qemu/util/cacheinfo.c
Richard Henderson 1da8de39a3 util: Enhance flush_icache_range with separate data pointer
We are shortly going to have a split rw/rx jit buffer.  Depending
on the host, we need to flush the dcache at the rw data pointer and
flush the icache at the rx code pointer.

For now, the two passed pointers are identical, so there is no
effective change in behaviour.

Reviewed-by: Joelle van Dyne <j@getutm.app>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-01-07 05:09:41 -10:00

200 lines
5.1 KiB
C

/*
* cacheinfo.c - helpers to query the host about its caches
*
* Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "qemu/atomic.h"
int qemu_icache_linesize = 0;
int qemu_icache_linesize_log;
int qemu_dcache_linesize = 0;
int qemu_dcache_linesize_log;
/*
* Operating system specific detection mechanisms.
*/
#if defined(_WIN32)
static void sys_cache_info(int *isize, int *dsize)
{
SYSTEM_LOGICAL_PROCESSOR_INFORMATION *buf;
DWORD size = 0;
BOOL success;
size_t i, n;
/* Check for the required buffer size first. Note that if the zero
size we use for the probe results in success, then there is no
data available; fail in that case. */
success = GetLogicalProcessorInformation(0, &size);
if (success || GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
return;
}
n = size / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
size = n * sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
buf = g_new0(SYSTEM_LOGICAL_PROCESSOR_INFORMATION, n);
if (!GetLogicalProcessorInformation(buf, &size)) {
goto fail;
}
for (i = 0; i < n; i++) {
if (buf[i].Relationship == RelationCache
&& buf[i].Cache.Level == 1) {
switch (buf[i].Cache.Type) {
case CacheUnified:
*isize = *dsize = buf[i].Cache.LineSize;
break;
case CacheInstruction:
*isize = buf[i].Cache.LineSize;
break;
case CacheData:
*dsize = buf[i].Cache.LineSize;
break;
default:
break;
}
}
}
fail:
g_free(buf);
}
#elif defined(__APPLE__)
# include <sys/sysctl.h>
static void sys_cache_info(int *isize, int *dsize)
{
/* There's only a single sysctl for both I/D cache line sizes. */
long size;
size_t len = sizeof(size);
if (!sysctlbyname("hw.cachelinesize", &size, &len, NULL, 0)) {
*isize = *dsize = size;
}
}
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
# include <sys/sysctl.h>
static void sys_cache_info(int *isize, int *dsize)
{
/* There's only a single sysctl for both I/D cache line sizes. */
int size;
size_t len = sizeof(size);
if (!sysctlbyname("machdep.cacheline_size", &size, &len, NULL, 0)) {
*isize = *dsize = size;
}
}
#else
/* POSIX */
static void sys_cache_info(int *isize, int *dsize)
{
# ifdef _SC_LEVEL1_ICACHE_LINESIZE
int tmp_isize = (int) sysconf(_SC_LEVEL1_ICACHE_LINESIZE);
if (tmp_isize > 0) {
*isize = tmp_isize;
}
# endif
# ifdef _SC_LEVEL1_DCACHE_LINESIZE
int tmp_dsize = (int) sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
if (tmp_dsize > 0) {
*dsize = tmp_dsize;
}
# endif
}
#endif /* sys_cache_info */
/*
* Architecture (+ OS) specific detection mechanisms.
*/
#if defined(__aarch64__)
static void arch_cache_info(int *isize, int *dsize)
{
if (*isize == 0 || *dsize == 0) {
uint64_t ctr;
/* The real cache geometry is in CCSIDR_EL1/CLIDR_EL1/CSSELR_EL1,
but (at least under Linux) these are marked protected by the
kernel. However, CTR_EL0 contains the minimum linesize in the
entire hierarchy, and is used by userspace cache flushing. */
asm volatile("mrs\t%0, ctr_el0" : "=r"(ctr));
if (*isize == 0) {
*isize = 4 << (ctr & 0xf);
}
if (*dsize == 0) {
*dsize = 4 << ((ctr >> 16) & 0xf);
}
}
}
#elif defined(_ARCH_PPC) && defined(__linux__)
# include "elf.h"
static void arch_cache_info(int *isize, int *dsize)
{
if (*isize == 0) {
*isize = qemu_getauxval(AT_ICACHEBSIZE);
}
if (*dsize == 0) {
*dsize = qemu_getauxval(AT_DCACHEBSIZE);
}
}
#else
static void arch_cache_info(int *isize, int *dsize) { }
#endif /* arch_cache_info */
/*
* ... and if all else fails ...
*/
static void fallback_cache_info(int *isize, int *dsize)
{
/* If we can only find one of the two, assume they're the same. */
if (*isize) {
if (*dsize) {
/* Success! */
} else {
*dsize = *isize;
}
} else if (*dsize) {
*isize = *dsize;
} else {
#if defined(_ARCH_PPC)
/*
* For PPC, we're going to use the cache sizes computed for
* flush_idcache_range. Which means that we must use the
* architecture minimum.
*/
*isize = *dsize = 16;
#else
/* Otherwise, 64 bytes is not uncommon. */
*isize = *dsize = 64;
#endif
}
}
static void __attribute__((constructor)) init_cache_info(void)
{
int isize = 0, dsize = 0;
sys_cache_info(&isize, &dsize);
arch_cache_info(&isize, &dsize);
fallback_cache_info(&isize, &dsize);
assert((isize & (isize - 1)) == 0);
assert((dsize & (dsize - 1)) == 0);
qemu_icache_linesize = isize;
qemu_icache_linesize_log = ctz32(isize);
qemu_dcache_linesize = dsize;
qemu_dcache_linesize_log = ctz32(dsize);
qatomic64_init();
}