From edb11a4423147833df4663d2f82f8c4154491663 Mon Sep 17 00:00:00 2001
From: "Le.Ma" <Le.Ma@amd.com>
Date: Wed, 25 Oct 2017 16:13:34 +0800
Subject: [PATCH 2061/4131] Revert "drm/amdkfd: Relaxed mm_access for CMA"

This reverts commit cc71bb438ee1830c9f971cb08d6e82b333cf18bb.
---
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 61 +++-----------------------------
 drivers/gpu/drm/amd/amdkfd/kfd_module.c  |  5 ---
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h    |  6 ----
 3 files changed, 5 insertions(+), 67 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 75a9a45..b2795af 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1681,58 +1681,12 @@ static int kfd_ioctl_get_tile_config(struct file *filep,
 }
 
 #if defined(BUILD_AS_DKMS)
-static bool kfd_may_access(struct task_struct *task, unsigned int mode)
-{
-	bool access = false;
-	const struct cred *cred = current_cred(), *tcred;
-	kuid_t caller_uid = cred->fsuid;
-	kgid_t caller_gid = cred->fsgid;
-
-	task_lock(task);
-
-	if (same_thread_group(task, current)) {
-		access = true;
-		goto ok;
-	}
-
-	tcred = __task_cred(task);
-	if (uid_eq(caller_uid, tcred->euid) &&
-	    uid_eq(caller_uid, tcred->suid) &&
-	    uid_eq(caller_uid, tcred->uid)  &&
-	    gid_eq(caller_gid, tcred->egid) &&
-	    gid_eq(caller_gid, tcred->sgid) &&
-	    gid_eq(caller_gid, tcred->gid))
-		access = true;
-
-ok:
-	task_unlock(task);
-	return access;
-}
-/* mm_access() is currently not exported. This is a relaxed implementation
- * that allows access as long as both process belong to same uid
- */
-static struct mm_struct *kfd_relaxed_mm_access(struct task_struct *task,
-					       unsigned int mode)
+static int kfd_ioctl_cross_memory_copy(struct file *filep,
+				       struct kfd_process *local_p, void *data)
 {
-	struct mm_struct *mm;
-	int err;
-
-	err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
-	if (err)
-		return ERR_PTR(err);
-
-	mm = get_task_mm(task);
-	if (mm && mm != current->mm &&
-			!kfd_may_access(task, mode)) {
-		mmput(mm);
-		mm = ERR_PTR(-EACCES);
-	}
-	mutex_unlock(&task->signal->cred_guard_mutex);
-
-	return mm;
+	return 0;
 }
-#endif
-
+#else
 static int kfd_ioctl_cross_memory_copy(struct file *filep,
 				       struct kfd_process *local_p, void *data)
 {
@@ -1794,13 +1748,7 @@ static int kfd_ioctl_cross_memory_copy(struct file *filep,
 	}
 
 	/* Check access permission */
-#if defined(BUILD_AS_DKMS)
-	remote_mm = cma_enable ? kfd_relaxed_mm_access(remote_task,
-				PTRACE_MODE_ATTACH_REALCREDS) :
-				ERR_PTR(-EACCES);
-#else
 	remote_mm = mm_access(remote_task, PTRACE_MODE_ATTACH_REALCREDS);
-#endif
 	if (!remote_mm || IS_ERR(remote_mm)) {
 		err = IS_ERR(remote_mm) ? PTR_ERR(remote_mm) : -ESRCH;
 		if (err == -EACCES) {
@@ -1980,6 +1928,7 @@ static int kfd_ioctl_cross_memory_copy(struct file *filep,
 	args->bytes_copied = total_copied;
 	return err;
 }
+#endif
 
 static int kfd_ioctl_get_queue_wave_state(struct file *filep,
 					  struct kfd_process *p, void *data)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_module.c b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
index 36da8c4..aba3e9d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_module.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
@@ -89,11 +89,6 @@ module_param_named(noretry, vega10_noretry, int, 0644);
 MODULE_PARM_DESC(noretry,
 	"Set sh_mem_config.retry_disable on Vega10 (0 = retry enabled (default), 1 = retry disabled)");
 
-int cma_enable;
-module_param(cma_enable, int, 0644);
-MODULE_PARM_DESC(cma_enable,
-	"Enable CMA (1 = enable, 0 = disable (default)). Warning! relaxed access check");
-
 int kgd2kfd_init(unsigned int interface_version,
 		const struct kgd2kfd_calls **g2f)
 {
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 1de2d91..cceaa89 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -139,12 +139,6 @@ extern int ignore_crat;
  */
 extern int vega10_noretry;
 
-/*
- * Currently, mm_access() function is not exported. So for DKMS build,
- * CMA will be enabled only if module param is set.
- */
-extern int cma_enable;
-
 /**
  * enum kfd_sched_policy
  *
-- 
2.7.4