thermosphere: add proper memory/instruction barriers for breakpoint stuff

thermosphere/src/breakpoints.c

@@ -49,6 +49,7 @@ static void commitAndBroadcastBreakpointHandler(void *p)
 
 static inline void commitAndBroadcastBreakpoints(void)
 {
+    __dmb_sy();
     executeFunctionOnAllCores(commitAndBroadcastBreakpointHandler, NULL, true);
 }
 
@@ -157,4 +158,4 @@ int removeAllBreakpoints(void)
     recursiveSpinlockUnlock(&g_breakpointManager.lock);
 
     return 0;
-}
+}

thermosphere/src/breakpoints_watchpoints_load.s

@@ -23,6 +23,8 @@
 .cfi_startproc
 loadBreakpointRegs:
     // x1 = number
+    dmb     sy
+
     adr     x16, 1f
     add     x0, x0, #(16 * 8)
     mov     x4, #(16 * 12)
@@ -51,6 +53,8 @@ loadBreakpointRegs:
 .cfi_startproc
 loadWatchpointRegs:
     // x1 = number
+    dmb     sy
+
     adr     x16, 1f
     add     x0, x0, #(16 * 8)
     mov     x4, #(16 * 12)

thermosphere/src/single_step.c

@@ -56,6 +56,7 @@ void singleStepSetNextState(ExceptionStackFrame *frame, SingleStepState state)
     }
 
     SET_SYSREG(mdscr_el1, mdscr);
+    __isb(); // TRM-mandated
 }
 
 void handleSingleStep(ExceptionStackFrame *frame, ExceptionSyndromeRegister esr)

thermosphere/src/software_breakpoints.c

@@ -74,12 +74,14 @@ static inline bool doApplySoftwareBreakpoint(size_t id)
 static void applySoftwareBreakpointHandler(void *p)
 {
     u64 flags = maskIrq();
+    __dmb_sy();
     doApplySoftwareBreakpoint(*(size_t *)p);
     restoreInterruptFlags(flags);
 }
 
 static void applySoftwareBreakpoint(size_t id)
 {
+    __dmb_sy();
     executeFunctionOnAllCores(applySoftwareBreakpointHandler, &id, true);
 }
 
@@ -101,12 +103,14 @@ static inline bool doRevertSoftwareBreakpoint(size_t id)
 static void revertSoftwareBreakpointHandler(void *p)
 {
     u64 flags = maskIrq();
+    __dmb_sy();
     doRevertSoftwareBreakpoint(*(size_t *)p);
     restoreInterruptFlags(flags);
 }
 
 static void revertSoftwareBreakpoint(size_t id)
 {
+    __dmb_sy();
     executeFunctionOnAllCores(revertSoftwareBreakpointHandler, &id, true);
 }
 
@@ -223,4 +227,4 @@ int removeAllSoftwareBreakpoints(bool keepPersistent)
     recursiveSpinlockUnlock(&g_softwareBreakpointManager.lock);
 
     return ret;
-}
+}

thermosphere/src/utils.h

@@ -56,6 +56,11 @@ static inline u##sz __##op##sz(u##sz n)\
 _DECLARE_ASM_ARITHMETIC_UNARY_HELPER64(rbit)
 _DECLARE_ASM_ARITHMETIC_UNARY_HELPER32(rbit)
 
+static inline void __dmb_sy(void)
+{
+    __asm__ __volatile__ ("dmb sy" ::: "memory");
+}
+
 static inline void __dsb_sy(void)
 {
     __asm__ __volatile__ ("dsb sy" ::: "memory");

thermosphere/src/watchpoints.c

@@ -56,6 +56,7 @@ static void commitAndBroadcastWatchpointHandler(void *p)
 
 static inline void commitAndBroadcastWatchpoints(void)
 {
+    __dmb_sy();
     executeFunctionOnAllCores(commitAndBroadcastWatchpointHandler, NULL, true);
 }
 
@@ -331,4 +332,4 @@ int removeAllWatchpoints(void)
     recursiveSpinlockUnlock(&g_watchpointManager.lock);
 
     return 0;
-}
+}