executor: arm64: syzos: prevent jump table emission

When compiling SYZOS into the executor binary, the compiler often
attempts to emit a jump table, putting it into the data section
of the executor. SYZOS is unable to access that data and crashes.

Use primes multiplied by 10 to defeat the compiler's heuristics
for jump table emission.

Author: ramosian-glider

executor/common_kvm_arm64_syzos.h

@@ -19,16 +19,16 @@
 extern char *__start_guest, *__stop_guest;
 
 typedef enum {
-	SYZOS_API_UEXIT,
-	SYZOS_API_CODE,
-	SYZOS_API_MSR,
-	SYZOS_API_SMC,
-	SYZOS_API_HVC,
-	SYZOS_API_IRQ_SETUP,
-	SYZOS_API_MEMWRITE,
-	SYZOS_API_ITS_SETUP,
-	SYZOS_API_ITS_SEND_CMD,
-	SYZOS_API_MRS,
+	SYZOS_API_UEXIT = 0,
+	SYZOS_API_CODE = 10,
+	SYZOS_API_MSR = 20,
+	SYZOS_API_SMC = 30,
+	SYZOS_API_HVC = 50,
+	SYZOS_API_IRQ_SETUP = 70,
+	SYZOS_API_MEMWRITE = 110,
+	SYZOS_API_ITS_SETUP = 130,
+	SYZOS_API_ITS_SEND_CMD = 170,
+	SYZOS_API_MRS = 190,
 	SYZOS_API_STOP, // Must be the last one
 } syzos_api_id;
 

sys/linux/dev_kvm_arm64.txt

@@ -203,13 +203,13 @@ type syzos_api[NUM, PAYLOAD] {
 
 syzos_api_call [
 	uexit		syzos_api[0, intptr]
-	code		syzos_api[1, syzos_api_code]
-	msr		syzos_api[2, syzos_api_msr]
-	smc		syzos_api[3, syzos_api_smccc]
-	hvc		syzos_api[4, syzos_api_smccc]
-	irq_setup	syzos_api[5, syzos_api_irq_setup]
-	memwrite	syzos_api[6, syzos_api_memwrite]
-	its_setup	syzos_api[7, syzos_api_its_setup]
-	its_send_cmd	syzos_api[8, syzos_api_its_send_cmd]
-	mrs		syzos_api[9, syzos_api_mrs]
+	code		syzos_api[10, syzos_api_code]
+	msr		syzos_api[20, syzos_api_msr]
+	smc		syzos_api[30, syzos_api_smccc]
+	hvc		syzos_api[50, syzos_api_smccc]
+	irq_setup	syzos_api[70, syzos_api_irq_setup]
+	memwrite	syzos_api[110, syzos_api_memwrite]
+	its_setup	syzos_api[130, syzos_api_its_setup]
+	its_send_cmd	syzos_api[170, syzos_api_its_send_cmd]
+	mrs		syzos_api[190, syzos_api_mrs]
 ] [varlen]