linux-user: Use correct target SHMLBA in shmat()
The shmat() handling needs to do target-specific handling
of the attach address for shmat():
* if the SHM_RND flag is passed, the address is rounded
down to a SHMLBA boundary
* if SHM_RND is not passed, then the call is failed EINVAL
if the address is not a multiple of SHMLBA
Since SHMLBA is target-specific, we need to do this
checking and rounding in QEMU and can't leave it up to the
host syscall.
Allow targets to define TARGET_FORCE_SHMLBA and provide
a target_shmlba() function if appropriate, and update
do_shmat() to honour them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e286907..85699f9 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4575,12 +4575,34 @@
return ret;
}
-static inline abi_ulong do_shmat(int shmid, abi_ulong shmaddr, int shmflg)
+#ifndef TARGET_FORCE_SHMLBA
+/* For most architectures, SHMLBA is the same as the page size;
+ * some architectures have larger values, in which case they should
+ * define TARGET_FORCE_SHMLBA and provide a target_shmlba() function.
+ * This corresponds to the kernel arch code defining __ARCH_FORCE_SHMLBA
+ * and defining its own value for SHMLBA.
+ *
+ * The kernel also permits SHMLBA to be set by the architecture to a
+ * value larger than the page size without setting __ARCH_FORCE_SHMLBA;
+ * this means that addresses are rounded to the large size if
+ * SHM_RND is set but addresses not aligned to that size are not rejected
+ * as long as they are at least page-aligned. Since the only architecture
+ * which uses this is ia64 this code doesn't provide for that oddity.
+ */
+static inline abi_ulong target_shmlba(CPUArchState *cpu_env)
+{
+ return TARGET_PAGE_SIZE;
+}
+#endif
+
+static inline abi_ulong do_shmat(CPUArchState *cpu_env,
+ int shmid, abi_ulong shmaddr, int shmflg)
{
abi_long raddr;
void *host_raddr;
struct shmid_ds shm_info;
int i,ret;
+ abi_ulong shmlba;
/* find out the length of the shared memory segment */
ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info));
@@ -4589,6 +4611,16 @@
return ret;
}
+ shmlba = target_shmlba(cpu_env);
+
+ if (shmaddr & (shmlba - 1)) {
+ if (shmflg & SHM_RND) {
+ shmaddr &= ~(shmlba - 1);
+ } else {
+ return -TARGET_EINVAL;
+ }
+ }
+
mmap_lock();
if (shmaddr)
@@ -4647,7 +4679,8 @@
#ifdef TARGET_NR_ipc
/* ??? This only works with linear mappings. */
/* do_ipc() must return target values and target errnos. */
-static abi_long do_ipc(unsigned int call, abi_long first,
+static abi_long do_ipc(CPUArchState *cpu_env,
+ unsigned int call, abi_long first,
abi_long second, abi_long third,
abi_long ptr, abi_long fifth)
{
@@ -4716,7 +4749,7 @@
default:
{
abi_ulong raddr;
- raddr = do_shmat(first, ptr, second);
+ raddr = do_shmat(cpu_env, first, ptr, second);
if (is_error(raddr))
return get_errno(raddr);
if (put_user_ual(raddr, third))
@@ -9304,8 +9337,8 @@
break;
#ifdef TARGET_NR_ipc
case TARGET_NR_ipc:
- ret = do_ipc(arg1, arg2, arg3, arg4, arg5, arg6);
- break;
+ ret = do_ipc(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
+ break;
#endif
#ifdef TARGET_NR_semget
case TARGET_NR_semget:
@@ -9354,7 +9387,7 @@
#endif
#ifdef TARGET_NR_shmat
case TARGET_NR_shmat:
- ret = do_shmat(arg1, arg2, arg3);
+ ret = do_shmat(cpu_env, arg1, arg2, arg3);
break;
#endif
#ifdef TARGET_NR_shmdt