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xemu/target/i386/gdbstub.c
Alex Bennée e618e1f9b4 target/i386: fix byte swap issue with XMM register access 
During the conversion to the gdb_get_reg128 helpers the high and low
parts of the XMM register where inadvertently swapped. This causes
reads of the register to report the incorrect value to gdb.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/971
Fixes: b7b8756a9c (target/i386: use gdb_get_reg helpers)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-stable@nongnu.org
Message-Id: <20220419091020.3008144-25-alex.bennee@linaro.org>
2022-04-20 16:04:20 +01:00

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/*
* x86 gdb server stub
*
* Copyright (c) 2003-2005 Fabrice Bellard
* Copyright (c) 2013 SUSE LINUX Products GmbH
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/gdbstub.h"
#ifdef TARGET_X86_64
static const int gpr_map[16] = {
R_EAX, R_EBX, R_ECX, R_EDX, R_ESI, R_EDI, R_EBP, R_ESP,
8, 9, 10, 11, 12, 13, 14, 15
};
#else
#define gpr_map gpr_map32
#endif
static const int gpr_map32[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };
/*
* Keep these in sync with assignment to
* gdb_num_core_regs in target/i386/cpu.c
* and with the machine description
*/
/*
* SEG: 6 segments, plus fs_base, gs_base, kernel_gs_base
*/
/*
* general regs -----> 8 or 16
*/
#define IDX_NB_IP 1
#define IDX_NB_FLAGS 1
#define IDX_NB_SEG (6 + 3)
#define IDX_NB_CTL 6
#define IDX_NB_FP 16
/*
* fpu regs ----------> 8 or 16
*/
#define IDX_NB_MXCSR 1
/*
* total ----> 8+1+1+9+6+16+8+1=50 or 16+1+1+9+6+16+16+1=66
*/
#define IDX_IP_REG CPU_NB_REGS
#define IDX_FLAGS_REG (IDX_IP_REG + IDX_NB_IP)
#define IDX_SEG_REGS (IDX_FLAGS_REG + IDX_NB_FLAGS)
#define IDX_CTL_REGS (IDX_SEG_REGS + IDX_NB_SEG)
#define IDX_FP_REGS (IDX_CTL_REGS + IDX_NB_CTL)
#define IDX_XMM_REGS (IDX_FP_REGS + IDX_NB_FP)
#define IDX_MXCSR_REG (IDX_XMM_REGS + CPU_NB_REGS)
#define IDX_CTL_CR0_REG (IDX_CTL_REGS + 0)
#define IDX_CTL_CR2_REG (IDX_CTL_REGS + 1)
#define IDX_CTL_CR3_REG (IDX_CTL_REGS + 2)
#define IDX_CTL_CR4_REG (IDX_CTL_REGS + 3)
#define IDX_CTL_CR8_REG (IDX_CTL_REGS + 4)
#define IDX_CTL_EFER_REG (IDX_CTL_REGS + 5)
#ifdef TARGET_X86_64
#define GDB_FORCE_64 1
#else
#define GDB_FORCE_64 0
#endif
static int gdb_read_reg_cs64(uint32_t hflags, GByteArray *buf, target_ulong val)
{
if ((hflags & HF_CS64_MASK) || GDB_FORCE_64) {
return gdb_get_reg64(buf, val);
}
return gdb_get_reg32(buf, val);
}
static int gdb_write_reg_cs64(uint32_t hflags, uint8_t *buf, target_ulong *val)
{
if (hflags & HF_CS64_MASK) {
*val = ldq_p(buf);
return 8;
}
*val = ldl_p(buf);
return 4;
}
int x86_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
uint64_t tpr;
/* N.B. GDB can't deal with changes in registers or sizes in the middle
of a session. So if we're in 32-bit mode on a 64-bit cpu, still act
as if we're on a 64-bit cpu. */
if (n < CPU_NB_REGS) {
if (TARGET_LONG_BITS == 64) {
if (env->hflags & HF_CS64_MASK) {
return gdb_get_reg64(mem_buf, env->regs[gpr_map[n]]);
} else if (n < CPU_NB_REGS32) {
return gdb_get_reg64(mem_buf,
env->regs[gpr_map[n]] & 0xffffffffUL);
} else {
return gdb_get_regl(mem_buf, 0);
}
} else {
return gdb_get_reg32(mem_buf, env->regs[gpr_map32[n]]);
}
} else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
int len = gdb_get_reg64(mem_buf, cpu_to_le64(fp->low));
len += gdb_get_reg16(mem_buf, cpu_to_le16(fp->high));
return len;
} else if (n >= IDX_XMM_REGS && n < IDX_XMM_REGS + CPU_NB_REGS) {
n -= IDX_XMM_REGS;
if (n < CPU_NB_REGS32 || TARGET_LONG_BITS == 64) {
return gdb_get_reg128(mem_buf,
env->xmm_regs[n].ZMM_Q(1),
env->xmm_regs[n].ZMM_Q(0));
}
} else {
switch (n) {
case IDX_IP_REG:
if (TARGET_LONG_BITS == 64) {
if (env->hflags & HF_CS64_MASK) {
return gdb_get_reg64(mem_buf, env->eip);
} else {
return gdb_get_reg64(mem_buf, env->eip & 0xffffffffUL);
}
} else {
return gdb_get_reg32(mem_buf, env->eip);
}
case IDX_FLAGS_REG:
return gdb_get_reg32(mem_buf, env->eflags);
case IDX_SEG_REGS:
return gdb_get_reg32(mem_buf, env->segs[R_CS].selector);
case IDX_SEG_REGS + 1:
return gdb_get_reg32(mem_buf, env->segs[R_SS].selector);
case IDX_SEG_REGS + 2:
return gdb_get_reg32(mem_buf, env->segs[R_DS].selector);
case IDX_SEG_REGS + 3:
return gdb_get_reg32(mem_buf, env->segs[R_ES].selector);
case IDX_SEG_REGS + 4:
return gdb_get_reg32(mem_buf, env->segs[R_FS].selector);
case IDX_SEG_REGS + 5:
return gdb_get_reg32(mem_buf, env->segs[R_GS].selector);
case IDX_SEG_REGS + 6:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->segs[R_FS].base);
case IDX_SEG_REGS + 7:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->segs[R_GS].base);
case IDX_SEG_REGS + 8:
#ifdef TARGET_X86_64
return gdb_read_reg_cs64(env->hflags, mem_buf, env->kernelgsbase);
#else
return gdb_get_reg32(mem_buf, 0);
#endif
case IDX_FP_REGS + 8:
return gdb_get_reg32(mem_buf, env->fpuc);
case IDX_FP_REGS + 9:
return gdb_get_reg32(mem_buf, (env->fpus & ~0x3800) |
(env->fpstt & 0x7) << 11);
case IDX_FP_REGS + 10:
return gdb_get_reg32(mem_buf, 0); /* ftag */
case IDX_FP_REGS + 11:
return gdb_get_reg32(mem_buf, 0); /* fiseg */
case IDX_FP_REGS + 12:
return gdb_get_reg32(mem_buf, 0); /* fioff */
case IDX_FP_REGS + 13:
return gdb_get_reg32(mem_buf, 0); /* foseg */
case IDX_FP_REGS + 14:
return gdb_get_reg32(mem_buf, 0); /* fooff */
case IDX_FP_REGS + 15:
return gdb_get_reg32(mem_buf, 0); /* fop */
case IDX_MXCSR_REG:
update_mxcsr_from_sse_status(env);
return gdb_get_reg32(mem_buf, env->mxcsr);
case IDX_CTL_CR0_REG:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->cr[0]);
case IDX_CTL_CR2_REG:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->cr[2]);
case IDX_CTL_CR3_REG:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->cr[3]);
case IDX_CTL_CR4_REG:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->cr[4]);
case IDX_CTL_CR8_REG:
#ifndef CONFIG_USER_ONLY
tpr = cpu_get_apic_tpr(cpu->apic_state);
#else
tpr = 0;
#endif
return gdb_read_reg_cs64(env->hflags, mem_buf, tpr);
case IDX_CTL_EFER_REG:
return gdb_read_reg_cs64(env->hflags, mem_buf, env->efer);
}
}
return 0;
}
static int x86_cpu_gdb_load_seg(X86CPU *cpu, X86Seg sreg, uint8_t *mem_buf)
{
CPUX86State *env = &cpu->env;
uint16_t selector = ldl_p(mem_buf);
if (selector != env->segs[sreg].selector) {
#if defined(CONFIG_USER_ONLY)
cpu_x86_load_seg(env, sreg, selector);
#else
unsigned int limit, flags;
target_ulong base;
if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
int dpl = (env->eflags & VM_MASK) ? 3 : 0;
base = selector << 4;
limit = 0xffff;
flags = DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
DESC_A_MASK | (dpl << DESC_DPL_SHIFT);
} else {
if (!cpu_x86_get_descr_debug(env, selector, &base, &limit,
&flags)) {
return 4;
}
}
cpu_x86_load_seg_cache(env, sreg, selector, base, limit, flags);
#endif
}
return 4;
}
int x86_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
target_ulong tmp;
int len;
/* N.B. GDB can't deal with changes in registers or sizes in the middle
of a session. So if we're in 32-bit mode on a 64-bit cpu, still act
as if we're on a 64-bit cpu. */
if (n < CPU_NB_REGS) {
if (TARGET_LONG_BITS == 64) {
if (env->hflags & HF_CS64_MASK) {
env->regs[gpr_map[n]] = ldtul_p(mem_buf);
} else if (n < CPU_NB_REGS32) {
env->regs[gpr_map[n]] = ldtul_p(mem_buf) & 0xffffffffUL;
}
return sizeof(target_ulong);
} else if (n < CPU_NB_REGS32) {
n = gpr_map32[n];
env->regs[n] &= ~0xffffffffUL;
env->regs[n] |= (uint32_t)ldl_p(mem_buf);
return 4;
}
} else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
fp->low = le64_to_cpu(* (uint64_t *) mem_buf);
fp->high = le16_to_cpu(* (uint16_t *) (mem_buf + 8));
return 10;
} else if (n >= IDX_XMM_REGS && n < IDX_XMM_REGS + CPU_NB_REGS) {
n -= IDX_XMM_REGS;
if (n < CPU_NB_REGS32 || TARGET_LONG_BITS == 64) {
env->xmm_regs[n].ZMM_Q(0) = ldq_p(mem_buf);
env->xmm_regs[n].ZMM_Q(1) = ldq_p(mem_buf + 8);
return 16;
}
} else {
switch (n) {
case IDX_IP_REG:
if (TARGET_LONG_BITS == 64) {
if (env->hflags & HF_CS64_MASK) {
env->eip = ldq_p(mem_buf);
} else {
env->eip = ldq_p(mem_buf) & 0xffffffffUL;
}
return 8;
} else {
env->eip &= ~0xffffffffUL;
env->eip |= (uint32_t)ldl_p(mem_buf);
return 4;
}
case IDX_FLAGS_REG:
env->eflags = ldl_p(mem_buf);
return 4;
case IDX_SEG_REGS:
return x86_cpu_gdb_load_seg(cpu, R_CS, mem_buf);
case IDX_SEG_REGS + 1:
return x86_cpu_gdb_load_seg(cpu, R_SS, mem_buf);
case IDX_SEG_REGS + 2:
return x86_cpu_gdb_load_seg(cpu, R_DS, mem_buf);
case IDX_SEG_REGS + 3:
return x86_cpu_gdb_load_seg(cpu, R_ES, mem_buf);
case IDX_SEG_REGS + 4:
return x86_cpu_gdb_load_seg(cpu, R_FS, mem_buf);
case IDX_SEG_REGS + 5:
return x86_cpu_gdb_load_seg(cpu, R_GS, mem_buf);
case IDX_SEG_REGS + 6:
return gdb_write_reg_cs64(env->hflags, mem_buf, &env->segs[R_FS].base);
case IDX_SEG_REGS + 7:
return gdb_write_reg_cs64(env->hflags, mem_buf, &env->segs[R_GS].base);
case IDX_SEG_REGS + 8:
#ifdef TARGET_X86_64
return gdb_write_reg_cs64(env->hflags, mem_buf, &env->kernelgsbase);
#endif
return 4;
case IDX_FP_REGS + 8:
cpu_set_fpuc(env, ldl_p(mem_buf));
return 4;
case IDX_FP_REGS + 9:
tmp = ldl_p(mem_buf);
env->fpstt = (tmp >> 11) & 7;
env->fpus = tmp & ~0x3800;
return 4;
case IDX_FP_REGS + 10: /* ftag */
return 4;
case IDX_FP_REGS + 11: /* fiseg */
return 4;
case IDX_FP_REGS + 12: /* fioff */
return 4;
case IDX_FP_REGS + 13: /* foseg */
return 4;
case IDX_FP_REGS + 14: /* fooff */
return 4;
case IDX_FP_REGS + 15: /* fop */
return 4;
case IDX_MXCSR_REG:
cpu_set_mxcsr(env, ldl_p(mem_buf));
return 4;
case IDX_CTL_CR0_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
cpu_x86_update_cr0(env, tmp);
#endif
return len;
case IDX_CTL_CR2_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
env->cr[2] = tmp;
#endif
return len;
case IDX_CTL_CR3_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
cpu_x86_update_cr3(env, tmp);
#endif
return len;
case IDX_CTL_CR4_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
cpu_x86_update_cr4(env, tmp);
#endif
return len;
case IDX_CTL_CR8_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
cpu_set_apic_tpr(cpu->apic_state, tmp);
#endif
return len;
case IDX_CTL_EFER_REG:
len = gdb_write_reg_cs64(env->hflags, mem_buf, &tmp);
#ifndef CONFIG_USER_ONLY
cpu_load_efer(env, tmp);
#endif
return len;
}
}
/* Unrecognised register. */
return 0;
}
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