Re: [Qemu-devel] [PATCH 01/10] target/riscv: avoid integer overflow in next_page PC check

[Michael Clark]

On Wed, Apr 11, 2018 at 4:19 AM, Emilio G. Cota  wrote:

> If the PC is in the last page of the address space, next_page_start
> overflows to 0. Fix it.
>
> Reported-by: Richard Henderson 
> Suggested-by: Richard Henderson 
> Cc: Michael Clark 
> Cc: Palmer Dabbelt 
> Cc: Sagar Karandikar 
> Cc: Bastian Koppelmann 
> Signed-off-by: Emilio G. Cota 
>

Reviewed-by: Michael Clark 


> ---
>  target/riscv/translate.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 808eab7..d2d2e5e 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -1849,11 +1849,11 @@ void gen_intermediate_code(CPUState *cs,
> TranslationBlock *tb)
>  CPURISCVState *env = cs->env_ptr;
>  DisasContext ctx;
>  target_ulong pc_start;
> -target_ulong next_page_start;
> +target_ulong page_start;
>  int num_insns;
>  int max_insns;
>  pc_start = tb->pc;
> -next_page_start = (pc_start & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
> +page_start = pc_start & TARGET_PAGE_MASK;
>  ctx.pc = pc_start;
>
>  /* once we have GDB, the rest of the translate.c implementation
> should be
> @@ -1903,7 +1903,7 @@ void gen_intermediate_code(CPUState *cs,
> TranslationBlock *tb)
>  if (cs->singlestep_enabled) {
>  break;
>  }
> -if (ctx.pc >= next_page_start) {
> +if (ctx.pc - page_start >= TARGET_PAGE_SIZE) {
>  break;
>  }
>  if (tcg_op_buf_full()) {
> --
> 2.7.4
>
>

Re: [Qemu-devel] [PATCH 01/10] target/riscv: avoid integer overflow in next_page PC check

[Bastian Koppelmann]

On 04/10/2018 06:19 PM, Emilio G. Cota wrote:
> If the PC is in the last page of the address space, next_page_start
> overflows to 0. Fix it.
> 
> Reported-by: Richard Henderson 
> Suggested-by: Richard Henderson 
> Cc: Michael Clark 
> Cc: Palmer Dabbelt 
> Cc: Sagar Karandikar 
> Cc: Bastian Koppelmann 
> Signed-off-by: Emilio G. Cota 
> ---

Acked-by: Bastian Koppelmann 

Cheers,
Bastian

[Qemu-devel] [PATCH 01/10] target/riscv: avoid integer overflow in next_page PC check

[Emilio G. Cota]

If the PC is in the last page of the address space, next_page_start
overflows to 0. Fix it.

Reported-by: Richard Henderson 
Suggested-by: Richard Henderson 
Cc: Michael Clark 
Cc: Palmer Dabbelt 
Cc: Sagar Karandikar 
Cc: Bastian Koppelmann 
Signed-off-by: Emilio G. Cota 
---
 target/riscv/translate.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 808eab7..d2d2e5e 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1849,11 +1849,11 @@ void gen_intermediate_code(CPUState *cs, 
TranslationBlock *tb)
 CPURISCVState *env = cs->env_ptr;
 DisasContext ctx;
 target_ulong pc_start;
-target_ulong next_page_start;
+target_ulong page_start;
 int num_insns;
 int max_insns;
 pc_start = tb->pc;
-next_page_start = (pc_start & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
+page_start = pc_start & TARGET_PAGE_MASK;
 ctx.pc = pc_start;
 
 /* once we have GDB, the rest of the translate.c implementation should be
@@ -1903,7 +1903,7 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock 
*tb)
 if (cs->singlestep_enabled) {
 break;
 }
-if (ctx.pc >= next_page_start) {
+if (ctx.pc - page_start >= TARGET_PAGE_SIZE) {
 break;
 }
 if (tcg_op_buf_full()) {
-- 
2.7.4