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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/ssx/occhw/occhw_cache.S $ */
/* */
/* OpenPOWER OnChipController Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2015,2016 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
/// \file occhw_cache.S
/// \brief Cache-management specific to OCCHW
#include "ssx.h"
/// \fn void dcache_flush_all()
/// \brief Flush the entire D-Cache by 0-filling and invalidating
///
/// This API is necessary whenever it is required to change data cacheability
/// after boot. This API operates in an SSX_SUPERCRITICAL critical section.
/// This API always issues a sync() after the flush.
///
/// This API runs with data translation disabled. This is necessary for
/// correctness, and also obviates the need to check whether a cache entry is
/// valid before flushing the entry.
///
/// This algorithm works by filling the cache with 0s to displace any dirty
/// lines. Then the cache is invalidated. In OCCHW the first 16 KB of the
/// 0x80000000 address range are used as the zero-fill range. This memory is
/// not mapped on the OCI so these lines must never escape the D-cache.
///
/// Note: Our Simics model includes this 16K memory area since Simics does not
/// default to having a cache. Since we run OCCHW with the MMU enabled and we
/// don't MMU-map this area, memory addressing bugs should not be able to slip
/// through.
#ifdef DOXYGEN_ONLY
void dcache_flush_all();
#endif
/// \cond
.global_function dcache_flush_all
dcache_flush_all:
## %r3 used as scratch throughout
## %r11 holds the original DCCR throughout
## %r12 holds the original MSR throughout
## Enter a super-critical section and go to real mode
_ssx_critical_section_enter SSX_SUPERCRITICAL, %r12, %r3
mfmsr %r3
_clrbit %r3, %r3, MSR_DR_BIT
mtmsr %r3
isync
## Save the DCCR, and make 0x80000000 cacheable. This is necessary for
## DCBZ to work.
mfdccr %r11
_liwa %r3, OCCHW_FLUSH_ZERO_DCCR
or %r3, %r3, %r11
mtdccr %r3
isync
## Fill the cache with 0, displacing any dirty lines
li %r3, DCACHE_LINES
mtctr %r3
_liwa %r3, OCCHW_FLUSH_ZERO_ADDRESS
1:
dcbz %r0, %r3
addi %r3, %r3, CACHE_LINE_SIZE
bdnz 1b
sync
## Now invalidate the cache
li %r3, DCACHE_LINES
mtctr %r3
_liwa %r3, OCCHW_FLUSH_ZERO_ADDRESS
1:
dcbi %r0, %r3
addi %r3, %r3, CACHE_LINE_SIZE
bdnz 1b
## Restore the DCCR and MSR and return
mtdccr %r11
isync
_ssx_critical_section_exit %r12
blr
.epilogue dcache_flush_all
/// \endcond
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