linux/arch/arm/mm
Geert Uytterhoeven eeedcea69e ARM: 8395/1: l2c: Add support for the "arm,shared-override" property
"CoreLink Level 2 Cache Controller L2C-310", p. 2-15, section 2.3.2
Shareable attribute" states:

    "The default behavior of the cache controller with respect to the
     shareable attribute is to transform Normal Memory Non-cacheable
     transactions into:
        - cacheable no allocate for reads
        - write through no write allocate for writes."

Depending on the system architecture, this may cause memory corruption
in the presence of bus mastering devices (e.g. OHCI). To avoid such
corruption, the default behavior can be disabled by setting the Shared
Override bit in the Auxiliary Control register.

Currently the Shared Override bit can be set only using C code:
  - by calling l2x0_init() directly, which is deprecated,
  - by setting/clearing the bit in the machine_desc.l2c_aux_val/mask
    fields, but using values differing from 0/~0 is also deprecated.

Hence add support for an "arm,shared-override" device tree property for
the l2c device node. By specifying this property, affected systems can
indicate that non-cacheable transactions must not be transformed.
Then, it's up to the OS to decide. The current behavior is to set the
"shared attribute override enable" bit, as there may exist kernel linear
mappings and cacheable aliases for the DMA buffers, even if CMA is
enabled.

See also commit 1a8e41cd67 ("ARM: 6395/1: VExpress: Set bit 22 in
the PL310 (cache controller) AuxCtlr register"):

    "Clearing bit 22 in the PL310 Auxiliary Control register (shared
     attribute override enable) has the side effect of transforming
     Normal Shared Non-cacheable reads into Cacheable no-allocate reads.

     Coherent DMA buffers in Linux always have a Cacheable alias via the
     kernel linear mapping and the processor can speculatively load
     cache lines into the PL310 controller. With bit 22 cleared,
     Non-cacheable reads would unexpectedly hit such cache lines leading
     to buffer corruption."

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-10 11:07:31 +01:00
..
abort-ev4.S
abort-ev4t.S
abort-ev5t.S
abort-ev5tj.S
abort-ev6.S ARM: 8128/1: abort: don't clear the exclusive monitors 2014-08-27 15:40:12 +01:00
abort-ev7.S ARM: 8128/1: abort: don't clear the exclusive monitors 2014-08-27 15:40:12 +01:00
abort-lv4t.S
abort-macro.S
abort-nommu.S
alignment.c ARM: 8322/1: keep .text and .fixup regions closer together 2015-03-29 23:11:56 +01:00
cache-aurora-l2.h ARM: 7547/4: cache-l2x0: add support for Aurora L2 cache ctrl 2012-11-06 19:47:35 +00:00
cache-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-feroceon-l2.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
cache-l2x0.c ARM: 8395/1: l2c: Add support for the "arm,shared-override" property 2015-07-10 11:07:31 +01:00
cache-nop.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-tauros2.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
cache-tauros3.h ARM: 7922/1: l2x0: add Marvell Tauros3 support 2013-12-29 12:32:47 +00:00
cache-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v4wb.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v4wt.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v7.S ARM: cache-v7: optimise test for Cortex A9 r0pX devices 2015-04-14 22:26:52 +01:00
cache-xsc3l2.c ARM: move CP15 definitions to separate header file 2012-03-28 18:30:01 +01:00
context.c ARM: 8299/1: mm: ensure local active ASID is marked as allocated on rollover 2015-02-03 12:57:33 +00:00
copypage-fa.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-feroceon.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4mc.c Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2012-03-29 16:53:48 -07:00
copypage-v4wb.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4wt.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v6.c ARM: 8236/1: mm: fix discard_old_kernel_data 2014-12-03 16:00:04 +00:00
copypage-xsc3.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-xscale.c Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2012-03-29 16:53:48 -07:00
dma-mapping.c Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
dump.c ARM: 8249/1: mm: dump: don't skip regions 2015-01-07 20:33:33 +00:00
extable.c ARM: 7876/1: clear Thumb-2 IT state on exception handling 2013-11-07 00:15:49 +00:00
fault-armv.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
fault.c mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler 2015-05-19 08:39:15 +02:00
fault.h ARM: LPAE: Add fault handling support 2011-12-08 10:30:40 +00:00
flush.c ARM: 8237/1: fix flush_pfn_alias 2014-12-03 16:00:04 +00:00
fsr-2level.c ARM: LPAE: Move the FSR definitions to separate files 2011-12-08 10:30:37 +00:00
fsr-3level.c ARM: mm: Transparent huge page support for LPAE systems. 2013-06-04 16:52:38 +01:00
highmem.c sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_* 2015-05-19 08:39:14 +02:00
hugetlbpage.c mm/hugetlb: reduce arch dependent code about huge_pmd_unshare 2015-06-24 17:49:41 -07:00
idmap.c ARM: 8152/1: Convert pr_warning to pr_warn 2014-09-26 14:39:53 +01:00
init.c of/fdt: split off FDT self reservation from memreserve processing 2015-06-02 16:31:25 +01:00
iomap.c arm/PCI: remove arch pci_flags definition 2012-02-23 20:18:56 -07:00
ioremap.c ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type 2014-06-01 01:15:04 +01:00
Kconfig Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
l2c-common.c ARM: outer cache: add WARN_ON() to outer_disable() 2014-05-30 00:47:23 +01:00
l2c-l2x0-resume.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
Makefile Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
mm.h ARM: provide common method to clear bits in CPU control register 2014-06-02 09:20:11 +01:00
mmap.c mm: expose arch_mmap_rnd when available 2015-04-14 16:49:05 -07:00
mmu.c Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
nommu.c ARM: cleanup early_paging_init() calling 2015-06-01 23:48:09 +01:00
pabort-legacy.S
pabort-v6.S
pabort-v7.S
pageattr.c ARM: 8311/1: Don't use is_module_addr in setting page attributes 2015-03-18 10:13:46 +00:00
pgd.c mm: fix false-positive warning on exit due mm_nr_pmds(mm) 2015-02-11 17:06:04 -08:00
proc-arm7tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm9tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm720.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm740.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm920.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm922.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm925.S ARM: 8349/1: arch/arm/mm/proc-arm925.S: remove dead #ifdef block 2015-05-03 23:22:27 +01:00
proc-arm926.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm940.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm946.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm1020.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1020e.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1022.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm1026.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-fa526.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-feroceon.S ARM: 8350/1: proc-feroceon: Fix feroceon_proc_info macro 2015-05-03 23:23:09 +01:00
proc-macros.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-mohawk.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-sa110.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-sa1100.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-syms.c ARM: modules: don't export cpu_set_pte_ext when !MMU 2013-03-26 09:55:34 +00:00
proc-v6.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-v7-2level.S Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
proc-v7-3level.S ARM: redo TTBR setup code for LPAE 2015-06-01 23:48:19 +01:00
proc-v7.S Merge branch 'for-arm-soc' into for-next 2015-06-12 21:18:59 +01:00
proc-v7m.S ARM: replace BSYM() with badr assembly macro 2015-05-08 17:33:50 +01:00
proc-xsc3.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-xscale.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
pv-fixup-asm.S ARM: re-implement physical address space switching 2015-06-01 23:46:33 +01:00
tcm.h ARM: 7694/1: ARM, TCM: initialize TCM in paging_init(), instead of setup_arch() 2013-04-17 16:53:24 +01:00
tlb-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wb.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wbi.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v7.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00