core/embed: enable/disable SDIO/DMA interrupts via supervisor calls

core/embed/firmware/main.c

@@ -40,6 +40,7 @@
 #include "mpu.h"
 #include "rng.h"
 #include "sdcard.h"
+#include "supervise.h"
 #include "touch.h"
 
 int main(void) {
@@ -113,6 +114,36 @@ void __attribute__((noreturn)) nlr_jump_fail(void *val) {
 
 void PendSV_Handler(void) { pendsv_isr_handler(); }
 
+void SVC_C_Handler(uint32_t *stack) {
+  uint8_t svc_number = ((uint8_t *)stack[6])[-2];
+  switch (svc_number) {
+    case SVC_ENABLE_IRQ:
+      HAL_NVIC_EnableIRQ(stack[0]);
+      break;
+    case SVC_DISABLE_IRQ:
+      HAL_NVIC_DisableIRQ(stack[0]);
+      break;
+    case SVC_SET_PRIORITY:
+      NVIC_SetPriority(stack[0], stack[1]);
+      break;
+    default:
+      stack[0] = 0xffffffff;
+      break;
+  }
+}
+
+__attribute__((naked)) void SVC_Handler(void) {
+  __asm volatile(
+      " tst lr, #4    \n"    // Test Bit 3 to see which stack pointer we should
+                             // use.
+      " ite eq        \n"    // Tell the assembler that the nest 2 instructions
+                             // are if-then-else
+      " mrseq r0, msp \n"    // Make R0 point to main stack pointer
+      " mrsne r0, psp \n"    // Make R0 point to process stack pointer
+      " b SVC_C_Handler \n"  // Off to C land
+  );
+}
+
 // MicroPython builtin stubs
 
 mp_import_stat_t mp_import_stat(const char *path) {

core/embed/firmware/supervise.h

@@ -0,0 +1,22 @@
+// supervisor call functions
+
+#define SVC_ENABLE_IRQ 0
+#define SVC_DISABLE_IRQ 1
+#define SVC_SET_PRIORITY 2
+
+inline void svc_enableIRQ(uint32_t IRQn) {
+  register uint32_t r0 __asm__("r0") = IRQn;
+  __asm__ __volatile__("svc %0" ::"i"(SVC_ENABLE_IRQ), "r"(r0) : "memory");
+}
+
+inline void svc_disableIRQ(uint32_t IRQn) {
+  register uint32_t r0 __asm__("r0") = IRQn;
+  __asm__ __volatile__("svc %0" ::"i"(SVC_DISABLE_IRQ), "r"(r0) : "memory");
+}
+
+inline void svc_setpriority(uint32_t IRQn, uint32_t priority) {
+  register uint32_t r0 __asm__("r0") = IRQn;
+  register uint32_t r1 __asm__("r1") = priority;
+  __asm__ __volatile__("svc %0" ::"i"(SVC_SET_PRIORITY), "r"(r0), "r"(r1)
+                       : "memory");
+}

core/embed/trezorhal/dma.c

@@ -33,6 +33,7 @@
 #include "dma.h"
 #include "irq.h"
 #include "systick.h"
+#include "supervise.h"
 
 #define DMA_IDLE_ENABLED()  (dma_idle.enabled != 0)
 #define DMA_SYSTICK_LOG2    (3)
@@ -233,7 +234,7 @@ void dma_init(DMA_HandleTypeDef *dma, const dma_descr_t *dma_descr, uint32_t dir
             // (dma->State is set to HAL_DMA_STATE_RESET by memset above)
             HAL_DMA_DeInit(dma);
             HAL_DMA_Init(dma);
-            NVIC_SetPriority(IRQn_NONNEG(dma_irqn[dma_id]), IRQ_PRI_DMA);
+            svc_setpriority(IRQn_NONNEG(dma_irqn[dma_id]), IRQ_PRI_DMA);
         } else {
             // only necessary initialization
             dma->State = HAL_DMA_STATE_READY;
@@ -242,13 +243,13 @@ void dma_init(DMA_HandleTypeDef *dma, const dma_descr_t *dma_descr, uint32_t dir
             DMA_CalcBaseAndBitshift(dma);
         }
 
-        HAL_NVIC_EnableIRQ(dma_irqn[dma_id]);
+        svc_enableIRQ(dma_irqn[dma_id]);
     }
 }
 
 void dma_deinit(const dma_descr_t *dma_descr) {
     if (dma_descr != NULL) {
-        HAL_NVIC_DisableIRQ(dma_irqn[dma_descr->id]);
+        svc_disableIRQ(dma_irqn[dma_descr->id]);
         dma_handle[dma_descr->id] = NULL;
 
         dma_disable_clock(dma_descr->id);

core/embed/trezorhal/sdcard.c

@@ -52,6 +52,7 @@
 #include "irq.h"
 #include "sdcard-set_clr_card_detect.h"
 #include "sdcard.h"
+#include "supervise.h"
 
 #define SDMMC_CLK_ENABLE() __HAL_RCC_SDMMC1_CLK_ENABLE()
 #define SDMMC_CLK_DISABLE() __HAL_RCC_SDMMC1_CLK_DISABLE()
@@ -122,8 +123,8 @@ void HAL_SD_MspInit(SD_HandleTypeDef *hsd) {
     SDMMC_CLK_ENABLE();
 
     // NVIC configuration for SDIO interrupts
-    NVIC_SetPriority(SDMMC_IRQn, IRQ_PRI_SDIO);
-    HAL_NVIC_EnableIRQ(SDMMC_IRQn);
+    svc_setpriority(SDMMC_IRQn, IRQ_PRI_SDIO);
+    svc_enableIRQ(SDMMC_IRQn);
   }
 
   // GPIO have already been initialised by sdcard_init
@@ -131,7 +132,7 @@ void HAL_SD_MspInit(SD_HandleTypeDef *hsd) {
 
 void HAL_SD_MspDeInit(SD_HandleTypeDef *hsd) {
   if (hsd->Instance == sd_handle.Instance) {
-    HAL_NVIC_DisableIRQ(SDMMC_IRQn);
+    svc_disableIRQ(SDMMC_IRQn);
     SDMMC_CLK_DISABLE();
   }
 }