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- From 226f58c078e55ba665fb49139cdc4990f4bde684 Mon Sep 17 00:00:00 2001
- From: Phil Elwell <phil@raspberrypi.org>
- Date: Tue, 29 Mar 2016 15:32:30 +0100
- Subject: [PATCH 215/381] copy_from_user: CPU_SW_DOMAIN_PAN compatibility
- The downstream copy_from_user acceleration must also play nice with
- CONFIG_CPU_SW_DOMAIN_PAN.
- See: https://github.com/raspberrypi/linux/issues/1381
- Signed-off-by: Phil Elwell <phil@raspberrypi.org>
- ---
- arch/arm/lib/uaccess_with_memcpy.c | 14 +++++++++++---
- 1 file changed, 11 insertions(+), 3 deletions(-)
- --- a/arch/arm/lib/uaccess_with_memcpy.c
- +++ b/arch/arm/lib/uaccess_with_memcpy.c
- @@ -186,6 +186,7 @@ out:
- unsigned long noinline
- __copy_from_user_memcpy(void *to, const void __user *from, unsigned long n)
- {
- + unsigned long ua_flags;
- int atomic;
-
- if (unlikely(segment_eq(get_fs(), KERNEL_DS))) {
- @@ -217,7 +218,9 @@ __copy_from_user_memcpy(void *to, const
- if (tocopy > n)
- tocopy = n;
-
- + ua_flags = uaccess_save_and_enable();
- memcpy(to, (const void *)from, tocopy);
- + uaccess_restore(ua_flags);
- to += tocopy;
- from += tocopy;
- n -= tocopy;
- @@ -261,9 +264,14 @@ arm_copy_from_user(void *to, const void
- * With frame pointer disabled, tail call optimization kicks in
- * as well making this test almost invisible.
- */
- - if (n < COPY_FROM_USER_THRESHOLD)
- - return __copy_from_user_std(to, from, n);
- - return __copy_from_user_memcpy(to, from, n);
- + if (n < COPY_TO_USER_THRESHOLD) {
- + unsigned long ua_flags = uaccess_save_and_enable();
- + n = __copy_from_user_std(to, from, n);
- + uaccess_restore(ua_flags);
- + } else {
- + n = __copy_from_user_memcpy(to, from, n);
- + }
- + return n;
- }
-
- static unsigned long noinline
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