fixed broken sys_clone syscall 2021-03-04 11:38:16 +01:00
openrisc sched/idle: Fix arch_cpu_idle() vs tracing 2020-11-24 16:47:35 +01:00
parisc parisc: Enable -mlong-calls gcc option by default when !CONFIG_MODULES 2021-02-03 23:28:37 +01:00
powerpc powerpc/32s: Add missing call to kuep_lock on syscall entry 2021-03-04 11:38:40 +01:00
riscv riscv: Disable KSAN_SANITIZE for vDSO 2021-03-04 11:38:36 +01:00
s390 s390/vtime: fix inline assembly clobber list 2021-03-04 11:38:42 +01:00
sh sh: Remove unused HAVE_COPY_THREAD_TLS macro 2021-01-27 11:55:20 +01:00
sparc sparc32: fix a user-triggerable oops in clear_user() 2021-03-04 11:38:43 +01:00
um um: defer killing userspace on page table update failures 2021-03-04 11:38:42 +01:00
x86 x86/build: Treat R_386_PLT32 relocation as R_386_PC32 2021-03-07 12:34:04 +01:00
xtensa local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
.gitignore
Kconfig fanotify: Fix sys_fanotify_mark() on native x86-32 2021-01-17 14:16:59 +01:00