Peter Hurley 5bb5d66d89 ARM: 8341/1: io: Unpessimize relaxed io accessors ... commit 195bbcac2e ("ARM: 7500/1: io: avoid writeback addressing modes for __raw_ accessors") disables writeback addressing modes for raw i/o. However, the "+Q" output constraint forces the compiler to disable load hoist optimizations (because the output constraint informs the compiler of memory stores which the compiler assumes may alias other memory). Since the relaxed accessors only guarantee ordering wrt i/o accesses to the same device and not to main memory, there's never a possibility of an accessor invalidating a hoisted load (because only non-i/o loads would have been hoisted). The effect is especially noticable with complex address inputs in loops. For example, the following code: #include <linux/kernel.h> #include <linux/io.h> static const int *remap; void wr_loop(void __iomem *base, int c, int val) { int i; for (i = 0; i < c; i++) writew_relaxed(val, base + remap[c >> 2]); } generates current master | this patch 0: e3510000 cmp r1, #0 | 0: e3510000 cmp r1, #0 4: d12fff1e bxle lr | 4: d12fff1e bxle lr 8: e3003000 movw r3, #0 | 8: e3c1c003 bic ip, r1, #3 c: e3403000 movt r3, #0 | c: e6ff2072 uxth r2, r2 10: e92d4010 push {r4, lr} | 10: e3a03000 mov r3, #0 14: e6ff2072 uxth r2, r2 | 14: e59cc000 ldr ip, [ip] 18: e3c14003 bic r4, r1, #3 | 18: e080000c add r0, r0, ip 1c: e593e000 ldr lr, [r3] | 20: e3a03000 mov r3, #0 | 1c: e1c020b0 strh r2, [r0] | 20: e2833001 add r3, r3, #1 24: e79ec004 ldr ip, [lr, r4] | 24: e1530001 cmp r3, r1 28: e080c00c add ip, r0, ip | 28: 1afffffb bne 1c 2c: e1cc20b0 strh r2, [ip] | 2c: e12fff1e bx lr 30: e2833001 add r3, r3, #1 | 34: e1530001 cmp r3, r1 | 38: 1afffff9 bne 24 | | 3c: e8bd8010 pop {r4, pc} | Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>		2015-05-08 10:42:33 +01:00
..
hardware	ARM: removing support for etb/etm in "arch/arm/kernel/"	2014-11-07 15:19:33 -08:00
mach	ARM, clocksource/drivers: Provide read_boot_clock64() and read_persistent_clock64() and use them	2015-04-03 08:18:23 +02:00
xen	xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs()	2015-01-28 14:03:10 +00:00
arch_timer.h	clocksource: arch_timer: Fix code to use physical timers when requested	2014-12-04 23:30:26 -08:00
arm-cci.h	arm-cci: Get rid of secure transactions for PMU driver	2015-03-27 13:44:35 +00:00
asm-offsets.h
assembler.h	ARM: allow 16-bit instructions in ALT_UP()	2015-04-14 22:26:51 +01:00
atomic.h	locking,arch: Use ACCESS_ONCE() instead of cast to volatile in atomic_read()	2014-10-03 06:06:23 +02:00
auxvec.h	ARM: 8329/1: miscellaneous vdso infrastructure, preparation	2015-03-27 22:20:45 +00:00
barrier.h	arch: Add lightweight memory barriers dma_rmb() and dma_wmb()	2014-12-11 21:15:06 -05:00
bitops.h	arch,arm: Convert smp_mb__*()	2014-04-18 11:40:32 +02:00
bitrev.h	ARM: 8287/1: add bitrev.h file to support rbit instruction	2015-01-16 14:06:18 +00:00
bL_switcher.h	ARM: bL_switcher: Add query interface to discover CPU affinities	2013-09-23 18:47:31 -04:00
bug.h	ARM: Correct BUG() assembly to ensure it is endian-agnostic	2013-10-19 20:46:35 +01:00
bugs.h
cache.h
cacheflush.h	ARM: mm: allow text and rodata sections to be read-only	2014-10-16 14:38:54 -07:00
cachetype.h
checksum.h	ARM: fix csum_tcpudp_magic() miscompilation	2013-12-29 12:32:41 +00:00
clkdev.h	clk: Add common __clk_get(), __clk_put() implementations	2013-12-04 17:19:44 +01:00
cmpxchg.h	ARM: 7984/1: prefetch: add prefetchw invocations for barriered atomics	2014-02-25 11:30:20 +00:00
compiler.h	ARM: 8300/1: teach __asmeq that r11 == fp and r12 == ip	2015-02-10 10:23:11 +00:00
cp15.h	ARM: remove global cr_no_alignment	2014-06-02 09:20:18 +01:00
cpu.h	ARM: kernel: add MIDR to per-CPU information data	2012-11-19 14:51:11 +00:00
cpuidle.h	ARM: cpuidle: Add a cpuidle ops structure to be used for DT	2015-03-24 10:16:01 +01:00
cputype.h	ARM: 8318/1: treat CPU feature register fields as signed quantities	2015-03-28 15:46:15 +00:00
cti.h	ARM: coresight: common definition for (OS) Lock Access Register key value	2013-01-10 21:13:05 +00:00
dcc.h	ARM: tty: Move HVC DCC assembly to arch/arm	2014-05-28 13:33:18 -07:00
delay.h	ARM: 7685/1: delay: use private ticks_per_jiffy field for timer-based delay ops	2013-04-03 16:45:50 +01:00
device.h	arm: introduce is_device_dma_coherent	2014-12-04 12:41:50 +00:00
div64.h	ARM: 8027/1: fix do_div() bug in big-endian systems	2014-04-22 22:23:57 +01:00
dma-contiguous.h	drivers: dma-contiguous: clean source code and prepare for device tree	2013-08-27 09:18:29 +02:00
dma-iommu.h	arm: dma-iommu: Clean up redundant variable	2014-05-20 13:43:26 +02:00
dma-mapping.h	ARM: SoC/iommu configuration for 3.19	2014-12-16 14:53:01 -08:00
dma.h	mm/memblock: add memblock memory allocation apis	2014-01-21 16:19:46 -08:00
domain.h
ecard.h
edac.h
elf.h	Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm	2015-04-14 21:03:26 -07:00
entry-macro-multi.S	ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+	2014-07-18 12:29:04 +01:00
exception.h
fb.h
fiq.h
firmware.h	ARM: firmware: add AFTR mode support to firmware do_idle method	2014-10-21 00:06:35 +09:00
fixmap.h	arm: use fixmap for text patching when text is RO	2014-10-16 14:38:53 -07:00
flat.h
floppy.h	ARM: 7996/1: floppy.h: remove deprecated IRQF_DISABLED	2014-03-12 10:32:29 +00:00
fncpy.h
fpstate.h
ftrace.h	ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.h	2014-09-26 14:40:03 +01:00
futex.h	ARM: 8322/1: keep .text and .fixup regions closer together	2015-03-29 23:11:56 +01:00
glue-cache.h	ARM: LLVMLinux: Change "extern inline" to "static inline" in glue-cache.h	2014-06-07 11:44:39 -07:00
glue-df.h	ARM: 8065/1: remove last use of CONFIG_CPU_ARM710	2014-05-30 01:12:30 +01:00
glue-pf.h
glue-proc.h	ARM: 8103/1: save/restore Cortex-A9 CP15 registers on suspend/resume	2014-07-18 12:29:37 +01:00
glue.h
gpio.h	ARM: delete old reference to ARM_GPIOLIB_COMPLEX	2014-06-30 21:37:39 +02:00
hardirq.h	Merge branch 'devel-stable' into for-next	2013-11-12 10:58:59 +00:00
highmem.h	ARM: 8031/2: change fixmap mapping region to support 32 CPUs	2014-04-23 11:09:42 +01:00
hugetlb-3level.h	ARM: mm: HugeTLB support for LPAE systems.	2013-06-04 16:52:37 +01:00
hugetlb.h	ARM: mm: HugeTLB support for LPAE systems.	2013-06-04 16:52:37 +01:00
hw_breakpoint.h	ARM: 7948/1: hw_breakpoint: Add ARMv8 support	2014-02-10 11:48:05 +00:00
hw_irq.h	ARM: 8218/1: warn if bad IRQ was scheduled	2014-11-27 16:15:33 +00:00
hwcap.h	ARM: 7981/1: add support for AT_HWCAP2 ELF auxv entry	2014-02-25 11:40:48 +00:00
hypervisor.h
ide.h
idmap.h	ARM: KVM: move to a KVM provided HYP idmap	2013-04-28 22:23:08 -07:00
insn.h	ARM: kprobes: enable OPTPROBES for ARM 32	2015-01-13 16:10:17 +00:00
io.h	ARM: 8341/1: io: Unpessimize relaxed io accessors	2015-05-08 10:42:33 +01:00
irq.h	arm: Move the set_handle_irq and handle_arch_irq declarations to asm/irq.h	2013-03-26 16:11:20 +00:00
irq_work.h	arm: Tell irq work about self IPI support	2014-09-13 18:38:39 +02:00
irqflags.h	ARM: Add base support for ARMv7-M	2013-04-17 21:38:10 +02:00
jump_label.h	jump_label: Allow asm/jump_label.h to be included in assembly	2015-04-09 09:40:23 +02:00
Kbuild	arm: use asm-generic for seccomp.h	2015-04-17 09:04:09 -04:00
kexec.h
kgdb.h	ARM: kdgb: use <asm/opcodes.h> for data to be assembled as intruction	2013-10-19 20:46:35 +01:00
kmap_types.h
kprobes.h	ARM: optprobes: execute instruction during restoring if possible.	2015-01-14 12:24:52 +00:00
kvm_arm.h	arm/arm64: KVM: Implement Stage-2 page aging	2015-03-12 22:34:43 +01:00
kvm_asm.h	KVM: arm: Add ARMv7 API to flush TLBs	2015-01-16 14:40:14 +01:00
kvm_coproc.h	KVM: ARM: User space API for getting/setting co-proc registers	2013-01-23 13:29:14 -05:00
kvm_emulate.h	Fairly small update, but there are some interesting new features.	2015-02-13 09:55:09 -08:00
kvm_host.h	arm/arm64: KVM: Implement Stage-2 page aging	2015-03-12 22:34:43 +01:00
kvm_mmio.h	KVM: arm/arm64: rework MMIO abort handling to use KVM MMIO bus	2015-03-30 17:07:19 +01:00
kvm_mmu.h	arm64 updates for 4.1:	2015-04-16 13:58:29 -05:00
kvm_psci.h	ARM/ARM64: KVM: Make kvm_psci_call() return convention more flexible	2014-04-30 04:18:57 -07:00
limits.h
linkage.h
mach-types.h
mc146818rtc.h
mcpm.h	ARM: MCPM: move the algorithmic complexity to the core code	2015-04-03 12:52:46 -07:00
mcs_spinlock.h	ARM: 8098/1: mcs lock: implement wfe-based polling for MCS locking	2014-07-18 12:29:35 +01:00
memblock.h	ARM: 8025/1: Get rid of meminfo	2014-06-01 01:17:12 +01:00
memory.h	ARM: Use include/asm-generic/io.h	2014-11-10 15:59:23 +01:00
mmu.h	ARM: 8329/1: miscellaneous vdso infrastructure, preparation	2015-03-27 22:20:45 +00:00
mmu_context.h	ARM: 7790/1: Fix deferred mm switch on VIVT processors	2013-07-26 12:02:09 +01:00
module.h	ARM: 7829/1: Add ".text.unlikely" and ".text.hot" to arm unwind tables	2013-09-02 13:49:47 +01:00
mpu.h	ARM: mpu: protect the vectors page with an MPU region	2013-06-17 15:13:18 +01:00
mtd-xip.h
mutex.h
neon.h	ARM: add support for kernel mode NEON	2013-07-08 22:08:51 +01:00
nwflash.h
opcodes-sec.h	ARM: opcodes: add opcodes definitions for ARM security extensions	2013-01-10 21:10:20 +00:00
opcodes-virt.h
opcodes.h	ARM: opcodes: add missing include of linux/linkage.h	2013-01-10 21:10:20 +00:00
outercache.h	ARM: 8260/1: l2c: Add interface to ask hypervisor to configure L2C	2015-01-16 14:35:31 +00:00
page-nommu.h
page.h	ARM: make vectors page inaccessible from userspace	2013-08-01 14:31:58 +01:00
patch.h	ARM: probes: move all probe code to dedicate directory	2015-01-09 09:36:50 +00:00
pci.h	ARM/PCI: Move to generic PCI domains	2014-12-27 18:19:18 -07:00
percpu.h	ARM: 8174/1: Use global stack register variable for percpu	2014-11-13 23:58:06 +00:00
perf_event.h	arm: perf: factor out callchain code	2014-10-30 12:16:58 +00:00
pgalloc.h	ARM: 8235/1: Support for the PXN CPU feature on ARMv7	2014-12-03 15:57:45 +00:00
pgtable-2level-hwdef.h	ARM: 8235/1: Support for the PXN CPU feature on ARMv7	2014-12-03 15:57:45 +00:00
pgtable-2level-types.h
pgtable-2level.h	arm: define __PAGETABLE_PMD_FOLDED for !LPAE	2015-02-11 17:06:04 -08:00
pgtable-3level-hwdef.h	ARM: 8235/1: Support for the PXN CPU feature on ARMv7	2014-12-03 15:57:45 +00:00
pgtable-3level-types.h
pgtable-3level.h	Fairly small update, but there are some interesting new features.	2015-02-13 09:55:09 -08:00
pgtable-hwdef.h
pgtable-nommu.h	mm: make FIRST_USER_ADDRESS unsigned long on all archs	2015-02-11 17:06:03 -08:00
pgtable.h	arm: drop L_PTE_FILE and pte_file()-related helpers	2015-02-10 14:30:31 -08:00
pmu.h	ARM: pmu: add support for interrupt-affinity property	2015-03-24 15:07:57 +00:00
probes.h	ARM: optprobes: execute instruction during restoring if possible.	2015-01-14 12:24:52 +00:00
proc-fns.h	Merge branch 'for-rmk/lpae' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable	2013-06-18 20:11:32 +01:00
processor.h	arch, locking: Ciao arch_mutex_cpu_relax()	2014-07-17 12:32:47 +02:00
procinfo.h
prom.h	of/fdt: move memreserve and dtb memory reservations into core	2014-04-30 00:59:17 -05:00
psci.h	arm: Fix compile warning for psci	2014-05-27 15:58:49 +02:00
ptrace.h	ARM: 8175/1: Use current_stack_pointer to calculate pt_regs address	2014-11-13 23:58:07 +00:00
setup.h	ARM: 8025/1: Get rid of meminfo	2014-06-01 01:17:12 +01:00
shmparam.h
signal.h	arm: switch to generic old sigaction()	2013-02-03 18:15:47 -05:00
smp.h	ARM: 8131/1: arm/smp: Absorb boot_secondary()	2014-08-27 15:44:13 +01:00
smp_plat.h	ARM: 8338/1: kexec: Relax SMP validation to improve DT compatibility	2015-04-02 09:59:43 +01:00
smp_scu.h	ARM: make it easier to check the CPU part number correctly	2014-07-18 12:29:02 +01:00
smp_twd.h	ARM: smp_twd: convert to use CLKSRC_OF init	2013-03-11 08:42:08 -05:00
sparsemem.h
spinlock.h	arm/spinlock: Replace ACCESS_ONCE with READ_ONCE	2014-12-18 09:54:40 +01:00
spinlock_types.h	ARM: locks: prefetch the destination word for write prior to strex	2013-09-30 16:42:55 +01:00
stackprotector.h
stacktrace.h	ARM: 8070/1: Introduce arm_get_current_stack_frame()	2014-07-18 12:29:11 +01:00
string.h
suspend.h	ARM: kernel: implement stack pointer save array through MPIDR hashing	2013-06-20 11:24:11 +01:00
swab.h
switch_to.h	ARM: spinlock: use inner-shareable dsb variant prior to sev instruction	2013-08-12 12:25:45 +01:00
sync_bitops.h	ARM: 7989/1: Delete asm/system.h	2014-02-25 11:33:37 +00:00
syscall.h	ARM: 8152/1: Convert pr_warning to pr_warn	2014-09-26 14:39:53 +01:00
system_info.h	ARM: Add base support for ARMv7-M	2013-04-17 21:38:10 +02:00
system_misc.h	reboot: arm: change reboot_mode to use enum reboot_mode	2013-07-09 10:33:29 -07:00
tcm.h
therm.h
thread_info.h	arm: Remove signal translation and exec_domain	2015-04-12 20:58:24 +02:00
thread_notify.h
timex.h	ARM: drop <mach/timex.h> for !ARCH_MULTIPLATFORM, too	2013-12-20 17:17:16 +01:00
tlb.h	arm: mm: enable HAVE_RCU_TABLE_FREE logic	2014-10-09 22:26:01 -04:00
tlbflush.h	ARM: 7855/1: Add check for Cortex-A15 errata 798181 ECO	2013-10-29 11:06:13 +00:00
tls.h	ARM: 8178/1: fix set_tls for !CONFIG_KUSER_HELPERS	2014-09-30 16:55:23 +01:00
topology.h	sched: Remove unused mc_capable() and smt_capable()	2014-03-11 12:05:45 +01:00
traps.h
trusted_foundations.h	ARM: trusted_foundations: fix compile error on non-SMP	2014-05-23 21:28:11 +02:00
types.h	ARM: 7822/1: add workaround for ambiguous C99 stdint.h types	2013-08-25 17:09:46 +01:00
uaccess.h	ARM: 8322/1: keep .text and .fixup regions closer together	2015-03-29 23:11:56 +01:00
ucontext.h
unified.h	ARM: 8327/1: zImage: add support for ARMv7-M	2015-03-28 16:54:53 +00:00
unistd.h	ARM: wire up getrandom syscall	2014-08-09 14:07:53 +01:00
unwind.h
uprobes.h	ARM: add uprobes support	2014-03-18 16:39:40 -04:00
user.h
v7m.h	ARM: 7828/1: ARMv7-M: implement restart routine common to all v7-M machines	2013-09-02 13:49:29 +01:00
vdso.h	ARM: 8329/1: miscellaneous vdso infrastructure, preparation	2015-03-27 22:20:45 +00:00
vdso_datapage.h	ARM: 8329/1: miscellaneous vdso infrastructure, preparation	2015-03-27 22:20:45 +00:00
vfp.h	ARM: 8197/1: vfp: Fix VFPv3 hwcap detection on CPUID based cpus	2014-11-21 15:24:43 +00:00
vfpmacros.h	ARM: 7566/1: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set	2012-10-29 10:04:05 +00:00
vga.h
virt.h	ARM: 7787/1: virt: ensure visibility of __boot_cpu_mode	2013-07-26 12:01:17 +01:00
word-at-a-time.h	ARM: 8322/1: keep .text and .fixup regions closer together	2015-03-29 23:11:56 +01:00
xor.h	ARM: crypto: add NEON accelerated XOR implementation	2013-07-08 22:09:06 +01:00