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Remove LDP_DRIVER_6

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The cause for this policy was due to dynamic linker behavior which could have
resulted in the wrong symbols being used. However, this didn't occur in
practical usage of the dynamic linker. Also drivers exporting Vulkan
entrypoints was a useful behavior to enable testing and more flexible usage
that this policy actively interfered with.
This commit is contained in:
Charles Giessen 2022-03-24 16:44:14 -06:00 committed by Charles Giessen
parent ea503f36e6
commit 8354f108f5
2 changed files with 38 additions and 36 deletions
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60
docs/LoaderDriverInterface.md
View File

@ -1334,29 +1334,12 @@ Android Vulkan documentation</a>.
</tr>
<tr>
<td><small><b>LDP_DRIVER_6</b></small></td>
<td>A driver supporting loader/driver interface version 1 or newer <b>must
not</b> directly export standard Vulkan entry-points.
<br/>
Instead, it <b>must</b> export only the loader interface functions
required by the interface versions it does support (for example
<i>vk_icdGetInstanceProcAddr</i>). <br/>
This is because the dynamic linking on some platforms has been
problematic in the past and incorrectly links to exported functions from
the wrong dynamic library at times. <br/>
<b>NOTE:</b> This is actually true for all exports.
When in doubt, don't export any items from a driver that could cause
conflicts in other libraries.
</td>
<td>The behavior is undefined and may result in crashes or corruption.</td>
<td>Yes (except it always applies)</td>
<td>Yes</td>
<td><small>
<a href="#loader-and-driver-interface-negotiation">
Interface Negotiation</a></small>
and
<a href="#driver-vulkan-entry-point-discovery">
Vulkan Entry-point Discovery</a></small>
<td>Removed - See <a href="#removed-driver-policies">Removed Driver Policies</a>
</td>
<td>-</td>
<td>-</td>
<td>-</td>
<td>-</td>
</tr>
<tr>
<td><small><b>LDP_DRIVER_7</b></small></td>
@ -1460,6 +1443,39 @@ Android Vulkan documentation</a>.
</tr>
</table>
#### Removed Driver Policies
These policies were in the loader source at some point but later removed. They are documented here for reference.
<table>
<tr>
<th>Requirement Number</th>
<th>Requirement Description</th>
<th>Removal Reason</th>
</tr>
<tr>
<td><small><b>LDP_DRIVER_6</b></small></td>
<td>A driver supporting loader/driver interface version 1 or newer <b>must
not</b> directly export standard Vulkan entry-points.
<br/>
Instead, it <b>must</b> export only the loader interface functions
required by the interface versions it does support (for example
<i>vk_icdGetInstanceProcAddr</i>). <br/>
This is because the dynamic linking on some platforms has been
problematic in the past and incorrectly links to exported functions from
the wrong dynamic library at times. <br/>
<b>NOTE:</b> This is actually true for all exports.
When in doubt, don't export any items from a driver that could cause
conflicts in other libraries.<br/>
</td>
<td>
This policy has been removed due to there being valid circumstances for
drivers to export core entrypoints.
Additionally, it was not found that dynamic linking would cause many
issues in practice.
</td>
</tr>
</table>
### Requirements of a Well-Behaved Loader

14
loader/loader.c
View File

@ -1483,20 +1483,6 @@ static VkResult loader_scanned_icd_add(const struct loader_instance *inst, struc
" Interface version 5 or newer required to support this version of Vulkan (Policy #LDP_DRIVER_7)",
filename, major_version, minor_version, interface_vers);
}
if (interface_vers >= 1) {
if ((loader_platform_get_proc_address(handle, "vkEnumerateInstanceExtensionProperties") != NULL) ||
(loader_platform_get_proc_address(handle, "vkEnumerateInstanceLayerProperties") != NULL) ||
(loader_platform_get_proc_address(handle, "vkEnumerateInstanceVersion") != NULL) ||
(loader_platform_get_proc_address(handle, "vkGetInstanceProcAddr") != NULL) ||
(loader_platform_get_proc_address(handle, "vkCreateInstance") != NULL) ||
(loader_platform_get_proc_address(handle, "vkGetDeviceProcAddr") != NULL) ||
(loader_platform_get_proc_address(handle, "vkCreateDevice") != NULL)) {
loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
"loader_scanned_icd_add: Driver %s says it supports interface version %u but still exports core "
"entrypoints (Policy #LDP_DRIVER_6)",
filename, interface_vers);
}
}
new_scanned_icd = &(icd_tramp_list->scanned_list[icd_tramp_list->count]);
new_scanned_icd->handle = handle;