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qemu-e2k/tcg/region.c

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/*
* Memory region management for Tiny Code Generator for QEMU
*
* Copyright (c) 2008 Fabrice Bellard
*
* 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.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qapi/error.h"
#include "exec/exec-all.h"
#include "tcg/tcg.h"
#include "tcg-internal.h"
struct tcg_region_tree {
QemuMutex lock;
GTree *tree;
/* padding to avoid false sharing is computed at run-time */
};
/*
* We divide code_gen_buffer into equally-sized "regions" that TCG threads
* dynamically allocate from as demand dictates. Given appropriate region
* sizing, this minimizes flushes even when some TCG threads generate a lot
* more code than others.
*/
struct tcg_region_state {
QemuMutex lock;
/* fields set at init time */
void *start_aligned;
void *after_prologue;
size_t n;
size_t size; /* size of one region */
size_t stride; /* .size + guard size */
size_t total_size; /* size of entire buffer, >= n * stride */
/* fields protected by the lock */
size_t current; /* current region index */
size_t agg_size_full; /* aggregate size of full regions */
};
static struct tcg_region_state region;
/*
* This is an array of struct tcg_region_tree's, with padding.
* We use void * to simplify the computation of region_trees[i]; each
* struct is found every tree_size bytes.
*/
static void *region_trees;
static size_t tree_size;
bool in_code_gen_buffer(const void *p)
{
/*
* Much like it is valid to have a pointer to the byte past the
* end of an array (so long as you don't dereference it), allow
* a pointer to the byte past the end of the code gen buffer.
*/
return (size_t)(p - region.start_aligned) <= region.total_size;
}
#ifdef CONFIG_DEBUG_TCG
const void *tcg_splitwx_to_rx(void *rw)
{
/* Pass NULL pointers unchanged. */
if (rw) {
g_assert(in_code_gen_buffer(rw));
rw += tcg_splitwx_diff;
}
return rw;
}
void *tcg_splitwx_to_rw(const void *rx)
{
/* Pass NULL pointers unchanged. */
if (rx) {
rx -= tcg_splitwx_diff;
/* Assert that we end with a pointer in the rw region. */
g_assert(in_code_gen_buffer(rx));
}
return (void *)rx;
}
#endif /* CONFIG_DEBUG_TCG */
/* compare a pointer @ptr and a tb_tc @s */
static int ptr_cmp_tb_tc(const void *ptr, const struct tb_tc *s)
{
if (ptr >= s->ptr + s->size) {
return 1;
} else if (ptr < s->ptr) {
return -1;
}
return 0;
}
static gint tb_tc_cmp(gconstpointer ap, gconstpointer bp, gpointer userdata)
{
const struct tb_tc *a = ap;
const struct tb_tc *b = bp;
/*
* When both sizes are set, we know this isn't a lookup.
* This is the most likely case: every TB must be inserted; lookups
* are a lot less frequent.
*/
if (likely(a->size && b->size)) {
if (a->ptr > b->ptr) {
return 1;
} else if (a->ptr < b->ptr) {
return -1;
}
/* a->ptr == b->ptr should happen only on deletions */
g_assert(a->size == b->size);
return 0;
}
/*
* All lookups have either .size field set to 0.
* From the glib sources we see that @ap is always the lookup key. However
* the docs provide no guarantee, so we just mark this case as likely.
*/
if (likely(a->size == 0)) {
return ptr_cmp_tb_tc(a->ptr, b);
}
return ptr_cmp_tb_tc(b->ptr, a);
}
static void tb_destroy(gpointer value)
{
TranslationBlock *tb = value;
qemu_spin_destroy(&tb->jmp_lock);
}
static void tcg_region_trees_init(void)
{
size_t i;
tree_size = ROUND_UP(sizeof(struct tcg_region_tree), qemu_dcache_linesize);
region_trees = qemu_memalign(qemu_dcache_linesize, region.n * tree_size);
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_init(&rt->lock);
rt->tree = g_tree_new_full(tb_tc_cmp, NULL, NULL, tb_destroy);
}
}
static struct tcg_region_tree *tc_ptr_to_region_tree(const void *p)
{
size_t region_idx;
/*
* Like tcg_splitwx_to_rw, with no assert. The pc may come from
* a signal handler over which the caller has no control.
*/
if (!in_code_gen_buffer(p)) {
p -= tcg_splitwx_diff;
if (!in_code_gen_buffer(p)) {
return NULL;
}
}
if (p < region.start_aligned) {
region_idx = 0;
} else {
ptrdiff_t offset = p - region.start_aligned;
if (offset > region.stride * (region.n - 1)) {
region_idx = region.n - 1;
} else {
region_idx = offset / region.stride;
}
}
return region_trees + region_idx * tree_size;
}
void tcg_tb_insert(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_insert(rt->tree, &tb->tc, tb);
qemu_mutex_unlock(&rt->lock);
}
void tcg_tb_remove(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_remove(rt->tree, &tb->tc);
qemu_mutex_unlock(&rt->lock);
}
/*
* Find the TB 'tb' such that
* tb->tc.ptr <= tc_ptr < tb->tc.ptr + tb->tc.size
* Return NULL if not found.
*/
TranslationBlock *tcg_tb_lookup(uintptr_t tc_ptr)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree((void *)tc_ptr);
TranslationBlock *tb;
struct tb_tc s = { .ptr = (void *)tc_ptr };
if (rt == NULL) {
return NULL;
}
qemu_mutex_lock(&rt->lock);
tb = g_tree_lookup(rt->tree, &s);
qemu_mutex_unlock(&rt->lock);
return tb;
}
static void tcg_region_tree_lock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_lock(&rt->lock);
}
}
static void tcg_region_tree_unlock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_unlock(&rt->lock);
}
}
void tcg_tb_foreach(GTraverseFunc func, gpointer user_data)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
g_tree_foreach(rt->tree, func, user_data);
}
tcg_region_tree_unlock_all();
}
size_t tcg_nb_tbs(void)
{
size_t nb_tbs = 0;
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
nb_tbs += g_tree_nnodes(rt->tree);
}
tcg_region_tree_unlock_all();
return nb_tbs;
}
static void tcg_region_tree_reset_all(void)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
/* Increment the refcount first so that destroy acts as a reset */
g_tree_ref(rt->tree);
g_tree_destroy(rt->tree);
}
tcg_region_tree_unlock_all();
}
static void tcg_region_bounds(size_t curr_region, void **pstart, void **pend)
{
void *start, *end;
start = region.start_aligned + curr_region * region.stride;
end = start + region.size;
if (curr_region == 0) {
start = region.after_prologue;
}
/* The final region may have a few extra pages due to earlier rounding. */
if (curr_region == region.n - 1) {
end = region.start_aligned + region.total_size;
}
*pstart = start;
*pend = end;
}
static void tcg_region_assign(TCGContext *s, size_t curr_region)
{
void *start, *end;
tcg_region_bounds(curr_region, &start, &end);
s->code_gen_buffer = start;
s->code_gen_ptr = start;
s->code_gen_buffer_size = end - start;
s->code_gen_highwater = end - TCG_HIGHWATER;
}
static bool tcg_region_alloc__locked(TCGContext *s)
{
if (region.current == region.n) {
return true;
}
tcg_region_assign(s, region.current);
region.current++;
return false;
}
/*
* Request a new region once the one in use has filled up.
* Returns true on error.
*/
bool tcg_region_alloc(TCGContext *s)
{
bool err;
/* read the region size now; alloc__locked will overwrite it on success */
size_t size_full = s->code_gen_buffer_size;
qemu_mutex_lock(&region.lock);
err = tcg_region_alloc__locked(s);
if (!err) {
region.agg_size_full += size_full - TCG_HIGHWATER;
}
qemu_mutex_unlock(&region.lock);
return err;
}
/*
* Perform a context's first region allocation.
* This function does _not_ increment region.agg_size_full.
*/
static void tcg_region_initial_alloc__locked(TCGContext *s)
{
bool err = tcg_region_alloc__locked(s);
g_assert(!err);
}
void tcg_region_initial_alloc(TCGContext *s)
{
qemu_mutex_lock(&region.lock);
tcg_region_initial_alloc__locked(s);
qemu_mutex_unlock(&region.lock);
}
/* Call from a safe-work context */
void tcg_region_reset_all(void)
{
unsigned int n_ctxs = qatomic_read(&tcg_cur_ctxs);
unsigned int i;
qemu_mutex_lock(&region.lock);
region.current = 0;
region.agg_size_full = 0;
for (i = 0; i < n_ctxs; i++) {
TCGContext *s = qatomic_read(&tcg_ctxs[i]);
tcg_region_initial_alloc__locked(s);
}
qemu_mutex_unlock(&region.lock);
tcg_region_tree_reset_all();
}
static size_t tcg_n_regions(size_t tb_size, unsigned max_cpus)
{
#ifdef CONFIG_USER_ONLY
return 1;
#else
size_t n_regions;
/*
* It is likely that some vCPUs will translate more code than others,
* so we first try to set more regions than max_cpus, with those regions
* being of reasonable size. If that's not possible we make do by evenly
* dividing the code_gen_buffer among the vCPUs.
*/
/* Use a single region if all we have is one vCPU thread */
if (max_cpus == 1 || !qemu_tcg_mttcg_enabled()) {
return 1;
}
/*
* Try to have more regions than max_cpus, with each region being >= 2 MB.
* If we can't, then just allocate one region per vCPU thread.
*/
n_regions = tb_size / (2 * MiB);
if (n_regions <= max_cpus) {
return max_cpus;
}
return MIN(n_regions, max_cpus * 8);
#endif
}
/*
* Minimum size of the code gen buffer. This number is randomly chosen,
* but not so small that we can't have a fair number of TB's live.
*
* Maximum size, MAX_CODE_GEN_BUFFER_SIZE, is defined in tcg-target.h.
* Unless otherwise indicated, this is constrained by the range of
* direct branches on the host cpu, as used by the TCG implementation
* of goto_tb.
*/
#define MIN_CODE_GEN_BUFFER_SIZE (1 * MiB)
#if TCG_TARGET_REG_BITS == 32
#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (32 * MiB)
#ifdef CONFIG_USER_ONLY
/*
* For user mode on smaller 32 bit systems we may run into trouble
* allocating big chunks of data in the right place. On these systems
* we utilise a static code generation buffer directly in the binary.
*/
#define USE_STATIC_CODE_GEN_BUFFER
#endif
#else /* TCG_TARGET_REG_BITS == 64 */
#ifdef CONFIG_USER_ONLY
/*
* As user-mode emulation typically means running multiple instances
* of the translator don't go too nuts with our default code gen
* buffer lest we make things too hard for the OS.
*/
#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (128 * MiB)
#else
/*
* We expect most system emulation to run one or two guests per host.
* Users running large scale system emulation may want to tweak their
* runtime setup via the tb-size control on the command line.
*/
#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (1 * GiB)
#endif
#endif
#define DEFAULT_CODE_GEN_BUFFER_SIZE \
(DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \
? DEFAULT_CODE_GEN_BUFFER_SIZE_1 : MAX_CODE_GEN_BUFFER_SIZE)
#ifdef USE_STATIC_CODE_GEN_BUFFER
static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE]
__attribute__((aligned(CODE_GEN_ALIGN)));
static int alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
{
void *buf, *end;
size_t size;
if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported");
return -1;
}
/* page-align the beginning and end of the buffer */
buf = static_code_gen_buffer;
end = static_code_gen_buffer + sizeof(static_code_gen_buffer);
buf = QEMU_ALIGN_PTR_UP(buf, qemu_real_host_page_size);
end = QEMU_ALIGN_PTR_DOWN(end, qemu_real_host_page_size);
size = end - buf;
/* Honor a command-line option limiting the size of the buffer. */
if (size > tb_size) {
size = QEMU_ALIGN_DOWN(tb_size, qemu_real_host_page_size);
}
region.start_aligned = buf;
region.total_size = size;
return PROT_READ | PROT_WRITE;
}
#elif defined(_WIN32)
static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{
void *buf;
if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported");
return -1;
}
buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (buf == NULL) {
error_setg_win32(errp, GetLastError(),
"allocate %zu bytes for jit buffer", size);
return false;
}
region.start_aligned = buf;
region.total_size = size;
return PAGE_READ | PAGE_WRITE | PAGE_EXEC;
}
#else
static int alloc_code_gen_buffer_anon(size_t size, int prot,
int flags, Error **errp)
{
void *buf;
buf = mmap(NULL, size, prot, flags, -1, 0);
if (buf == MAP_FAILED) {
error_setg_errno(errp, errno,
"allocate %zu bytes for jit buffer", size);
return -1;
}
region.start_aligned = buf;
region.total_size = size;
return prot;
}
#ifndef CONFIG_TCG_INTERPRETER
#ifdef CONFIG_POSIX
#include "qemu/memfd.h"
static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
{
void *buf_rw = NULL, *buf_rx = MAP_FAILED;
int fd = -1;
buf_rw = qemu_memfd_alloc("tcg-jit", size, 0, &fd, errp);
if (buf_rw == NULL) {
goto fail;
}
buf_rx = mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_SHARED, fd, 0);
if (buf_rx == MAP_FAILED) {
goto fail_rx;
}
close(fd);
region.start_aligned = buf_rw;
region.total_size = size;
tcg_splitwx_diff = buf_rx - buf_rw;
return PROT_READ | PROT_WRITE;
fail_rx:
error_setg_errno(errp, errno, "failed to map shared memory for execute");
fail:
if (buf_rx != MAP_FAILED) {
munmap(buf_rx, size);
}
if (buf_rw) {
munmap(buf_rw, size);
}
if (fd >= 0) {
close(fd);
}
return -1;
}
#endif /* CONFIG_POSIX */
#ifdef CONFIG_DARWIN
#include <mach/mach.h>
extern kern_return_t mach_vm_remap(vm_map_t target_task,
mach_vm_address_t *target_address,
mach_vm_size_t size,
mach_vm_offset_t mask,
int flags,
vm_map_t src_task,
mach_vm_address_t src_address,
boolean_t copy,
vm_prot_t *cur_protection,
vm_prot_t *max_protection,
vm_inherit_t inheritance);
static int alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
{
kern_return_t ret;
mach_vm_address_t buf_rw, buf_rx;
vm_prot_t cur_prot, max_prot;
/* Map the read-write portion via normal anon memory. */
if (!alloc_code_gen_buffer_anon(size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, errp)) {
return -1;
}
buf_rw = (mach_vm_address_t)region.start_aligned;
buf_rx = 0;
ret = mach_vm_remap(mach_task_self(),
&buf_rx,
size,
0,
VM_FLAGS_ANYWHERE,
mach_task_self(),
buf_rw,
false,
&cur_prot,
&max_prot,
VM_INHERIT_NONE);
if (ret != KERN_SUCCESS) {
/* TODO: Convert "ret" to a human readable error message. */
error_setg(errp, "vm_remap for jit splitwx failed");
munmap((void *)buf_rw, size);
return -1;
}
if (mprotect((void *)buf_rx, size, PROT_READ | PROT_EXEC) != 0) {
error_setg_errno(errp, errno, "mprotect for jit splitwx");
munmap((void *)buf_rx, size);
munmap((void *)buf_rw, size);
return -1;
}
tcg_splitwx_diff = buf_rx - buf_rw;
return PROT_READ | PROT_WRITE;
}
#endif /* CONFIG_DARWIN */
#endif /* CONFIG_TCG_INTERPRETER */
static int alloc_code_gen_buffer_splitwx(size_t size, Error **errp)
{
#ifndef CONFIG_TCG_INTERPRETER
# ifdef CONFIG_DARWIN
return alloc_code_gen_buffer_splitwx_vmremap(size, errp);
# endif
# ifdef CONFIG_POSIX
return alloc_code_gen_buffer_splitwx_memfd(size, errp);
# endif
#endif
error_setg(errp, "jit split-wx not supported");
return -1;
}
static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{
ERRP_GUARD();
int prot, flags;
if (splitwx) {
prot = alloc_code_gen_buffer_splitwx(size, errp);
if (prot >= 0) {
return prot;
}
/*
* If splitwx force-on (1), fail;
* if splitwx default-on (-1), fall through to splitwx off.
*/
if (splitwx > 0) {
return -1;
}
error_free_or_abort(errp);
}
/*
* macOS 11.2 has a bug (Apple Feedback FB8994773) in which mprotect
* rejects a permission change from RWX -> NONE when reserving the
* guard pages later. We can go the other way with the same number
* of syscalls, so always begin with PROT_NONE.
*/
prot = PROT_NONE;
flags = MAP_PRIVATE | MAP_ANONYMOUS;
#ifdef CONFIG_DARWIN
/* Applicable to both iOS and macOS (Apple Silicon). */
if (!splitwx) {
flags |= MAP_JIT;
}
#endif
return alloc_code_gen_buffer_anon(size, prot, flags, errp);
}
#endif /* USE_STATIC_CODE_GEN_BUFFER, WIN32, POSIX */
/*
* Initializes region partitioning.
*
* Called at init time from the parent thread (i.e. the one calling
* tcg_context_init), after the target's TCG globals have been set.
*
* Region partitioning works by splitting code_gen_buffer into separate regions,
* and then assigning regions to TCG threads so that the threads can translate
* code in parallel without synchronization.
*
* In softmmu the number of TCG threads is bounded by max_cpus, so we use at
* least max_cpus regions in MTTCG. In !MTTCG we use a single region.
* Note that the TCG options from the command-line (i.e. -accel accel=tcg,[...])
* must have been parsed before calling this function, since it calls
* qemu_tcg_mttcg_enabled().
*
* In user-mode we use a single region. Having multiple regions in user-mode
* is not supported, because the number of vCPU threads (recall that each thread
* spawned by the guest corresponds to a vCPU thread) is only bounded by the
* OS, and usually this number is huge (tens of thousands is not uncommon).
* Thus, given this large bound on the number of vCPU threads and the fact
* that code_gen_buffer is allocated at compile-time, we cannot guarantee
* that the availability of at least one region per vCPU thread.
*
* However, this user-mode limitation is unlikely to be a significant problem
* in practice. Multi-threaded guests share most if not all of their translated
* code, which makes parallel code generation less appealing than in softmmu.
*/
void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
{
const size_t page_size = qemu_real_host_page_size;
size_t region_size;
int have_prot, need_prot;
/* Size the buffer. */
if (tb_size == 0) {
size_t phys_mem = qemu_get_host_physmem();
if (phys_mem == 0) {
tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
} else {
tb_size = QEMU_ALIGN_DOWN(phys_mem / 8, page_size);
tb_size = MIN(DEFAULT_CODE_GEN_BUFFER_SIZE, tb_size);
}
}
if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {
tb_size = MIN_CODE_GEN_BUFFER_SIZE;
}
if (tb_size > MAX_CODE_GEN_BUFFER_SIZE) {
tb_size = MAX_CODE_GEN_BUFFER_SIZE;
}
have_prot = alloc_code_gen_buffer(tb_size, splitwx, &error_fatal);
assert(have_prot >= 0);
/* Request large pages for the buffer and the splitwx. */
qemu_madvise(region.start_aligned, region.total_size, QEMU_MADV_HUGEPAGE);
if (tcg_splitwx_diff) {
qemu_madvise(region.start_aligned + tcg_splitwx_diff,
region.total_size, QEMU_MADV_HUGEPAGE);
}
/*
* Make region_size a multiple of page_size, using aligned as the start.
* As a result of this we might end up with a few extra pages at the end of
* the buffer; we will assign those to the last region.
*/
region.n = tcg_n_regions(tb_size, max_cpus);
region_size = tb_size / region.n;
region_size = QEMU_ALIGN_DOWN(region_size, page_size);
/* A region must have at least 2 pages; one code, one guard */
g_assert(region_size >= 2 * page_size);
region.stride = region_size;
/* Reserve space for guard pages. */
region.size = region_size - page_size;
region.total_size -= page_size;
/*
* The first region will be smaller than the others, via the prologue,
* which has yet to be allocated. For now, the first region begins at
* the page boundary.
*/
region.after_prologue = region.start_aligned;
/* init the region struct */
qemu_mutex_init(&region.lock);
/*
* Set guard pages in the rw buffer, as that's the one into which
* buffer overruns could occur. Do not set guard pages in the rx
* buffer -- let that one use hugepages throughout.
* Work with the page protections set up with the initial mapping.
*/
need_prot = PAGE_READ | PAGE_WRITE;
#ifndef CONFIG_TCG_INTERPRETER
if (tcg_splitwx_diff == 0) {
need_prot |= PAGE_EXEC;
}
#endif
for (size_t i = 0, n = region.n; i < n; i++) {
void *start, *end;
tcg_region_bounds(i, &start, &end);
if (have_prot != need_prot) {
int rc;
if (need_prot == (PAGE_READ | PAGE_WRITE | PAGE_EXEC)) {
rc = qemu_mprotect_rwx(start, end - start);
} else if (need_prot == (PAGE_READ | PAGE_WRITE)) {
rc = qemu_mprotect_rw(start, end - start);
} else {
g_assert_not_reached();
}
if (rc) {
error_setg_errno(&error_fatal, errno,
"mprotect of jit buffer");
}
}
if (have_prot != 0) {
/* Guard pages are nice for bug detection but are not essential. */
(void)qemu_mprotect_none(end, page_size);
}
}
tcg_region_trees_init();
/*
* Leave the initial context initialized to the first region.
* This will be the context into which we generate the prologue.
* It is also the only context for CONFIG_USER_ONLY.
*/
tcg_region_initial_alloc__locked(&tcg_init_ctx);
}
void tcg_region_prologue_set(TCGContext *s)
{
/* Deduct the prologue from the first region. */
g_assert(region.start_aligned == s->code_gen_buffer);
region.after_prologue = s->code_ptr;
/* Recompute boundaries of the first region. */
tcg_region_assign(s, 0);
/* Register the balance of the buffer with gdb. */
tcg_register_jit(tcg_splitwx_to_rx(region.after_prologue),
region.start_aligned + region.total_size -
region.after_prologue);
}
/*
* Returns the size (in bytes) of all translated code (i.e. from all regions)
* currently in the cache.
* See also: tcg_code_capacity()
* Do not confuse with tcg_current_code_size(); that one applies to a single
* TCG context.
*/
size_t tcg_code_size(void)
{
unsigned int n_ctxs = qatomic_read(&tcg_cur_ctxs);
unsigned int i;
size_t total;
qemu_mutex_lock(&region.lock);
total = region.agg_size_full;
for (i = 0; i < n_ctxs; i++) {
const TCGContext *s = qatomic_read(&tcg_ctxs[i]);
size_t size;
size = qatomic_read(&s->code_gen_ptr) - s->code_gen_buffer;
g_assert(size <= s->code_gen_buffer_size);
total += size;
}
qemu_mutex_unlock(&region.lock);
return total;
}
/*
* Returns the code capacity (in bytes) of the entire cache, i.e. including all
* regions.
* See also: tcg_code_size()
*/
size_t tcg_code_capacity(void)
{
size_t guard_size, capacity;
/* no need for synchronization; these variables are set at init time */
guard_size = region.stride - region.size;
capacity = region.total_size;
capacity -= (region.n - 1) * guard_size;
capacity -= region.n * TCG_HIGHWATER;
return capacity;
}
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