[Qemu-devel] [PATCH] target-xtensa: fix cross-page jumps/calls at the end of TB

[Qemu-devel] [PATCH] target-xtensa: fix cross-page jumps/calls at the end of TB

[Max Filippov]

Move cross-page jump check to gen_jump_slot and use tb->pc instead of
dc->pc to check for cross-page jumps.
When TB ends at the page boundary dc->pc points to the next page
allowing chaining to TBs in it.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 target-xtensa/translate.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index 764cee9..d93d0a3 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -401,7 +401,7 @@ static void gen_jump_slot(DisasContext *dc, TCGv dest, int slot)
     if (dc->singlestep_enabled) {
         gen_exception(dc, EXCP_DEBUG);
     } else {
-        if (slot >= 0) {
+        if (slot >= 0 && ((dc->tb->pc ^ dest) & TARGET_PAGE_MASK) == 0) {
             tcg_gen_goto_tb(slot);
             tcg_gen_exit_tb((uintptr_t)dc->tb + slot);
         } else {
@@ -419,9 +419,6 @@ static void gen_jump(DisasContext *dc, TCGv dest)
 static void gen_jumpi(DisasContext *dc, uint32_t dest, int slot)
 {
     TCGv_i32 tmp = tcg_const_i32(dest);
-    if (((dc->pc ^ dest) & TARGET_PAGE_MASK) != 0) {
-        slot = -1;
-    }
     gen_jump_slot(dc, tmp, slot);
     tcg_temp_free(tmp);
 }
@@ -447,9 +444,6 @@ static void gen_callw(DisasContext *dc, int callinc, TCGv_i32 dest)
 static void gen_callwi(DisasContext *dc, int callinc, uint32_t dest, int slot)
 {
     TCGv_i32 tmp = tcg_const_i32(dest);
-    if (((dc->pc ^ dest) & TARGET_PAGE_MASK) != 0) {
-        slot = -1;
-    }
     gen_callw_slot(dc, callinc, tmp, slot);
     tcg_temp_free(tmp);
 }
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH] target-xtensa: fix cross-page jumps/calls at the end of TB

[Max Filippov]

On Tue, May 20, 2014 at 3:17 PM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> Move cross-page jump check to gen_jump_slot and use tb->pc instead of
> dc->pc to check for cross-page jumps.
> When TB ends at the page boundary dc->pc points to the next page
> allowing chaining to TBs in it.
>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  target-xtensa/translate.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
> index 764cee9..d93d0a3 100644
> --- a/target-xtensa/translate.c
> +++ b/target-xtensa/translate.c
> @@ -401,7 +401,7 @@ static void gen_jump_slot(DisasContext *dc, TCGv dest, int slot)
>      if (dc->singlestep_enabled) {
>          gen_exception(dc, EXCP_DEBUG);
>      } else {
> -        if (slot >= 0) {
> +        if (slot >= 0 && ((dc->tb->pc ^ dest) & TARGET_PAGE_MASK) == 0) {

Ugh, complete nonsense, please ignore. ):

-- 
Thanks.
-- Max