[Qemu-devel] [PULL 21/33] target/arm: Define new EXCP type for v8M stack overflows

[Peter Maydell <peter.maydell@linaro.org>]

Define EXCP_STKOF, and arrange for it to cause us to take
a UsageFault with CFSR.STKOF set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20181002163556.10279-3-peter.maydell@linaro.org
---
 target/arm/cpu.h    | 2 ++
 target/arm/helper.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index fde96845034..3a2aff11928 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -56,6 +56,7 @@
 #define EXCP_SEMIHOST       16   /* semihosting call */
 #define EXCP_NOCP           17   /* v7M NOCP UsageFault */
 #define EXCP_INVSTATE       18   /* v7M INVSTATE UsageFault */
+#define EXCP_STKOF          19   /* v8M STKOF UsageFault */
 /* NB: add new EXCP_ defines to the array in arm_log_exception() too */
 
 #define ARMV7M_EXCP_RESET   1
@@ -1388,6 +1389,7 @@ FIELD(V7M_CFSR, UNDEFINSTR, 16 + 0, 1)
 FIELD(V7M_CFSR, INVSTATE, 16 + 1, 1)
 FIELD(V7M_CFSR, INVPC, 16 + 2, 1)
 FIELD(V7M_CFSR, NOCP, 16 + 3, 1)
+FIELD(V7M_CFSR, STKOF, 16 + 4, 1)
 FIELD(V7M_CFSR, UNALIGNED, 16 + 8, 1)
 FIELD(V7M_CFSR, DIVBYZERO, 16 + 9, 1)
 
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 0807173eac9..a9a2173cb2f 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -7539,6 +7539,7 @@ static void arm_log_exception(int idx)
             [EXCP_SEMIHOST] = "Semihosting call",
             [EXCP_NOCP] = "v7M NOCP UsageFault",
             [EXCP_INVSTATE] = "v7M INVSTATE UsageFault",
+            [EXCP_STKOF] = "v8M STKOF UsageFault",
         };
 
         if (idx >= 0 && idx < ARRAY_SIZE(excnames)) {
@@ -7694,6 +7695,10 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure);
         env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVSTATE_MASK;
         break;
+    case EXCP_STKOF:
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure);
+        env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_STKOF_MASK;
+        break;
     case EXCP_SWI:
         /* The PC already points to the next instruction.  */
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC, env->v7m.secure);
-- 
2.19.0