target/arm: Implement v8M stack limit checks

[Qemu-devel] [PATCH 11/13] target/arm: Add v8M stack checks for Thumb push/pop

Posted by Peter Maydell 7 years, 4 months ago

Add v8M stack checks for the 16-bit Thumb push/pop
encodings: STMDB, STMFD, LDM, LDMIA, LDMFD.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/translate.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 65df8d6975c..ef64d2559de 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -12251,7 +12251,10 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
             store_reg(s, rd, tmp);
             break;
         case 4: case 5: case 0xc: case 0xd:
-            /* push/pop */
+            /*
+             * 0b1011_x10x_xxxx_xxxx
+             *  - push/pop
+             */
             addr = load_reg(s, 13);
             if (insn & (1 << 8))
                 offset = 4;
@@ -12264,6 +12267,17 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
             if ((insn & (1 << 11)) == 0) {
                 tcg_gen_addi_i32(addr, addr, -offset);
             }
+
+            if (s->v8m_stackcheck) {
+                /*
+                 * Here 'addr' is the lower of "old SP" and "new SP";
+                 * if this is a pop that starts below the limit and ends
+                 * above it, it is UNKNOWN whether the limit check triggers;
+                 * we choose to trigger.
+                 */
+                gen_helper_v8m_stackcheck(cpu_env, addr);
+            }
+
             for (i = 0; i < 8; i++) {
                 if (insn & (1 << i)) {
                     if (insn & (1 << 11)) {
-- 
2.19.0

Re: [Qemu-devel] [PATCH 11/13] target/arm: Add v8M stack checks for Thumb push/pop

Posted by Philippe Mathieu-Daudé 7 years, 4 months ago

On 02/10/2018 18:35, Peter Maydell wrote:
> Add v8M stack checks for the 16-bit Thumb push/pop
> encodings: STMDB, STMFD, LDM, LDMIA, LDMFD.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  target/arm/translate.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 65df8d6975c..ef64d2559de 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -12251,7 +12251,10 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
>              store_reg(s, rd, tmp);
>              break;
>          case 4: case 5: case 0xc: case 0xd:
> -            /* push/pop */
> +            /*
> +             * 0b1011_x10x_xxxx_xxxx
> +             *  - push/pop
> +             */
>              addr = load_reg(s, 13);
>              if (insn & (1 << 8))
>                  offset = 4;
> @@ -12264,6 +12267,17 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
>              if ((insn & (1 << 11)) == 0) {
>                  tcg_gen_addi_i32(addr, addr, -offset);
>              }
> +
> +            if (s->v8m_stackcheck) {
> +                /*
> +                 * Here 'addr' is the lower of "old SP" and "new SP";
> +                 * if this is a pop that starts below the limit and ends
> +                 * above it, it is UNKNOWN whether the limit check triggers;
> +                 * we choose to trigger.
> +                 */
> +                gen_helper_v8m_stackcheck(cpu_env, addr);
> +            }
> +
>              for (i = 0; i < 8; i++) {
>                  if (insn & (1 << i)) {
>                      if (insn & (1 << 11)) {
>

Re: [Qemu-devel] [PATCH 11/13] target/arm: Add v8M stack checks for Thumb push/pop

Posted by Richard Henderson 7 years, 4 months ago

On 10/2/18 11:35 AM, Peter Maydell wrote:
> Add v8M stack checks for the 16-bit Thumb push/pop
> encodings: STMDB, STMFD, LDM, LDMIA, LDMFD.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  target/arm/translate.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~