gpu: nvgpu: Create unique share id

This is fixing a race in address space identifier
creation by making atomic variable increment.

Bug 3684734

Change-Id: I864e8f61257569e35f926822c2a5260532d41360
Signed-off-by: Dinesh T <dt@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2742206
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-cert <svc-mobile-cert@nvidia.com>
Reviewed-by: Vaibhav Kachore <vkachore@nvidia.com>
Reviewed-by: Sagar Kamble <skamble@nvidia.com>
Reviewed-by: Richard Zhao <rizhao@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/gpu/nvgpu/common/mm/as.c

@@ -1,7 +1,7 @@
 /*
  * GK20A Address Spaces
  *
- * Copyright (c) 2011-2021, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2022, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -32,32 +32,28 @@
 
 #define VM_NAME_PREFIX	"as_"
 
-/* dumb allocator... */
+static nvgpu_atomic_t unique_share_id = NVGPU_ATOMIC_INIT(0);
-static int generate_as_share_id(struct gk20a_as *as)
+/*
+ * Generate unique id by doing atomic increment on unique_share_id.
+ */
+static int generate_unique_share_id(void)
 {
-	struct gk20a *g = gk20a_from_as(as);
+	int ret = 0;
 
-	nvgpu_log_fn(g, " ");
+	ret = nvgpu_atomic_inc_return(&unique_share_id);
-	as->last_share_id = nvgpu_safe_add_s32(as->last_share_id, 1);
+	if (ret == 0) {
-	return as->last_share_id;
+		nvgpu_err(NULL, "incrementing share_id overflow");
-}
-/* still dumb */
-static void release_as_share_id(struct gk20a_as_share *as_share)
-{
-	struct gk20a *g = gk20a_from_as(as_share->as);
-
-	nvgpu_log_fn(g, " ");
-	return;
 	}
 
+	return ret;
+}
 /* address space interfaces for the gk20a module */
 static int gk20a_vm_alloc_share(struct gk20a_as_share *as_share,
 				u32 big_page_size, u32 flags,
 				u64 va_range_start, u64 va_range_end,
 				u64 va_range_split)
 {
-	struct gk20a_as *as = as_share->as;
+	struct gk20a *g = as_share->g;
-	struct gk20a *g = gk20a_from_as(as);
 	struct mm_gk20a *mm = &g->mm;
 	struct vm_gk20a *vm;
 	char name[NVGPU_VM_NAME_LEN] = VM_NAME_PREFIX;
@@ -171,8 +167,8 @@ int gk20a_as_alloc_share(struct gk20a *g,
 		return -ENOMEM;
 	}
 
-	as_share->as = &g->as;
+	as_share->g = g;
-	as_share->id = generate_as_share_id(as_share->as);
+	as_share->id = generate_unique_share_id();
 
 	/* this will set as_share->vm. */
 	err = gk20a_busy(g);
@@ -232,14 +228,8 @@ int gk20a_as_release_share(struct gk20a_as_share *as_share)
 	gk20a_idle(g);
 
 release_fail:
-	release_as_share_id(as_share);
 	nvgpu_put(g);
 	nvgpu_kfree(g, as_share);
 
 	return err;
 }
-
-struct gk20a *gk20a_from_as(struct gk20a_as *as)
-{
-	return (struct gk20a *)((uintptr_t)as - offsetof(struct gk20a, as));
-}

drivers/gpu/nvgpu/include/nvgpu/as.h

@@ -1,7 +1,7 @@
 /*
  * GK20A Address Spaces
  *
- * Copyright (c) 2011-2021, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2022, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -29,16 +29,6 @@
 struct vm_gk20a;
 struct gk20a;
 
-/**
- * Basic structure to identify an address space (AS).
- */
-struct gk20a_as {
-	/**
-	 * Incrementing id to identify the AS, dummy allocator for now.
-	 */
-	int last_share_id;
-};
-
 /**
  * Basic structure to share an AS.
  */
@@ -46,7 +36,7 @@ struct gk20a_as_share {
 	/**
 	 * The AS to share.
 	 */
-	struct gk20a_as *as;
+	struct gk20a *g;
 
 	/**
 	 * The VM used by the AS.
@@ -144,15 +134,4 @@ int gk20a_as_alloc_share(struct gk20a *g, u32 big_page_size,
 			u64 va_range_end, u64 va_range_split,
 			struct gk20a_as_share **out);
 
-/**
- * @brief Retrieve the instance of gk20a from a gk20a_as instance.
- *
- * @param as [in] The address space
- *
- * Given an instance of gk20a_as, retrieve a pointer to the underlying gk20a
- * instance.
- *
- * @return pointer to the underlying GPU (gk20a).
- */
-struct gk20a *gk20a_from_as(struct gk20a_as *as);
 #endif /* NVGPU_AS_H */

drivers/gpu/nvgpu/include/nvgpu/gk20a.h

@@ -693,9 +693,6 @@ struct gk20a {
 	u32 pg_ms_gating_cnt;
 #endif
 
-	/** GPU address-space identifier. */
-	struct gk20a_as as;
-
 	/** The HAL function pointers */
 	struct gpu_ops ops;
 

drivers/gpu/nvgpu/os/linux/ioctl_as.c

@@ -1,7 +1,7 @@
 /*
  * GK20A Address Spaces
  *
- * Copyright (c) 2011-2021, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2022, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -457,7 +457,7 @@ long gk20a_as_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	int err = 0;
 	struct gk20a_as_share *as_share = filp->private_data;
-	struct gk20a *g = gk20a_from_as(as_share->as);
+	struct gk20a *g = as_share->g;
 	bool always_copy_to_user = false;
 	u8 buf[NVGPU_AS_IOCTL_MAX_ARG_SIZE];
 

libs/igpu/libnvgpu-drv-igpu_safe.export

@@ -17,7 +17,6 @@ gk20a_fifo_intr_1_isr
 gk20a_fifo_intr_handle_chsw_error
 gk20a_fifo_intr_handle_runlist_event
 gk20a_fifo_pbdma_isr
-gk20a_from_as
 gk20a_get_pde_pgsz
 gk20a_get_pte_pgsz
 gk20a_mm_fb_flush

userspace/required_tests.ini

@@ -333,18 +333,17 @@ test_pause_resume_mask.pause_resume_mask=0
 test_unit_config.unit_config=2
 
 [mm.as]
-test_as_alloc_share.as_alloc_share_0k_um=0
+test_as_alloc_share.as_alloc_share_0k_um=2
-test_as_alloc_share.as_alloc_share_64k_um=0
+test_as_alloc_share.as_alloc_share_64k_um=2
 test_as_alloc_share.as_alloc_share_64k_um_as_fail=0
 test_as_alloc_share.as_alloc_share_64k_um_busy_fail_1=0
-test_as_alloc_share.as_alloc_share_64k_um_busy_fail_2=0
+test_as_alloc_share.as_alloc_share_64k_um_busy_fail_2=2
 test_as_alloc_share.as_alloc_share_64k_um_vm_fail=0
 test_as_alloc_share.as_alloc_share_einval_um=0
 test_as_alloc_share.as_alloc_share_notp2_um=0
-test_as_alloc_share.as_alloc_share_uva=0
+test_as_alloc_share.as_alloc_share_uva=2
-test_as_alloc_share.as_alloc_share_uva_enabled=0
+test_as_alloc_share.as_alloc_share_uva_enabled=2
 test_init_mm.init=0
-test_gk20a_from_as.gk20a_from_as=0
 
 [mm.dma]
 test_mm_dma_alloc.alloc=0

userspace/units/mm/as/as.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2022, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -268,33 +268,6 @@ int test_as_alloc_share(struct unit_module *m, struct gk20a *g, void *args)
 	return UNIT_SUCCESS;
 }
 
-int test_gk20a_from_as(struct unit_module *m, struct gk20a *g, void *args)
-{
-	int ret = UNIT_FAIL;
-	struct gk20a_as_share *out;
-	int err;
-
-	err = gk20a_as_alloc_share(g, SZ_64K, NVGPU_AS_ALLOC_USERSPACE_MANAGED,
-			(SZ_64K << 10), (1ULL << 37),
-			nvgpu_gmmu_va_small_page_limit(), &out);
-	if (err != 0) {
-		unit_return_fail(m, "gk20a_as_alloc_share failed err=%d\n",
-			err);
-	}
-
-	if (g != gk20a_from_as(out->as)) {
-		unit_err(m, "ptr mismatch in gk20a_from_as\n");
-		goto exit;
-	}
-
-	ret = UNIT_SUCCESS;
-
-exit:
-	gk20a_as_release_share(out);
-
-	return ret;
-}
-
 struct unit_module_test nvgpu_mm_as_tests[] = {
 	UNIT_TEST(init, test_init_mm, NULL, 0),
 	UNIT_TEST(as_alloc_share_64k_um_as_fail, test_as_alloc_share,
@@ -304,20 +277,19 @@ struct unit_module_test nvgpu_mm_as_tests[] = {
 	UNIT_TEST(as_alloc_share_64k_um_busy_fail_1, test_as_alloc_share,
 		(void *) &test_64k_user_managed_busy_fail_1, 0),
 	UNIT_TEST(as_alloc_share_64k_um_busy_fail_2, test_as_alloc_share,
-		(void *) &test_64k_user_managed_busy_fail_2, 0),
+		(void *) &test_64k_user_managed_busy_fail_2, 2),
 	UNIT_TEST(as_alloc_share_64k_um, test_as_alloc_share,
-		(void *) &test_64k_user_managed, 0),
+		(void *) &test_64k_user_managed, 2),
 	UNIT_TEST(as_alloc_share_0k_um, test_as_alloc_share,
-		(void *) &test_0k_user_managed, 0),
+		(void *) &test_0k_user_managed, 2),
 	UNIT_TEST(as_alloc_share_einval_um, test_as_alloc_share,
 		(void *) &test_einval_user_managed, 0),
 	UNIT_TEST(as_alloc_share_notp2_um, test_as_alloc_share,
 		(void *) &test_notp2_user_managed, 0),
 	UNIT_TEST(as_alloc_share_uva, test_as_alloc_share,
-		(void *) &test_64k_unified_va, 0),
+		(void *) &test_64k_unified_va, 2),
 	UNIT_TEST(as_alloc_share_uva_enabled, test_as_alloc_share,
-		(void *) &test_64k_unified_va_enabled, 0),
+		(void *) &test_64k_unified_va_enabled, 2),
-	UNIT_TEST(gk20a_from_as, test_gk20a_from_as, NULL, 0),
 };
 
 UNIT_MODULE(mm.as, nvgpu_mm_as_tests, UNIT_PRIO_NVGPU_TEST);

userspace/units/mm/as/as.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2022, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -119,7 +119,7 @@ int test_init_mm(struct unit_module *m, struct gk20a *g, void *args);
  * Test Type: Feature
  *
  * Targets: gk20a_as_alloc_share, gk20a_as_release_share,
- * gk20a_vm_release_share, gk20a_from_as
+ * gk20a_vm_release_share
  *
  * Input:
  * - The test_init_mm must have been executed
@@ -153,24 +153,4 @@ int test_init_mm(struct unit_module *m, struct gk20a *g, void *args);
  */
 int test_as_alloc_share(struct unit_module *m, struct gk20a *g, void *args);
 
-/**
- * Test specification for: test_gk20a_from_as
- *
- * Description: Simple test to check gk20a_from_as.
- *
- * Test Type: Feature
- *
- * Targets: gk20a_from_as
- *
- * Input: None
- *
- * Steps:
- * - Call gk20a_from_as with an 'as' pointer and ensure it returns a
- *   pointer on g.
- *
- * Output: Returns PASS if the steps above were executed successfully. FAIL
- * otherwise.
- */
-int test_gk20a_from_as(struct unit_module *m, struct gk20a *g, void *args);
-
 #endif /* UNIT_MM_AS_H */