[PATCH v4 32/48] linux-user: Disable more prctl subcodes

[Richard Henderson]

Create a list of subcodes that we want to pass on, a list of
subcodes that should not be passed on because they would affect
the running qemu itself, and a list that probably could be
implemented but require extra work. Do not pass on unknown subcodes.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 linux-user/syscall.c | 56 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 4 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a417396981..7635c2397a 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6334,6 +6334,13 @@ abi_long do_arch_prctl(CPUX86State *env, int code, 
abi_ulong addr)
 # define PR_MTE_TAG_SHIFT       3
 # define PR_MTE_TAG_MASK        (0xffffUL << PR_MTE_TAG_SHIFT)
 #endif
+#ifndef PR_SET_IO_FLUSHER
+# define PR_SET_IO_FLUSHER 57
+# define PR_GET_IO_FLUSHER 58
+#endif
+#ifndef PR_SET_SYSCALL_USER_DISPATCH
+# define PR_SET_SYSCALL_USER_DISPATCH 59
+#endif
 
 #include "target_prctl.h"
 
@@ -6430,13 +6437,54 @@ static abi_long do_prctl(CPUArchState *env, abi_long 
option, abi_long arg2,
             return -TARGET_EINVAL;
         }
         return do_prctl_get_tagged_addr_ctrl(env);
+
+    case PR_GET_DUMPABLE:
+    case PR_SET_DUMPABLE:
+    case PR_GET_KEEPCAPS:
+    case PR_SET_KEEPCAPS:
+    case PR_GET_TIMING:
+    case PR_SET_TIMING:
+    case PR_GET_TIMERSLACK:
+    case PR_SET_TIMERSLACK:
+    case PR_MCE_KILL:
+    case PR_MCE_KILL_GET:
+    case PR_GET_NO_NEW_PRIVS:
+    case PR_SET_NO_NEW_PRIVS:
+    case PR_GET_IO_FLUSHER:
+    case PR_SET_IO_FLUSHER:
+        /* Some prctl options have no pointer arguments and we can pass on. */
+        return get_errno(prctl(option, arg2, arg3, arg4, arg5));
+
+    case PR_GET_CHILD_SUBREAPER:
+    case PR_SET_CHILD_SUBREAPER:
+    case PR_GET_SPECULATION_CTRL:
+    case PR_SET_SPECULATION_CTRL:
+    case PR_GET_TID_ADDRESS:
+        /* TODO */
+        return -TARGET_EINVAL;
+
+    case PR_GET_FPEXC:
+    case PR_SET_FPEXC:
+        /* Was used for SPE on PowerPC. */
+        return -TARGET_EINVAL;
+
+    case PR_GET_ENDIAN:
+    case PR_SET_ENDIAN:
+    case PR_GET_FPEMU:
+    case PR_SET_FPEMU:
+    case PR_SET_MM:
     case PR_GET_SECCOMP:
     case PR_SET_SECCOMP:
-        /* Disable seccomp to prevent the target disabling syscalls we need. */
-        return -TARGET_EINVAL;
+    case PR_SET_SYSCALL_USER_DISPATCH:
+    case PR_GET_THP_DISABLE:
+    case PR_SET_THP_DISABLE:
+    case PR_GET_TSC:
+    case PR_SET_TSC:
+    case PR_GET_UNALIGN:
+    case PR_SET_UNALIGN:
     default:
-        /* Most prctl options have no pointer arguments */
-        return get_errno(prctl(option, arg2, arg3, arg4, arg5));
+        /* Disable to prevent the target disabling stuff we need. */
+        return -TARGET_EINVAL;
     }
 }
 
-- 
2.25.1