34 lines
1.6 KiB
Diff
34 lines
1.6 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Samuel Attard <marshallofsound@electronjs.org>
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Date: Wed, 15 Nov 2023 13:31:14 -0800
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Subject: Fix AVX detection
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The old/faulty code would try to use AVX/AVX2 if either the SSE bit or
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the AVX bit were set in XCR0, but did not check if both bits were set.
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In most cases, this still worked, but on some machines, enabling linux
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kernel mitigations for the "gather data sampling" vulnerability results
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in only the SSE bit but not the AVX bit being set, thus resulting in an
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illegal instruction and crashing the application.
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Fix this by checking that both bits are set.
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Fixes: 4bbb590 ("Proper check of CPU's AVX2 feature support (with MSVC support)")
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Signed-off-by: Pascal Ernster <git@hardfalcon.net>
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Cherry-Picked from https://github.com/aklomp/base64/commit/9003f9b183327df80fda97aa82dfc8054e1d3dce
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diff --git a/deps/base64/base64/lib/codec_choose.c b/deps/base64/base64/lib/codec_choose.c
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index 6a07d6a74cc24f61cf2b16d13c075234d5c7e2a3..f4215f1ef9d42087ef6735e6817c714ecc43a0ca 100644
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--- a/deps/base64/base64/lib/codec_choose.c
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+++ b/deps/base64/base64/lib/codec_choose.c
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@@ -194,7 +194,7 @@ codec_choose_x86 (struct codec *codec)
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if (ecx & bit_XSAVE_XRSTORE) {
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uint64_t xcr_mask;
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xcr_mask = _xgetbv(_XCR_XFEATURE_ENABLED_MASK);
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- if (xcr_mask & _XCR_XMM_AND_YMM_STATE_ENABLED_BY_OS) {
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+ if ((xcr_mask & _XCR_XMM_AND_YMM_STATE_ENABLED_BY_OS) == _XCR_XMM_AND_YMM_STATE_ENABLED_BY_OS) { // check multiple bits at once
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#if HAVE_AVX2
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if (max_level >= 7) {
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__cpuid_count(7, 0, eax, ebx, ecx, edx);
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