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Remove mips MD atomic_load_64 and atomic_store_64.

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The only users of the functions were db_read_bytes() and
db_write_bytes() ddb(4) interfaces.  Replace the calls with direct
reads and writes, which are automatically atomic on 64bits and n32.

Note that removed assembler implementation for mips32 is not atomic
anyway.

Reviewed by:	jhb
Discussed with:	imp
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D13586
This commit is contained in:
Konstantin Belousov 2017-12-22 23:27:03 +00:00
parent 0f33cc3472
commit 7aea69e54a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=327097
3 changed files with 4 additions and 89 deletions
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18
sys/mips/include/atomic.h
View File

@ -341,24 +341,6 @@ atomic_store_rel_##WIDTH(__volatile uint##WIDTH##_t *p, uint##WIDTH##_t v)\
ATOMIC_STORE_LOAD(32)
ATOMIC_STORE_LOAD(64)
#if !defined(__mips_n64) && !defined(__mips_n32)
void atomic_store_64(__volatile uint64_t *, uint64_t);
uint64_t atomic_load_64(__volatile uint64_t *);
#elif defined (__mips_n32)
static __inline void
atomic_store_64(__volatile uint64_t *p, uint64_t v)
{
*p = v;
}
static __inline uint64_t
atomic_load_64(__volatile uint64_t *p)
{
return (*p);
}
/* #else atomic_common.h definitions of atomic_load/store_64 are used */
#endif
#undef ATOMIC_STORE_LOAD
/*

8
sys/mips/mips/db_interface.c
View File

@ -152,6 +152,7 @@ db_read_bytes(vm_offset_t addr, size_t size, char *data)
/*
* 'addr' could be a memory-mapped I/O address. Try to
* do atomic load/store in unit of size requested.
* size == 8 is only atomic on 64bit or n32 kernel.
*/
if ((size == 2 || size == 4 || size == 8) &&
((addr & (size -1)) == 0) &&
@ -164,8 +165,7 @@ db_read_bytes(vm_offset_t addr, size_t size, char *data)
*(uint32_t *)data = *(uint32_t *)addr;
break;
case 8:
*(uint64_t *)data = atomic_load_64(
(void *)addr);
*(uint64_t *)data = *(uint64_t *)addr;
break;
}
} else {
@ -195,6 +195,7 @@ db_write_bytes(vm_offset_t addr, size_t size, char *data)
/*
* 'addr' could be a memory-mapped I/O address. Try to
* do atomic load/store in unit of size requested.
* size == 8 is only atomic on 64bit or n32 kernel.
*/
if ((size == 2 || size == 4 || size == 8) &&
((addr & (size -1)) == 0) &&
@ -207,8 +208,7 @@ db_write_bytes(vm_offset_t addr, size_t size, char *data)
*(uint32_t *)addr = *(uint32_t *)data;
break;
case 8:
atomic_store_64((uint64_t *)addr,
*(uint64_t *)data);
*(uint64_t *)addr = *(uint64_t *)data;
break;
}
} else {

67
sys/mips/mips/support.S
View File

@ -839,75 +839,8 @@ LEAF(atomic_subtract_8)
nop
END(atomic_subtract_8)
/*
* atomic 64-bit register read/write assembly language support routines.
*/
.set noreorder # Noreorder is default style!
#if !defined(__mips_n64) && !defined(__mips_n32)
/*
* I don't know if these routines have the right number of
* NOPs in it for all processors. XXX
*
* Maybe it would be better to just leave this undefined in that case.
*
* XXX These routines are not safe in the case of a TLB miss on a1 or
* a0 unless the trapframe is 64-bit, which it just isn't with O32.
* If we take any exception, not just an interrupt, the upper
* 32-bits will be clobbered. Use only N32 and N64 kernels if you
* want to use 64-bit registers while interrupts are enabled or
* with memory operations. Since this isn't even using load-linked
* and store-conditional, perhaps it should just use two registers
* instead, as is right and good with the O32 ABI.
*/
LEAF(atomic_store_64)
mfc0 t1, MIPS_COP_0_STATUS
and t2, t1, ~MIPS_SR_INT_IE
mtc0 t2, MIPS_COP_0_STATUS
nop
nop
nop
nop
ld t0, (a1)
nop
nop
sd t0, (a0)
nop
nop
mtc0 t1,MIPS_COP_0_STATUS
nop
nop
nop
nop
j ra
nop
END(atomic_store_64)
LEAF(atomic_load_64)
mfc0 t1, MIPS_COP_0_STATUS
and t2, t1, ~MIPS_SR_INT_IE
mtc0 t2, MIPS_COP_0_STATUS
nop
nop
nop
nop
ld t0, (a0)
nop
nop
sd t0, (a1)
nop
nop
mtc0 t1,MIPS_COP_0_STATUS
nop
nop
nop
nop
j ra
nop
END(atomic_load_64)
#endif
#if defined(DDB) || defined(DEBUG)
LEAF(kdbpeek)