Ard Biesheuvel
7290d58095
module: use relative references for __ksymtab entries
...
An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries,
each consisting of two 64-bit fields containing absolute references, to
the symbol itself and to a char array containing its name, respectively.
When we build the same configuration with KASLR enabled, we end up with an
additional ~192 KB of relocations in the .init section, i.e., one 24 byte
entry for each absolute reference, which all need to be processed at boot
time.
Given how the struct kernel_symbol that describes each entry is completely
local to module.c (except for the references emitted by EXPORT_SYMBOL()
itself), we can easily modify it to contain two 32-bit relative references
instead. This reduces the size of the __ksymtab section by 50% for all
64-bit architectures, and gets rid of the runtime relocations entirely for
architectures implementing KASLR, either via standard PIE linking (arm64)
or using custom host tools (x86).
Note that the binary search involving __ksymtab contents relies on each
section being sorted by symbol name. This is implemented based on the
input section names, not the names in the ksymtab entries, so this patch
does not interfere with that.
Given that the use of place-relative relocations requires support both in
the toolchain and in the module loader, we cannot enable this feature for
all architectures. So make it dependent on whether
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.
Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:47 -07:00
..
bitops
locking/atomics, asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()
2018-06-21 12:52:12 +02:00
4level-fixup.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
5level-fixup.h
x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable
2018-02-14 13:11:14 +01:00
asm-offsets.h
asm-prototypes.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
atomic-instrumented.h
locking/atomics: Instrument cmpxchg_double*()
2018-07-25 11:53:59 +02:00
atomic-long.h
locking/mutex: Optimize __mutex_trylock_fast()
2018-05-04 10:02:39 +02:00
atomic.h
atomics/treewide: Make unconditional inc/dec ops optional
2018-06-21 14:25:24 +02:00
atomic64.h
atomics/treewide: Make conditional inc/dec ops optional
2018-06-21 14:25:24 +02:00
audit_change_attr.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
audit_dir_write.h
audit: Avoid build failures on systems without renameat
2018-01-30 19:07:54 -08:00
audit_read.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
audit_signal.h
audit_write.h
audit/stable-4.15 PR 20171113
2017-11-15 13:28:48 -08:00
barrier.h
locking/barriers: Introduce smp_cond_load_relaxed() and atomic_cond_read_relaxed()
2018-04-27 09:48:44 +02:00
bitops.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
bitsperlong.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
bug.h
include/asm-generic/bug.h: clarify valid uses of WARN()
2018-08-22 10:52:46 -07:00
bugs.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
cache.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
cacheflush.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
checksum.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
cmpxchg-local.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
cmpxchg.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
compat.h
time: Add an asm-generic/compat.h file
2018-04-19 13:28:51 +02:00
current.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
delay.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
device.h
div64.h
A relatively calm cycle for the docs tree again.
2017-11-13 08:25:06 -08:00
dma-contiguous.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
dma-mapping.h
dma-mapping: provide a generic dma-noncoherent implementation
2018-05-19 08:46:12 +02:00
dma.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
early_ioremap.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
emergency-restart.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
error-injection.h
error-injection: Add injectable error types
2018-01-12 17:33:38 -08:00
exec.h
mn10300: Remove the architecture
2018-03-09 23:19:56 +01:00
export.h
module: use relative references for __ksymtab entries
2018-08-22 10:52:47 -07:00
extable.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
fb.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
fixmap.h
ftrace.h
futex.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
getorder.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
gpio.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
hardirq.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
hugetlb.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
hw_irq.h
ide_iops.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
int-ll64.h
int-ll64.h: define u{8,16,32,64} and s{8,16,32,64} based on uapi header
2018-06-07 17:34:38 -07:00
io.h
asm-generic fixes for v4.17-rc1
2018-04-12 09:15:48 -07:00
ioctl.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
iomap.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
irq.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
irq_regs.h
irq_work.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
irqflags.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
kdebug.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
kmap_types.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
kprobes.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
kvm_para.h
KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED
2018-03-06 18:40:44 +01:00
linkage.h
local.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
local64.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
mcs_spinlock.h
memory_model.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
mm-arch-hooks.h
mm_hooks.h
arch, mm: Allow arch_dup_mmap() to fail
2017-12-22 20:13:01 +01:00
mmu.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
mmu_context.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
module.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
msi.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
page.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
param.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
parport.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pci.h
PCI: remove PCI_DMA_BUS_IS_PHYS
2018-05-07 07:15:41 +02:00
pci_iomap.h
mn10300: Remove the architecture
2018-03-09 23:19:56 +01:00
percpu.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pgalloc.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pgtable-nop4d-hack.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pgtable-nop4d.h
x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable
2018-02-14 13:11:14 +01:00
pgtable-nopmd.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pgtable-nopud.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
pgtable.h
mm: provide a fallback for PAGE_KERNEL_EXEC for architectures
2018-08-17 16:20:29 -07:00
preempt.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
ptrace.h
qrwlock.h
locking/qrwlock: Prevent slowpath writers getting held up by fastpath
2017-10-25 10:57:25 +02:00
qrwlock_types.h
locking/qrwlock: include asm/byteorder.h as needed
2018-02-06 10:28:58 +01:00
qspinlock.h
locking/spinlocks: Clean up comment and #ifndef for {,queued_}spin_is_locked()
2018-05-15 08:11:15 +02:00
qspinlock_types.h
locking/qspinlock: Fix build for anonymous union in older GCC compilers
2018-06-22 04:19:16 +02:00
resource.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
rwsem.h
Merge branch 'linus' into locking/core, to resolve conflicts
2017-11-07 10:32:44 +01:00
seccomp.h
seccomp: Get compat syscalls from asm-generic header
2016-05-13 14:02:00 +02:00
sections.h
sections: split dereference_function_descriptor()
2018-01-09 10:45:37 +01:00
segment.h
serial.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
set_memory.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
signal.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
simd.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
sizes.h
spinlock.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
statfs.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
string.h
switch_to.h
mn10300: Remove the architecture
2018-03-09 23:19:56 +01:00
syscall.h
syscalls.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
termios-base.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
termios.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
timex.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
tlb.h
x86/mm/tlb: Leave lazy TLB mode at page table free time
2018-07-17 09:35:31 +02:00
tlbflush.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
topology.h
include/asm-generic/topology.h: remove unused parent_node() macro
2017-11-17 16:10:05 -08:00
trace_clock.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
uaccess.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
unaligned.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
unistd.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
user.h
vga.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
vmlinux.lds.h
iommu: Remove IOMMU_OF_DECLARE
2018-07-10 17:22:35 +02:00
vtime.h
word-at-a-time.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
xor.h