From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50936) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqXzG-0004aZ-9j for qemu-devel@nongnu.org; Tue, 27 Feb 2018 00:39:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eqXzC-0000Q6-Kw for qemu-devel@nongnu.org; Tue, 27 Feb 2018 00:39:38 -0500 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:47437) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eqXzC-0000PS-Fk for qemu-devel@nongnu.org; Tue, 27 Feb 2018 00:39:34 -0500 From: "Emilio G. Cota" Date: Tue, 27 Feb 2018 00:39:14 -0500 Message-Id: <1519709965-29833-6-git-send-email-cota@braap.org> In-Reply-To: <1519709965-29833-1-git-send-email-cota@braap.org> References: <1519709965-29833-1-git-send-email-cota@braap.org> Subject: [Qemu-devel] [PATCH 05/16] translate-all: iterate over TBs in a page with PAGE_FOR_EACH_TB List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Richard Henderson , Paolo Bonzini 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. - 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(). Signed-off-by: Emilio G. Cota --- accel/tcg/translate-all.c | 65 +++++++++++++++++++++++------------------------ include/exec/exec-all.h | 2 +- 2 files changed, 33 insertions(+), 34 deletions(-) diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 20ad3fc..06aa905 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 +114,18 @@ 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) @@ -818,7 +830,7 @@ 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 { @@ -946,21 +958,21 @@ 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 */ @@ -1048,12 +1060,12 @@ 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); } @@ -1084,10 +1096,7 @@ 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 @@ -1102,7 +1111,6 @@ 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 @@ -1125,9 +1133,9 @@ 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) @@ -1404,7 +1412,7 @@ 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; @@ -1435,11 +1443,7 @@ 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 @@ -1476,7 +1480,6 @@ 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 */ @@ -1570,18 +1573,15 @@ 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) { @@ -1598,9 +1598,8 @@ 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 17e08b3..5f7e65a 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -356,7 +356,7 @@ 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 -- 2.7.4