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author | Hans de Goede <hdegoede@redhat.com> | 2016-04-09 11:53:48 (GMT) |
---|---|---|
committer | Tom Rini <trini@konsulko.com> | 2016-04-12 00:48:26 (GMT) |
commit | c09d29057ab0b04db0857d319c6bff74de31b9c3 (patch) | |
tree | 9f01964012e2eadce3e7d8e1b33e3d2e6d2264f9 /arch/arm/mach-uniphier/arm32 | |
parent | 456ecd08ec026e67a17a77baa3778c9f1b8e474d (diff) | |
download | u-boot-c09d29057ab0b04db0857d319c6bff74de31b9c3.tar.xz |
arm: Replace v7_maint_dcache_all(ARMV7_DCACHE_CLEAN_INVAL_ALL) with asm code
v7_maint_dcache_all() does not work reliable when build with gcc6,
see: https://bugzilla.redhat.com/show_bug.cgi?id=1318788
While debugging this I learned that v7_maint_dcache_all() is unreliable
when build with gcc5 too when it is marked as noinline.
This commit fixes the reliability issues by replacing the C-code with
the ready to use asm implementation from the kernel.
Given that this code when written as C-code clearly is quite fragile
(also see the existing comments about the C-code being the way it is
to get optimal assembly) and that we have a proven asm alternative,
I believe that this is the best solution.
Note that we actually already had a copy of the kernel's
v7_flush_dcache_all() before this commit in
arch/arm/mach-uniphier/arm32/lowlevel_init.S.
This commit moves that code arch/arm/cpu/armv7/cache_v7_asm.S, renames
it to __v7_flush_dcache_all(), and adds a v7_flush_dcache_all() wrapper
which saves / restores the clobbered registers for use from C-code.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'arch/arm/mach-uniphier/arm32')
-rw-r--r-- | arch/arm/mach-uniphier/arm32/lowlevel_init.S | 67 |
1 files changed, 1 insertions, 66 deletions
diff --git a/arch/arm/mach-uniphier/arm32/lowlevel_init.S b/arch/arm/mach-uniphier/arm32/lowlevel_init.S index dd03ad8..e2bb1fc 100644 --- a/arch/arm/mach-uniphier/arm32/lowlevel_init.S +++ b/arch/arm/mach-uniphier/arm32/lowlevel_init.S @@ -38,7 +38,7 @@ ENTRY(lowlevel_init) * to do next is to create a page table and switch over to it. */ bl create_page_table - bl v7_flush_dcache_all + bl __v7_flush_dcache_all /* Disable MMU and Dcache before switching Page Table */ mrc p15, 0, r0, c1, c0, 0 @ SCTLR (System Control Register) @@ -140,68 +140,3 @@ ENTRY(create_page_table) str r0, [r12, #4] @ mark the second section as Normal mov pc, lr ENDPROC(create_page_table) - -/* We don't use Thumb instructions for now */ -#define ARM(x...) x -#define THUMB(x...) - -/* - * v7_flush_dcache_all() - * - * Flush the whole D-cache. - * - * Corrupted registers: r0-r7, r9-r11 (r6 only in Thumb mode) - * - * - mm - mm_struct describing address space - * - * Note: copied from arch/arm/mm/cache-v7.S of Linux 4.4 - */ -ENTRY(v7_flush_dcache_all) - dmb @ ensure ordering with previous memory accesses - mrc p15, 1, r0, c0, c0, 1 @ read clidr - mov r3, r0, lsr #23 @ move LoC into position - ands r3, r3, #7 << 1 @ extract LoC*2 from clidr - beq finished @ if loc is 0, then no need to clean -start_flush_levels: - mov r10, #0 @ start clean at cache level 0 -flush_levels: - add r2, r10, r10, lsr #1 @ work out 3x current cache level - mov r1, r0, lsr r2 @ extract cache type bits from clidr - and r1, r1, #7 @ mask of the bits for current cache only - cmp r1, #2 @ see what cache we have at this level - blt skip @ skip if no cache, or just i-cache - mcr p15, 2, r10, c0, c0, 0 @ select current cache level in cssr - isb @ isb to sych the new cssr&csidr - mrc p15, 1, r1, c0, c0, 0 @ read the new csidr - and r2, r1, #7 @ extract the length of the cache lines - add r2, r2, #4 @ add 4 (line length offset) - movw r4, #0x3ff - ands r4, r4, r1, lsr #3 @ find maximum number on the way size - clz r5, r4 @ find bit position of way size increment - movw r7, #0x7fff - ands r7, r7, r1, lsr #13 @ extract max number of the index size -loop1: - mov r9, r7 @ create working copy of max index -loop2: - ARM( orr r11, r10, r4, lsl r5 ) @ factor way and cache number into r11 - THUMB( lsl r6, r4, r5 ) - THUMB( orr r11, r10, r6 ) @ factor way and cache number into r11 - ARM( orr r11, r11, r9, lsl r2 ) @ factor index number into r11 - THUMB( lsl r6, r9, r2 ) - THUMB( orr r11, r11, r6 ) @ factor index number into r11 - mcr p15, 0, r11, c7, c14, 2 @ clean & invalidate by set/way - subs r9, r9, #1 @ decrement the index - bge loop2 - subs r4, r4, #1 @ decrement the way - bge loop1 -skip: - add r10, r10, #2 @ increment cache number - cmp r3, r10 - bgt flush_levels -finished: - mov r10, #0 @ swith back to cache level 0 - mcr p15, 2, r10, c0, c0, 0 @ select current cache level in cssr - dsb st - isb - mov pc, lr -ENDPROC(v7_flush_dcache_all) |