base-foc: enable CPU state modification

With this patch, the register contents of a paused thread (which is not
currently executing a syscall) can get modified by the
'Cpu_session::state()' function.

Fixes #896.

base-foc/include/base/ipc_pager.h

@@ -156,6 +156,11 @@ namespace Genode {
 			 */
 			void acknowledge_wakeup();
 
+			/**
+			 * Reply to an exception IPC
+			 */
+			void acknowledge_exception();
+
 			/**
 			 * Return thread ID of last faulter
 			 */
@@ -183,9 +188,15 @@ namespace Genode {
 
 			/**
 			 * Copy the exception registers from the last exception
-			 * to the given thread_state object.
+			 * to the given Thread_state object.
 			 */
-			void copy_regs(Thread_state *state);
+			void get_regs(Thread_state *state);
+
+			/*
+			 * Copy the exception reply registers from the given
+			 * Thread_state object
+			 */
+			void set_regs(Thread_state state);
 	};
 }
 

base-foc/src/base/ipc/arm/pager.cc

@@ -17,23 +17,46 @@
 #include <base/ipc_pager.h>
 
 
-void Genode::Ipc_pager::copy_regs(Thread_state *state)
+void Genode::Ipc_pager::get_regs(Thread_state *state)
 {
-	state->ip = _regs.pc;
+	state->ip   = _regs.pc;
-	state->sp = _regs.sp;
+	state->sp   = _regs.sp;
-	state->r0  = _regs.r[0];
+	state->r0   = _regs.r[0];
-	state->r1  = _regs.r[1];
+	state->r1   = _regs.r[1];
-	state->r2  = _regs.r[2];
+	state->r2   = _regs.r[2];
-	state->r3  = _regs.r[3];
+	state->r3   = _regs.r[3];
-	state->r4  = _regs.r[4];
+	state->r4   = _regs.r[4];
-	state->r5  = _regs.r[5];
+	state->r5   = _regs.r[5];
-	state->r6  = _regs.r[6];
+	state->r6   = _regs.r[6];
-	state->r7  = _regs.r[7];
+	state->r7   = _regs.r[7];
-	state->r8  = _regs.r[8];
+	state->r8   = _regs.r[8];
-	state->r9  = _regs.r[9];
+	state->r9   = _regs.r[9];
-	state->r10 = _regs.r[10];
+	state->r10  = _regs.r[10];
-	state->r11 = _regs.r[11];
+	state->r11  = _regs.r[11];
-	state->r12 = _regs.r[12];
+	state->r12  = _regs.r[12];
-	state->lr = _regs.ulr;
+	state->lr   = _regs.ulr;
 	state->cpsr = _regs.cpsr;
 }
+
+
+void Genode::Ipc_pager::set_regs(Thread_state state)
+{
+	_regs.pc    = state.ip;
+	_regs.sp    = state.sp;
+	_regs.r[0]  = state.r0;
+	_regs.r[1]  = state.r1;
+	_regs.r[2]  = state.r2;
+	_regs.r[3]  = state.r3;
+	_regs.r[4]  = state.r4;
+	_regs.r[5]  = state.r5;
+	_regs.r[6]  = state.r6;
+	_regs.r[7]  = state.r7;
+	_regs.r[8]  = state.r8;
+	_regs.r[9]  = state.r9;
+	_regs.r[10] = state.r10;
+	_regs.r[11] = state.r11;
+	_regs.r[12] = state.r12;
+	_regs.ulr   = state.lr;
+	_regs.cpsr  = state.cpsr;
+}
+

base-foc/src/base/ipc/pager.cc

@@ -112,6 +112,14 @@ void Ipc_pager::acknowledge_wakeup()
 }
 
 
+void Ipc_pager::acknowledge_exception()
+{
+	memcpy(l4_utcb_exc(), &_regs, sizeof(l4_exc_regs_t));
+	l4_cap_idx_t dst = Fiasco::Capability::valid(_last) ? _last : L4_SYSF_REPLY;
+	l4_ipc_send(dst, l4_utcb(), l4_msgtag(0, L4_UTCB_EXCEPTION_REGS_SIZE, 0, 0), L4_IPC_SEND_TIMEOUT_0);
+}
+
+
 Ipc_pager::Ipc_pager()
 : Native_capability((Cap_index*)Fiasco::l4_utcb_tcr()->user[Fiasco::UTCB_TCR_BADGE]),
   _badge(0) { }

base-foc/src/base/ipc/x86_32/pager.cc

@@ -17,7 +17,7 @@
 #include <base/ipc_pager.h>
 
 
-void Genode::Ipc_pager::copy_regs(Thread_state *state)
+void Genode::Ipc_pager::get_regs(Genode::Thread_state *state)
 {
 	state->ip     = _regs.ip;
 	state->sp     = _regs.sp;
@@ -33,3 +33,22 @@ void Genode::Ipc_pager::copy_regs(Thread_state *state)
 	state->eflags = _regs.flags;
 	state->trapno = _regs.trapno;
 }
+
+
+void Genode::Ipc_pager::set_regs(Genode::Thread_state state)
+{
+	_regs.ip     = state.ip;
+	_regs.sp     = state.sp;
+	_regs.edi    = state.edi;
+	_regs.esi    = state.esi;
+	_regs.ebp    = state.ebp;
+	_regs.ebx    = state.ebx;
+	_regs.edx    = state.edx;
+	_regs.ecx    = state.ecx;
+	_regs.eax    = state.eax;
+	_regs.gs     = state.gs;
+	_regs.fs     = state.fs;
+	_regs.flags  = state.eflags;
+	_regs.trapno = state.trapno;
+}
+

base-foc/src/base/ipc/x86_64/pager.cc

@@ -17,7 +17,7 @@
 #include <base/ipc_pager.h>
 
 
-void Genode::Ipc_pager::copy_regs(Thread_state *state)
+void Genode::Ipc_pager::get_regs(Thread_state *state)
 {
 	state->ip     = _regs.ip;
 	state->sp     = _regs.sp;
@@ -40,3 +40,29 @@ void Genode::Ipc_pager::copy_regs(Thread_state *state)
 	state->eflags = _regs.flags;
 	state->trapno = _regs.trapno;
 }
+
+
+void Genode::Ipc_pager::set_regs(Thread_state state)
+{
+	_regs.ip     = state.ip;
+	_regs.sp     = state.sp;
+	_regs.r8     = state.r8;
+	_regs.r9     = state.r9;
+	_regs.r10    = state.r10;
+	_regs.r11    = state.r11;
+	_regs.r12    = state.r12;
+	_regs.r13    = state.r13;
+	_regs.r14    = state.r14;
+	_regs.r15    = state.r15;
+	_regs.rax    = state.rax;
+	_regs.rbx    = state.rbx;
+	_regs.rcx    = state.rcx;
+	_regs.rdx    = state.rdx;
+	_regs.rdi    = state.rdi;
+	_regs.rsi    = state.rsi;
+	_regs.rbp    = state.rbp;
+	_regs.ss     = state.ss;
+	_regs.flags  = state.eflags;
+	_regs.trapno = state.trapno;
+}
+

base-foc/src/base/pager/pager.cc

@@ -71,7 +71,7 @@ void Pager_activation_base::entry()
 			{
 				if (pager.is_exception()) {
 					Lock::Guard guard(obj->state.lock);
-					pager.copy_regs(&obj->state);
+					pager.get_regs(&obj->state);
 					obj->state.exceptions++;
 					obj->state.in_exception = true;
 					obj->submit_exception_signal();
@@ -105,15 +105,17 @@ void Pager_activation_base::entry()
 				pager.set_reply_dst(Native_thread());
 				pager.acknowledge_wakeup();
 
-				/* revert exception flag */
 				{
 					Lock::Guard guard(obj->state.lock);
+					/* revert exception flag */
 					obj->state.in_exception = false;
+					/* set new register contents */
+					pager.set_regs(obj->state);
 				}
 
 				/* send wake up message to requested thread */
 				pager.set_reply_dst(obj->badge());
-				pager.acknowledge_wakeup();
+				pager.acknowledge_exception();
 				break;
 			}
 
@@ -124,8 +126,7 @@ void Pager_activation_base::entry()
 		case Ipc_pager::PAUSE:
 			{
 				Lock::Guard guard(obj->state.lock);
-				pager.copy_regs(&obj->state);
+				pager.get_regs(&obj->state);
-
 				obj->state.exceptions++;
 				obj->state.in_exception = true;
 

base-foc/src/core/platform_thread.cc

@@ -174,8 +174,8 @@ void Platform_thread::pager(Pager_object *pager_obj)
 
 void Platform_thread::state(Thread_state s)
 {
-	PDBG("Not implemented");
+	if (_pager_obj)
-	throw Cpu_session::State_access_failed();
+		_pager_obj->state = s;
 }