forked from Imagelibrary/binutils-gdb
d01e823438
This updates the copyright headers to include 2025. I did this by running gdb/copyright.py and then manually modifying a few files as noted by the script. Approved-By: Eli Zaretskii <eliz@gnu.org>
267 lines
7.1 KiB
C
267 lines
7.1 KiB
C
/* Target description related code for GNU/Linux x86 (i386 and x86-64).
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Copyright (C) 2024-2025 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "arch/x86-linux-tdesc-features.h"
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/* A structure used to describe a single xstate feature bit that might, or
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might not, be checked for when creating a target description for one of
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i386, amd64, or x32.
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The different CPU/ABI types check for different xstate features when
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creating a target description.
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We want to cache target descriptions, and this is currently done in
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three separate caches, one each for i386, amd64, and x32. Additionally,
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the caching we're discussing here is Linux only, and for Linux, the only
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thing that has an impact on target description creation is the xcr0
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value.
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In order to ensure the cache functions correctly we need to filter out
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only those xcr0 feature bits that are relevant, we can then cache target
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descriptions based on the relevant feature bits. Two xcr0 values might
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be different, but have the same relevant feature bits. In this case we
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would expect the two xcr0 values to map to the same cache entry. */
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struct x86_xstate_feature {
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/* The xstate feature mask. This is a mask against an xcr0 value. */
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uint64_t feature;
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/* Is this feature checked when creating an i386 target description. */
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bool is_i386;
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/* Is this feature checked when creating an amd64 target description. */
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bool is_amd64;
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/* Is this feature checked when creating an x32 target description. */
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bool is_x32;
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};
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/* A constant table that describes all of the xstate features that are
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checked when building a target description for i386, amd64, or x32.
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If in the future, due to simplifications or refactoring, this table ever
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ends up with 'true' for every xcr0 feature on every target type, then this
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is an indication that this table should probably be removed, and that the
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rest of the code in this file can be simplified. */
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static constexpr x86_xstate_feature x86_linux_all_xstate_features[] = {
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/* Feature, i386, amd64, x32. */
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{ X86_XSTATE_PKRU, true, true, true },
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{ X86_XSTATE_AVX512, true, true, true },
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{ X86_XSTATE_AVX, true, true, true },
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{ X86_XSTATE_SSE, true, false, false },
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{ X86_XSTATE_X87, true, false, false }
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};
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/* Return a compile time constant which is a mask of all the xstate features
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that are checked for when building an i386 target description. */
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static constexpr uint64_t
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x86_linux_i386_xcr0_feature_mask_1 ()
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{
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uint64_t mask = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_i386)
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mask |= entry.feature;
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return mask;
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}
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/* Return a compile time constant which is a mask of all the xstate features
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that are checked for when building an amd64 target description. */
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static constexpr uint64_t
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x86_linux_amd64_xcr0_feature_mask_1 ()
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{
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uint64_t mask = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_amd64)
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mask |= entry.feature;
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return mask;
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}
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/* Return a compile time constant which is a mask of all the xstate features
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that are checked for when building an x32 target description. */
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static constexpr uint64_t
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x86_linux_x32_xcr0_feature_mask_1 ()
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{
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uint64_t mask = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_x32)
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mask |= entry.feature;
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return mask;
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}
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/* See arch/x86-linux-tdesc-features.h. */
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uint64_t
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x86_linux_i386_xcr0_feature_mask ()
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{
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return x86_linux_i386_xcr0_feature_mask_1 ();
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}
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/* See arch/x86-linux-tdesc-features.h. */
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uint64_t
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x86_linux_amd64_xcr0_feature_mask ()
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{
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return x86_linux_amd64_xcr0_feature_mask_1 ();
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}
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/* See arch/x86-linux-tdesc-features.h. */
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uint64_t
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x86_linux_x32_xcr0_feature_mask ()
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{
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return x86_linux_x32_xcr0_feature_mask_1 ();
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}
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#ifdef GDBSERVER
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/* See arch/x86-linux-tdesc-features.h. */
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int
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x86_linux_xcr0_to_tdesc_idx (uint64_t xcr0)
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{
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/* The following table shows which features are checked for when creating
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the target descriptions (see nat/x86-linux-tdesc.c), the feature order
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represents the bit order within the generated index number.
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i386 | x87 sse avx avx512 pkru
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amd64 | avx avx512 pkru
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i32 | avx avx512 pkru
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The features are ordered so that for each mode (i386, amd64, i32) the
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generated index will form a continuous range. */
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int idx = 0;
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for (int i = 0; i < ARRAY_SIZE (x86_linux_all_xstate_features); ++i)
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{
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if ((xcr0 & x86_linux_all_xstate_features[i].feature)
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== x86_linux_all_xstate_features[i].feature)
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idx |= (1 << i);
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}
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return idx;
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}
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#endif /* GDBSERVER */
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#ifdef IN_PROCESS_AGENT
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/* Return a compile time constant which is a count of the number of xstate
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features that are checked for when building an i386 target description. */
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static constexpr int
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x86_linux_i386_tdesc_count_1 ()
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{
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uint64_t count = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_i386)
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++count;
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gdb_assert (count > 0);
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return (1 << count);
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}
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/* Return a compile time constant which is a count of the number of xstate
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features that are checked for when building an amd64 target description. */
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static constexpr int
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x86_linux_amd64_tdesc_count_1 ()
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{
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uint64_t count = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_amd64)
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++count;
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gdb_assert (count > 0);
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return (1 << count);
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}
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/* Return a compile time constant which is a count of the number of xstate
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features that are checked for when building an x32 target description. */
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static constexpr int
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x86_linux_x32_tdesc_count_1 ()
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{
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uint64_t count = 0;
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for (const auto &entry : x86_linux_all_xstate_features)
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if (entry.is_x32)
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++count;
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gdb_assert (count > 0);
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return (1 << count);
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}
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/* See arch/x86-linux-tdesc-features.h. */
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int
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x86_linux_amd64_tdesc_count ()
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{
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return x86_linux_amd64_tdesc_count_1 ();
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}
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/* See arch/x86-linux-tdesc-features.h. */
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int
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x86_linux_x32_tdesc_count ()
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{
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return x86_linux_x32_tdesc_count_1 ();
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}
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/* See arch/x86-linux-tdesc-features.h. */
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int
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x86_linux_i386_tdesc_count ()
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{
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return x86_linux_i386_tdesc_count_1 ();
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}
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/* See arch/x86-linux-tdesc-features.h. */
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uint64_t
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x86_linux_tdesc_idx_to_xcr0 (int idx)
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{
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uint64_t xcr0 = 0;
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for (int i = 0; i < ARRAY_SIZE (x86_linux_all_xstate_features); ++i)
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{
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if ((idx & (1 << i)) != 0)
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xcr0 |= x86_linux_all_xstate_features[i].feature;
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}
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return xcr0;
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}
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#endif /* IN_PROCESS_AGENT */
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