[PATCH v2] drm/xe/pt: Allow for stricter type- and range checking
Thomas Hellström
thomas.hellstrom at linux.intel.com
Fri Feb 9 11:26:55 UTC 2024
Distinguish between xe_pt and the xe_pt_dir subclass when
allocating and freeing. Also use a fixed-size array for the
xe_pt_dir page entries to make life easier for dynamic range-
checkers. Finally rename the page-directory child pointer array
to "children".
While no functional change, this fixes ubsan splats similar to:
[ 51.463021] ------------[ cut here ]------------
[ 51.463022] UBSAN: array-index-out-of-bounds in drivers/gpu/drm/xe/xe_pt.c:47:9
[ 51.463023] index 0 is out of range for type 'xe_ptw *[*]'
[ 51.463024] CPU: 5 PID: 2778 Comm: xe_vm Tainted: G U 6.8.0-rc1+ #218
[ 51.463026] Hardware name: ASUS System Product Name/PRIME B560M-A AC, BIOS 2001 02/01/2023
[ 51.463027] Call Trace:
[ 51.463028] <TASK>
[ 51.463029] dump_stack_lvl+0x47/0x60
[ 51.463030] __ubsan_handle_out_of_bounds+0x95/0xd0
[ 51.463032] xe_pt_destroy+0xa5/0x150 [xe]
[ 51.463088] __xe_pt_unbind_vma+0x36c/0x9b0 [xe]
[ 51.463144] xe_vm_unbind+0xd8/0x580 [xe]
[ 51.463204] ? drm_exec_prepare_obj+0x3f/0x60 [drm_exec]
[ 51.463208] __xe_vma_op_execute+0x5da/0x910 [xe]
[ 51.463268] ? __drm_gpuvm_sm_unmap+0x1cb/0x220 [drm_gpuvm]
[ 51.463272] ? radix_tree_node_alloc.constprop.0+0x89/0xc0
[ 51.463275] ? drm_gpuva_it_remove+0x1f3/0x2a0 [drm_gpuvm]
[ 51.463279] ? drm_gpuva_remove+0x2f/0xc0 [drm_gpuvm]
[ 51.463283] xe_vm_bind_ioctl+0x1a55/0x20b0 [xe]
[ 51.463344] ? __pfx_xe_vm_bind_ioctl+0x10/0x10 [xe]
[ 51.463414] drm_ioctl_kernel+0xb6/0x120
[ 51.463416] drm_ioctl+0x287/0x4e0
[ 51.463418] ? __pfx_xe_vm_bind_ioctl+0x10/0x10 [xe]
[ 51.463481] __x64_sys_ioctl+0x94/0xd0
[ 51.463484] do_syscall_64+0x86/0x170
[ 51.463486] ? syscall_exit_to_user_mode+0x7d/0x200
[ 51.463488] ? do_syscall_64+0x96/0x170
[ 51.463490] ? do_syscall_64+0x96/0x170
[ 51.463492] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 51.463494] RIP: 0033:0x7f246bfe817d
[ 51.463498] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
[ 51.463501] RSP: 002b:00007ffc1bd19ad0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 51.463502] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f246bfe817d
[ 51.463504] RDX: 00007ffc1bd19b60 RSI: 0000000040886445 RDI: 0000000000000003
[ 51.463505] RBP: 00007ffc1bd19b20 R08: 0000000000000000 R09: 0000000000000000
[ 51.463506] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc1bd19b60
[ 51.463508] R13: 0000000040886445 R14: 0000000000000003 R15: 0000000000010000
[ 51.463510] </TASK>
[ 51.463517] ---[ end trace ]---
v2
- Fix kerneldoc warning (Matthew Brost)
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
drivers/gpu/drm/xe/xe_pt.c | 39 +++++++++++++++++++++------------
drivers/gpu/drm/xe/xe_pt_walk.c | 2 +-
drivers/gpu/drm/xe/xe_pt_walk.h | 19 +++-------------
3 files changed, 29 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 3a99bf6e558f..1e35c7525447 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -20,8 +20,8 @@
struct xe_pt_dir {
struct xe_pt pt;
- /** @dir: Directory structure for the xe_pt_walk functionality */
- struct xe_ptw_dir dir;
+ /** @children: Array of page-table child nodes */
+ struct xe_ptw *children[XE_PDES];
};
#if IS_ENABLED(CONFIG_DRM_XE_DEBUG_VM)
@@ -44,7 +44,7 @@ static struct xe_pt_dir *as_xe_pt_dir(struct xe_pt *pt)
static struct xe_pt *xe_pt_entry(struct xe_pt_dir *pt_dir, unsigned int index)
{
- return container_of(pt_dir->dir.entries[index], struct xe_pt, base);
+ return container_of(pt_dir->children[index], struct xe_pt, base);
}
static u64 __xe_pt_empty_pte(struct xe_tile *tile, struct xe_vm *vm,
@@ -65,6 +65,14 @@ static u64 __xe_pt_empty_pte(struct xe_tile *tile, struct xe_vm *vm,
XE_PTE_NULL;
}
+static void xe_pt_free(struct xe_pt *pt)
+{
+ if (pt->level)
+ kfree(as_xe_pt_dir(pt));
+ else
+ kfree(pt);
+}
+
/**
* xe_pt_create() - Create a page-table.
* @vm: The vm to create for.
@@ -85,15 +93,19 @@ struct xe_pt *xe_pt_create(struct xe_vm *vm, struct xe_tile *tile,
{
struct xe_pt *pt;
struct xe_bo *bo;
- size_t size;
int err;
- size = !level ? sizeof(struct xe_pt) : sizeof(struct xe_pt_dir) +
- XE_PDES * sizeof(struct xe_ptw *);
- pt = kzalloc(size, GFP_KERNEL);
+ if (level) {
+ struct xe_pt_dir *dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+
+ pt = (dir) ? &dir->pt : NULL;
+ } else {
+ pt = kzalloc(sizeof(*pt), GFP_KERNEL);
+ }
if (!pt)
return ERR_PTR(-ENOMEM);
+ pt->level = level;
bo = xe_bo_create_pin_map(vm->xe, tile, vm, SZ_4K,
ttm_bo_type_kernel,
XE_BO_CREATE_VRAM_IF_DGFX(tile) |
@@ -106,8 +118,7 @@ struct xe_pt *xe_pt_create(struct xe_vm *vm, struct xe_tile *tile,
goto err_kfree;
}
pt->bo = bo;
- pt->level = level;
- pt->base.dir = level ? &as_xe_pt_dir(pt)->dir : NULL;
+ pt->base.children = level ? as_xe_pt_dir(pt)->children : NULL;
if (vm->xef)
xe_drm_client_add_bo(vm->xef->client, pt->bo);
@@ -116,7 +127,7 @@ struct xe_pt *xe_pt_create(struct xe_vm *vm, struct xe_tile *tile,
return pt;
err_kfree:
- kfree(pt);
+ xe_pt_free(pt);
return ERR_PTR(err);
}
@@ -193,7 +204,7 @@ void xe_pt_destroy(struct xe_pt *pt, u32 flags, struct llist_head *deferred)
deferred);
}
}
- kfree(pt);
+ xe_pt_free(pt);
}
/**
@@ -358,7 +369,7 @@ xe_pt_insert_entry(struct xe_pt_stage_bind_walk *xe_walk, struct xe_pt *parent,
struct iosys_map *map = &parent->bo->vmap;
if (unlikely(xe_child))
- parent->base.dir->entries[offset] = &xe_child->base;
+ parent->base.children[offset] = &xe_child->base;
xe_pt_write(xe_walk->vm->xe, map, offset, pte);
parent->num_live++;
@@ -853,7 +864,7 @@ static void xe_pt_commit_bind(struct xe_vma *vma,
xe_pt_destroy(xe_pt_entry(pt_dir, j_),
xe_vma_vm(vma)->flags, deferred);
- pt_dir->dir.entries[j_] = &newpte->base;
+ pt_dir->children[j_] = &newpte->base;
}
kfree(entries[i].pt_entries);
}
@@ -1506,7 +1517,7 @@ xe_pt_commit_unbind(struct xe_vma *vma,
xe_pt_destroy(xe_pt_entry(pt_dir, i),
xe_vma_vm(vma)->flags, deferred);
- pt_dir->dir.entries[i] = NULL;
+ pt_dir->children[i] = NULL;
}
}
}
diff --git a/drivers/gpu/drm/xe/xe_pt_walk.c b/drivers/gpu/drm/xe/xe_pt_walk.c
index 8f6c8d063f39..b8b3d2aea492 100644
--- a/drivers/gpu/drm/xe/xe_pt_walk.c
+++ b/drivers/gpu/drm/xe/xe_pt_walk.c
@@ -74,7 +74,7 @@ int xe_pt_walk_range(struct xe_ptw *parent, unsigned int level,
u64 addr, u64 end, struct xe_pt_walk *walk)
{
pgoff_t offset = xe_pt_offset(addr, level, walk);
- struct xe_ptw **entries = parent->dir ? parent->dir->entries : NULL;
+ struct xe_ptw **entries = parent->children ? parent->children : NULL;
const struct xe_pt_walk_ops *ops = walk->ops;
enum page_walk_action action;
struct xe_ptw *child;
diff --git a/drivers/gpu/drm/xe/xe_pt_walk.h b/drivers/gpu/drm/xe/xe_pt_walk.h
index ec3d1e9efa6d..5ecc4d2f0f65 100644
--- a/drivers/gpu/drm/xe/xe_pt_walk.h
+++ b/drivers/gpu/drm/xe/xe_pt_walk.h
@@ -8,28 +8,15 @@
#include <linux/pagewalk.h>
#include <linux/types.h>
-struct xe_ptw_dir;
-
/**
* struct xe_ptw - base class for driver pagetable subclassing.
- * @dir: Pointer to an array of children if any.
+ * @children: Pointer to an array of children if any.
*
* Drivers could subclass this, and if it's a page-directory, typically
- * embed the xe_ptw_dir::entries array in the same allocation.
+ * embed an array of xe_ptw pointers.
*/
struct xe_ptw {
- struct xe_ptw_dir *dir;
-};
-
-/**
- * struct xe_ptw_dir - page directory structure
- * @entries: Array holding page directory children.
- *
- * It is the responsibility of the user to ensure @entries is
- * correctly sized.
- */
-struct xe_ptw_dir {
- struct xe_ptw *entries[0];
+ struct xe_ptw **children;
};
/**
--
2.43.0
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