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From 46df5a4cda4c703d075b980359d0bac2a3cd9fc5 Mon Sep 17 00:00:00 2001
From: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Date: Mon, 23 Oct 2017 17:34:52 -0400
Subject: [PATCH 2036/4131] drm/amdkfd: Relaxed mm_access for CMA
mm_access() is not exported. So for DKMS build implement a relaxed
version of mm_access. This will be enabled only when module param
amdkfd.cma_enable is set.
BUG:SWDEV-136049
Change-Id: I4bbab6e74da1c8db465e33bb44f9cc9bc2df6f3a
Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
---
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, 67 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index b2795af..75a9a45 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1681,12 +1681,58 @@ static int kfd_ioctl_get_tile_config(struct file *filep,
}
#if defined(BUILD_AS_DKMS)
-static int kfd_ioctl_cross_memory_copy(struct file *filep,
- struct kfd_process *local_p, void *data)
+static bool kfd_may_access(struct task_struct *task, unsigned int mode)
{
- return 0;
+ 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;
}
-#else
+/* 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)
+{
+ 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;
+}
+#endif
+
static int kfd_ioctl_cross_memory_copy(struct file *filep,
struct kfd_process *local_p, void *data)
{
@@ -1748,7 +1794,13 @@ 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) {
@@ -1928,7 +1980,6 @@ 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 aba3e9d..36da8c4 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_module.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
@@ -89,6 +89,11 @@ 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 cceaa89..1de2d91 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -139,6 +139,12 @@ 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
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