Implement basic support for MIPS64LE

Add basic stuff to enable MIPS64ELR2 target:
 - build
 - make extract
 - make generate
 - qemu execution
 - system call parsing from /proc/kallsyms

9 files changed, 39 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index aeb3c4ace..4d1601208 100644
--- a/Makefile
+++ b/Makefile
@@ -97,7 +97,7 @@ endif
 	arch arch_darwin_amd64_host arch_linux_amd64_host \
 	arch_freebsd_amd64_host arch_netbsd_amd64_host \
 	arch_linux_amd64_target arch_linux_386_target \
-	arch_linux_arm64_target arch_linux_arm_target arch_linux_ppc64le_target \
+	arch_linux_arm64_target arch_linux_arm_target arch_linux_ppc64le_target arch_linux_mips64le_target \
 	arch_freebsd_amd64_target arch_freebsd_386_target \
 	arch_netbsd_amd64_target arch_windows_amd64_target \
 	arch_test presubmit presubmit_parallel clean
@@ -242,7 +242,7 @@ lint:
 arch: arch_darwin_amd64_host arch_linux_amd64_host arch_freebsd_amd64_host \
 	arch_netbsd_amd64_host arch_openbsd_amd64_host \
 	arch_linux_amd64_target arch_linux_386_target \
-	arch_linux_arm64_target arch_linux_arm_target arch_linux_ppc64le_target \
+	arch_linux_arm64_target arch_linux_arm_target arch_linux_ppc64le_target arch_linux_mips64le_target \
 	arch_freebsd_amd64_target arch_freebsd_386_target \
 	arch_netbsd_amd64_target arch_openbsd_amd64_target \
 	arch_windows_amd64_target arch_test
@@ -265,6 +265,9 @@ arch_linux_arm64_target:
 arch_linux_arm_target:
 	env TARGETOS=linux TARGETARCH=arm $(MAKE) target
 
+arch_linux_mips64le_target:
+	env TARGETOS=linux TARGETARCH=mips64le $(MAKE) target
+
 arch_linux_ppc64le_target:
 	env TARGETOS=linux TARGETARCH=ppc64le $(MAKE) target
 
@@ -333,10 +336,11 @@ install_prerequisites:
 	uname -a
 	sudo apt-get update
 	sudo apt-get install -y -q libc6-dev-i386 linux-libc-dev \
-		gcc-aarch64-linux-gnu gcc-arm-linux-gnueabi gcc-powerpc64le-linux-gnu || true
+		gcc-aarch64-linux-gnu gcc-arm-linux-gnueabi gcc-powerpc64le-linux-gnu gcc-mips64el-linux-gnuabi64 || true
 	sudo apt-get install -y -q g++-aarch64-linux-gnu || true
 	sudo apt-get install -y -q g++-powerpc64le-linux-gnu || true
 	sudo apt-get install -y -q g++-arm-linux-gnueabi || true
+	sudo apt-get install -y -q g++-mips64el-linux-gnuabi64 || true
 	sudo apt-get install -y -q ragel clang-format
 	go get -u golang.org/x/tools/cmd/goyacc \
 		github.com/golangci/golangci-lint/cmd/golangci-lint \
diff --git a/docs/syscall_descriptions.md b/docs/syscall_descriptions.md
index dd9762823..7cf715250 100644
--- a/docs/syscall_descriptions.md
+++ b/docs/syscall_descriptions.md
@@ -139,7 +139,7 @@ make generate
 make
 ```
 
-`$ARCH` is one of `amd64`, `386` `arm64`, `arm`, `ppc64le`.
+`$ARCH` is one of `amd64`, `386` `arm64`, `arm`, `ppc64le`, `mips64le`.
 If the subsystem is supported on several architectures, then run `syz-extract` for each arch.
 `$LINUX` should point to kernel source checkout, which is configured for the
 corresponding arch (i.e. you need to run `make ARCH=arch someconfig && make ARCH=arch` there first,
diff --git a/executor/common_linux.h b/executor/common_linux.h
index f333c41f1..23f830a8f 100644
--- a/executor/common_linux.h
+++ b/executor/common_linux.h
@@ -1229,6 +1229,8 @@ struct fs_image_segment {
 #define sys_memfd_create 279
 #elif GOARCH_ppc64le
 #define sys_memfd_create 360
+#elif GOARCH_mips64le
+#define sys_memfd_create 314
 #endif
 
 static unsigned long fs_image_segment_check(unsigned long size, unsigned long nsegs, long segments)
diff --git a/pkg/cover/report.go b/pkg/cover/report.go
index 9268f733d..419fd4ba1 100644
--- a/pkg/cover/report.go
+++ b/pkg/cover/report.go
@@ -435,6 +435,8 @@ func PreviousInstructionPC(arch string, pc uint64) uint64 {
 		return (pc - 3) & ^uint64(1)
 	case "ppc64le":
 		return pc - 4
+	case "mips64le":
+		return pc - 4
 	default:
 		panic(fmt.Sprintf("unknown arch %q", arch))
 	}
@@ -458,6 +460,9 @@ func archCallInsn(arch string) (string, string) {
 	case "ppc64le":
 		// c00000000006d904:       bl      c000000000350780 <.__sanitizer_cov_trace_pc>
 		return "\tbl ", " <.__sanitizer_cov_trace_pc>"
+	case "mips64le":
+		// ffffffff80100420:       jal     ffffffff80205880 <__sanitizer_cov_trace_pc>
+		return "\tjal\t", callName
 	default:
 		panic(fmt.Sprintf("unknown arch %q", arch))
 	}
diff --git a/pkg/host/syscalls_linux.go b/pkg/host/syscalls_linux.go
index 5e67d05eb..d9c247c88 100644
--- a/pkg/host/syscalls_linux.go
+++ b/pkg/host/syscalls_linux.go
@@ -75,6 +75,8 @@ func parseKallsyms(kallsyms []byte, arch string) map[string]bool {
 		re = regexp.MustCompile(` T (__arm64_)?sys_([^\n]+)\n`)
 	case "ppc64le":
 		re = regexp.MustCompile(` T ()?sys_([^\n]+)\n`)
+	case "mips64le":
+		re = regexp.MustCompile(` T sys_(mips_)?([^\n]+)\n`)
 	default:
 		panic("unsupported arch for kallsyms parsing")
 	}
diff --git a/pkg/osutil/osutil_linux.go b/pkg/osutil/osutil_linux.go
index 8a99a5f84..79df69999 100644
--- a/pkg/osutil/osutil_linux.go
+++ b/pkg/osutil/osutil_linux.go
@@ -58,7 +58,7 @@ func removeImmutable(fname string) error {
 		cmd = 1074030082
 	case "amd64", "arm64":
 		cmd = 1074292226
-	case "ppc64le":
+	case "ppc64le", "mips64le":
 		cmd = 2148034050
 	default:
 		panic("unknown arch")
diff --git a/sys/linux/init.go b/sys/linux/init.go
index 64df47a3f..91bf32be8 100644
--- a/sys/linux/init.go
+++ b/sys/linux/init.go
@@ -83,6 +83,7 @@ func InitTarget(target *prog.Target) {
 	case "arm64":
 	case "arm":
 	case "ppc64le":
+	case "mips64le":
 	default:
 		panic("unknown arch")
 	}
diff --git a/sys/targets/targets.go b/sys/targets/targets.go
index 34c06d5c6..e1d5731d8 100644
--- a/sys/targets/targets.go
+++ b/sys/targets/targets.go
@@ -174,6 +174,16 @@ var List = map[string]map[string]*Target{
 			KernelArch:       "arm",
 			KernelHeaderArch: "arm",
 		},
+		"mips64le": {
+			VMArch:           "mips64le",
+			PtrSize:          8,
+			PageSize:         4 << 10,
+			CFlags:           []string{"-D_MIPS_SZLONG=64", "-D__MIPSEL__", "-D__KERNEL__", "-D_MIPS_SIM=_MIPS_SIM_ABI64"},
+			CrossCFlags:      []string{"-static", "-march=mips64r2", "-mabi=64", "-EL"},
+			CCompilerPrefix:  "mips64el-linux-gnuabi64-",
+			KernelArch:       "mips",
+			KernelHeaderArch: "mips",
+		},
 		"ppc64le": {
 			PtrSize:  8,
 			PageSize: 4 << 10,
diff --git a/vm/qemu/qemu.go b/vm/qemu/qemu.go
index dae8f493b..bddace8f6 100644
--- a/vm/qemu/qemu.go
+++ b/vm/qemu/qemu.go
@@ -136,6 +136,16 @@ var archConfigs = map[string]*archConfig{
 			"console=ttyAMA0",
 		),
 	},
+	"linux/mips64le": {
+		Qemu:      "qemu-system-mips64el",
+		TargetDir: "/",
+		QemuArgs:  "-M malta -cpu MIPS64R2-generic -nodefaults",
+		NicModel:  ",model=e1000",
+		CmdLine: append(linuxCmdline,
+			"root=/dev/sda",
+			"console=ttyS0",
+		),
+	},
 	"linux/ppc64le": {
 		Qemu:      "qemu-system-ppc64",
 		TargetDir: "/",