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tcg: Manage splitwx in tc_ptr_to_region_tree by hand 

The use in tcg_tb_lookup is given a random pc that comes from the pc
of a signal handler.  Do not assert that the pointer is already within
the code gen buffer at all, much less the writable mirror of it.

Fixes: db0c51a380
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
master
Richard Henderson 2021-01-27 21:47:05 -10:00
parent db6b7d0c69
commit 0610067ec0
1 changed files with 18 additions and 2 deletions
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20
tcg/tcg.c
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@ -513,11 +513,21 @@ static void tcg_region_trees_init(void)
}
}
static struct tcg_region_tree *tc_ptr_to_region_tree(const void *cp)
static struct tcg_region_tree *tc_ptr_to_region_tree(const void *p)
{
void *p = tcg_splitwx_to_rw(cp);
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 {
@ -536,6 +546,7 @@ 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);
@ -545,6 +556,7 @@ 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);
@ -561,6 +573,10 @@ TranslationBlock *tcg_tb_lookup(uintptr_t 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);