app/idt: refactoring

app/idt/Makefile

@@ -25,7 +25,7 @@ LDFLAGS             += -lsgx-step -lsgx_urts \
                        -lsgx_uae_service -pthread $(SUBDIRS:%=-L %) -L$(SGX_SDK)/lib64/
 
 SOURCES              = $(shell ls *.c)
-OBJECTS              = $(SOURCES:.c=.o) asm.o
+OBJECTS              = $(SOURCES:.c=.o)
 OUTPUT               = app
 
 BUILDDIRS            = $(SUBDIRS:%=build-%)

app/idt/main.c

@@ -25,74 +25,112 @@
 #include "libsgxstep/sched.h"
 #include "libsgxstep/config.h"
 
+#define DO_APIC_SW_IRQ              1
 #define DO_APIC_TMR_IRQ             1
-#define DO_APIC_SW_IRQ              0
-#define DO_USER_HANDLER             0
-#define DO_USER_LOOP                0
-
-void __ss_irq_handler(void);
-extern int volatile __ss_irq_fired, __ss_irq_count, __ss_irq_cpl;
+#define DO_EXEC_PRIV                1
 
 /* ------------------------------------------------------------ */
 /* This code may execute with ring0 privileges */
 int my_cpl = -1;
 
-void do_irq_loop(void)
+void pre_irq(void)
 {
     my_cpl = get_cpl();
     __ss_irq_fired = 0;
-    apic_timer_irq(10);
-    while(!__ss_irq_fired);
 }
 
-void my_ring0_func(void)
+void do_irq_sw(void)
 {
-    my_cpl = get_cpl();
+    pre_irq();
+    asm("int %0\n\t" ::"i"(IRQ_VECTOR):);
 }
-/* ------------------------------------------------------------ */
 
-int main( int argc, char **argv )
+void do_irq_tmr(void)
 {
-    idt_t idt = {0};
-    ASSERT( !claim_cpu(VICTIM_CPU) );
+    pre_irq();
+    apic_timer_irq(10);
+    while(!__ss_irq_fired);
+}
 
-    info_event("Establishing user space IDT mapping");
-    map_idt(&idt);
-    #if DO_USER_HANDLER
-        install_user_asm_irq_handler(&idt, __ss_irq_handler, IRQ_VECTOR);
-    #else
-        install_kernel_irq_handler(&idt, __ss_irq_handler, IRQ_VECTOR);
-    #endif
-    //dump_idt(&idt);
+/* ------------------------------------------------------------ */
 
-    #if !DO_USER_LOOP
-        exec_priv(my_ring0_func);
-        info("back from my_ring0_func w CPL=%d", my_cpl);
-    #endif
+void post_irq(void)
+{
+    ASSERT(__ss_irq_fired);
+    info("returned from IRQ: my_cpl=%d; irq_cpl=%d; count=%02d; flags=%p",
+            my_cpl, __ss_irq_cpl, __ss_irq_count, read_flags());
+}
 
+void do_irq_test(int skip_priv)
+{
     #if DO_APIC_SW_IRQ
-        info_event("Triggering user space software interrupts");
-        asm("int %0\n\t" ::"i"(IRQ_VECTOR):);
-        asm("int %0\n\t" ::"i"(IRQ_VECTOR):);
+        printf("\n");
+        info("Triggering ring3 software interrupts..");
+        for (int i=0; i < 3; i++)
+        {
+            do_irq_sw();
+            post_irq();
+        }
+
+        #if DO_EXEC_PRIV
+        if (!skip_priv)
+        {
+            printf("\n");
+            info("Triggering ring0 software interrupts..");
+            for (int i=0; i < 3; i++)
+            {
+                exec_priv(do_irq_sw);
+                post_irq();
+            }
+        }
+        #endif
     #endif
 
     #if DO_APIC_TMR_IRQ
-        info_event("Triggering user space APIC timer interrupts");
+        printf("\n");
+        info("Triggering ring3 APIC timer interrupts..");
         apic_timer_oneshot(IRQ_VECTOR);
 
         for (int i=0; i < 3; i++)
         {
-            //apic_send_ipi_self(IRQ_VECTOR);
-            #if DO_USER_LOOP
-                do_irq_loop();
-            #else
-                exec_priv(do_irq_loop);
-            #endif
-            info("returned from timer IRQ: my_cpl=%d; irq_cpl=%d; count=%d; flags=%p", my_cpl, __ss_irq_cpl, __ss_irq_count, read_flags());
+            do_irq_tmr();
+            post_irq();
         }
 
+        #if DO_EXEC_PRIV
+        if (!skip_priv)
+        {
+            printf("\n");
+            info("Triggering ring0 APIC timer interrupts..");
+            for (int i=0; i < 3; i++)
+            {
+                exec_priv(do_irq_tmr);
+                post_irq();
+            }
+        }
+        #endif
+
         apic_timer_deadline();
     #endif
+}
+
+int main( int argc, char **argv )
+{
+    idt_t idt = {0};
+    ASSERT( !claim_cpu(VICTIM_CPU) );
+
+    info_event("Installing and testing ring3 IDT handler");
+    map_idt(&idt);
+    install_user_asm_irq_handler(&idt, __ss_irq_handler, IRQ_VECTOR);
+    do_irq_test(/*skip_priv=*/1);
+
+    info_event("Installing and testing ring0 IDT handler");
+    install_kernel_irq_handler(&idt, __ss_irq_handler, IRQ_VECTOR);
+    #if DO_EXEC_PRIV
+        exec_priv(pre_irq);
+        info("back from exec_priv(pre_irq) with CPL=%d", my_cpl);
+    #endif
+    do_irq_test(/*skip_priv=*/0);
 
     info("all is well; irq_count=%d; exiting..", __ss_irq_count);
     return 0;

libsgxstep/idt.h

@@ -42,4 +42,7 @@ void install_user_irq_handler(idt_t *idt, irq_cb_t handler, int vector);
 void install_user_asm_irq_handler(idt_t *idt, void* asm_handler, int vector);
 void install_kernel_irq_handler(idt_t *idt, void *asm_handler, int vector);
 
+void __ss_irq_handler(void);
+extern int volatile __ss_irq_fired, __ss_irq_count, __ss_irq_cpl;
+
 #endif

libsgxstep/irq_entry.S

@@ -1,3 +1,39 @@
+/* ********************************************************************** */
+    .data
+    .global __ss_irq_fired, __ss_irq_count, __ss_irq_cpl
+__ss_irq_fired:
+    .int 0x0
+__ss_irq_count:
+    .int 0x0
+__ss_irq_cpl:
+    .int 0xff
+    /* not sure there's a kernel stack we can use(?) */
+__ss_irq_rax:
+    .quad 0x0
+
+    .text
+    .global __ss_irq_handler
+__ss_irq_handler:
+    incl __ss_irq_fired(%rip)
+    incl __ss_irq_count(%rip)
+
+    mov %cs,  __ss_irq_cpl(%rip)
+    and $0x3, __ss_irq_cpl(%rip)
+
+    /* apic_write(APIC_EOI, 0x0); */
+    mov %rax, __ss_irq_rax(%rip)
+    lea apic_base(%rip), %rax
+    mov (%rax),%rax
+    test %rax, %rax
+    jz 1f
+    add $0xb0, %rax
+    movl $0x0, (%rax)
+1:
+    mov __ss_irq_rax(%rip), %rax
+    iretq
+
+/* ********************************************************************** */
+
     .text
     .global sgx_step_irq_entry
     .type sgx_step_irq_entry,@function