Initial drop

Add some riscv code

Signed-off-by: Carlos Maiolino <[email protected]>

2 files changed, 28 insertions, 0 deletions

diff --git a/riscv/riscv-probe/examples/user/rules.mk b/riscv/riscv-probe/examples/user/rules.mk
new file mode 100644
index 0000000..63c6868
--- /dev/null
+++ b/riscv/riscv-probe/examples/user/rules.mk
@@ -0,0 +1 @@
+user_objs = user.o
diff --git a/riscv/riscv-probe/examples/user/user.c b/riscv/riscv-probe/examples/user/user.c
new file mode 100644
index 0000000..e37397f
--- /dev/null
+++ b/riscv/riscv-probe/examples/user/user.c
@@ -0,0 +1,27 @@
+#include "femto.h"
+
+#ifdef __riscv
+#include "arch/riscv/encoding.h"
+#include "arch/riscv/machine.h"
+#endif
+
+int main(int argc, char **argv)
+{
+	/*
+	 * Set up PMP (Physical Memory Protection)
+	 *
+	 * PMP is optional; bit if implemented enforcement is mandatory
+	 * and user-mode is prevented access to all memory by default.
+	 * We should change this code to restrict user mode to its .text
+	 * .rodata, .data, .bss and devices.
+	 */
+#ifdef __riscv
+	if (pmp_entry_count() > 0) {
+		pmp_allow_all();
+	}
+	mode_set_and_continue(PRV_U);
+	puts("riscv-user-mode");
+#else
+	puts("architecture-not-supported");
+#endif
+}