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05123fef09
linux/arch/arm/kernel
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Ard Biesheuvel 05123fef09 ARM: kernel: allocate PLT entries only for external symbols 
When CONFIG_ARM_MODULE_PLTS is enabled, jump and call instructions in
modules no longer need to be within 16 MB (8 MB for Thumb2) of their
targets. If they are further away, a PLT entry will be generated on the
fly for each of them, which extends the range to the entire 32-bit
address space.

However, since these PLT entries will become the branch targets of the
original jump and call instructions, the PLT itself needs to be in
range, or we end up in the same situation we started in. Since the PLT
is in a separate section, this essentially means that all jumps and calls
inside the same module must be resolvable without PLT entries.

The PLT allocation code executes before the module itself is loaded in
its final location, and so it has to use a worst-case estimate for
which jumps and calls will require an entry in the PLT at relocation
time. As an optimization, this code deduplicates entries pointing to
the same symbol, using a O(n^2) algorithm. However, it does not take
the above into account, i.e., that PLT entries will only be needed for
jump and call relocations against symbols that are not defined in the
module.

So disregard relocations against symbols that are defined in the module
itself.

As an additional minor optimization, ignore input sections that lack
the SHF_EXECINSTR flag. Since jump and call relocations operate on
executable instructions only, there is no need to look in sections that
do not contain executable code.

Tested-by: Jongsung Kim <neidhard.kim@lge.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2016-08-30 17:45:34 +01:00
..
.gitignore
arch_timer.c
armksyms.c ARM: 8479/2: add implementation for arm-smccc 2016-01-04 16:24:34 +00:00
asm-offsets.c ARM: save and reset the address limit when entering an exception 2016-07-07 16:01:01 +01:00
atags_compat.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
atags_parse.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
atags_proc.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
atags.h ARM: 8495/1: ATAGS: move save_atags() to arch/arm/include/asm/setup.h 2016-01-04 11:26:00 +00:00
bios32.c Merge branches 'pci/demodularize-hosts' and 'pci/host-request-windows' into next 2016-08-01 12:23:57 -05:00
calls.S ARM: wire up preadv2 and pwritev2 syscalls 2016-04-07 21:57:02 +01:00
cpuidle.c ARM: 8586/1: cpuidle: make arm_cpuidle_suspend() a bit more efficient 2016-07-14 16:30:45 +01:00
crash_dump.c ARM: 8012/1: kdump: Avoid overflow when converting pfn to physaddr 2014-04-07 12:10:00 +01:00
debug.S ARM: unify MMU/!MMU addruart calls 2015-05-20 23:09:51 +02:00
devtree.c ARM: 8581/1: add missing <asm/prom.h> to arch/arm/kernel/devtree.c 2016-06-22 19:55:12 +01:00
dma-isa.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
dma.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
early_printk.c
efi.c ARM/efi: Apply strict permissions for UEFI Runtime Services regions 2016-04-28 11:33:53 +02:00
elf.c
entry-armv.S ARM: fix address limit restoration for undefined instructions 2016-08-09 22:57:59 +01:00
entry-common.S ARM: rename S_FRAME_SIZE to PT_REGS_SIZE 2016-06-22 19:54:28 +01:00
entry-ftrace.S ARM: replace BSYM() with badr assembly macro 2015-05-08 17:33:50 +01:00
entry-header.S ARM: save and reset the address limit when entering an exception 2016-07-07 16:01:01 +01:00
entry-v7m.S ARM: rename S_FRAME_SIZE to PT_REGS_SIZE 2016-06-22 19:54:28 +01:00
fiq.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
fiqasm.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
ftrace.c ARM: kprobes: enable OPTPROBES for ARM 32 2015-01-13 16:10:17 +00:00
head-common.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
head-nommu.S ARM: 8572/1: nommu: change memory reserve for the vectors 2016-05-05 19:03:02 +01:00
head.S Merge branch 'uaccess' into fixes 2015-09-11 19:18:28 +01:00
hibernate.c ARM: use virt_to_idmap() for soft_restart() 2016-02-08 15:48:32 +00:00
hw_breakpoint.c perf/core: Set event's default ::overflow_handler() 2016-03-31 10:30:47 +02:00
hyp-stub.S ARM: 8527/1: virt: enable GICv3 system registers 2016-02-16 16:33:02 +00:00
insn.c
io.c ARM: io.c: clean up EXPORT_SYMBOL()s 2014-11-21 15:25:02 +00:00
irq.c ARM: 8499/1: irq: l2c: do not print error in case of missing l2c from 2016-01-26 23:49:02 +00:00
isa.c arm: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:15 -07:00
iwmmxt.S ARM: 8221/1: PJ4: allow building in Thumb-2 mode 2014-12-03 16:08:00 +00:00
jump_label.c jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP} 2015-08-03 11:34:12 +02:00
kgdb.c ARM: 8428/1: kgdb: Fix registers on sleeping tasks 2015-10-03 16:36:45 +01:00
machine_kexec.c ARM: kexec: fix kexec for Keystone 2 2016-08-02 19:35:29 -04:00
Makefile ARM: 8534/1: virt: fix hyp-stub build for pre-ARMv7 CPUs 2016-02-22 11:39:41 +00:00
module-plts.c ARM: kernel: allocate PLT entries only for external symbols 2016-08-30 17:45:34 +01:00
module.c ARM: 8518/1: Use correct symbols for XIP_KERNEL 2016-02-11 15:43:14 +00:00
module.lds ARM: kernel: merge core and init PLTs 2016-08-30 17:45:34 +01:00
opcodes.c
paravirt.c arm: introduce CONFIG_PARAVIRT, PARAVIRT_TIME_ACCOUNTING and pv_time_ops 2015-12-21 14:40:54 +00:00
patch.c ARM: probes: move all probe code to dedicate directory 2015-01-09 09:36:50 +00:00
perf_callchain.c perf core: Add a 'nr' field to perf_event_callchain_context 2016-05-16 23:11:51 -03:00
perf_event_v6.c arm: perf: factor arm_pmu core out to drivers 2015-07-31 15:01:14 +01:00
perf_event_v7.c ARM: perf: Set ARMv7 SDER SUNIDEN bit 2016-01-25 18:37:44 +00:00
perf_event_xscale.c arm: perf: factor arm_pmu core out to drivers 2015-07-31 15:01:14 +01:00
perf_regs.c perf: Move task_pt_regs sampling into arch code 2015-01-09 11:12:28 +01:00
pj4-cp0.c ARM: 8452/3: PJ4: make coprocessor access sequences buildable in Thumb2 mode 2016-01-04 11:12:10 +00:00
process.c ARM: save and reset the address limit when entering an exception 2016-07-07 16:01:01 +01:00
psci_smp.c ARM: use const and __initconst for smp_operations 2015-12-01 22:17:45 +01:00
ptrace.c arm/ptrace: run seccomp after ptrace 2016-06-14 10:54:42 -07:00
reboot.c ARM: 8568/1: reboot: remove duplicated local_irq_disable() 2016-05-05 19:02:09 +01:00
reboot.h ARM: move reboot code to arch/arm/kernel/reboot.c 2015-04-02 09:50:45 +01:00
relocate_kernel.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
return_address.c ARM: 8328/1: remove empty preprocessor #else branch 2015-03-28 16:54:53 +00:00
setup.c ARM: kexec: advertise location of bootable RAM 2016-08-02 19:35:25 -04:00
signal.c Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-09-19 21:05:02 -07:00
sigreturn_codes.S ARM: 7895/1: signal: fix armv7-m build issue in sigreturn_codes.S 2013-11-30 22:21:00 +00:00
sleep.S ARM: fix new BSYM() usage introduced via for-arm-soc branch 2015-06-12 21:19:35 +01:00
smccc-call.S ARM: 8479/2: add implementation for arm-smccc 2016-01-04 16:24:34 +00:00
smp_scu.c ARM: 8122/1: smp_scu: enable SCU standby support 2014-08-02 08:51:53 +01:00
smp_tlb.c ARM: 8577/1: Fix Cortex-A15 798181 errata initialization 2016-07-02 12:13:03 +01:00
smp_twd.c arm/twd: Convert to hotplug state machine 2016-07-15 10:40:28 +02:00
smp.c Fixes for omaps for v4.7-rc cycle: 2016-06-18 22:21:52 -07:00
stacktrace.c ARM: 8172/1: Use current_stack_pointer in save_stack_trace_tsk 2014-11-13 23:58:03 +00:00
suspend.c ARM: 8248/1: pm: remove outdated comment 2015-01-21 15:58:57 +00:00
swp_emulate.c ARM: 8475/1: SWP emulation: Restore original *data when failed 2015-12-15 11:51:42 +00:00
sys_arm.c
sys_oabi-compat.c arm: oabi compat: add missing access checks 2016-08-10 12:57:45 -07:00
tcm.c ARM: 8388/1: tcm: Don't crash when TCM banks are protected by TrustZone 2015-06-06 10:37:28 +01:00
thumbee.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
time.c clocksource: cosmetic: Drop OF 'dependency' from symbols 2015-10-01 02:18:39 +02:00
topology.c ARM: 8497/1: initialize cpu_scale to its default 2016-01-26 23:49:02 +00:00
traps.c ARM: remove user cmpxchg syscall 2015-10-03 16:36:45 +01:00
unwind.c ARM: 8176/1: Use current_stack_pointer in unwind_backtrace 2014-11-13 23:58:09 +00:00
v7m.c
vdso.c ARM: 8476/1: VDSO: use PTR_ERR_OR_ZERO for vma check 2015-12-17 10:29:01 +00:00
vmlinux-xip.lds.S ARM: 8537/1: drop unused DEBUG_RODATA from XIP_KERNEL 2016-02-22 11:39:43 +00:00
vmlinux.lds.S arm: jump label may reference text in __exit 2016-08-04 08:50:07 -04:00
xscale-cp0.c ARM: make xscale iwmmxt code multiplatform aware 2015-12-01 21:44:24 +01:00