arm64: compat: align cacheflush syscall with arch/arm
Update handling of cacheflush syscall with changes made in arch/arm
counterpart:
- return error to userspace when flushing syscall fails
- split user cache-flushing into interruptible chunks
- don't bother rounding to nearest vma
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
[will: changed internal return value from -EINTR to 0 to match arch/arm/]
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 689b637..7ae31a2 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -73,7 +73,7 @@
extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
extern void flush_icache_range(unsigned long start, unsigned long end);
extern void __flush_dcache_area(void *addr, size_t len);
-extern void __flush_cache_user_range(unsigned long start, unsigned long end);
+extern long __flush_cache_user_range(unsigned long start, unsigned long end);
static inline void flush_cache_mm(struct mm_struct *mm)
{
diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c
index dc47e53..28c511b 100644
--- a/arch/arm64/kernel/sys_compat.c
+++ b/arch/arm64/kernel/sys_compat.c
@@ -28,29 +28,39 @@
#include <asm/cacheflush.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;
+ do {
+ unsigned long chunk = min(PAGE_SIZE, end - start);
- 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);
+ if (fatal_signal_pending(current))
+ return 0;
+
+ ret = __flush_cache_user_range(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(VERIFY_READ, start, end - start))
+ return -EFAULT;
+
+ return __do_compat_cache_op(start, end);
+}
/*
* Handle all unrecognised system calls.
*/
@@ -74,8 +84,7 @@
* 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];
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 8eaf185..2560e1e 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -17,6 +17,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
@@ -140,9 +141,12 @@
add x4, x4, x2
cmp x4, x1
b.lo 1b
-9: // ignore any faulting cache operation
dsb ish
isb
+ mov x0, #0
+ ret
+9:
+ mov x0, #-EFAULT
ret
ENDPROC(flush_icache_range)
ENDPROC(__flush_cache_user_range)