[PATCH] lightweight robust futexes: compat
32-bit syscall compatibility support. (This patch also moves all futex
related compat functionality into kernel/futex_compat.c.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 24d659c..6d3a654 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -147,6 +147,24 @@
} _sigev_un;
} compat_sigevent_t;
+struct compat_robust_list {
+ compat_uptr_t next;
+};
+
+struct compat_robust_list_head {
+ struct compat_robust_list list;
+ compat_long_t futex_offset;
+ compat_uptr_t list_op_pending;
+};
+
+extern void compat_exit_robust_list(struct task_struct *curr);
+
+asmlinkage long
+compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
+ compat_size_t len);
+asmlinkage long
+compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
+ compat_size_t __user *len_ptr);
long compat_sys_semctl(int first, int second, int third, void __user *uptr);
long compat_sys_msgsnd(int first, int second, int third, void __user *uptr);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index fd4848f..20b4f03 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -874,6 +874,9 @@
int cpuset_mem_spread_rotor;
#endif
struct robust_list_head __user *robust_list;
+#ifdef CONFIG_COMPAT
+ struct compat_robust_list_head __user *compat_robust_list;
+#endif
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
diff --git a/kernel/Makefile b/kernel/Makefile
index ff1c11d..58908f9 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -12,6 +12,9 @@
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_FUTEX) += futex.o
+ifeq ($(CONFIG_COMPAT),y)
+obj-$(CONFIG_FUTEX) += futex_compat.o
+endif
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += cpu.o spinlock.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
diff --git a/kernel/compat.c b/kernel/compat.c
index b9bdd12..c1601a8 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -17,7 +17,6 @@
#include <linux/time.h>
#include <linux/signal.h>
#include <linux/sched.h> /* for MAX_SCHEDULE_TIMEOUT */
-#include <linux/futex.h> /* for FUTEX_WAIT */
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/security.h>
@@ -239,28 +238,6 @@
return ret;
}
-#ifdef CONFIG_FUTEX
-asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, int val,
- struct compat_timespec __user *utime, u32 __user *uaddr2,
- int val3)
-{
- struct timespec t;
- unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
- int val2 = 0;
-
- if ((op == FUTEX_WAIT) && utime) {
- if (get_compat_timespec(&t, utime))
- return -EFAULT;
- timeout = timespec_to_jiffies(&t) + 1;
- }
- if (op >= FUTEX_REQUEUE)
- val2 = (int) (unsigned long) utime;
-
- return do_futex((unsigned long)uaddr, op, val, timeout,
- (unsigned long)uaddr2, val2, val3);
-}
-#endif
-
asmlinkage long compat_sys_setrlimit(unsigned int resource,
struct compat_rlimit __user *rlim)
{
diff --git a/kernel/exit.c b/kernel/exit.c
index aecb48c..a8c7efc 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -32,6 +32,7 @@
#include <linux/cn_proc.h>
#include <linux/mutex.h>
#include <linux/futex.h>
+#include <linux/compat.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -855,6 +856,10 @@
}
if (unlikely(tsk->robust_list))
exit_robust_list(tsk);
+#ifdef CONFIG_COMPAT
+ if (unlikely(tsk->compat_robust_list))
+ compat_exit_robust_list(tsk);
+#endif
exit_mm(tsk);
exit_sem(tsk);
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
new file mode 100644
index 0000000..c153559
--- /dev/null
+++ b/kernel/futex_compat.c
@@ -0,0 +1,142 @@
+/*
+ * linux/kernel/futex_compat.c
+ *
+ * Futex compatibililty routines.
+ *
+ * Copyright 2006, Red Hat, Inc., Ingo Molnar
+ */
+
+#include <linux/linkage.h>
+#include <linux/compat.h>
+#include <linux/futex.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+void compat_exit_robust_list(struct task_struct *curr)
+{
+ struct compat_robust_list_head __user *head = curr->compat_robust_list;
+ struct robust_list __user *entry, *pending;
+ compat_uptr_t uentry, upending;
+ unsigned int limit = ROBUST_LIST_LIMIT;
+ compat_long_t futex_offset;
+
+ /*
+ * Fetch the list head (which was registered earlier, via
+ * sys_set_robust_list()):
+ */
+ if (get_user(uentry, &head->list.next))
+ return;
+ entry = compat_ptr(uentry);
+ /*
+ * Fetch the relative futex offset:
+ */
+ if (get_user(futex_offset, &head->futex_offset))
+ return;
+ /*
+ * Fetch any possibly pending lock-add first, and handle it
+ * if it exists:
+ */
+ if (get_user(upending, &head->list_op_pending))
+ return;
+ pending = compat_ptr(upending);
+ if (upending)
+ handle_futex_death((void *)pending + futex_offset, curr);
+
+ while (compat_ptr(uentry) != &head->list) {
+ /*
+ * A pending lock might already be on the list, so
+ * dont process it twice:
+ */
+ if (entry != pending)
+ if (handle_futex_death((void *)entry + futex_offset,
+ curr))
+ return;
+
+ /*
+ * Fetch the next entry in the list:
+ */
+ if (get_user(uentry, (compat_uptr_t *)&entry->next))
+ return;
+ entry = compat_ptr(uentry);
+ /*
+ * Avoid excessively long or circular lists:
+ */
+ if (!--limit)
+ break;
+
+ cond_resched();
+ }
+}
+
+asmlinkage long
+compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
+ compat_size_t len)
+{
+ if (unlikely(len != sizeof(*head)))
+ return -EINVAL;
+
+ current->compat_robust_list = head;
+
+ return 0;
+}
+
+asmlinkage long
+compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
+ compat_size_t __user *len_ptr)
+{
+ struct compat_robust_list_head *head;
+ unsigned long ret;
+
+ if (!pid)
+ head = current->compat_robust_list;
+ else {
+ struct task_struct *p;
+
+ ret = -ESRCH;
+ read_lock(&tasklist_lock);
+ p = find_task_by_pid(pid);
+ if (!p)
+ goto err_unlock;
+ ret = -EPERM;
+ if ((current->euid != p->euid) && (current->euid != p->uid) &&
+ !capable(CAP_SYS_PTRACE))
+ goto err_unlock;
+ head = p->compat_robust_list;
+ read_unlock(&tasklist_lock);
+ }
+
+ if (put_user(sizeof(*head), len_ptr))
+ return -EFAULT;
+ return put_user(ptr_to_compat(head), head_ptr);
+
+err_unlock:
+ read_unlock(&tasklist_lock);
+
+ return ret;
+}
+
+asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, int val,
+ struct compat_timespec __user *utime, u32 __user *uaddr2,
+ int val3)
+{
+ struct timespec t;
+ unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
+ int val2 = 0;
+
+ if ((op == FUTEX_WAIT) && utime) {
+ if (get_compat_timespec(&t, utime))
+ return -EFAULT;
+ timeout = timespec_to_jiffies(&t) + 1;
+ }
+ if (op >= FUTEX_REQUEUE)
+ val2 = (int) (unsigned long) utime;
+
+ return do_futex((unsigned long)uaddr, op, val, timeout,
+ (unsigned long)uaddr2, val2, val3);
+}
