[PATCH v2 21/31] arm64: 32-bit (compat) applications support

On Tuesday 14 August 2012, Catalin Marinas wrote:

+#ifdef CONFIG_AARCH32_EMULATION
+#include <linux/compat.h>
+
+#define AARCH32_KERN_SIGRET_CODE_OFFSET	0x500
+
+extern const compat_ulong_t aarch32_sigret_code[6];
+
+int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set,
+		       struct pt_regs *regs);
+int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
+			  sigset_t *set, struct pt_regs *regs);
+
+void compat_setup_restart_syscall(struct pt_regs *regs);
+#else
+
+static inline int compat_setup_frame(int usid, struct k_sigaction *ka,
+				     sigset_t *set, struct pt_regs *regs)
+{
+	BUG();
+}

What good is the run-time BUG() here? Nothing should be calling these
when CONFIG_COMPAT is disabled, so I think you should just remove
the #ifdef around the declarations, and the entire #else case.

+asmlinkage int compat_sys_sched_rr_get_interval(compat_pid_t pid,
+						struct compat_timespec __user *interval)
+{
+	struct timespec t;
+	int ret;
+	mm_segment_t old_fs = get_fs();
+
+	set_fs(KERNEL_DS);
+	ret = sys_sched_rr_get_interval(pid, (struct timespec __user *)&t);
+	set_fs(old_fs);
+	if (put_compat_timespec(&t, interval))
+		return -EFAULT;
+	return ret;
+}
+
+asmlinkage int compat_sys_sendfile(int out_fd, int in_fd,
+				   compat_off_t __user *offset, s32 count)
+{
+	mm_segment_t old_fs = get_fs();
+	int ret;
+	off_t of;
+
+	if (offset && get_user(of, offset))
+		return -EFAULT;
+
+	set_fs(KERNEL_DS);
+	ret = sys_sendfile(out_fd, in_fd, offset ? (off_t __user *)&of : NULL,
+			   count);
+	set_fs(old_fs);
+
+	if (offset && put_user(of, offset))
+		return -EFAULT;
+	return ret;
+}

I guess it's time to move these two into common code. They look like they should
be shared across most architectures that have compat support.

+asmlinkage int compat_sys_personality(compat_ulong_t personality)
+{
+	int ret;
+
+	if (personality(current->personality) == PER_LINUX32 &&
+		personality == PER_LINUX)
+		personality = PER_LINUX32;
+	ret = sys_personality(personality);
+	if (ret == PER_LINUX32)
+		ret = PER_LINUX;
+	return ret;
+}

Where did you get this from?

You should not need compat_sys_personality, just call the native function.

	Arnd