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From: Richard Henderson <rth@twiddle.net>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, Sergey Fedorov <serge.fdrv@gmail.com>,
	Sergey Fedorov <sergey.fedorov@linaro.org>
Subject: [Qemu-devel] [PULL 17/39] tcg: Use uintptr_t type for jmp_list_{next|first} fields of TB
Date: Thu, 12 May 2016 14:13:18 -1000	[thread overview]
Message-ID: <1463098420-29113-18-git-send-email-rth@twiddle.net> (raw)
In-Reply-To: <1463098420-29113-1-git-send-email-rth@twiddle.net>

From: Sergey Fedorov <serge.fdrv@gmail.com>

These fields do not contain pure pointers to a TranslationBlock
structure. So uintptr_t is the most appropriate type for them.
Also put some asserts to assure that the two least significant bits of
the pointer are always zero before assigning it to jmp_list_first.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 include/exec/exec-all.h | 12 +++++++-----
 translate-all.c         | 38 ++++++++++++++++++++------------------
 2 files changed, 27 insertions(+), 23 deletions(-)

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 445d946..64c2a66 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -277,14 +277,16 @@ struct TranslationBlock {
      * jmp_list_first points to the first TB jumping to this one.
      * jmp_list_next is used to point to the next TB in a list.
      * Since each TB can have two jumps, it can participate in two lists.
-     * The two least significant bits of a pointer are used to choose which
-     * data field holds a pointer to the next TB:
+     * jmp_list_first and jmp_list_next are 4-byte aligned pointers to a
+     * TranslationBlock structure, but the two least significant bits of
+     * them are used to encode which data field of the pointed TB should
+     * be used to traverse the list further from that TB:
      * 0 => jmp_list_next[0], 1 => jmp_list_next[1], 2 => jmp_list_first.
      * In other words, 0/1 tells which jump is used in the pointed TB,
      * and 2 means that this is a pointer back to the target TB of this list.
      */
-    struct TranslationBlock *jmp_list_next[2];
-    struct TranslationBlock *jmp_list_first;
+    uintptr_t jmp_list_next[2];
+    uintptr_t jmp_list_first;
 };
 
 #include "qemu/thread.h"
@@ -382,7 +384,7 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
 
         /* add in TB jmp circular list */
         tb->jmp_list_next[n] = tb_next->jmp_list_first;
-        tb_next->jmp_list_first = (TranslationBlock *)((uintptr_t)tb | n);
+        tb_next->jmp_list_first = (uintptr_t)tb | n;
     }
 }
 
diff --git a/translate-all.c b/translate-all.c
index c6613d1..2fb1646 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -928,17 +928,17 @@ static inline void tb_page_remove(TranslationBlock **ptb, TranslationBlock *tb)
 
 static inline void tb_jmp_remove(TranslationBlock *tb, int n)
 {
-    TranslationBlock *tb1, **ptb;
+    TranslationBlock *tb1;
+    uintptr_t *ptb, ntb;
     unsigned int n1;
 
     ptb = &tb->jmp_list_next[n];
-    tb1 = *ptb;
-    if (tb1) {
+    if (*ptb) {
         /* find tb(n) in circular list */
         for (;;) {
-            tb1 = *ptb;
-            n1 = (uintptr_t)tb1 & 3;
-            tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
+            ntb = *ptb;
+            n1 = ntb & 3;
+            tb1 = (TranslationBlock *)(ntb & ~3);
             if (n1 == n && tb1 == tb) {
                 break;
             }
@@ -951,7 +951,7 @@ static inline void tb_jmp_remove(TranslationBlock *tb, int n)
         /* now we can suppress tb(n) from the list */
         *ptb = tb->jmp_list_next[n];
 
-        tb->jmp_list_next[n] = NULL;
+        tb->jmp_list_next[n] = (uintptr_t)NULL;
     }
 }
 
@@ -970,7 +970,7 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
     PageDesc *p;
     unsigned int h, n1;
     tb_page_addr_t phys_pc;
-    TranslationBlock *tb1, *tb2;
+    uintptr_t tb1, tb2;
 
     /* remove the TB from the hash list */
     phys_pc = tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);
@@ -1006,19 +1006,20 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
     /* suppress any remaining jumps to this TB */
     tb1 = tb->jmp_list_first;
     for (;;) {
-        n1 = (uintptr_t)tb1 & 3;
+        TranslationBlock *tmp_tb;
+        n1 = tb1 & 3;
         if (n1 == 2) {
             break;
         }
-        tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
-        tb2 = tb1->jmp_list_next[n1];
-        tb_reset_jump(tb1, n1);
-        tb1->jmp_list_next[n1] = NULL;
+        tmp_tb = (TranslationBlock *)(tb1 & ~3);
+        tb2 = tmp_tb->jmp_list_next[n1];
+        tb_reset_jump(tmp_tb, n1);
+        tmp_tb->jmp_list_next[n1] = (uintptr_t)NULL;
         tb1 = tb2;
     }
 
-    /* fail safe */
-    tb->jmp_list_first = (TranslationBlock *)((uintptr_t)tb | 2);
+    assert(((uintptr_t)tb & 3) == 0);
+    tb->jmp_list_first = (uintptr_t)tb | 2; /* fail safe */
 
     tcg_ctx.tb_ctx.tb_phys_invalidate_count++;
 }
@@ -1492,9 +1493,10 @@ static void tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc,
         tb->page_addr[1] = -1;
     }
 
-    tb->jmp_list_first = (TranslationBlock *)((uintptr_t)tb | 2);
-    tb->jmp_list_next[0] = NULL;
-    tb->jmp_list_next[1] = NULL;
+    assert(((uintptr_t)tb & 3) == 0);
+    tb->jmp_list_first = (uintptr_t)tb | 2;
+    tb->jmp_list_next[0] = (uintptr_t)NULL;
+    tb->jmp_list_next[1] = (uintptr_t)NULL;
 
     /* init original jump addresses */
     if (tb->jmp_reset_offset[0] != TB_JMP_RESET_OFFSET_INVALID) {
-- 
2.5.5

  parent reply	other threads:[~2016-05-13  0:15 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-13  0:13 [Qemu-devel] [PULL 00/39] tcg-next patch queue Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 01/39] tb: consistently use uint32_t for tb->flags Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 02/39] include/qemu/osdep.h: Add a macro to check for alignment Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 03/39] include/qemu/osdep.h: Add macros for pointer alignment Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 04/39] tci: Make direct jump patching thread-safe Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 05/39] tcg/ppc: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 06/39] tcg/i386: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 07/39] tcg/s390: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 08/39] tcg/arm: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 09/39] tcg/aarch64: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 10/39] tcg/sparc: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 11/39] tcg/mips: " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 12/39] tcg: Note requirement on atomic direct jump patching Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 13/39] translate-all: remove redundant setting of tcg_ctx.code_gen_buffer_size Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 14/39] translate-all: add missing munmap of the code_gen guard page for MIPS Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 15/39] translate-all: Adjust 256mb testing for mips64 Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 16/39] tcg: Clean up direct block chaining data fields Richard Henderson
2016-05-13  0:13 ` Richard Henderson [this message]
2016-05-13  0:13 ` [Qemu-devel] [PULL 18/39] tcg: Rearrange tb_link_page() to avoid forward declaration Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 19/39] tcg: Init TB's direct jumps before making it visible Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 20/39] tcg: Clarify thread safety check in tb_add_jump() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 21/39] tcg: Rename tb_jmp_remove() to tb_remove_from_jmp_list() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 22/39] tcg: Extract removing of jumps to TB from tb_phys_invalidate() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 23/39] tcg: Clean up tb_jmp_unlink() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 24/39] tcg: Clean up direct block chaining safety checks Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 25/39] tcg: Allow goto_tb to any target PC in user mode Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 26/39] tcg: code_bitmap and code_write_count are not used by user-mode emulation Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 27/39] tcg: reorganize tb_find_physical loop Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 28/39] cpu-exec: elide more icount code if CONFIG_USER_ONLY Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 29/39] tcg: Clean up from 'next_tb' Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 30/39] tcg: Rework tb_invalidated_flag Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 31/39] cpu-exec: Move TB chaining into tb_find_fast() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 32/39] tcg: Remove needless CPUState::current_tb Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 33/39] cpu-exec: Remove relic orphaned comment Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 34/39] cpu-exec: Move halt handling out of cpu_exec() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 35/39] cpu-exec: Move exception " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 36/39] cpu-exec: Move interrupt " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 37/39] cpu-exec: Move TB execution stuff " Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 38/39] cpu-exec: Remove unused 'x86_cpu' and 'env' from cpu_exec() Richard Henderson
2016-05-13  0:13 ` [Qemu-devel] [PULL 39/39] cpu-exec: Clean up 'interrupt_request' reloading in cpu_handle_interrupt() Richard Henderson
2016-05-13 10:30 ` [Qemu-devel] [PULL 00/39] tcg-next patch queue Peter Maydell

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