arm64: Cache maintenance routines
The patch adds functionality required for cache maintenance. The AArch64
architecture mandates non-aliasing VIPT or PIPT D-cache and VIPT (may
have aliases) or ASID-tagged VIVT I-cache. Cache maintenance operations
are automatically broadcast in hardware between CPUs.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
new file mode 100644
index 0000000..abe69b8
--- /dev/null
+++ b/arch/arm64/mm/cache.S
@@ -0,0 +1,168 @@
+/*
+ * Cache maintenance
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/assembler.h>
+
+#include "proc-macros.S"
+
+/*
+ * __flush_dcache_all()
+ *
+ * Flush the whole D-cache.
+ *
+ * Corrupted registers: x0-x7, x9-x11
+ */
+ENTRY(__flush_dcache_all)
+ dsb sy // ensure ordering with previous memory accesses
+ mrs x0, clidr_el1 // read clidr
+ and x3, x0, #0x7000000 // extract loc from clidr
+ lsr x3, x3, #23 // left align loc bit field
+ cbz x3, finished // if loc is 0, then no need to clean
+ mov x10, #0 // start clean at cache level 0
+loop1:
+ add x2, x10, x10, lsr #1 // work out 3x current cache level
+ lsr x1, x0, x2 // extract cache type bits from clidr
+ and x1, x1, #7 // mask of the bits for current cache only
+ cmp x1, #2 // see what cache we have at this level
+ b.lt skip // skip if no cache, or just i-cache
+ save_and_disable_irqs x9 // make CSSELR and CCSIDR access atomic
+ msr csselr_el1, x10 // select current cache level in csselr
+ isb // isb to sych the new cssr&csidr
+ mrs x1, ccsidr_el1 // read the new ccsidr
+ restore_irqs x9
+ and x2, x1, #7 // extract the length of the cache lines
+ add x2, x2, #4 // add 4 (line length offset)
+ mov x4, #0x3ff
+ and x4, x4, x1, lsr #3 // find maximum number on the way size
+ clz x5, x4 // find bit position of way size increment
+ mov x7, #0x7fff
+ and x7, x7, x1, lsr #13 // extract max number of the index size
+loop2:
+ mov x9, x4 // create working copy of max way size
+loop3:
+ lsl x6, x9, x5
+ orr x11, x10, x6 // factor way and cache number into x11
+ lsl x6, x7, x2
+ orr x11, x11, x6 // factor index number into x11
+ dc cisw, x11 // clean & invalidate by set/way
+ subs x9, x9, #1 // decrement the way
+ b.ge loop3
+ subs x7, x7, #1 // decrement the index
+ b.ge loop2
+skip:
+ add x10, x10, #2 // increment cache number
+ cmp x3, x10
+ b.gt loop1
+finished:
+ mov x10, #0 // swith back to cache level 0
+ msr csselr_el1, x10 // select current cache level in csselr
+ dsb sy
+ isb
+ ret
+ENDPROC(__flush_dcache_all)
+
+/*
+ * flush_cache_all()
+ *
+ * Flush the entire cache system. The data cache flush is now achieved
+ * using atomic clean / invalidates working outwards from L1 cache. This
+ * is done using Set/Way based cache maintainance instructions. The
+ * instruction cache can still be invalidated back to the point of
+ * unification in a single instruction.
+ */
+ENTRY(flush_cache_all)
+ mov x12, lr
+ bl __flush_dcache_all
+ mov x0, #0
+ ic ialluis // I+BTB cache invalidate
+ ret x12
+ENDPROC(flush_cache_all)
+
+/*
+ * flush_icache_range(start,end)
+ *
+ * Ensure that the I and D caches are coherent within specified region.
+ * This is typically used when code has been written to a memory region,
+ * and will be executed.
+ *
+ * - start - virtual start address of region
+ * - end - virtual end address of region
+ */
+ENTRY(flush_icache_range)
+ /* FALLTHROUGH */
+
+/*
+ * __flush_cache_user_range(start,end)
+ *
+ * Ensure that the I and D caches are coherent within specified region.
+ * This is typically used when code has been written to a memory region,
+ * and will be executed.
+ *
+ * - start - virtual start address of region
+ * - end - virtual end address of region
+ */
+ENTRY(__flush_cache_user_range)
+ dcache_line_size x2, x3
+ sub x3, x2, #1
+ bic x4, x0, x3
+1:
+USER(9f, dc cvau, x4 ) // clean D line to PoU
+ add x4, x4, x2
+ cmp x4, x1
+ b.lo 1b
+ dsb sy
+
+ icache_line_size x2, x3
+ sub x3, x2, #1
+ bic x4, x0, x3
+1:
+USER(9f, ic ivau, x4 ) // invalidate I line PoU
+ add x4, x4, x2
+ cmp x4, x1
+ b.lo 1b
+9: // ignore any faulting cache operation
+ dsb sy
+ isb
+ ret
+ENDPROC(flush_icache_range)
+ENDPROC(__flush_cache_user_range)
+
+/*
+ * __flush_kern_dcache_page(kaddr)
+ *
+ * Ensure that the data held in the page kaddr is written back to the
+ * page in question.
+ *
+ * - kaddr - kernel address
+ * - size - size in question
+ */
+ENTRY(__flush_dcache_area)
+ dcache_line_size x2, x3
+ add x1, x0, x1
+ sub x3, x2, #1
+ bic x0, x0, x3
+1: dc civac, x0 // clean & invalidate D line / unified line
+ add x0, x0, x2
+ cmp x0, x1
+ b.lo 1b
+ dsb sy
+ ret
+ENDPROC(__flush_dcache_area)