[Qemu-devel] [PATCH 18/18] armv7m: prevent unprivileged write to STIR

[Michael Davidsaver]

Prevent unprivileged from writing to the
Software Triggered Interrupt register

Signed-off-by: Michael Davidsaver <address@hidden>
---
 hw/intc/armv7m_nvic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index ca8c93c..b744cd5 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -654,7 +654,9 @@ static void nvic_writel(nvic_state *s, uint32_t offset, 
uint32_t value)
                       "NVIC: fault status registers unimplemented\n");
         break;
     case 0xf00: /* Software Triggered Interrupt Register */
-        if ((value & 0x1ff) < NVIC_MAX_IRQ) {
+        /* STIR write allowed if privlaged or USERSETMPEND set */
+        if ((arm_current_el(&cpu->env) || (cpu->env.v7m.ccr&2))
+            && ((value & 0x1ff) < NVIC_MAX_IRQ)) {
             armv7m_nvic_set_pending(s, (value&0x1ff)+16);
         }
         break;
-- 
2.1.4