From 0a7914e3f71093399ce7f62d77d79ba685b04264 Mon Sep 17 00:00:00 2001
From: sys64738 <sys64738@hellsite.site>
Date: Sat, 29 Jan 2022 03:24:18 +0100
Subject: [PATCH] linux stuff

---
 jazelle.c      | 36 ++++++++++++++++++++++++++++++++----
 rpi/.gitignore |  3 +++
 rpi/Makefile   |  6 ++++++
 rpi/linux.c    |  8 ++++++++
 4 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 rpi/.gitignore
 create mode 100644 rpi/linux.c

diff --git a/jazelle.c b/jazelle.c
index ccde2fe..679fec0 100644
--- a/jazelle.c
+++ b/jazelle.c
@@ -13,9 +13,11 @@
 
 #if defined(__linux__) && !defined(__KERNEL__)
 
+// FIXME: (on musl) seems to crash upon entry before reaching main()
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/mman.h>
 #define iprintf(fmt, ...) printf((fmt), ##__VA_ARGS__)
 
 #elif defined(__KERNEL__)
@@ -174,7 +176,7 @@ static void DC_InvalidateAll(void) {
 	DC_FlushAll();
 }
 __attribute__((__naked__, __no_inline__))
-static void IC_InvalidateAll(void) {
+void IC_InvalidateAll(void) {
 	asm volatile(
 		".fill 65536, 4, 0\n" // 64k nop instructions because eh
 		"bx lr\n"
@@ -329,6 +331,7 @@ static void handler_0xfe(void) {
 		"bxj r12\n" // FIXME: r12 can be modified by jazelle so it should be restored to something
 		//:
 		//:[br5]"m"(backup_r5)
+		".pool\n"
 	);
 }
 
@@ -426,7 +429,7 @@ static void handler_noexec() {
 	);
 }
 
-static uint8_t bytecode_testh[] = {
+static uint8_t bytecode_testh_base[] = {
 	0x06, 0x06,
 	0x07, 0x07,
 	0x05, 0x05,
@@ -439,6 +442,22 @@ static uint8_t bytecode_testh[] = {
 };
 
 static void jazelle_test_handlers(uint8_t hflags[256/8]) {
+#ifdef __linux__
+#ifdef __KERNEL__
+#error "TODO: kernel: alloc rwx page"
+#else
+	uint8_t* bytecode_testh = mmap(NULL, 4096, PROT_READ|PROT_WRITE|PROT_EXEC,
+			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+	if (!bytecode_testh || !~(uint32_t)bytecode_testh) {
+		printf("Can't map a page RWX, need it for instruction enumeration.\n");
+		return;
+	}
+	memcpy(bytecode_testh, bytecode_testh_base, sizeof bytecode_testh_base);
+#endif
+#else
+	#define bytecode_testh bytecode_testh_base
+#endif
+
 	memset(hflags, 0, 256/8);
 	for (int i = 0x00; i < 0xff /* bytecode 0xff is hardwired to bkpt #0 */; ++i) {
 		if (i == 0xba) {
@@ -490,9 +509,19 @@ static void jazelle_test_handlers(uint8_t hflags[256/8]) {
 
 		jazelle_block.handlers[i] = NULL;
 	}
+#ifdef __linux__
+#ifdef __KERNEL__
+#error "TODO: kernel: alloc rwx page"
+#else
+	munmap(bytecode_testh, 4096);
+#endif
+#else
+	#undef bytecode_testh
+#endif
 }
 
 // https://github.com/SonoSooS/libjz/wiki/Java-instruction-set
+__attribute__((__section__(".text"), __align__(4)))
 static uint8_t bytecode_test1[] = {
 	0x06, // iconst_3
 	0x07, // iconst_4
@@ -503,6 +532,7 @@ static uint8_t bytecode_test1[] = {
 	0x60, // iadd
 	0x60, // iadd
 	0xAC, // ireturn
+	0x00, 0x00, 0x00 // alignment to keep gcc happy
 };
 
 // returns 6 if idiv implemented natively, else 10
@@ -551,7 +581,5 @@ void jazelle_main(void) {
 		}
 		printf("\r\n");
 	}
-
-	while (true) ;
 }
 
diff --git a/rpi/.gitignore b/rpi/.gitignore
new file mode 100644
index 0000000..02138fb
--- /dev/null
+++ b/rpi/.gitignore
@@ -0,0 +1,3 @@
+*.o
+*.elf
+jazlinux
diff --git a/rpi/Makefile b/rpi/Makefile
index 078709a..f5796c3 100644
--- a/rpi/Makefile
+++ b/rpi/Makefile
@@ -11,6 +11,9 @@ GDB ?= $(PREFIX)gdb
 PYTHON3 ?= python3
 NC ?= nc
 
+LNXPREFIX ?= arm-linux-gnueabihf-
+LNXCC = $(LNXPREFIX)gcc
+
 default: all
 
 all: rpi.elf
@@ -27,6 +30,9 @@ rpi.elf: rpi.o
 jazelle.o: ../jazelle.c
 	$(CC) $(CFLAGS) -c -o "$@" "$<"
 
+jazlinux: linux.c ../jazelle.c
+	$(LNXCC) $(CLFAGS) -o "$@" $^
+
 openocd-launch:
 	openocd -f interface/cmsis-dap.cfg -c "transport select jtag" \
         -c "adapter speed 50" -f target/bcm2835.cfg \
diff --git a/rpi/linux.c b/rpi/linux.c
new file mode 100644
index 0000000..05a1264
--- /dev/null
+++ b/rpi/linux.c
@@ -0,0 +1,8 @@
+
+void jazelle_main(void);
+
+int main() {
+	jazelle_main();
+	return 0;
+}
+