GPUCORE-32592 Fix userbuf imports to respect RO memory

Fix the pinning stage of userbuf imports to correctly respect RO memory
for both CPU and GPU write access, not just GPU access.

Hence, a userbuf that is read-write at import time but then read-only at
map time (by munmap() and then mmap() a different mapping at exactly the
same address) will properly respect the read-only permissions.

In addition, ensure we mark the pages as dirty for both CPU writes as
well as GPU writes.

Signed-off-by: Sean Callanan <spyffe@google.com>
Change-Id: I3eb899277705b82aa344355cd1d2cd5f343ccfff

mali_kbase/mali_kbase_mem.c

diff --git a/mali_kbase/mali_kbase_mem.c b/mali_kbase/mali_kbase_mem.c
index 4b9721f..a2407a0 100644
--- a/mali_kbase/mali_kbase_mem.c
+++ b/mali_kbase/mali_kbase_mem.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
 /*
  *
- * (C) COPYRIGHT 2010-2021 ARM Limited. All rights reserved.
+ * (C) COPYRIGHT 2010-2022 ARM Limited. All rights reserved.
  *
  * This program is free software and is provided to you under the terms of the
  * GNU General Public License version 2 as published by the Free Software
@@ -1683,7 +1683,8 @@
 				/* The allocation could still have active mappings. */
 				if (user_buf->current_mapping_usage_count == 0) {
 					kbase_jd_user_buf_unmap(kctx, reg->gpu_alloc,
-						(reg->flags & KBASE_REG_GPU_WR));
+						(reg->flags & (KBASE_REG_CPU_WR |
+							       KBASE_REG_GPU_WR)));
 				}
 			}
 		}
@@ -4561,6 +4562,7 @@
 	struct mm_struct *mm = alloc->imported.user_buf.mm;
 	long pinned_pages;
 	long i;
+	int write;
 
 	if (WARN_ON(alloc->type != KBASE_MEM_TYPE_IMPORTED_USER_BUF))
 		return -EINVAL;
@@ -4575,41 +4577,37 @@
 	if (WARN_ON(reg->gpu_alloc->imported.user_buf.mm != current->mm))
 		return -EINVAL;
 
+	write = reg->flags & (KBASE_REG_CPU_WR | KBASE_REG_GPU_WR);
+
 #if KERNEL_VERSION(4, 6, 0) > LINUX_VERSION_CODE
-	pinned_pages = get_user_pages(NULL, mm,
-			address,
-			alloc->imported.user_buf.nr_pages,
+	pinned_pages = get_user_pages(
+		NULL, mm, address,
+		alloc->imported.user_buf.nr_pages,
 #if KERNEL_VERSION(4, 4, 168) <= LINUX_VERSION_CODE && \
 KERNEL_VERSION(4, 5, 0) > LINUX_VERSION_CODE
-			reg->flags & KBASE_REG_GPU_WR ? FOLL_WRITE : 0,
-			pages, NULL);
+		write ? FOLL_WRITE : 0, pages, NULL);
 #else
-			reg->flags & KBASE_REG_GPU_WR,
-			0, pages, NULL);
+		write, 0, pages, NULL);
 #endif
 #elif KERNEL_VERSION(4, 9, 0) > LINUX_VERSION_CODE
-	pinned_pages = get_user_pages_remote(NULL, mm,
-			address,
-			alloc->imported.user_buf.nr_pages,
-			reg->flags & KBASE_REG_GPU_WR,
-			0, pages, NULL);
+	pinned_pages = get_user_pages_remote(
+		NULL, mm,
+		address, alloc->imported.user_buf.nr_pages,
+		write, 0, pages, NULL);
 #elif KERNEL_VERSION(4, 10, 0) > LINUX_VERSION_CODE
-	pinned_pages = get_user_pages_remote(NULL, mm,
-			address,
-			alloc->imported.user_buf.nr_pages,
-			reg->flags & KBASE_REG_GPU_WR ? FOLL_WRITE : 0,
-			pages, NULL);
+	pinned_pages = get_user_pages_remote(
+		NULL, mm,
+		address, alloc->imported.user_buf.nr_pages,
+		write ? FOLL_WRITE : 0, pages, NULL);
 #elif KERNEL_VERSION(5, 9, 0) > LINUX_VERSION_CODE
-	pinned_pages = get_user_pages_remote(NULL, mm,
-			address,
-			alloc->imported.user_buf.nr_pages,
-			reg->flags & KBASE_REG_GPU_WR ? FOLL_WRITE : 0,
-			pages, NULL, NULL);
+	pinned_pages = get_user_pages_remote(
+		NULL, mm,
+		address, alloc->imported.user_buf.nr_pages,
+		write ? FOLL_WRITE : 0, pages, NULL, NULL);
 #else
 	pinned_pages = pin_user_pages_remote(
 		mm, address, alloc->imported.user_buf.nr_pages,
-		reg->flags & KBASE_REG_GPU_WR ? FOLL_WRITE : 0, pages, NULL,
-		NULL);
+		write ? FOLL_WRITE : 0, pages, NULL, NULL);
 #endif
 
 	if (pinned_pages <= 0)
@@ -4843,7 +4841,7 @@
 						kbase_reg_current_backed_size(reg),
 						kctx->as_nr);
 
-			if (reg && ((reg->flags & KBASE_REG_GPU_WR) == 0))
+			if (reg && ((reg->flags & (KBASE_REG_CPU_WR | KBASE_REG_GPU_WR)) == 0))
 				writeable = false;
 
 			kbase_jd_user_buf_unmap(kctx, alloc, writeable);