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Revert "gdb/gdbserver: share x86/linux tdesc caching"

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This reverts commit 198ff6ff81.
This commit is contained in:
Andrew Burgess
2024-03-26 18:52:17 +00:00
parent 57d8b51d90
commit 69324a74e3
11 changed files with 396 additions and 358 deletions
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291
gdbserver/linux-x86-tdesc.cc
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@@ -19,19 +19,292 @@
#include "server.h"
#include "tdesc.h"
#include "linux-x86-tdesc.h"
#include "arch/i386.h"
#include "gdbsupport/x86-xstate.h"
#ifdef __x86_64__
#include "arch/amd64.h"
#endif
#include "x86-tdesc.h"
#include "nat/x86-linux-tdesc.h"
/* See nat/x86-linux-tdesc.h. */
/* A structure used to describe a single cpu feature that might, or might
not, be checked for when creating a target description for one of i386,
amd64, or x32. */
void
x86_linux_post_init_tdesc (target_desc *tdesc, bool is_64bit)
struct x86_tdesc_feature {
/* The cpu feature mask. This is a mask against an xcr0 value. */
uint64_t feature;
/* Is this feature checked when creating an i386 target description. */
bool is_i386;
/* Is this feature checked when creating an amd64 target description. */
bool is_amd64;
/* Is this feature checked when creating an x32 target description. */
bool is_x32;
};
/* A constant table that describes all of the cpu features that are
checked when building a target description for i386, amd64, or x32. */
static constexpr x86_tdesc_feature x86_linux_all_tdesc_features[] = {
/* Feature, i386, amd64, x32. */
{ X86_XSTATE_PKRU, true, true, true },
{ X86_XSTATE_AVX512, true, true, true },
{ X86_XSTATE_AVX, true, true, true },
{ X86_XSTATE_MPX, true, true, false },
{ X86_XSTATE_SSE, true, false, false },
{ X86_XSTATE_X87, true, false, false }
};
/* Return a compile time constant which is a mask of all the cpu features
that are checked for when building an i386 target description. */
static constexpr uint64_t
x86_linux_i386_tdesc_feature_mask ()
{
#ifdef __x86_64__
if (is_64bit)
init_target_desc (tdesc, amd64_expedite_regs);
else
#endif
init_target_desc (tdesc, i386_expedite_regs);
uint64_t mask = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_i386)
mask |= entry.feature;
return mask;
}
/* Return a compile time constant which is a mask of all the cpu features
that are checked for when building an amd64 target description. */
static constexpr uint64_t
x86_linux_amd64_tdesc_feature_mask ()
{
uint64_t mask = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_amd64)
mask |= entry.feature;
return mask;
}
/* Return a compile time constant which is a mask of all the cpu features
that are checked for when building an x32 target description. */
static constexpr uint64_t
x86_linux_x32_tdesc_feature_mask ()
{
uint64_t mask = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_x32)
mask |= entry.feature;
return mask;
}
/* Return a compile time constant which is a count of the number of cpu
features that are checked for when building an i386 target description. */
static constexpr int
x86_linux_i386_tdesc_count ()
{
uint64_t count = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_i386)
++count;
gdb_assert (count > 0);
return (1 << count);
}
/* Return a compile time constant which is a count of the number of cpu
features that are checked for when building an amd64 target description. */
static constexpr int
x86_linux_amd64_tdesc_count ()
{
uint64_t count = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_amd64)
++count;
gdb_assert (count > 0);
return (1 << count);
}
/* Return a compile time constant which is a count of the number of cpu
features that are checked for when building an x32 target description. */
static constexpr int
x86_linux_x32_tdesc_count ()
{
uint64_t count = 0;
for (const auto &entry : x86_linux_all_tdesc_features)
if (entry.is_x32)
++count;
gdb_assert (count > 0);
return (1 << count);
}
#ifdef IN_PROCESS_AGENT
/* See linux-x86-tdesc.h. */
int
x86_linux_amd64_ipa_tdesc_count ()
{
return x86_linux_amd64_tdesc_count ();
}
/* See linux-x86-tdesc.h. */
int
x86_linux_x32_ipa_tdesc_count ()
{
return x86_linux_x32_tdesc_count ();
}
/* See linux-x86-tdesc.h. */
int
x86_linux_i386_ipa_tdesc_count ()
{
return x86_linux_i386_tdesc_count ();
}
#endif /* IN_PROCESS_AGENT */
/* Convert an xcr0 value into an integer. The integer will be passed to
the in-process-agent where it will then be passed to
x86_linux_tdesc_idx_to_xcr0 to get back the xcr0 value. */
int
x86_linux_xcr0_to_tdesc_idx (uint64_t xcr0)
{
/* The following table shows which features are checked for when creating
the target descriptions (see nat/x86-linux-tdesc.c), the feature order
represents the bit order within the generated index number.
i386 | x87 sse mpx avx avx512 pkru
amd64 | mpx avx avx512 pkru
i32 | avx avx512 pkru
The features are ordered so that for each mode (i386, amd64, i32) the
generated index will form a continuous range. */
int idx = 0;
for (int i = 0; i < ARRAY_SIZE (x86_linux_all_tdesc_features); ++i)
{
if ((xcr0 & x86_linux_all_tdesc_features[i].feature) != 0)
idx |= (1 << i);
}
return idx;
}
#ifdef IN_PROCESS_AGENT
/* Convert an index number (as returned from x86_linux_xcr0_to_tdesc_idx)
into an xcr0 value which can then be used to create a target
description. */
uint64_t
x86_linux_tdesc_idx_to_xcr0 (int idx)
{
uint64_t xcr0 = 0;
for (int i = 0; i < ARRAY_SIZE (x86_linux_all_tdesc_features); ++i)
{
if ((idx & (1 << i)) != 0)
xcr0 |= x86_linux_all_tdesc_features[i].feature;
}
return xcr0;
}
#endif /* IN_PROCESS_AGENT */
#if defined __i386__ || !defined IN_PROCESS_AGENT
/* A cache of all possible i386 target descriptions. */
static struct target_desc *i386_tdescs[x86_linux_i386_tdesc_count ()] = { };
/* See nat/x86-linux-tdesc.h. */
const struct target_desc *
i386_linux_read_description (uint64_t xcr0)
{
xcr0 &= x86_linux_i386_tdesc_feature_mask ();
int idx = x86_linux_xcr0_to_tdesc_idx (xcr0);
gdb_assert (idx >= 0 && idx < x86_linux_i386_tdesc_count ());
target_desc **tdesc = &i386_tdescs[idx];
if (*tdesc == nullptr)
{
*tdesc = i386_create_target_description (xcr0, true, false);
init_target_desc (*tdesc, i386_expedite_regs);
}
return *tdesc;
}
#endif
#ifdef __x86_64__
/* A cache of all possible amd64 target descriptions. */
static target_desc *amd64_tdescs[x86_linux_amd64_tdesc_count ()] = { };
/* A cache of all possible x32 target descriptions. */
static target_desc *x32_tdescs[x86_linux_x32_tdesc_count ()] = { };
/* See nat/x86-linux-tdesc.h. */
const struct target_desc *
amd64_linux_read_description (uint64_t xcr0, bool is_x32)
{
if (is_x32)
xcr0 &= x86_linux_x32_tdesc_feature_mask ();
else
xcr0 &= x86_linux_amd64_tdesc_feature_mask ();
int idx = x86_linux_xcr0_to_tdesc_idx (xcr0);
if (is_x32)
gdb_assert (idx >= 0 && idx < x86_linux_x32_tdesc_count ());
else
gdb_assert (idx >= 0 && idx < x86_linux_amd64_tdesc_count ());
target_desc **tdesc = nullptr;
if (is_x32)
tdesc = &x32_tdescs[idx];
else
tdesc = &amd64_tdescs[idx];
if (*tdesc == nullptr)
{
*tdesc = amd64_create_target_description (xcr0, is_x32, true, true);
init_target_desc (*tdesc, amd64_expedite_regs);
}
return *tdesc;
}
#endif