From: Paolo Bonzini <pbonzini@redhat.com>
To: Doug Evans <dje@google.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] x86: Fix x86_64 'g' packet response to gdb from 32-bit mode.
Date: Wed, 14 Dec 2016 18:14:44 +0100 [thread overview]
Message-ID: <08b0eb45-e85e-a68c-aa45-721d8d046376@redhat.com> (raw)
In-Reply-To: <001a113dca8274572005406e03c3@google.com>
On 04/11/2016 00:35, Doug Evans wrote:
> The remote protocol can't handle flipping back and forth
> between 32-bit and 64-bit regs. To compensate, pretend "as if"
> on 64-bit cpu when in 32-bit mode.
>
> Signed-off-by: Doug Evans <dje@google.com>
> ---
> target-i386/gdbstub.c | 52
> ++++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/target-i386/gdbstub.c b/target-i386/gdbstub.c
> index c494535..9b94ab8 100644
> --- a/target-i386/gdbstub.c
> +++ b/target-i386/gdbstub.c
> @@ -44,10 +44,22 @@ int x86_cpu_gdb_read_register(CPUState *cs, uint8_t
> *mem_buf, int n)
> X86CPU *cpu = X86_CPU(cs);
> CPUX86State *env = &cpu->env;
>
> + /* 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 && env->hflags & HF_CS64_MASK) {
> - return gdb_get_reg64(mem_buf, env->regs[gpr_map[n]]);
> - } else if (n < CPU_NB_REGS32) {
> + 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 {
> + memset(mem_buf, 0, sizeof(target_ulong));
> + return sizeof(target_ulong);
> + }
> + } else {
> return gdb_get_reg32(mem_buf, env->regs[gpr_map32[n]]);
> }
> } else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
> @@ -60,8 +72,7 @@ int x86_cpu_gdb_read_register(CPUState *cs, uint8_t
> *mem_buf, int n)
> 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->hflags & HF_CS64_MASK)) {
> + if (n < CPU_NB_REGS32 || TARGET_LONG_BITS == 64) {
> stq_p(mem_buf, env->xmm_regs[n].ZMM_Q(0));
> stq_p(mem_buf + 8, env->xmm_regs[n].ZMM_Q(1));
> return 16;
> @@ -69,8 +80,12 @@ int x86_cpu_gdb_read_register(CPUState *cs, uint8_t
> *mem_buf, int n)
> } else {
> switch (n) {
> case IDX_IP_REG:
> - if (TARGET_LONG_BITS == 64 && env->hflags & HF_CS64_MASK) {
> - return gdb_get_reg64(mem_buf, env->eip);
> + 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);
> }
> @@ -151,9 +166,17 @@ int x86_cpu_gdb_write_register(CPUState *cs,
> uint8_t *mem_buf, int n)
> CPUX86State *env = &cpu->env;
> uint32_t tmp;
>
> + /* 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 && env->hflags & HF_CS64_MASK) {
> - env->regs[gpr_map[n]] = ldtul_p(mem_buf);
> + 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];
> @@ -169,8 +192,7 @@ int x86_cpu_gdb_write_register(CPUState *cs, uint8_t
> *mem_buf, int n)
> 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->hflags & HF_CS64_MASK)) {
> + 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;
> @@ -178,8 +200,12 @@ int x86_cpu_gdb_write_register(CPUState *cs,
> uint8_t *mem_buf, int n)
> } else {
> switch (n) {
> case IDX_IP_REG:
> - if (TARGET_LONG_BITS == 64 && env->hflags & HF_CS64_MASK) {
> - env->eip = ldq_p(mem_buf);
> + 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;
Queued for 2.9, thanks.
Paolo
next prev parent reply other threads:[~2016-12-14 17:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-03 23:35 [Qemu-devel] [PATCH] x86: Fix x86_64 'g' packet response to gdb from 32-bit mode Doug Evans
2016-11-04 16:29 ` Richard Henderson
2016-11-04 16:34 ` Peter Maydell
2016-11-04 19:01 ` Pedro Alves
2016-11-04 19:27 ` Doug Evans
2016-12-14 17:14 ` Paolo Bonzini [this message]
2016-12-14 17:39 ` Doug Evans
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