mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

translate-all: iterate over TBs in a page with PAGE_FOR_EACH_TB

Browse Source 
This commit does several things, but to avoid churn I merged them all
into the same commit. To wit:

- Use uintptr_t instead of TranslationBlock * for the list of TBs in a page.
  Just like we did in (c37e6d7e "tcg: Use uintptr_t type for
  jmp_list_{next|first} fields of TB"), the rationale is the same: these
  are tagged pointers, not pointers. So use a more appropriate type.

- Only check the least significant bit of the tagged pointers. Masking
  with 3/~3 is unnecessary and confusing.

- Introduce the TB_FOR_EACH_TAGGED macro, and use it to define
  PAGE_FOR_EACH_TB, which improves readability. Note that
  TB_FOR_EACH_TAGGED will gain another user in a subsequent patch.

- Update tb_page_remove to use PAGE_FOR_EACH_TB. In case there
  is a bug and we attempt to remove a TB that is not in the list, instead
  of segfaulting (since the list is NULL-terminated) we will reach
  g_assert_not_reached().

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Emilio G. Cota 2017-08-03 18:37:15 -04:00 committed by Richard Henderson
parent 128ed2278c
commit 1e05197f24
2 changed files with 30 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
accel/tcg/translate-all.c
View File

@ -103,7 +103,7 @@
typedef struct PageDesc {
/* list of TBs intersecting this ram page */
TranslationBlock *first_tb;
uintptr_t first_tb;
#ifdef CONFIG_SOFTMMU
/* in order to optimize self modifying code, we count the number
of lookups we do to a given page to use a bitmap */
@ -114,6 +114,15 @@ typedef struct PageDesc {
#endif
} PageDesc;
/* list iterators for lists of tagged pointers in TranslationBlock */
#define TB_FOR_EACH_TAGGED(head, tb, n, field) \
for (n = (head) & 1, tb = (TranslationBlock *)((head) & ~1); \
tb; tb = (TranslationBlock *)tb->field[n], n = (uintptr_t)tb & 1, \
tb = (TranslationBlock *)((uintptr_t)tb & ~1))
#define PAGE_FOR_EACH_TB(pagedesc, tb, n) \
TB_FOR_EACH_TAGGED((pagedesc)->first_tb, tb, n, page_next)
/* In system mode we want L1_MAP to be based on ram offsets,
while in user mode we want it to be based on virtual addresses. */
#if !defined(CONFIG_USER_ONLY)
@ -815,7 +824,7 @@ static void page_flush_tb_1(int level, void **lp)
PageDesc *pd = *lp;
for (i = 0; i < V_L2_SIZE; ++i) {
pd[i].first_tb = NULL;
pd[i].first_tb = (uintptr_t)NULL;
invalidate_page_bitmap(pd + i);
}
} else {
@ -943,21 +952,21 @@ static void tb_page_check(void)
#endif /* CONFIG_USER_ONLY */
static inline void tb_page_remove(TranslationBlock **ptb, TranslationBlock *tb)
static inline void tb_page_remove(PageDesc *pd, TranslationBlock *tb)
{
TranslationBlock *tb1;
uintptr_t *pprev;
unsigned int n1;
for (;;) {
tb1 = *ptb;
n1 = (uintptr_t)tb1 & 3;
tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
pprev = &pd->first_tb;
PAGE_FOR_EACH_TB(pd, tb1, n1) {
if (tb1 == tb) {
*ptb = tb1->page_next[n1];
break;
*pprev = tb1->page_next[n1];
return;
}
ptb = &tb1->page_next[n1];
pprev = &tb1->page_next[n1];
}
g_assert_not_reached();
}
/* remove the TB from a list of TBs jumping to the n-th jump target of the TB */
@ -1045,12 +1054,12 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
/* remove the TB from the page list */
if (tb->page_addr[0] != page_addr) {
p = page_find(tb->page_addr[0] >> TARGET_PAGE_BITS);
tb_page_remove(&p->first_tb, tb);
tb_page_remove(p, tb);
invalidate_page_bitmap(p);
}
if (tb->page_addr[1] != -1 && tb->page_addr[1] != page_addr) {
p = page_find(tb->page_addr[1] >> TARGET_PAGE_BITS);
tb_page_remove(&p->first_tb, tb);
tb_page_remove(p, tb);
invalidate_page_bitmap(p);
}
@ -1081,10 +1090,7 @@ static void build_page_bitmap(PageDesc *p)
p->code_bitmap = bitmap_new(TARGET_PAGE_SIZE);
tb = p->first_tb;
while (tb != NULL) {
n = (uintptr_t)tb & 3;
tb = (TranslationBlock *)((uintptr_t)tb & ~3);
PAGE_FOR_EACH_TB(p, tb, n) {
/* NOTE: this is subtle as a TB may span two physical pages */
if (n == 0) {
/* NOTE: tb_end may be after the end of the page, but
@ -1099,7 +1105,6 @@ static void build_page_bitmap(PageDesc *p)
tb_end = ((tb->pc + tb->size) & ~TARGET_PAGE_MASK);
}
bitmap_set(p->code_bitmap, tb_start, tb_end - tb_start);
tb = tb->page_next[n];
}
}
#endif
@ -1122,9 +1127,9 @@ static inline void tb_alloc_page(TranslationBlock *tb,
p = page_find_alloc(page_addr >> TARGET_PAGE_BITS, 1);
tb->page_next[n] = p->first_tb;
#ifndef CONFIG_USER_ONLY
page_already_protected = p->first_tb != NULL;
page_already_protected = p->first_tb != (uintptr_t)NULL;
#endif
p->first_tb = (TranslationBlock *)((uintptr_t)tb | n);
p->first_tb = (uintptr_t)tb | n;
invalidate_page_bitmap(p);
#if defined(CONFIG_USER_ONLY)
@ -1401,7 +1406,7 @@ void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end)
void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
int is_cpu_write_access)
{
TranslationBlock *tb, *tb_next;
TranslationBlock *tb;
tb_page_addr_t tb_start, tb_end;
PageDesc *p;
int n;
@ -1432,11 +1437,7 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
/* we remove all the TBs in the range [start, end[ */
/* XXX: see if in some cases it could be faster to invalidate all
the code */
tb = p->first_tb;
while (tb != NULL) {
n = (uintptr_t)tb & 3;
tb = (TranslationBlock *)((uintptr_t)tb & ~3);
tb_next = tb->page_next[n];
PAGE_FOR_EACH_TB(p, tb, n) {
/* NOTE: this is subtle as a TB may span two physical pages */
if (n == 0) {
/* NOTE: tb_end may be after the end of the page, but
@ -1474,7 +1475,6 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
#endif /* TARGET_HAS_PRECISE_SMC */
tb_phys_invalidate(tb, -1);
}
tb = tb_next;
}
#if !defined(CONFIG_USER_ONLY)
/* if no code remaining, no need to continue to use slow writes */
@ -1568,18 +1568,15 @@ static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc)
}
tb_lock();
tb = p->first_tb;
#ifdef TARGET_HAS_PRECISE_SMC
if (tb && pc != 0) {
if (p->first_tb && pc != 0) {
current_tb = tcg_tb_lookup(pc);
}
if (cpu != NULL) {
env = cpu->env_ptr;
}
#endif
while (tb != NULL) {
n = (uintptr_t)tb & 3;
tb = (TranslationBlock *)((uintptr_t)tb & ~3);
PAGE_FOR_EACH_TB(p, tb, n) {
#ifdef TARGET_HAS_PRECISE_SMC
if (current_tb == tb &&
(current_tb->cflags & CF_COUNT_MASK) != 1) {
@ -1596,9 +1593,8 @@ static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc)
}
#endif /* TARGET_HAS_PRECISE_SMC */
tb_phys_invalidate(tb, addr);
tb = tb->page_next[n];
}
p->first_tb = NULL;
p->first_tb = (uintptr_t)NULL;
#ifdef TARGET_HAS_PRECISE_SMC
if (current_tb_modified) {
/* Force execution of one insn next time. */

2
include/exec/exec-all.h
View File

@ -360,7 +360,7 @@ struct TranslationBlock {
struct TranslationBlock *orig_tb;
/* first and second physical page containing code. The lower bit
of the pointer tells the index in page_next[] */
struct TranslationBlock *page_next[2];
uintptr_t page_next[2];
tb_page_addr_t page_addr[2];
/* The following data are used to directly call another TB from