From 1e05197f24c49d52f339de9053bb1d17082f1be3 Mon Sep 17 00:00:00 2001 From: "Emilio G. Cota" Date: Thu, 3 Aug 2017 18:37:15 -0400 Subject: [PATCH] translate-all: iterate over TBs in a page with PAGE_FOR_EACH_TB 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 Signed-off-by: Emilio G. Cota Signed-off-by: Richard Henderson --- accel/tcg/translate-all.c | 62 ++++++++++++++++++--------------------- include/exec/exec-all.h | 2 +- 2 files changed, 30 insertions(+), 34 deletions(-) diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index a9f2bfb468..52e62125ed 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -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. */ diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index 8d4306ac25..07653d3c92 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -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 -- GitLab