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linux/arch/arm/include/asm
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Ard Biesheuvel 0b1674638a ARM: assembler: introduce adr_l, ldr_l and str_l macros 
Like arm64, ARM supports position independent code sequences that
produce symbol references with a greater reach than the ordinary
adr/ldr instructions. Since on ARM, the adrl pseudo-instruction is
only supported in ARM mode (and not at all when using Clang), having
a adr_l macro like we do on arm64 is useful, and increases symmetry
as well.

Currently, we use open coded instruction sequences involving literals
and arithmetic operations. Instead, we can use movw/movt pairs on v7
CPUs, circumventing the D-cache entirely.

E.g., on v7+ CPUs, we can emit a PC-relative reference as follows:

       movw         <reg>, #:lower16:<sym> - (1f + 8)
       movt         <reg>, #:upper16:<sym> - (1f + 8)
  1:   add          <reg>, <reg>, pc

For older CPUs, we can emit the literal into a subsection, allowing it
to be emitted out of line while retaining the ability to perform
arithmetic on label offsets.

E.g., on pre-v7 CPUs, we can emit a PC-relative reference as follows:

       ldr          <reg>, 2f
  1:   add          <reg>, <reg>, pc
       .subsection  1
  2:   .long        <sym> - (1b + 8)
       .previous

This is allowed by the assembler because, unlike ordinary sections,
subsections are combined into a single section in the object file, and
so the label references are not true cross-section references that are
visible as relocations. (Subsections have been available in binutils
since 2004 at least, so they should not cause any issues with older
toolchains.)

So use the above to implement the macros mov_l, adr_l, ldr_l and str_l,
all of which will use movw/movt pairs on v7 and later CPUs, and use
PC-relative literals otherwise.

Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-10-28 16:59:43 +01:00
..
hardware ARM: 8993/1: remove it8152 PCI controller driver 2020-07-21 16:33:41 +01:00
mach treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
vdso vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter() 2020-08-06 10:57:30 +02:00
xen xen/arm: do not setup the runstate info page if kpti is enabled 2020-10-04 18:41:33 -05:00
arch_gicv3.h arm: Remove GICv3 vgic compatibility macros 2020-03-24 10:56:05 +00:00
arch_timer.h clocksource/drivers/arm_arch_timer: Extract elf_hwcap use to arch-helper 2019-06-25 19:49:18 +02:00
arm-cci.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
asm-offsets.h
assembler.h ARM: assembler: introduce adr_l, ldr_l and str_l macros 2020-10-28 16:59:43 +01:00
atomic.h locking/atomic: Move ATOMIC_INIT into linux/types.h 2020-07-29 16:14:18 +02:00
auxvec.h
barrier.h
bitops.h
bitrev.h
bL_switcher.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
bug.h arm/asm: add loglvl to c_backtrace() 2020-06-09 09:39:10 -07:00
bugs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
cacheflush.h arm: rename flush_cache_user_range to flush_icache_user_range 2020-06-08 11:05:58 -07:00
cachetype.h
checksum.h arm: propagate the calling convention changes down to csum_partial_copy_from_user() 2020-08-20 15:45:16 -04:00
clocksource.h arm: Introduce asm/vdso/clocksource.h 2020-03-21 15:23:54 +01:00
cmpxchg.h
compiler.h
cp15.h arm: vdso: Enable arm to use common headers 2020-03-21 15:24:03 +01:00
cpu.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cpufeature.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cpuidle.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
cputype.h
cti.h
dcc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284 2019-06-05 17:36:37 +02:00
delay.h
device.h arm: Remove dev->archdata.iommu pointer 2020-06-30 11:59:48 +02:00
div64.h
dma-direct.h ARM/omap1: switch to use dma_direct_set_offset for lbus DMA offsets 2020-09-25 06:15:32 +02:00
dma-iommu.h dma-mapping: move dma-debug.h to kernel/dma/ 2020-10-06 07:07:05 +02:00
dma-mapping.h dma-mapping: move dma-debug.h to kernel/dma/ 2020-10-06 07:07:05 +02:00
dma.h
dmi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
domain.h ARM: 8908/1: add __always_inline to functions called from __get_user_check() 2019-10-10 22:23:19 +01:00
ecard.h
edac.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
efi.h efi/libstub: arm32: Base FDT and initrd placement on image address 2020-09-16 18:53:42 +03:00
elf.h
entry-macro-multi.S
exception.h
fb.h
fiq.h
firmware.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
fixmap.h mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
floppy.h floppy: split the base port from the register in I/O accesses 2020-05-12 19:34:52 +03:00
fncpy.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
fpstate.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
ftrace.h ARM: 8940/1: ftrace: remove mcount(),ftrace_caller_old() and ftrace_call_old() 2019-11-22 00:19:16 +00:00
futex.h ARM: futex: Address build warning 2020-05-07 00:41:47 +02:00
glue-cache.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
glue-df.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
glue-pf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
glue-proc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
glue.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
gpio.h
hardirq.h ARM: Remove custom IRQ stat accounting 2020-09-17 16:37:28 +01:00
highmem.h kmap: consolidate kmap_prot definitions 2020-06-04 19:06:22 -07:00
hugetlb-3level.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
hugetlb.h mm/hugetlb: define a generic fallback for arch_clear_hugepage_flags() 2020-06-03 20:09:46 -07:00
hw_breakpoint.h ARM: 8927/1: ARM/hw_breakpoint: add more ARMv8 debug architecture versions support 2019-11-15 22:21:08 +00:00
hw_irq.h
hwcap.h
hypervisor.h
ide.h
idmap.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
insn.h
io.h remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
irq.h
irq_work.h
irqflags.h
jump_label.h
Kbuild asm-generic: make more kernel-space headers mandatory 2020-04-02 09:35:25 -07:00
kexec.h
kgdb.h
kmap_types.h
kprobes.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
krait-l2-accessors.h
linkage.h
mc146818rtc.h
mcpm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mcs_spinlock.h
memblock.h
memory.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mmu.h
mmu_context.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
module.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
module.lds.h kbuild: preprocess module linker script 2020-09-25 00:36:41 +09:00
mpu.h
mtd-xip.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
neon.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
nwflash.h misc: move FLASH_MINOR into miscdevice.h and fix conflicts 2020-03-18 12:27:04 +01:00
opcodes-sec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
opcodes-virt.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
opcodes.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
outercache.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
page-nommu.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
page.h mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS 2020-04-10 15:36:21 -07:00
paravirt.h
patch.h
pci.h ARM: 8911/1: move pcibios_report_status to <asm/pci.h> 2019-10-27 21:14:40 +00:00
percpu.h ARM: percpu.h: fix build error 2020-07-30 13:01:04 -07:00
perf_event.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pgalloc.h asm-generic: pgalloc: provide generic pgd_free() 2020-08-07 11:33:26 -07:00
pgtable-2level-hwdef.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pgtable-2level-types.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
pgtable-2level.h mm: consolidate pte_index() and pte_offset_*() definitions 2020-06-09 09:39:14 -07:00
pgtable-3level-hwdef.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
pgtable-3level-types.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
pgtable-3level.h mm: consolidate pte_index() and pte_offset_*() definitions 2020-06-09 09:39:14 -07:00
pgtable-hwdef.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pgtable-nommu.h mm: consolidate pte_index() and pte_offset_*() definitions 2020-06-09 09:39:14 -07:00
pgtable.h mm: consolidate pte_index() and pte_offset_*() definitions 2020-06-09 09:39:14 -07:00
probes.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
proc-fns.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
processor.h arm: vdso: Enable arm to use common headers 2020-03-21 15:24:03 +01:00
procinfo.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
prom.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
psci.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
ptdump.h arm: dump: no need to check return value of debugfs_create functions 2019-06-03 15:49:07 +02:00
ptrace.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sections.h arm: Remove HYP/Stage-2 page-table support 2020-03-24 10:56:05 +00:00
secure_cntvoff.h
set_memory.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
setup.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
shmparam.h
signal.h
smp.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
smp_plat.h
smp_scu.h
smp_twd.h
sparsemem.h
spinlock.h
spinlock_types.h
stackprotector.h
stacktrace.h
string.h
suspend.h
swab.h
switch_to.h sched/rt, ARM: Use CONFIG_PREEMPTION 2019-12-08 14:37:32 +01:00
sync_bitops.h
syscall.h audit/stable-5.2 PR 20190507 2019-05-07 19:06:04 -07:00
system_info.h
system_misc.h
tcm.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
therm.h
thread_info.h arm: Break cyclic percpu include 2020-07-10 12:00:02 +02:00
thread_notify.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
timex.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tlb.h mm: account PMD tables like PTE tables 2020-10-13 18:38:31 -07:00
tlbflush.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tls.h
topology.h arm: disable frequency invariance for CONFIG_BL_SWITCHER 2020-10-08 17:17:27 +02:00
traps.h arm/asm: add loglvl to c_backtrace() 2020-06-09 09:39:10 -07:00
uaccess-asm.h ARM: uaccess: fix DACR mismatch with nested exceptions 2020-05-03 17:30:27 +01:00
uaccess.h uaccess: remove segment_eq 2020-08-12 10:57:58 -07:00
ucontext.h
unaligned.h
unified.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
unistd.h clone3-v5.3 2019-07-11 10:09:44 -07:00
unwind.h arm: add loglvl to unwind_backtrace() 2020-06-09 09:39:10 -07:00
uprobes.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
user.h
v7m.h
vdso.h
vdso_datapage.h ARM: 8930/1: Add support for generic vDSO 2019-11-15 22:21:12 +00:00
vermagic.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
vfp.h ARM: 8991/1: use VFP assembler mnemonics if available 2020-07-21 16:33:39 +01:00
vfpmacros.h ARM: 8991/1: use VFP assembler mnemonics if available 2020-07-21 16:33:39 +01:00
vga.h
virt.h arm: Remove the ability to set HYP vectors outside of the decompressor 2020-03-24 10:56:05 +00:00
vmalloc.h mm/vmalloc: Add empty <asm/vmalloc.h> headers and use them from <linux/vmalloc.h> 2019-12-10 10:12:55 +01:00
vmlinux.lds.h arm/build: Assert for unwanted sections 2020-09-01 10:03:18 +02:00
word-at-a-time.h
xor.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00