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<div class="moz-cite-prefix">On 21-03-2024 02:27, Rodrigo Vivi
wrote:<br>
</div>
<blockquote type="cite" cite="mid:ZftN0eDAtRN1YnsG@intel.com">
<pre class="moz-quote-pre" wrap="">On Wed, Mar 20, 2024 at 03:48:35PM +0530, Himal Prasad Ghimiray wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Cast to proper datatypes to avoid overflows.
</pre>
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<pre class="moz-quote-pre" wrap="">
I'm afraid that the cast wont prevent the overflow, but mask it.
probably safer to move the multiplication to some of the helpers
in linux/math64.h ?!</pre>
</blockquote>
<font face="monospace">Hi Rodrigo,<br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Thank you for your response. The modifications are inspired by the inline </span><code style="border: 0px solid rgb(227, 227, 227); box-sizing: border-box; --tw-border-spacing-x: 0; --tw-border-spacing-y: 0; --tw-translate-x: 0; --tw-translate-y: 0; --tw-rotate: 0; --tw-skew-x: 0; --tw-skew-y: 0; --tw-scale-x: 1; --tw-scale-y: 1; --tw-pan-x: ; --tw-pan-y: ; --tw-pinch-zoom: ; --tw-scroll-snap-strictness: proximity; --tw-gradient-from-position: ; --tw-gradient-via-position: ; --tw-gradient-to-position: ; --tw-ordinal: ; --tw-slashed-zero: ; --tw-numeric-figure: ; --tw-numeric-spacing: ; --tw-numeric-fraction: ; --tw-ring-inset: ; --tw-ring-offset-width: 0px; --tw-ring-offset-color: #fff; --tw-ring-color: rgba(69,89,164,.5); --tw-ring-offset-shadow: 0 0 transparent; --tw-ring-shadow: 0 0 transparent; --tw-shadow: 0 0 transparent; --tw-shadow-colored: 0 0 transparent; --tw-blur: ; --tw-brightness: ; --tw-contrast: ; --tw-grayscale: ; --tw-hue-rotate: ; --tw-invert: ; --tw-saturate: ; --tw-sepia: ; --tw-drop-shadow: ; --tw-backdrop-blur: ; --tw-backdrop-brightness: ; --tw-backdrop-contrast: ; --tw-backdrop-grayscale: ; --tw-backdrop-hue-rotate: ; --tw-backdrop-invert: ; --tw-backdrop-opacity: ; --tw-backdrop-saturate: ; --tw-backdrop-sepia: ; font-size: 0.875em; color: rgb(13, 13, 13); font-weight: 600; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">u64 mul_u32_u32(u32 a, u32 b)</code><span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"> </span><br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">function defined in </span><code style="border: 0px solid rgb(227, 227, 227); box-sizing: border-box; --tw-border-spacing-x: 0; --tw-border-spacing-y: 0; --tw-translate-x: 0; --tw-translate-y: 0; --tw-rotate: 0; --tw-skew-x: 0; --tw-skew-y: 0; --tw-scale-x: 1; --tw-scale-y: 1; --tw-pan-x: ; --tw-pan-y: ; --tw-pinch-zoom: ; --tw-scroll-snap-strictness: proximity; --tw-gradient-from-position: ; --tw-gradient-via-position: ; --tw-gradient-to-position: ; --tw-ordinal: ; --tw-slashed-zero: ; --tw-numeric-figure: ; --tw-numeric-spacing: ; --tw-numeric-fraction: ; --tw-ring-inset: ; --tw-ring-offset-width: 0px; --tw-ring-offset-color: #fff; --tw-ring-color: rgba(69,89,164,.5); --tw-ring-offset-shadow: 0 0 transparent; --tw-ring-shadow: 0 0 transparent; --tw-shadow: 0 0 transparent; --tw-shadow-colored: 0 0 transparent; --tw-blur: ; --tw-brightness: ; --tw-contrast: ; --tw-grayscale: ; --tw-hue-rotate: ; --tw-invert: ; --tw-saturate: ; --tw-sepia: ; --tw-drop-shadow: ; --tw-backdrop-blur: ; --tw-backdrop-brightness: ; --tw-backdrop-contrast: ; --tw-backdrop-grayscale: ; --tw-backdrop-hue-rotate: ; --tw-backdrop-invert: ; --tw-backdrop-opacity: ; --tw-backdrop-saturate: ; --tw-backdrop-sepia: ; font-size: 0.875em; color: rgb(13, 13, 13); font-weight: 600; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">linux/math64.h</code><span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">. Initially, I considered using the same approach. </span><br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">However, I discovered an architecture-specific implementation for </span><code style="border: 0px solid rgb(227, 227, 227); box-sizing: border-box; --tw-border-spacing-x: 0; --tw-border-spacing-y: 0; --tw-translate-x: 0; --tw-translate-y: 0; --tw-rotate: 0; --tw-skew-x: 0; --tw-skew-y: 0; --tw-scale-x: 1; --tw-scale-y: 1; --tw-pan-x: ; --tw-pan-y: ; --tw-pinch-zoom: ; --tw-scroll-snap-strictness: proximity; --tw-gradient-from-position: ; --tw-gradient-via-position: ; --tw-gradient-to-position: ; --tw-ordinal: ; --tw-slashed-zero: ; --tw-numeric-figure: ; --tw-numeric-spacing: ; --tw-numeric-fraction: ; --tw-ring-inset: ; --tw-ring-offset-width: 0px; --tw-ring-offset-color: #fff; --tw-ring-color: rgba(69,89,164,.5); --tw-ring-offset-shadow: 0 0 transparent; --tw-ring-shadow: 0 0 transparent; --tw-shadow: 0 0 transparent; --tw-shadow-colored: 0 0 transparent; --tw-blur: ; --tw-brightness: ; --tw-contrast: ; --tw-grayscale: ; --tw-hue-rotate: ; --tw-invert: ; --tw-saturate: ; --tw-sepia: ; --tw-drop-shadow: ; --tw-backdrop-blur: ; --tw-backdrop-brightness: ; --tw-backdrop-contrast: ; --tw-backdrop-grayscale: ; --tw-backdrop-hue-rotate: ; --tw-backdrop-invert: ; --tw-backdrop-opacity: ; --tw-backdrop-saturate: ; --tw-backdrop-sepia: ; font-size: 0.875em; color: rgb(13, 13, 13); font-weight: 600; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;">mul_u32_u32</code><span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">. </span><br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">To prevent ambiguity, I opted for casting, which I observed is a standard practice throughout Linux code.</span><br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">BR</span><br>
<span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Himal </span><span style="color: rgb(13, 13, 13); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">
</span></font>
<blockquote type="cite" cite="mid:ZftN0eDAtRN1YnsG@intel.com">
<pre class="moz-quote-pre" wrap="">
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">
Cc: Matthew Auld <a class="moz-txt-link-rfc2396E" href="mailto:matthew.auld@intel.com"><matthew.auld@intel.com></a>
Cc: Matthew Brost <a class="moz-txt-link-rfc2396E" href="mailto:matthew.brost@intel.com"><matthew.brost@intel.com></a>
Cc: Rodrigo Vivi <a class="moz-txt-link-rfc2396E" href="mailto:rodrigo.vivi@intel.com"><rodrigo.vivi@intel.com></a>
Signed-off-by: Himal Prasad Ghimiray <a class="moz-txt-link-rfc2396E" href="mailto:himal.prasad.ghimiray@intel.com"><himal.prasad.ghimiray@intel.com></a>
---
These errors were highlighted by Coverity. I'm uncertain whether they
require attention or if it would be more appropriate to label them as
false positives within the tool.
I've submitted this patch in case addressing the issues is necessary.
However, if reviewers determine that these issues should be marked as
false positives or ignored within the tool, that option is also
available
drivers/gpu/drm/xe/xe_migrate.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index ee1bb938c493..2ba4fb9511f6 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -227,7 +227,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
if (vm->flags & XE_VM_FLAG_64K && level == 1)
flags = XE_PDE_64K;
- entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level - 1) *
+ entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (u64)(level - 1) *
XE_PAGE_SIZE, pat_index);
xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE * level, u64,
entry | flags);
@@ -235,7 +235,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
/* Write PDE's that point to our BO. */
for (i = 0; i < num_entries - num_level; i++) {
- entry = vm->pt_ops->pde_encode_bo(bo, i * XE_PAGE_SIZE,
+ entry = vm->pt_ops->pde_encode_bo(bo, (u64)i * XE_PAGE_SIZE,
pat_index);
xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE +
@@ -291,7 +291,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
#define VM_SA_UPDATE_UNIT_SIZE (XE_PAGE_SIZE / NUM_VMUSA_UNIT_PER_PAGE)
#define NUM_VMUSA_WRITES_PER_UNIT (VM_SA_UPDATE_UNIT_SIZE / sizeof(u64))
drm_suballoc_manager_init(&m->vm_update_sa,
- (map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
+ (size_t)(map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
NUM_VMUSA_UNIT_PER_PAGE, 0);
m->pt_bo = bo;
@@ -490,7 +490,7 @@ static void emit_pte(struct xe_migrate *m,
struct xe_vm *vm = m->q->vm;
u16 pat_index;
u32 ptes;
- u64 ofs = at_pt * XE_PAGE_SIZE;
+ u64 ofs = (u64)at_pt * XE_PAGE_SIZE;
u64 cur_ofs;
/* Indirect access needs compression enabled uncached PAT index */
--
2.25.1
</pre>
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