Ard Biesheuvel
71810db27c
modversions: treat symbol CRCs as 32 bit quantities
...
The modversion symbol CRCs are emitted as ELF symbols, which allows us
to easily populate the kcrctab sections by relying on the linker to
associate each kcrctab slot with the correct value.
This has a couple of downsides:
- Given that the CRCs are treated as memory addresses, we waste 4 bytes
for each CRC on 64 bit architectures,
- On architectures that support runtime relocation, a R_<arch>_RELATIVE
relocation entry is emitted for each CRC value, which identifies it
as a quantity that requires fixing up based on the actual runtime
load offset of the kernel. This results in corrupted CRCs unless we
explicitly undo the fixup (and this is currently being handled in the
core module code)
- Such runtime relocation entries take up 24 bytes of __init space
each, resulting in a x8 overhead in [uncompressed] kernel size for
CRCs.
Switching to explicit 32 bit values on 64 bit architectures fixes most
of these issues, given that 32 bit values are not treated as quantities
that require fixing up based on the actual runtime load offset. Note
that on some ELF64 architectures [such as PPC64], these 32-bit values
are still emitted as [absolute] runtime relocatable quantities, even if
the value resolves to a build time constant. Since relative relocations
are always resolved at build time, this patch enables MODULE_REL_CRCS on
powerpc when CONFIG_RELOCATABLE=y, which turns the absolute CRC
references into relative references into .rodata where the actual CRC
value is stored.
So redefine all CRC fields and variables as u32, and redefine the
__CRC_SYMBOL() macro for 64 bit builds to emit the CRC reference using
inline assembler (which is necessary since 64-bit C code cannot use
32-bit types to hold memory addresses, even if they are ultimately
resolved using values that do not exceed 0xffffffff). To avoid
potential problems with legacy 32-bit architectures using legacy
toolchains, the equivalent C definition of the kcrctab entry is retained
for 32-bit architectures.
Note that this mostly reverts commit d4703aefdb ("module: handle ppc64
relocating kcrctabs when CONFIG_RELOCATABLE=y")
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 08:28:25 -08:00
..
bitops
bitops: Do not default to __clear_bit() for __clear_bit_unlock()
2016-03-21 10:50:48 +01:00
4level-fixup.h
mm, asm-generic: define PUD_SHIFT in <asm-generic/4level-fixup.h>
2015-02-11 17:06:03 -08:00
asm-offsets.h
asm-generic: Add common asm-offsets.h
2015-06-23 13:35:49 +09:00
asm-prototypes.h
asm-prototypes: Clear any CPP defines before declaring the functions
2017-01-05 12:57:42 +01:00
atomic-long.h
locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API
2016-07-07 09:16:20 +02:00
atomic.h
locking/atomic: Remove linux/atomic.h:atomic_fetch_or()
2016-06-16 10:48:32 +02:00
atomic64.h
locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()
2016-06-16 10:48:32 +02:00
audit_change_attr.h
audit: Modify a set of system calls in audit class definitions
2014-01-17 17:01:46 -05:00
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h
audit: Modify a set of system calls in audit class definitions
2014-01-17 17:01:46 -05:00
barrier.h
locking/spinlock, arch: Update and fix spin_unlock_wait() implementations
2016-06-14 11:55:15 +02:00
bitops.h
arch: Prepare for smp_mb__{before,after}_atomic()
2014-04-18 11:40:30 +02:00
bitsperlong.h
bug.h
asm-generic changes for 4.6
2016-03-24 23:13:48 -07:00
bugs.h
cache.h
cacheflush.h
checksum.h
ipv4: Update parameters for csum_tcpudp_magic to their original types
2016-03-13 23:55:13 -04:00
clkdev.h
asm-generic: COMMON_CLK defines __clk_{get,put}
2014-09-25 18:00:45 -07:00
cmpxchg-local.h
LLVMLinux: Remove warning about returning an uninitialized variable
2014-04-09 13:44:35 -07:00
cmpxchg.h
asm-generic: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
2015-10-15 00:21:13 +02:00
cputime.h
cputime: Generic on-demand virtual cputime accounting
2013-01-27 19:23:27 +01:00
cputime_jiffies.h
sched/cputime, powerpc: Remove cputime_to_scaled()
2016-11-15 09:51:04 +01:00
cputime_nsecs.h
sched/cputime, powerpc: Remove cputime_to_scaled()
2016-11-15 09:51:04 +01:00
current.h
delay.h
device.h
div64.h
__div64_32(): make it overridable at compile time
2015-11-16 14:42:12 -05:00
dma-contiguous.h
asm-generic: Add dma-contiguous.h
2014-09-22 13:35:51 +02:00
dma.h
early_ioremap.h
Merge branch 'akpm' (patches from Andrew)
2015-09-08 17:52:23 -07:00
emergency-restart.h
exec.h
export.h
modversions: treat symbol CRCs as 32 bit quantities
2017-02-03 08:28:25 -08:00
fb.h
fixmap.h
asm-generic: Fix local variable shadow in __set_fixmap_offset
2016-02-16 15:10:44 +00:00
ftrace.h
futex.h
asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()
2016-04-21 11:06:09 +02:00
getorder.h
gpio.h
gpio: allow setting ARCH_NR_GPIOS from Kconfig
2016-02-19 00:22:54 +01:00
hardirq.h
hugetlb.h
mm: Fix generic hugetlb pte check return type.
2013-10-02 20:02:35 -04:00
hw_irq.h
ide_iops.h
int-ll64.h
io.h
asm-generic/io.h: add io{read,write}64 accessors
2016-05-31 16:41:50 +08:00
ioctl.h
include/asm-generic/ioctl.h: fix _IOC_TYPECHECK sparse error
2014-06-06 16:08:13 -07:00
iomap.h
asm-generic/io.h: add io{read,write}64 accessors
2016-05-31 16:41:50 +08:00
irq.h
irq_regs.h
irq_work.h
irq_work: Introduce arch_irq_work_has_interrupt()
2014-09-13 18:38:07 +02:00
irqflags.h
Kbuild.asm
kdebug.h
kmap_types.h
kvm_para.h
KVM: add kvm_para_available to asm-generic/kvm_para.h
2013-06-05 13:21:29 +03:00
linkage.h
local.h
local64.h
mcs_spinlock.h
locking/mcs: Allow architecture specific asm files to be used for contended case
2014-02-09 21:18:52 +01:00
memory_model.h
mm: add PHYS_PFN, use it in __phys_to_pfn()
2016-01-14 16:00:49 -08:00
mm-arch-hooks.h
mm: clean up per architecture MM hook header files
2015-07-17 16:39:53 -07:00
mm_hooks.h
mm/core, x86/mm/pkeys: Differentiate instruction fetches
2016-02-18 19:46:29 +01:00
mmu.h
asm-generic/mmu.h: Add support for FDPIC
2012-12-09 23:14:14 +01:00
mmu_context.h
asm-generic: Remove asm-generic arch_bprm_mm_init()
2014-11-22 21:52:08 +01:00
module.h
msi.h
asm-generic: Add msi.h
2014-11-23 13:01:47 +01:00
page.h
asm-generic: page.h: Remove useless get_user_page and free_user_page
2016-02-26 15:24:55 +01:00
param.h
parport.h
include: remove __dev* attributes.
2013-01-03 15:57:16 -08:00
pci.h
PCI: Remove unused pcibios_select_root() (again)
2015-06-08 07:56:21 -05:00
pci_iomap.h
PCI: Add pci_iomap_wc() variants
2015-08-25 09:59:45 +02:00
percpu.h
percpu: use notrace variant of preempt_disable/preempt_enable
2016-11-08 10:29:44 +01:00
pgalloc.h
pgtable-nopmd.h
pgtable-nopud.h
pgtable.h
mm: THP page cache support for ppc64
2016-12-12 18:55:08 -08:00
preempt.h
sched/preempt: Fix preempt_count manipulations
2016-05-17 12:24:21 +02:00
ptrace.h
qrwlock.h
locking/qrwlock: Fix write unlock bug on big endian systems
2016-08-10 14:13:27 +02:00
qrwlock_types.h
locking/qrwlock: Rename ->lock to ->wait_lock
2015-09-18 09:27:29 +02:00
qspinlock.h
locking/qspinlock: Use atomic_sub_return_release() in queued_spin_unlock()
2016-06-08 15:17:01 +02:00
qspinlock_types.h
locking/qspinlock: Move __ARCH_SPIN_LOCK_UNLOCKED to qspinlock_types.h
2016-02-29 10:02:43 +01:00
resource.h
asm-generic: remove _STK_LIM_MAX
2014-05-15 00:32:09 +01:00
rwsem.h
locking/rwsem: Remove rwsem_atomic_add() and rwsem_atomic_update()
2016-06-08 15:16:59 +02:00
seccomp.h
seccomp: Get compat syscalls from asm-generic header
2016-05-13 14:02:00 +02:00
sections.h
mm: kmemleak: scan .data.ro_after_init
2016-11-11 08:12:37 -08:00
segment.h
serial.h
siginfo.h
SIGNAL: Move generic copy_siginfo() to signal.h
2016-05-13 14:02:10 +02:00
signal.h
simd.h
crypto: create generic version of ablk_helper
2013-09-24 06:02:24 +10:00
sizes.h
spinlock.h
statfs.h
string.h
switch_to.h
syscall.h
syscall.h: fix doc text for syscall_get_arch()
2014-09-23 16:20:00 -04:00
syscalls.h
burying unused conditionals
2013-02-14 09:21:15 -05:00
termios-base.h
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
termios.h
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
timex.h
tlb.h
mm: remove the page size change check in tlb_remove_page
2016-12-12 18:55:07 -08:00
tlbflush.h
topology.h
trace_clock.h
uaccess-unaligned.h
uaccess.h
exceptions: detritus removal
2016-09-27 21:15:14 -04:00
unaligned.h
asm-generic: allow generic unaligned access if the arch supports it
2014-05-08 10:22:23 +02:00
unistd.h
We get rid of the general module prefix confusion with a binary config option,
2013-05-05 10:58:06 -07:00
user.h
vga.h
vmlinux.lds.h
Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
2016-12-17 16:24:13 -08:00
vtime.h
include/asm-generic/vtime.h: avoid zero-length file
2013-09-30 14:31:02 -07:00
word-at-a-time.h
Make asm/word-at-a-time.h available on all architectures
2015-07-08 16:41:55 -04:00
xor.h