Add support for using seccomp_bpf on mips64el.

Currently, seccomp_bpf is not supported on mips64el, and the build 
configuration sets use_seccomp_bpf=false on mips64el. This CL adds support
for seccomp-bpf on mips64el, and resolves many compiler errors when
compiling on mips64el.

R= machenbach@chromium.org, brettw@chromium.org
TBR=jorgelo

Bug: 742738
Change-Id: I79c5d1800c0a198a70c1f19a818885b726cbcc4f
Reviewed-on: https://chromium-review.googlesource.com/571385
Reviewed-by: Chris Palmer <palmer@chromium.org>
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Chris Palmer <palmer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502712}

AUTHORS

@@ -879,6 +879,7 @@ Google Inc. <*@google.com>
 Hewlett-Packard Development Company, L.P. <*@hp.com>
 Igalia S.L. <*@igalia.com>
 NIKE, Inc. <*@nike.com>
+Loongson Technology Corporation Limited. <*@loongson.cn>
 NVIDIA Corporation <*@nvidia.com>
 Neverware Inc. <*@neverware.com>
 Opera Software ASA <*@opera.com>

base/macros.h

@@ -12,6 +12,16 @@
 
 #include <stddef.h>  // For size_t.
 
+// Distinguish mips32.
+#if defined(__mips__) && (_MIPS_SIM == _ABIO32)
+#define __mips32__
+#endif
+
+// Distinguish mips64.
+#if defined(__mips__) && (_MIPS_SIM == _ABI64)
+#define __mips64__
+#endif
+
 // Put this in the declarations for a class to be uncopyable.
 #define DISALLOW_COPY(TypeName) \
   TypeName(const TypeName&) = delete

content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc

@@ -49,9 +49,9 @@ using sandbox::bpf_dsl::ResultExpr;
 
 // Make sure that seccomp-bpf does not get disabled by mistake. Also make sure
 // that we think twice about this when adding a new architecture.
-#if !defined(ARCH_CPU_ARM64)
+#if !defined(ARCH_CPU_ARM64) && !defined(ARCH_CPU_MIPS64EL)
 #error "Seccomp-bpf disabled on supported architecture!"
-#endif  // !defined(ARCH_CPU_ARM64)
+#endif  // !defined(ARCH_CPU_ARM64) && !defined(ARCH_CPU_MIPS64EL)
 
 #endif  // BUILDFLAG(USE_SECCOMP_BPF)
 

sandbox/features.gni

@@ -4,13 +4,14 @@
 
 import("//build/config/nacl/config.gni")
 
-# The seccomp-bpf sandbox is only supported on five architectures
+# The seccomp-bpf sandbox is only supported on six architectures
 # currently.
 # Do not disable seccomp_bpf anywhere without talking to
 # security@chromium.org!
 use_seccomp_bpf =
     (is_linux || is_android) &&
     (current_cpu == "x86" || current_cpu == "x64" || current_cpu == "arm" ||
-     current_cpu == "arm64" || current_cpu == "mipsel")
+     current_cpu == "arm64" || current_cpu == "mipsel" ||
+     current_cpu == "mips64el")
 
 use_seccomp_bpf = use_seccomp_bpf || is_nacl_nonsfi

sandbox/linux/BUILD.gn

@@ -431,6 +431,7 @@ source_set("sandbox_services_headers") {
     "system_headers/linux_time.h",
     "system_headers/linux_ucontext.h",
     "system_headers/mips64_linux_syscalls.h",
+    "system_headers/mips64_linux_ucontext.h",
     "system_headers/mips_linux_syscalls.h",
     "system_headers/mips_linux_ucontext.h",
     "system_headers/x86_32_linux_syscalls.h",

sandbox/linux/bpf_dsl/linux_syscall_ranges.h

@@ -33,16 +33,19 @@
 #define MIN_GHOST_SYSCALL   (MIN_PRIVATE_SYSCALL + 0xfff0u)
 #define MAX_SYSCALL         (MIN_GHOST_SYSCALL + 4u)
 
-#elif defined(__mips__) && (_MIPS_SIM == _ABIO32)
+#elif defined(__mips32__)
 
 #include <asm/unistd.h>  // for __NR_O32_Linux and __NR_Linux_syscalls
 #define MIN_SYSCALL         __NR_O32_Linux
 #define MAX_PUBLIC_SYSCALL  (MIN_SYSCALL + __NR_Linux_syscalls)
 #define MAX_SYSCALL         MAX_PUBLIC_SYSCALL
 
-#elif defined(__mips__) && (_MIPS_SIM == _ABI64)
+#elif defined(__mips64__)
 
-#error "Add support to header file"
+#include <asm/unistd.h>  // for __NR_64_Linux and __NR_64_Linux_syscalls
+#define MIN_SYSCALL         __NR_64_Linux
+#define MAX_PUBLIC_SYSCALL  (MIN_SYSCALL + __NR_64_Linux_syscalls)
+#define MAX_SYSCALL         MAX_PUBLIC_SYSCALL
 
 #elif defined(__aarch64__)
 

sandbox/linux/bpf_dsl/seccomp_macros.h

@@ -190,7 +190,7 @@ typedef user_regs regs_struct;
 #define SECCOMP_PT_PARM5(_regs)   (_regs).REG_r4
 #define SECCOMP_PT_PARM6(_regs)   (_regs).REG_r5
 
-#elif defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+#elif defined(__mips32__)
 #define SECCOMP_ARCH        AUDIT_ARCH_MIPSEL
 #define SYSCALL_EIGHT_ARGS
 // MIPS sigcontext_t is different from i386/x86_64 and ARM.
@@ -224,7 +224,7 @@ typedef user_regs regs_struct;
 #define SECCOMP_ARG_LSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                  8*(nr) + 0)
 
-// On Mips we don't have structures like user_regs or user_regs_struct in
+// On MIPS we don't have structures like user_regs or user_regs_struct in
 // sys/user.h that we could use, so we just define regs_struct directly.
 struct regs_struct {
   unsigned long long regs[32];
@@ -244,6 +244,65 @@ struct regs_struct {
 #define SECCOMP_PT_PARM3(_regs)   (_regs).REG_a2
 #define SECCOMP_PT_PARM4(_regs)   (_regs).REG_a3
 
+#elif defined(__mips64__)
+#define SECCOMP_ARCH        AUDIT_ARCH_MIPSEL64
+#define SYSCALL_EIGHT_ARGS
+// MIPS sigcontext_t is different from i386/x86_64 and ARM.
+// See </arch/mips/include/uapi/asm/sigcontext.h> in the Linux kernel.
+#define SECCOMP_REG(_ctx, _reg) ((_ctx)->uc_mcontext.gregs[_reg])
+// Based on MIPS n64 ABI syscall convention.
+// On MIPS, when an indirect syscall is being made (syscall(__NR_foo)),
+// the real identifier (__NR_foo) is not in v0, but in a0.
+#define SECCOMP_RESULT(_ctx)    SECCOMP_REG(_ctx, 2)
+#define SECCOMP_SYSCALL(_ctx)   SECCOMP_REG(_ctx, 2)
+#define SECCOMP_IP(_ctx)        (_ctx)->uc_mcontext.pc
+#define SECCOMP_PARM1(_ctx)     SECCOMP_REG(_ctx, 4)
+#define SECCOMP_PARM2(_ctx)     SECCOMP_REG(_ctx, 5)
+#define SECCOMP_PARM3(_ctx)     SECCOMP_REG(_ctx, 6)
+#define SECCOMP_PARM4(_ctx)     SECCOMP_REG(_ctx, 7)
+#define SECCOMP_PARM5(_ctx)     SECCOMP_REG(_ctx, 8)
+#define SECCOMP_PARM6(_ctx)     SECCOMP_REG(_ctx, 9)
+#define SECCOMP_PARM7(_ctx)     SECCOMP_REG(_ctx, 10)
+#define SECCOMP_PARM8(_ctx)     SECCOMP_REG(_ctx, 11)
+#define SECCOMP_NR_IDX          (offsetof(struct arch_seccomp_data, nr))
+#define SECCOMP_ARCH_IDX        (offsetof(struct arch_seccomp_data, arch))
+#define SECCOMP_IP_MSB_IDX      (offsetof(struct arch_seccomp_data,           \
+                                          instruction_pointer) + 4)
+#define SECCOMP_IP_LSB_IDX      (offsetof(struct arch_seccomp_data,           \
+                                          instruction_pointer) + 0)
+#define SECCOMP_ARG_MSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
+                                 8*(nr) + 4)
+#define SECCOMP_ARG_LSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
+                                 8*(nr) + 0)
+
+// On MIPS we don't have structures like user_regs or user_regs_struct in
+// sys/user.h that we could use, so we just define regs_struct directly.
+struct regs_struct {
+  unsigned long long regs[32];
+};
+
+#define REG_a7 regs[11]
+#define REG_a6 regs[10]
+#define REG_a5 regs[9]
+#define REG_a4 regs[8]
+#define REG_a3 regs[7]
+#define REG_a2 regs[6]
+#define REG_a1 regs[5]
+#define REG_a0 regs[4]
+#define REG_v1 regs[3]
+#define REG_v0 regs[2]
+
+#define SECCOMP_PT_RESULT(_regs)  (_regs).REG_v0
+#define SECCOMP_PT_SYSCALL(_regs) (_regs).REG_v0
+#define SECCOMP_PT_PARM1(_regs)   (_regs).REG_a0
+#define SECCOMP_PT_PARM2(_regs)   (_regs).REG_a1
+#define SECCOMP_PT_PARM3(_regs)   (_regs).REG_a2
+#define SECCOMP_PT_PARM4(_regs)   (_regs).REG_a3
+#define SECCOMP_PT_PARM5(_regs)   (_regs).REG_a4
+#define SECCOMP_PT_PARM6(_regs)   (_regs).REG_a5
+#define SECCOMP_PT_PARM7(_regs)   (_regs).REG_a6
+#define SECCOMP_PT_PARM8(_regs)   (_regs).REG_a7
+
 #elif defined(__aarch64__)
 struct regs_struct {
   unsigned long long regs[31];

sandbox/linux/bpf_dsl/syscall_set.cc

@@ -14,9 +14,12 @@ namespace sandbox {
 
 namespace {
 
-#if defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+#if defined(__mips32__)
 // This is true for Mips O32 ABI.
 static_assert(MIN_SYSCALL == __NR_Linux, "min syscall number should be 4000");
+#elif defined(__mips64__)
+// This is true for MIPS N64 ABI.
+static_assert(MIN_SYSCALL == __NR_Linux, "min syscall number should be 5000");
 #else
 // This true for supported architectures (Intel and ARM EABI).
 static_assert(MIN_SYSCALL == 0u,

sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc

@@ -86,7 +86,7 @@ bool IsBaselinePolicyWatched(int sysno) {
          SyscallSets::IsNuma(sysno) ||
          SyscallSets::IsPrctl(sysno) ||
          SyscallSets::IsProcessGroupOrSession(sysno) ||
-#if defined(__i386__) || defined(__mips__)
+#if defined(__i386__) || defined(__mips32__)
          SyscallSets::IsSocketCall(sysno) ||
 #endif
 #if defined(__arm__)
@@ -147,7 +147,7 @@ ResultExpr EvaluateSyscallImpl(int fs_denied_errno,
   if (sysno == __NR_fcntl)
     return RestrictFcntlCommands();
 
-#if defined(__i386__) || defined(__arm__) || defined(__mips__)
+#if defined(__i386__) || defined(__arm__) || defined(__mips32__)
   if (sysno == __NR_fcntl64)
     return RestrictFcntlCommands();
 #endif
@@ -191,7 +191,7 @@ ResultExpr EvaluateSyscallImpl(int fs_denied_errno,
     return RestrictMmapFlags();
 #endif
 
-#if defined(__i386__) || defined(__arm__) || defined(__mips__)
+#if defined(__i386__) || defined(__arm__) || defined(__mips32__)
   if (sysno == __NR_mmap2)
     return RestrictMmapFlags();
 #endif
@@ -241,7 +241,7 @@ ResultExpr EvaluateSyscallImpl(int fs_denied_errno,
     return Error(EPERM);
   }
 
-#if defined(__i386__) || defined(__mips__)
+#if defined(__i386__) || defined(__mips32__)
   if (SyscallSets::IsSocketCall(sysno))
     return RestrictSocketcallCommand();
 #endif

sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.cc

@@ -95,7 +95,7 @@ void PrintSyscallError(uint32_t sysno) {
     sysno_base10[i] = '0' + mod;
   }
 
-#if defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+#if defined(__mips32__)
   static const char kSeccompErrorPrefix[] = __FILE__
       ":**CRASHING**:" SECCOMP_MESSAGE_COMMON_CONTENT " in syscall 4000 + ";
 #else