bcc: Add some basic support for MIPS

In order to fix the following errors when running bpf program
on the MIPS Loongson64 platform, add some basic support, with
this patch, running hello_world.py can get the expected result.

 root@linux:/home/loongson/bcc# python examples/hello_world.py
 In file included from <built-in>:3:
 In file included from /virtual/include/bcc/helpers.h:51:
 In file included from include/uapi/linux/if_packet.h:5:
 arch/mips/include/uapi/asm/byteorder.h:17:3: error: "MIPS, but neither __MIPSEB__, nor __MIPSEL__???"
 # error "MIPS, but neither __MIPSEB__, nor __MIPSEL__???"
   ^
 In file included from <built-in>:3:
 In file included from /virtual/include/bcc/helpers.h:53:
 In file included from include/linux/log2.h:12:
 In file included from include/linux/bitops.h:32:
 In file included from arch/mips/include/asm/bitops.h:19:
 In file included from arch/mips/include/asm/barrier.h:11:
 arch/mips/include/asm/addrspace.h:13:10: fatal error: 'spaces.h' file not found
 #include <spaces.h>
         ^~~~~~~~~~
 2 errors generated.
 Traceback (most recent call last):
   File "examples/hello_world.py", line 12, in <module>
     BPF(text='int kprobe__sys_clone(void *ctx) { bpf_trace_printk("Hello, World!\\n"); return 0; }').trace_print()
   File "/usr/lib/python2.7/site-packages/bcc/__init__.py", line 364, in __init__
     raise Exception("Failed to compile BPF module %s" % (src_file or "<text>"))
 Exception: Failed to compile BPF module <text>

 root@linux:/home/loongson/bcc# python examples/hello_world.py
 In file included from <built-in>:3:
 In file included from /virtual/include/bcc/helpers.h:53:
 In file included from include/linux/log2.h:12:
 In file included from include/linux/bitops.h:32:
 arch/mips/include/asm/bitops.h:101:3: error: invalid output constraint '+ZC' in asm
                 __bit_op(*m, __INS "%0, %3, %2, 1", "i"(bit), "r"(~0));
                 ^
 arch/mips/include/asm/bitops.h:40:19: note: expanded from macro '__bit_op'
         : "=&r"(__temp), "+" GCC_OFF_SMALL_ASM()(mem)           \
                          ^
 [...]
 arch/mips/include/asm/atomic.h:154:1: error: invalid output constraint '+ZC' in asm
 arch/mips/include/asm/atomic.h:151:2: note: expanded from macro 'ATOMIC_OPS'
         ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc)
         ^
 arch/mips/include/asm/atomic.h:141:4: note: expanded from macro 'ATOMIC_FETCH_OP'
           "+" GCC_OFF_SMALL_ASM() (v->counter)                          \
           ^
 fatal error: too many errors emitted, stopping now [-ferror-limit=]
 20 errors generated.
 Traceback (most recent call last):
   File "examples/hello_world.py", line 12, in <module>
     BPF(text='int kprobe__sys_clone(void *ctx) { bpf_trace_printk("Hello, World!\\n"); return 0; }').trace_print()
   File "/usr/lib/python2.7/site-packages/bcc/__init__.py", line 364, in __init__
     raise Exception("Failed to compile BPF module %s" % (src_file or "<text>"))
 Exception: Failed to compile BPF module <text>

Signed-off-by: Tiezhu Yang <[email protected]>

libbpf-tools/Makefile

@@ -9,7 +9,7 @@ INCLUDES := -I$(OUTPUT)
 CFLAGS := -g -O2 -Wall
 INSTALL ?= install
 prefix ?= /usr/local
-ARCH := $(shell uname -m | sed 's/x86_64/x86/' | sed 's/aarch64/arm64/' | sed 's/ppc64le/powerpc/')
+ARCH := $(shell uname -m | sed 's/x86_64/x86/' | sed 's/aarch64/arm64/' | sed 's/ppc64le/powerpc/' | sed 's/mips.*/mips/')
 
 ifeq ($(wildcard $(ARCH)/),)
 $(error Architecture $(ARCH) is not supported yet. Please open an issue)

src/cc/export/helpers.h

@@ -1099,6 +1099,9 @@ int bpf_usdt_readarg_p(int argc, struct pt_regs *ctx, void *buf, u64 len) asm("l
 #elif defined(__TARGET_ARCH_powerpc)
 #define bpf_target_powerpc
 #define bpf_target_defined
+#elif defined(__TARGET_ARCH_mips)
+#define bpf_target_mips
+#define bpf_target_defined
 #else
 #undef bpf_target_defined
 #endif
@@ -1113,6 +1116,8 @@ int bpf_usdt_readarg_p(int argc, struct pt_regs *ctx, void *buf, u64 len) asm("l
 #define bpf_target_arm64
 #elif defined(__powerpc__)
 #define bpf_target_powerpc
+#elif defined(__mips__)
+#define bpf_target_mips
 #endif
 #endif
 
@@ -1161,6 +1166,18 @@ int bpf_usdt_readarg_p(int argc, struct pt_regs *ctx, void *buf, u64 len) asm("l
 #define PT_REGS_RC(x) ((x)->regs[0])
 #define PT_REGS_SP(x) ((x)->sp)
 #define PT_REGS_IP(x) ((x)->pc)
+#elif defined(bpf_target_mips)
+#define PT_REGS_PARM1(x) ((x)->regs[4])
+#define PT_REGS_PARM2(x) ((x)->regs[5])
+#define PT_REGS_PARM3(x) ((x)->regs[6])
+#define PT_REGS_PARM4(x) ((x)->regs[7])
+#define PT_REGS_PARM5(x) ((x)->regs[8])
+#define PT_REGS_PARM6(x) ((x)->regs[9])
+#define PT_REGS_RET(x) ((x)->regs[31])
+#define PT_REGS_FP(x) ((x)->regs[30]) /* Works only with CONFIG_FRAME_POINTER */
+#define PT_REGS_RC(x) ((x)->regs[2])
+#define PT_REGS_SP(x) ((x)->regs[29])
+#define PT_REGS_IP(x) ((x)->cp0_epc)
 #else
 #error "bcc does not support this platform yet"
 #endif

src/cc/frontends/clang/arch_helper.h

@@ -22,6 +22,7 @@ typedef enum {
  BCC_ARCH_PPC_LE,
  BCC_ARCH_S390X,
  BCC_ARCH_ARM64,
+ BCC_ARCH_MIPS,
  BCC_ARCH_X86
 } bcc_arch_t;
 
@@ -43,6 +44,8 @@ static void *run_arch_callback(arch_callback_t fn, bool for_syscall = false)
  return fn(BCC_ARCH_S390X, for_syscall);
 #elif defined(__aarch64__)
  return fn(BCC_ARCH_ARM64, for_syscall);
+#elif defined(__mips__)
+ return fn(BCC_ARCH_MIPS, for_syscall);
 #else
  return fn(BCC_ARCH_X86, for_syscall);
 #endif
@@ -59,6 +62,8 @@ static void *run_arch_callback(arch_callback_t fn, bool for_syscall = false)
  return fn(BCC_ARCH_S390X, for_syscall);
  } else if (!strcmp(archenv, "arm64")) {
  return fn(BCC_ARCH_ARM64, for_syscall);
+ } else if (!strcmp(archenv, "mips")) {
+ return fn(BCC_ARCH_MIPS, for_syscall);
  } else {
  return fn(BCC_ARCH_X86, for_syscall);
  }

src/cc/frontends/clang/b_frontend_action.cc

@@ -57,6 +57,9 @@ const char *calling_conv_regs_s390x[] = {"gprs[2]", "gprs[3]", "gprs[4]",
 const char *calling_conv_regs_arm64[] = {"regs[0]", "regs[1]", "regs[2]",
  "regs[3]", "regs[4]", "regs[5]"};
 
+const char *calling_conv_regs_mips[] = {"regs[4]", "regs[5]", "regs[6]",
+ "regs[7]", "regs[8]", "regs[9]"};
+
 void *get_call_conv_cb(bcc_arch_t arch, bool for_syscall)
 {
  const char **ret;
@@ -72,6 +75,9 @@ void *get_call_conv_cb(bcc_arch_t arch, bool for_syscall)
  case BCC_ARCH_ARM64:
  ret = calling_conv_regs_arm64;
  break;
+ case BCC_ARCH_MIPS:
+ ret = calling_conv_regs_mips;
+ break;
  default:
  if (for_syscall)
  ret = calling_conv_syscall_regs_x86;

src/cc/frontends/clang/kbuild_helper.cc

@@ -115,6 +115,11 @@ int KBuildHelper::get_flags(const char *uname_machine, vector<string> *cflags) {
  cflags->push_back("-Iinclude/generated/uapi");
  }
 
+ if (arch == "mips") {
+ cflags->push_back("-Iarch/mips/include/asm/mach-loongson64");
+ cflags->push_back("-Iarch/mips/include/asm/mach-generic");
+ }
+
  cflags->push_back("-include");
  cflags->push_back("./include/linux/kconfig.h");
  cflags->push_back("-D__KERNEL__");

src/cc/frontends/clang/loader.cc

@@ -195,6 +195,15 @@ int ClangLoader::parse(unique_ptr<llvm::Module> *mod, TableStorage &ts,
  "-fno-asynchronous-unwind-tables",
  "-x", "c", "-c", abs_file.c_str()});
 
+ const char *arch = getenv("ARCH");
+ if (!arch)
+ arch = un.machine;
+
+ if (!strncmp(arch, "mips", 4)) {
+ flags_cstr.push_back("-D__MIPSEL__");
+ flags_cstr.push_back("-D_MIPS_SZLONG=64");
+ }
+
  KBuildHelper kbuild_helper(kpath_env ? kpath : kdir, has_kpath_source);
 
  vector<string> kflags;
@@ -270,6 +279,9 @@ void *get_clang_target_cb(bcc_arch_t arch, bool for_syscall)
  case BCC_ARCH_ARM64:
  ret = "aarch64-unknown-linux-gnu";
  break;
+ case BCC_ARCH_MIPS:
+ ret = "mips64el-unknown-linux-gnuabi64";
+ break;
  default:
  ret = "x86_64-unknown-linux-gnu";
  }