Add Windows Arm64 support #291
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To add Windows Arm64 support was added detection of features via Windows API function IsProcessorFeaturePresent. Added _M_ARM64 to detect CPU_FEATURES_AARCH64 macro on Windows. Added initial code for Windows Arm64 testing and provided test for Raspberry PI 4. We can't use "define_introspection_and_hwcaps.inl" as a common file for all operating systems due to msvc compiler error C2099: initializer is not a constant, so as a workaround for Windows I used separate "define_introspection.inl" See also: google#268, google#284, google#186
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Need to change Lines 80 to 85 in 4590768
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src/impl_aarch64_windows.c
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| // A note on Windows AArch64 implementation: | ||
| // ----------------------------------------------------------- | ||
| // Since getting of cpu info via EL1 system registers is not possible. |
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"Getting cpu info via EL1 system registers is not possible, so we delegate it to the Windows API (i.e., IsProcessorFeaturePresent and GetNativeSystemInfo)."
src/impl_aarch64_windows.c
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| // Hence, we delegate detection to info via Windows API methods such | ||
| // as `IsProcessorFeaturePresent` and `GetNativeSystemInfo`. The fields of | ||
| // `Aarch64Info` struct such as `implementer`, `variant` and `part` are not | ||
| // used, so they will always be 0. To get `revision` we use `wProcessorRevision` |
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"The implementer, variant and part fields of the Aarch64Info struct are not used, so they are set to 0."
Also you may want to document this behaviour in include/cpuinfo_aarch64.h.
test/cpuinfo_aarch64_test.cc
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| void SetWindowsNativeSystemInfoProcessorRevision(WORD wProcessorRevision) { | ||
| processor_revision_ = wProcessorRevision; | ||
| } | ||
| #endif // CPU_FEATURES_OS_WINDOWS |
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No need to close the #endif here to open it up again a few lines below.
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I was focused to leave space for the osx implementation 😄 (https://github.com/arkivm/cpu_features/blob/aarch64-darwin-support/test/cpuinfo_aarch64_test.cc#L50). Will update
include/cpuinfo_aarch64.h
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| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
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| // A note on Windows AArch64 implementation: |
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Can you add a comment on the fields themselves so it's clear when we use the API?
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Do yo mean like this:
typedef struct {
Aarch64Features features;
int implementer; // We set 0 for Windows.
int variant; // We set 0 for Windows.
int part; // We set 0 for Windows.
int revision; // We use GetNativeSystemInfo to get processor revision for
// Windows.
} Aarch64Info;There was a problem hiding this comment.
Yes this. Can you update the PR?
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LGTM @toor1245 . Thx a lot for the PR ! |
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Actually the comments on the struct fields in include/cpuinfo_aarch64.h is missing, but apart from that I think it's good to go. |
Added comments to specify that implementer, part and variant we set 0 for Windows, since Win API does not provide a way to get information. For revision added comment that we use GetNativeSystemInfo
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Should the table in the readme be updated with this? |
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@MichalPetryka We would like to have a CI up and running before claiming we support Windows / Arm64. |
4 participants
To add Windows Arm64 support was added detection of features via Windows API function IsProcessorFeaturePresent. Added _M_ARM64 to detect CPU_FEATURES_AARCH64 macro on Windows. Added initial code for Windows Arm64 testing and provided test for Raspberry PI 4. We can't use "define_introspection_and_hwcaps.inl" as a common file for all operating systems due to msvc compiler error C2099: initializer is not a constant, so as a workaround for Windows I used separate "define_introspection.inl"
Refs to review:
https://developer.arm.com/documentation/ddi0487/latest
https://sourceware.org/binutils/docs/as/AArch64-Extensions.html
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-isprocessorfeaturepresent
Note: MicrosoftDocs/sdk-api#1409 created PR to update ms docs arm64 features and fix value for
PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE