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56 lines
2.1 KiB
56 lines
2.1 KiB
commit 1d401d1fccb85046402089268b94d86d822070e6 |
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Author: Aurelien Jarno <aurelien@aurel32.net> |
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Date: Mon Jan 17 19:41:40 2022 +0100 |
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x86: use default cache size if it cannot be determined [BZ #28784] |
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In some cases (e.g QEMU, non-Intel/AMD CPU) the cache information can |
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not be retrieved and the corresponding values are set to 0. |
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Commit 2d651eb9265d ("x86: Move x86 processor cache info to |
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cpu_features") changed the behaviour in such case by defining the |
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__x86_shared_cache_size and __x86_data_cache_size variables to 0 instead |
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of using the default values. This cause an issue with the i686 SSE2 |
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optimized bzero/routine which assumes that the cache size is at least |
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128 bytes, and otherwise tries to zero/set the whole address space minus |
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128 bytes. |
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Fix that by restoring the original code to only update |
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__x86_shared_cache_size and __x86_data_cache_size variables if the |
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corresponding cache sizes are not zero. |
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Fixes bug 28784 |
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Fixes commit 2d651eb9265d |
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com> |
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(cherry picked from commit c242fcce06e3102ca663b2f992611d0bda4f2668) |
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diff --git a/sysdeps/x86/cacheinfo.h b/sysdeps/x86/cacheinfo.h |
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index 41d2c81369840ada..63f36877e3f35d99 100644 |
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--- a/sysdeps/x86/cacheinfo.h |
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+++ b/sysdeps/x86/cacheinfo.h |
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@@ -61,14 +61,20 @@ init_cacheinfo (void) |
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long int data = cpu_features->data_cache_size; |
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/* Round data cache size to multiple of 256 bytes. */ |
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data = data & ~255L; |
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- __x86_data_cache_size_half = data / 2; |
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- __x86_data_cache_size = data; |
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+ if (data > 0) |
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+ { |
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+ __x86_data_cache_size_half = data / 2; |
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+ __x86_data_cache_size = data; |
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+ } |
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long int shared = cpu_features->shared_cache_size; |
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/* Round shared cache size to multiple of 256 bytes. */ |
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shared = shared & ~255L; |
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- __x86_shared_cache_size_half = shared / 2; |
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- __x86_shared_cache_size = shared; |
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+ if (shared > 0) |
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+ { |
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+ __x86_shared_cache_size_half = shared / 2; |
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+ __x86_shared_cache_size = shared; |
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+ } |
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__x86_shared_non_temporal_threshold |
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= cpu_features->non_temporal_threshold;
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