Merge pull request #372 in SEL4/sel4 from ~HALMATARY/sel4:BenchmarkNullSyscall to master

* commit '9c507cffd1472a41700417c91d87d7e12d1eb641':
  SELFOUR-603 - Benchmark: Add null syscall
  Benchmarks: Add new generic benchmark entry mode

Kconfig

@@ -552,6 +552,12 @@ menu "Build Options"
         config NO_BENCHMARKS
              bool "No benchmarking features enabled"
 
+        config BENCHMARK_GENERIC
+            bool "Enable generic benchmarks"
+            select ENABLE_BENCHMARKS
+            help
+                Enable global benchmarks config variable with no specific features
+
         config BENCHMARK_TRACK_KERNEL_ENTRIES
             bool "Keep track of kernel entries"
             select ENABLE_BENCHMARKS

libsel4/include/api/syscall.xml

@@ -41,6 +41,7 @@
             <syscall name="BenchmarkResetLog" />
             <syscall name="BenchmarkFinalizeLog"  />
             <syscall name="BenchmarkSetLogBuffer"  />
+            <syscall name="BenchmarkNullSyscall"  />
         </config>
         <config condition="defined CONFIG_BENCHMARK_TRACK_UTILISATION">
             <syscall name="BenchmarkGetThreadUtilisation"  />

libsel4/sel4_arch_include/aarch32/sel4/sel4_arch/syscalls.h

@@ -626,6 +626,17 @@ seL4_BenchmarkSetLogBuffer(seL4_Word frame_cptr)
 
     return (seL4_Error) arg1;
 }
+
+static inline void
+seL4_BenchmarkNullSyscall(void)
+{
+    register seL4_Word scno asm("r7") = seL4_SysBenchmarkNullSyscall;
+    asm volatile ("swi %[swi_num]"
+                  : /* no outputs */
+                  : [swi_num] "i" __SEL4_SWINUM(seL4_SysBenchmarkNullSyscall), "r"(scno)
+                  : "memory");
+}
+
 #ifdef CONFIG_BENCHMARK_TRACK_UTILISATION
 static inline void
 seL4_BenchmarkGetThreadUtilisation(seL4_Word tcp_cptr)

libsel4/sel4_arch_include/ia32/sel4/sel4_arch/syscalls.h

@@ -730,6 +730,25 @@ seL4_BenchmarkSetLogBuffer(seL4_Word frame_cptr)
     return (seL4_Error) frame_cptr;
 }
 
+
+static inline void
+seL4_BenchmarkNullSyscall(void)
+{
+    asm volatile (
+        "pushl %%ebp       \n"
+        SEL4_REGS_SAVE
+        "movl %%esp, %%ecx \n"
+        "leal 1f, %%edx    \n"
+        "1:                \n"
+        "sysenter          \n"
+        SEL4_REGS_RESTORE
+        "popl %%ebp        \n"
+        :
+        : "a" (seL4_SysBenchmarkNullSyscall)
+        : SEL4_REGS_CLOBBER_EBX "%ecx", "%edx", "%esi", "%edi", "memory"
+    );
+}
+
 #ifdef CONFIG_BENCHMARK_TRACK_UTILISATION
 static inline void
 seL4_BenchmarkGetThreadUtilisation(seL4_Word tcb_cptr)

src/api/syscall.c

@@ -171,6 +171,9 @@ handleUnknownSyscall(word_t w)
     }
 #endif /* CONFIG_BENCHMARK_TRACK_UTILISATION */
 
+    else if (w == SysBenchmarkNullSyscall) {
+        return EXCEPTION_NONE;
+    }
 #endif /* CONFIG_ENABLE_BENCHMARKS */
 
     current_fault = fault_unknown_syscall_new(w);