esp-idf/components/xtensa/include/xtensa/cacheattrasm.h
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C

/*
* xtensa/cacheattrasm.h -- assembler-specific CACHEATTR register related definitions
* that depend on CORE configuration
*
* This file is logically part of xtensa/coreasm.h (or perhaps xtensa/cacheasm.h),
* but is kept separate for modularity / compilation-performance.
*/
/*
* Copyright (c) 2001-2009 Tensilica Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef XTENSA_CACHEATTRASM_H
#define XTENSA_CACHEATTRASM_H
#include <xtensa/coreasm.h>
/* Determine whether cache attributes are controlled using eight 512MB entries: */
#define XCHAL_CA_8X512 (XCHAL_HAVE_CACHEATTR || XCHAL_HAVE_MIMIC_CACHEATTR || XCHAL_HAVE_XLT_CACHEATTR \
|| (XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY))
/*
* This header file defines assembler macros of the form:
* <x>cacheattr_<func>
* where:
* <x> is 'i', 'd' or absent for instruction, data
* or both caches; and
* <func> indicates the function of the macro.
*
* The following functions are defined:
*
* icacheattr_get
* Reads I-cache CACHEATTR into a2 (clobbers a3-a5).
*
* dcacheattr_get
* Reads D-cache CACHEATTR into a2 (clobbers a3-a5).
* (Note: for configs with a real CACHEATTR register, the
* above two macros are identical.)
*
* cacheattr_set
* Writes both I-cache and D-cache CACHEATTRs from a2 (a3-a8 clobbered).
* Works even when changing one's own code's attributes.
*
* icacheattr_is_enabled label
* Branches to \label if I-cache appears to have been enabled
* (eg. if CACHEATTR contains a cache-enabled attribute).
* (clobbers a2-a5,SAR)
*
* dcacheattr_is_enabled label
* Branches to \label if D-cache appears to have been enabled
* (eg. if CACHEATTR contains a cache-enabled attribute).
* (clobbers a2-a5,SAR)
*
* cacheattr_is_enabled label
* Branches to \label if either I-cache or D-cache appears to have been enabled
* (eg. if CACHEATTR contains a cache-enabled attribute).
* (clobbers a2-a5,SAR)
*
* The following macros are only defined under certain conditions:
*
* icacheattr_set (if XCHAL_HAVE_MIMIC_CACHEATTR || XCHAL_HAVE_XLT_CACHEATTR)
* Writes I-cache CACHEATTR from a2 (a3-a8 clobbered).
*
* dcacheattr_set (if XCHAL_HAVE_MIMIC_CACHEATTR || XCHAL_HAVE_XLT_CACHEATTR)
* Writes D-cache CACHEATTR from a2 (a3-a8 clobbered).
*/
/*************************** GENERIC -- ALL CACHES ***************************/
/*
* _cacheattr_get
*
* (Internal macro.)
* Returns value of CACHEATTR register (or closest equivalent) in a2.
*
* Entry:
* (none)
* Exit:
* a2 value read from CACHEATTR
* a3-a5 clobbered (temporaries)
*/
.macro _cacheattr_get tlb
#if XCHAL_HAVE_CACHEATTR
rsr.cacheattr a2
#elif XCHAL_CA_8X512
// We have a config that "mimics" CACHEATTR using a simplified
// "MMU" composed of a single statically-mapped way.
// DTLB and ITLB are independent, so there's no single
// cache attribute that can describe both. So for now
// just return the DTLB state.
movi a5, 0xE0000000
movi a2, 0
movi a3, XCHAL_SPANNING_WAY
1: add a3, a3, a5 // next segment
r&tlb&1 a4, a3 // get PPN+CA of segment at 0xE0000000, 0xC0000000, ..., 0
dsync // interlock???
slli a2, a2, 4
extui a4, a4, 0, 4 // extract CA
or a2, a2, a4
bgeui a3, 16, 1b
#else
// This macro isn't applicable to arbitrary MMU configurations.
// Just return zero.
movi a2, 0
#endif
.endm
.macro icacheattr_get
_cacheattr_get itlb
.endm
.macro dcacheattr_get
_cacheattr_get dtlb
.endm
/* Default (powerup/reset) value of CACHEATTR,
all BYPASS mode (ie. disabled/bypassed caches): */
#if XCHAL_HAVE_PTP_MMU
# define XCHAL_CACHEATTR_ALL_BYPASS 0x33333333
#else
# define XCHAL_CACHEATTR_ALL_BYPASS 0x22222222
#endif
#if XCHAL_CA_8X512
#if XCHAL_HAVE_PTP_MMU
# define XCHAL_FCA_ENAMASK 0x0AA0 /* bitmap of fetch attributes that require enabled icache */
# define XCHAL_LCA_ENAMASK 0x0FF0 /* bitmap of load attributes that require enabled dcache */
# define XCHAL_SCA_ENAMASK 0x0CC0 /* bitmap of store attributes that require enabled dcache */
#else
# define XCHAL_FCA_ENAMASK 0x003A /* bitmap of fetch attributes that require enabled icache */
# define XCHAL_LCA_ENAMASK 0x0033 /* bitmap of load attributes that require enabled dcache */
# define XCHAL_SCA_ENAMASK 0x0033 /* bitmap of store attributes that require enabled dcache */
#endif
#define XCHAL_LSCA_ENAMASK (XCHAL_LCA_ENAMASK|XCHAL_SCA_ENAMASK) /* l/s attrs requiring enabled dcache */
#define XCHAL_ALLCA_ENAMASK (XCHAL_FCA_ENAMASK|XCHAL_LSCA_ENAMASK) /* all attrs requiring enabled caches */
/*
* _cacheattr_is_enabled
*
* (Internal macro.)
* Branches to \label if CACHEATTR in a2 indicates an enabled
* cache, using mask in a3.
*
* Parameters:
* label where to branch to if cache is enabled
* Entry:
* a2 contains CACHEATTR value used to determine whether
* caches are enabled
* a3 16-bit constant where each bit correspond to
* one of the 16 possible CA values (in a CACHEATTR mask);
* CA values that indicate the cache is enabled
* have their corresponding bit set in this mask
* (eg. use XCHAL_xCA_ENAMASK , above)
* Exit:
* a2,a4,a5 clobbered
* SAR clobbered
*/
.macro _cacheattr_is_enabled label
movi a4, 8 // loop 8 times
.Lcaife\@:
extui a5, a2, 0, 4 // get CA nibble
ssr a5 // index into mask according to CA...
srl a5, a3 // ...and get CA's mask bit in a5 bit 0
bbsi.l a5, 0, \label // if CA indicates cache enabled, jump to label
srli a2, a2, 4 // next nibble
addi a4, a4, -1
bnez a4, .Lcaife\@ // loop for each nibble
.endm
#else /* XCHAL_CA_8X512 */
.macro _cacheattr_is_enabled label
j \label // macro not applicable, assume caches always enabled
.endm
#endif /* XCHAL_CA_8X512 */
/*
* icacheattr_is_enabled
*
* Branches to \label if I-cache is enabled.
*
* Parameters:
* label where to branch to if icache is enabled
* Entry:
* (none)
* Exit:
* a2-a5, SAR clobbered (temporaries)
*/
.macro icacheattr_is_enabled label
#if XCHAL_CA_8X512
icacheattr_get
movi a3, XCHAL_FCA_ENAMASK
#endif
_cacheattr_is_enabled \label
.endm
/*
* dcacheattr_is_enabled
*
* Branches to \label if D-cache is enabled.
*
* Parameters:
* label where to branch to if dcache is enabled
* Entry:
* (none)
* Exit:
* a2-a5, SAR clobbered (temporaries)
*/
.macro dcacheattr_is_enabled label
#if XCHAL_CA_8X512
dcacheattr_get
movi a3, XCHAL_LSCA_ENAMASK
#endif
_cacheattr_is_enabled \label
.endm
/*
* cacheattr_is_enabled
*
* Branches to \label if either I-cache or D-cache is enabled.
*
* Parameters:
* label where to branch to if a cache is enabled
* Entry:
* (none)
* Exit:
* a2-a5, SAR clobbered (temporaries)
*/
.macro cacheattr_is_enabled label
#if XCHAL_HAVE_CACHEATTR
rsr.cacheattr a2
movi a3, XCHAL_ALLCA_ENAMASK
#elif XCHAL_CA_8X512
icacheattr_get
movi a3, XCHAL_FCA_ENAMASK
_cacheattr_is_enabled \label
dcacheattr_get
movi a3, XCHAL_LSCA_ENAMASK
#endif
_cacheattr_is_enabled \label
.endm
/*
* The ISA does not have a defined way to change the
* instruction cache attributes of the running code,
* ie. of the memory area that encloses the current PC.
* However, each micro-architecture (or class of
* configurations within a micro-architecture)
* provides a way to deal with this issue.
*
* Here are a few macros used to implement the relevant
* approach taken.
*/
#if XCHAL_CA_8X512 && !XCHAL_HAVE_CACHEATTR
// We have a config that "mimics" CACHEATTR using a simplified
// "MMU" composed of a single statically-mapped way.
/*
* icacheattr_set
*
* Entry:
* a2 cacheattr value to set
* Exit:
* a2 unchanged
* a3-a8 clobbered (temporaries)
*/
.macro icacheattr_set
movi a5, 0xE0000000 // mask of upper 3 bits
movi a6, 3f // PC where ITLB is set
movi a3, XCHAL_SPANNING_WAY // start at region 0 (0 .. 7)
mov a7, a2 // copy a2 so it doesn't get clobbered
and a6, a6, a5 // upper 3 bits of local PC area
j 3f
// Use micro-architecture specific method.
// The following 4-instruction sequence is aligned such that
// it all fits within a single I-cache line. Sixteen byte
// alignment is sufficient for this (using XCHAL_ICACHE_LINESIZE
// actually causes problems because that can be greater than
// the alignment of the reset vector, where this macro is often
// invoked, which would cause the linker to align the reset
// vector code away from the reset vector!!).
.begin no-transform
.align 16 /*XCHAL_ICACHE_LINESIZE*/
1: witlb a4, a3 // write wired PTE (CA, no PPN) of 512MB segment to ITLB
isync
.end no-transform
nop
nop
sub a3, a3, a5 // next segment (add 0x20000000)
bltui a3, 16, 4f // done?
// Note that in the WITLB loop, we don't do any load/stores
// (may not be an issue here, but it is important in the DTLB case).
2: srli a7, a7, 4 // next CA
3:
# if XCHAL_HAVE_MIMIC_CACHEATTR
extui a4, a7, 0, 4 // extract CA to set
# else /* have translation, preserve it: */
ritlb1 a8, a3 // get current PPN+CA of segment
//dsync // interlock???
extui a4, a7, 0, 4 // extract CA to set
srli a8, a8, 4 // clear CA but keep PPN ...
slli a8, a8, 4 // ...
add a4, a4, a8 // combine new CA with PPN to preserve
# endif
beq a3, a6, 1b // current PC's region? if so, do it in a safe way
witlb a4, a3 // write wired PTE (CA [+PPN]) of 512MB segment to ITLB
sub a3, a3, a5 // next segment (add 0x20000000)
bgeui a3, 16, 2b
isync // make sure all ifetch changes take effect
4:
.endm // icacheattr_set
/*
* dcacheattr_set
*
* Entry:
* a2 cacheattr value to set
* Exit:
* a2 unchanged
* a3-a8 clobbered (temporaries)
*/
.macro dcacheattr_set
movi a5, 0xE0000000 // mask of upper 3 bits
movi a3, XCHAL_SPANNING_WAY // start at region 0 (0 .. 7)
mov a7, a2 // copy a2 so it doesn't get clobbered
// Note that in the WDTLB loop, we don't do any load/stores
2: // (including implicit l32r via movi) because it isn't safe.
# if XCHAL_HAVE_MIMIC_CACHEATTR
extui a4, a7, 0, 4 // extract CA to set
# else /* have translation, preserve it: */
rdtlb1 a8, a3 // get current PPN+CA of segment
//dsync // interlock???
extui a4, a7, 0, 4 // extract CA to set
srli a8, a8, 4 // clear CA but keep PPN ...
slli a8, a8, 4 // ...
add a4, a4, a8 // combine new CA with PPN to preserve
# endif
wdtlb a4, a3 // write wired PTE (CA [+PPN]) of 512MB segment to DTLB
sub a3, a3, a5 // next segment (add 0x20000000)
srli a7, a7, 4 // next CA
bgeui a3, 16, 2b
dsync // make sure all data path changes take effect
.endm // dcacheattr_set
#endif /* XCHAL_CA_8X512 && !XCHAL_HAVE_CACHEATTR */
/*
* cacheattr_set
*
* Macro that sets the current CACHEATTR safely
* (both i and d) according to the current contents of a2.
* It works even when changing the cache attributes of
* the currently running code.
*
* Entry:
* a2 cacheattr value to set
* Exit:
* a2 unchanged
* a3-a8 clobbered (temporaries)
*/
.macro cacheattr_set
#if XCHAL_HAVE_CACHEATTR
# if XCHAL_ICACHE_LINESIZE < 4
// No i-cache, so can always safely write to CACHEATTR:
wsr.cacheattr a2
# else
// The Athens micro-architecture, when using the old
// exception architecture option (ie. with the CACHEATTR register)
// allows changing the cache attributes of the running code
// using the following exact sequence aligned to be within
// an instruction cache line. (NOTE: using XCHAL_ICACHE_LINESIZE
// alignment actually causes problems because that can be greater
// than the alignment of the reset vector, where this macro is often
// invoked, which would cause the linker to align the reset
// vector code away from the reset vector!!).
j 1f
.begin no-transform
.align 16 /*XCHAL_ICACHE_LINESIZE*/ // align to within an I-cache line
1: wsr.cacheattr a2
isync
.end no-transform
nop
nop
# endif
#elif XCHAL_CA_8X512
// DTLB and ITLB are independent, but to keep semantics
// of this macro we simply write to both.
icacheattr_set
dcacheattr_set
#else
// This macro isn't applicable to arbitrary MMU configurations.
// Do nothing in this case.
#endif
.endm
#endif /*XTENSA_CACHEATTRASM_H*/