[PATCH v6 13/15] gdbserver: Use x86_xstate_layout to parse the XSAVE extended state area.

John Baldwin
2023-07-14T15:57:30Z

From: Aleksandar Paunovic <aleksandar.paunovic@intel.com>

Replace the extended state area fields of i387_xsave with methods which
return an offset into the XSAVE buffer.

The two changed functions are called within all tests which runs
gdbserver.

Signed-off-by: Aleksandar Paunovic <aleksandar.paunovic@intel.com>
Co-authored-by: John Baldwin <jhb@FreeBSD.org>
---
gdbserver/i387-fp.cc | 117 +++++++++++++++++++++++++------------------
1 file changed, 69 insertions(+), 48 deletions(-)

diff --git a/gdbserver/i387-fp.cc b/gdbserver/i387-fp.cc
index a122e2d860b..f53a6cfc477 100644
--- a/gdbserver/i387-fp.cc
+++ b/gdbserver/i387-fp.cc
@@ -82,6 +82,8 @@ struct i387_fxsave {
};

struct i387_xsave : public i387_fxsave {
+ /* Size of i387_fxsave is 416 bytes. */
+
unsigned char reserved1[48];

/* The extended control register 0 (the XFEATURE_ENABLED_MASK
@@ -93,34 +95,53 @@ struct i387_xsave : public i387_fxsave {
/* The XSTATE_BV bit vector. */
unsigned long long xstate_bv;

- unsigned char reserved3[56];
+ /* The XCOMP_BV bit vector. */
+ unsigned long long xcomp_bv;

- /* Space for eight upper 128-bit YMM values, or 16 on x86-64. */
- unsigned char ymmh_space[256];
+ unsigned char reserved3[48];

- unsigned char reserved4[128];
+ /* Byte 576. End of registers with fixed position in XSAVE.
+ The position of other XSAVE registers will be calculated
+ from the appropriate CPUID calls. */

- /* Space for 4 bound registers values of 128 bits. */
- unsigned char mpx_bnd_space[64];
+private:
+ /* Base address of XSAVE data as an unsigned char *. Used to derive
+ pointers to XSAVE state components in the extended state
+ area. */
+ unsigned char *xsave ()
+ { return reinterpret_cast<unsigned char *> (this); }

- /* Space for 2 MPX configuration registers of 64 bits
+public:
+ /* Memory address of eight upper 128-bit YMM values, or 16 on x86-64. */
+ unsigned char *ymmh_space ()
+ { return xsave () + xsave_layout.avx_offset; }
+
+ /* Memory address of 4 bound registers values of 128 bits. */
+ unsigned char *bndregs_space ()
+ { return xsave () + xsave_layout.bndregs_offset; }
+
+ /* Memory address of 2 MPX configuration registers of 64 bits
plus reserved space. */
- unsigned char mpx_cfg_space[16];
+ unsigned char *bndcfg_space ()
+ { return xsave () + xsave_layout.bndcfg_offset; }

- unsigned char reserved5[48];
+ /* Memory address of 8 OpMask register values of 64 bits. */
+ unsigned char *k_space ()
+ { return xsave () + xsave_layout.k_offset; }

- /* Space for 8 OpMask register values of 64 bits. */
- unsigned char k_space[64];
+ /* Memory address of 16 256-bit zmm0-15. */
+ unsigned char *zmmh_space ()
+ { return xsave () + xsave_layout.zmm_h_offset; }

- /* Space for 16 256-bit zmm0-15. */
- unsigned char zmmh_low_space[512];
+ /* Memory address of 16 512-bit zmm16-31 values. */
+ unsigned char *zmm_space ()
+ { return xsave () + xsave_layout.zmm_offset; }

- /* Space for 16 512-bit zmm16-31 values. */
- unsigned char zmmh_high_space[1024];
-
- /* Space for 1 32-bit PKRU register. The HW XSTATE size for this feature is
- actually 64 bits, but WRPKRU/RDPKRU instructions ignore upper 32 bits. */
- unsigned char pkru_space[8];
+ /* Memory address of 1 32-bit PKRU register. The HW XSTATE size for this
+ feature is actually 64 bits, but WRPKRU/RDPKRU instructions ignore upper
+ 32 bits. */
+ unsigned char *pkru_space ()
+ { return xsave () + xsave_layout.pkru_offset; }
};

void
@@ -242,7 +263,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
unsigned long long xstate_bv = 0;
unsigned long long clear_bv = 0;
char raw[64];
- char *p;
+ unsigned char *p;

/* Amd64 has 16 xmm regs; I386 has 8 xmm regs. */
int num_xmm_registers = amd64 ? 16 : 8;
@@ -282,40 +303,40 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)

if ((clear_bv & X86_XSTATE_AVX))
for (i = 0; i < num_xmm_registers; i++)
- memset (((char *) &fp->ymmh_space[0]) + i * 16, 0, 16);
+ memset (fp->ymmh_space () + i * 16, 0, 16);

if ((clear_bv & X86_XSTATE_SSE) && (clear_bv & X86_XSTATE_AVX))
memset (((char *) &fp->mxcsr), 0, 4);

if ((clear_bv & X86_XSTATE_BNDREGS))
for (i = 0; i < num_mpx_bnd_registers; i++)
- memset (((char *) &fp->mpx_bnd_space[0]) + i * 16, 0, 16);
+ memset (fp->bndregs_space () + i * 16, 0, 16);

if ((clear_bv & X86_XSTATE_BNDCFG))
for (i = 0; i < num_mpx_cfg_registers; i++)
- memset (((char *) &fp->mpx_cfg_space[0]) + i * 8, 0, 8);
+ memset (fp->bndcfg_space () + i * 8, 0, 8);

if ((clear_bv & X86_XSTATE_K))
for (i = 0; i < num_avx512_k_registers; i++)
- memset (((char *) &fp->k_space[0]) + i * 8, 0, 8);
+ memset (fp->k_space () + i * 8, 0, 8);

if ((clear_bv & X86_XSTATE_ZMM_H))
for (i = 0; i < num_avx512_zmmh_low_registers; i++)
- memset (((char *) &fp->zmmh_low_space[0]) + i * 32, 0, 32);
+ memset (fp->zmmh_space () + i * 32, 0, 32);

if ((clear_bv & X86_XSTATE_ZMM))
{
for (i = 0; i < num_avx512_zmmh_high_registers; i++)
- memset (((char *) &fp->zmmh_high_space[0]) + 32 + i * 64, 0, 32);
+ memset (fp->zmm_space () + 32 + i * 64, 0, 32);
for (i = 0; i < num_avx512_xmm_registers; i++)
- memset (((char *) &fp->zmmh_high_space[0]) + i * 64, 0, 16);
+ memset (fp->zmm_space () + i * 64, 0, 16);
for (i = 0; i < num_avx512_ymmh_registers; i++)
- memset (((char *) &fp->zmmh_high_space[0]) + 16 + i * 64, 0, 16);
+ memset (fp->zmm_space () + 16 + i * 64, 0, 16);
}

if ((clear_bv & X86_XSTATE_PKRU))
for (i = 0; i < num_pkeys_registers; i++)
- memset (((char *) &fp->pkru_space[0]) + i * 4, 0, 4);
+ memset (fp->pkru_space () + i * 4, 0, 4);
}

/* Check if any x87 registers are changed. */
@@ -326,7 +347,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < 8; i++)
{
collect_register (regcache, i + st0_regnum, raw);
- p = ((char *) &fp->st_space[0]) + i * 16;
+ p = fp->st_space + i * 16;
if (memcmp (raw, p, 10))
{
xstate_bv |= X86_XSTATE_X87;
@@ -343,7 +364,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_xmm_registers; i++)
{
collect_register (regcache, i + xmm0_regnum, raw);
- p = ((char *) &fp->xmm_space[0]) + i * 16;
+ p = fp->xmm_space + i * 16;
if (memcmp (raw, p, 16))
{
xstate_bv |= X86_XSTATE_SSE;
@@ -360,7 +381,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_xmm_registers; i++)
{
collect_register (regcache, i + ymm0h_regnum, raw);
- p = ((char *) &fp->ymmh_space[0]) + i * 16;
+ p = fp->ymmh_space () + i * 16;
if (memcmp (raw, p, 16))
{
xstate_bv |= X86_XSTATE_AVX;
@@ -377,7 +398,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_mpx_bnd_registers; i++)
{
collect_register (regcache, i + bnd0r_regnum, raw);
- p = ((char *) &fp->mpx_bnd_space[0]) + i * 16;
+ p = fp->bndregs_space () + i * 16;
if (memcmp (raw, p, 16))
{
xstate_bv |= X86_XSTATE_BNDREGS;
@@ -394,7 +415,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_mpx_cfg_registers; i++)
{
collect_register (regcache, i + bndcfg_regnum, raw);
- p = ((char *) &fp->mpx_cfg_space[0]) + i * 8;
+ p = fp->bndcfg_space () + i * 8;
if (memcmp (raw, p, 8))
{
xstate_bv |= X86_XSTATE_BNDCFG;
@@ -411,7 +432,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_avx512_k_registers; i++)
{
collect_register (regcache, i + k0_regnum, raw);
- p = ((char *) &fp->k_space[0]) + i * 8;
+ p = fp->k_space () + i * 8;
if (memcmp (raw, p, 8) != 0)
{
xstate_bv |= X86_XSTATE_K;
@@ -428,7 +449,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_avx512_zmmh_low_registers; i++)
{
collect_register (regcache, i + zmm0h_regnum, raw);
- p = ((char *) &fp->zmmh_low_space[0]) + i * 32;
+ p = fp->zmmh_space () + i * 32;
if (memcmp (raw, p, 32) != 0)
{
xstate_bv |= X86_XSTATE_ZMM_H;
@@ -447,7 +468,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_avx512_zmmh_high_registers; i++)
{
collect_register (regcache, i + zmm16h_regnum, raw);
- p = ((char *) &fp->zmmh_high_space[0]) + 32 + i * 64;
+ p = fp->zmm_space () + 32 + i * 64;
if (memcmp (raw, p, 32) != 0)
{
xstate_bv |= X86_XSTATE_ZMM;
@@ -466,7 +487,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_avx512_xmm_registers; i++)
{
collect_register (regcache, i + xmm_avx512_regnum, raw);
- p = ((char *) &fp->zmmh_high_space[0]) + i * 64;
+ p = fp->zmm_space () + i * 64;
if (memcmp (raw, p, 16) != 0)
{
xstate_bv |= X86_XSTATE_ZMM;
@@ -485,7 +506,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_avx512_ymmh_registers; i++)
{
collect_register (regcache, i + ymmh_avx512_regnum, raw);
- p = ((char *) &fp->zmmh_high_space[0]) + 16 + i * 64;
+ p = fp->zmm_space () + 16 + i * 64;
if (memcmp (raw, p, 16) != 0)
{
xstate_bv |= X86_XSTATE_ZMM;
@@ -502,7 +523,7 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf)
for (i = 0; i < num_pkeys_registers; i++)
{
collect_register (regcache, i + pkru_regnum, raw);
- p = ((char *) &fp->pkru_space[0]) + i * 4;
+ p = fp->pkru_space () + i * 4;
if (memcmp (raw, p, 4) != 0)
{
xstate_bv |= X86_XSTATE_PKRU;
@@ -707,7 +728,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
int i, top;
unsigned long val;
unsigned long long clear_bv;
- gdb_byte *p;
+ unsigned char *p;

/* Amd64 has 16 xmm regs; I386 has 8 xmm regs. */
int num_xmm_registers = amd64 ? 16 : 8;
@@ -768,7 +789,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->ymmh_space[0];
+ p = fp->ymmh_space ();
for (i = 0; i < num_xmm_registers; i++)
supply_register (regcache, i + ymm0h_regnum, p + i * 16);
}
@@ -786,7 +807,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->mpx_bnd_space[0];
+ p = fp->bndregs_space ();
for (i = 0; i < num_mpx_bnd_registers; i++)
supply_register (regcache, i + bnd0r_regnum, p + i * 16);
}
@@ -804,7 +825,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->mpx_cfg_space[0];
+ p = fp->bndcfg_space ();
for (i = 0; i < num_mpx_cfg_registers; i++)
supply_register (regcache, i + bndcfg_regnum, p + i * 8);
}
@@ -821,7 +842,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->k_space[0];
+ p = fp->k_space ();
for (i = 0; i < num_avx512_k_registers; i++)
supply_register (regcache, i + k0_regnum, p + i * 8);
}
@@ -838,7 +859,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->zmmh_low_space[0];
+ p = fp->zmmh_space ();
for (i = 0; i < num_avx512_zmmh_low_registers; i++)
supply_register (regcache, i + zmm0h_regnum, p + i * 32);
}
@@ -867,7 +888,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->zmmh_high_space[0];
+ p = fp->zmm_space ();
for (i = 0; i < num_avx512_zmmh_high_registers; i++)
supply_register (regcache, i + zmm16h_regnum, p + 32 + i * 64);
for (i = 0; i < num_avx512_ymmh_registers; i++)
@@ -888,7 +909,7 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf)
}
else
{
- p = (gdb_byte *) &fp->pkru_space[0];
+ p = fp->pkru_space ();
for (i = 0; i < num_pkeys_registers; i++)
supply_register (regcache, i + pkru_regnum, p + i * 4);
}
--
2.40.0