1 files changed, 71 insertions, 41 deletions

diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c
index 26e9c4eeaba8..4a609e9b65de 100644
--- a/arch/arm64/kernel/sys_compat.c
+++ b/arch/arm64/kernel/sys_compat.c
@@ -1,64 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Based on arch/arm/kernel/sys_arm.c
  *
  * Copyright (C) People who wrote linux/arch/i386/kernel/sys_i386.c
  * Copyright (C) 1995, 1996 Russell King.
  * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <linux/compat.h>
-#include <linux/personality.h>
+#include <linux/cpufeature.h>
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 
 #include <asm/cacheflush.h>
-#include <asm/unistd32.h>
+#include <asm/system_misc.h>
+#include <asm/tlbflush.h>
+#include <asm/unistd.h>
 
-static inline void
-do_compat_cache_op(unsigned long start, unsigned long end, int flags)
+static long
+__do_compat_cache_op(unsigned long start, unsigned long end)
 {
-	struct mm_struct *mm = current->active_mm;
-	struct vm_area_struct *vma;
+	long ret;
 
-	if (end < start || flags)
-		return;
-
-	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, start);
-	if (vma && vma->vm_start < end) {
-		if (start < vma->vm_start)
-			start = vma->vm_start;
-		if (end > vma->vm_end)
-			end = vma->vm_end;
-		up_read(&mm->mmap_sem);
-		__flush_cache_user_range(start & PAGE_MASK, PAGE_ALIGN(end));
-		return;
-	}
-	up_read(&mm->mmap_sem);
+	do {
+		unsigned long chunk = min(PAGE_SIZE, end - start);
+
+		if (fatal_signal_pending(current))
+			return 0;
+
+		if (cpus_have_final_cap(ARM64_WORKAROUND_1542419)) {
+			/*
+			 * The workaround requires an inner-shareable tlbi.
+			 * We pick the reserved-ASID to minimise the impact.
+			 */
+			__tlbi(aside1is, __TLBI_VADDR(0, 0));
+			dsb(ish);
+		}
+
+		ret = caches_clean_inval_user_pou(start, start + chunk);
+		if (ret)
+			return ret;
+
+		cond_resched();
+		start += chunk;
+	} while (start < end);
+
+	return 0;
 }
 
+static inline long
+do_compat_cache_op(unsigned long start, unsigned long end, int flags)
+{
+	if (end < start || flags)
+		return -EINVAL;
+
+	if (!access_ok((const void __user *)start, end - start))
+		return -EFAULT;
+
+	return __do_compat_cache_op(start, end);
+}
 /*
  * Handle all unrecognised system calls.
  */
-long compat_arm_syscall(struct pt_regs *regs)
+long compat_arm_syscall(struct pt_regs *regs, int scno)
 {
-	unsigned int no = regs->regs[7];
+	unsigned long addr;
 
-	switch (no) {
+	switch (scno) {
 	/*
 	 * Flush a region from virtual address 'r0' to virtual address 'r1'
 	 * _exclusive_.  There is no alignment requirement on either address;
@@ -74,15 +85,34 @@ long compat_arm_syscall(struct pt_regs *regs)
 	 * the specified region).
 	 */
 	case __ARM_NR_compat_cacheflush:
-		do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]);
-		return 0;
+		return do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]);
 
 	case __ARM_NR_compat_set_tls:
-		current->thread.tp_value = regs->regs[0];
-		asm ("msr tpidrro_el0, %0" : : "r" (regs->regs[0]));
+		current->thread.uw.tp_value = regs->regs[0];
+
+		/*
+		 * Protect against register corruption from context switch.
+		 * See comment in tls_thread_flush.
+		 */
+		barrier();
+		write_sysreg(regs->regs[0], tpidrro_el0);
 		return 0;
 
 	default:
-		return -ENOSYS;
+		/*
+		 * Calls 0xf0xxx..0xf07ff are defined to return -ENOSYS
+		 * if not implemented, rather than raising SIGILL. This
+		 * way the calling program can gracefully determine whether
+		 * a feature is supported.
+		 */
+		if (scno < __ARM_NR_COMPAT_END)
+			return -ENOSYS;
+		break;
 	}
+
+	addr = instruction_pointer(regs) - (compat_thumb_mode(regs) ? 2 : 4);
+
+	arm64_notify_die("Oops - bad compat syscall(2)", regs,
+			 SIGILL, ILL_ILLTRP, addr, 0);
+	return 0;
 }