This requires extra work for each target, but adds the
common syscall code, and the necessary flag in CPUState.
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/hw/core/cpu.h | 3 +++
linux-user/generic/target_prctl_unalign.h | 27 +++++++++++++++++++++++
cpu.c | 20 ++++++++++++-----
linux-user/syscall.c | 13 +++++++++--
4 files changed, 56 insertions(+), 7 deletions(-)
create mode 100644 linux-user/generic/target_prctl_unalign.h
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index e948e81f1a..76ab3b851c 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -413,6 +413,9 @@ struct CPUState {
bool ignore_memory_transaction_failures;
+ /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */
+ bool prctl_unalign_sigbus;
+
struct hax_vcpu_state *hax_vcpu;
struct hvf_vcpu_state *hvf;
diff --git a/linux-user/generic/target_prctl_unalign.h b/linux-user/generic/target_prctl_unalign.h
new file mode 100644
index 0000000000..bc3b83af2a
--- /dev/null
+++ b/linux-user/generic/target_prctl_unalign.h
@@ -0,0 +1,27 @@
+/*
+ * Generic prctl unalign functions for linux-user
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef GENERIC_TARGET_PRCTL_UNALIGN_H
+#define GENERIC_TARGET_PRCTL_UNALIGN_H
+
+static abi_long do_prctl_get_unalign(CPUArchState *env, target_long arg2)
+{
+ CPUState *cs = env_cpu(env);
+ uint32_t res = PR_UNALIGN_NOPRINT;
+ if (cs->prctl_unalign_sigbus) {
+ res |= PR_UNALIGN_SIGBUS;
+ }
+ return put_user_u32(res, arg2);
+}
+#define do_prctl_get_unalign do_prctl_get_unalign
+
+static abi_long do_prctl_set_unalign(CPUArchState *env, target_long arg2)
+{
+ env_cpu(env)->prctl_unalign_sigbus = arg2 & PR_UNALIGN_SIGBUS;
+ return 0;
+}
+#define do_prctl_set_unalign do_prctl_set_unalign
+
+#endif /* GENERIC_TARGET_PRCTL_UNALIGN_H */
diff --git a/cpu.c b/cpu.c
index 945dd3dded..016bf06a1a 100644
--- a/cpu.c
+++ b/cpu.c
@@ -174,13 +174,23 @@ void cpu_exec_unrealizefn(CPUState *cpu)
cpu_list_remove(cpu);
}
+/*
+ * This can't go in hw/core/cpu.c because that file is compiled only
+ * once for both user-mode and system builds.
+ */
static Property cpu_common_props[] = {
-#ifndef CONFIG_USER_ONLY
+#ifdef CONFIG_USER_ONLY
/*
- * Create a memory property for softmmu CPU object,
- * so users can wire up its memory. (This can't go in hw/core/cpu.c
- * because that file is compiled only once for both user-mode
- * and system builds.) The default if no link is set up is to use
+ * Create a property for the user-only object, so users can
+ * adjust prctl(PR_SET_UNALIGN) from the command-line.
+ * Has no effect if the target does not support the feature.
+ */
+ DEFINE_PROP_BOOL("prctl-unalign-sigbus", CPUState,
+ prctl_unalign_sigbus, false),
+#else
+ /*
+ * Create a memory property for softmmu CPU object, so users can
+ * wire up its memory. The default if no link is set up is to use
* the system address space.
*/
DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ef7a955dbb..3f481eb5b2 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6377,6 +6377,12 @@ static abi_long do_prctl_inval1(CPUArchState *env, abi_long arg2)
#ifndef do_prctl_get_tagged_addr_ctrl
#define do_prctl_get_tagged_addr_ctrl do_prctl_inval0
#endif
+#ifndef do_prctl_get_unalign
+#define do_prctl_get_unalign do_prctl_inval1
+#endif
+#ifndef do_prctl_set_unalign
+#define do_prctl_set_unalign do_prctl_inval1
+#endif
static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
abi_long arg3, abi_long arg4, abi_long arg5)
@@ -6440,6 +6446,11 @@ static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
}
return do_prctl_get_tagged_addr_ctrl(env);
+ case PR_GET_UNALIGN:
+ return do_prctl_get_unalign(env, arg2);
+ case PR_SET_UNALIGN:
+ return do_prctl_set_unalign(env, arg2);
+
case PR_GET_DUMPABLE:
case PR_SET_DUMPABLE:
case PR_GET_KEEPCAPS:
@@ -6482,8 +6493,6 @@ static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
case PR_SET_THP_DISABLE:
case PR_GET_TSC:
case PR_SET_TSC:
- case PR_GET_UNALIGN:
- case PR_SET_UNALIGN:
default:
/* Disable to prevent the target disabling stuff we need. */
return -TARGET_EINVAL;
--
2.25.1
Hi Richard,
(revisiting this old patch.)
On 20/12/21 22:41, Richard Henderson wrote:
> This requires extra work for each target, but adds the
> common syscall code, and the necessary flag in CPUState.
>
> Reviewed-by: Warner Losh <imp@bsdimp.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> include/hw/core/cpu.h | 3 +++
> linux-user/generic/target_prctl_unalign.h | 27 +++++++++++++++++++++++
> cpu.c | 20 ++++++++++++-----
> linux-user/syscall.c | 13 +++++++++--
> 4 files changed, 56 insertions(+), 7 deletions(-)
> create mode 100644 linux-user/generic/target_prctl_unalign.h
>
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index e948e81f1a..76ab3b851c 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -413,6 +413,9 @@ struct CPUState {
>
> bool ignore_memory_transaction_failures;
>
> + /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */
> + bool prctl_unalign_sigbus;
> +
> struct hax_vcpu_state *hax_vcpu;
>
> struct hvf_vcpu_state *hvf;
> diff --git a/linux-user/generic/target_prctl_unalign.h b/linux-user/generic/target_prctl_unalign.h
> new file mode 100644
> index 0000000000..bc3b83af2a
> --- /dev/null
> +++ b/linux-user/generic/target_prctl_unalign.h
> @@ -0,0 +1,27 @@
> +/*
> + * Generic prctl unalign functions for linux-user
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#ifndef GENERIC_TARGET_PRCTL_UNALIGN_H
> +#define GENERIC_TARGET_PRCTL_UNALIGN_H
> +
> +static abi_long do_prctl_get_unalign(CPUArchState *env, target_long arg2)
> +{
> + CPUState *cs = env_cpu(env);
> + uint32_t res = PR_UNALIGN_NOPRINT;
> + if (cs->prctl_unalign_sigbus) {
> + res |= PR_UNALIGN_SIGBUS;
> + }
> + return put_user_u32(res, arg2);
> +}
> +#define do_prctl_get_unalign do_prctl_get_unalign
> +
> +static abi_long do_prctl_set_unalign(CPUArchState *env, target_long arg2)
> +{
> + env_cpu(env)->prctl_unalign_sigbus = arg2 & PR_UNALIGN_SIGBUS;
> + return 0;
> +}
> +#define do_prctl_set_unalign do_prctl_set_unalign
> +
> +#endif /* GENERIC_TARGET_PRCTL_UNALIGN_H */
> diff --git a/cpu.c b/cpu.c
> index 945dd3dded..016bf06a1a 100644
> --- a/cpu.c
> +++ b/cpu.c
> @@ -174,13 +174,23 @@ void cpu_exec_unrealizefn(CPUState *cpu)
> cpu_list_remove(cpu);
> }
>
> +/*
> + * This can't go in hw/core/cpu.c because that file is compiled only
> + * once for both user-mode and system builds.
> + */
> static Property cpu_common_props[] = {
> -#ifndef CONFIG_USER_ONLY
> +#ifdef CONFIG_USER_ONLY
> /*
> - * Create a memory property for softmmu CPU object,
> - * so users can wire up its memory. (This can't go in hw/core/cpu.c
> - * because that file is compiled only once for both user-mode
> - * and system builds.) The default if no link is set up is to use
> + * Create a property for the user-only object, so users can
> + * adjust prctl(PR_SET_UNALIGN) from the command-line.
How can I test this per-thread property?
Shouldn't this be an accel (TCG/user) property, for all threads?
> + * Has no effect if the target does not support the feature.
> + */
> + DEFINE_PROP_BOOL("prctl-unalign-sigbus", CPUState,
> + prctl_unalign_sigbus, false),
> +#else
> + /*
> + * Create a memory property for softmmu CPU object, so users can
> + * wire up its memory. The default if no link is set up is to use
> * the system address space.
> */
> DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index ef7a955dbb..3f481eb5b2 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6377,6 +6377,12 @@ static abi_long do_prctl_inval1(CPUArchState *env, abi_long arg2)
> #ifndef do_prctl_get_tagged_addr_ctrl
> #define do_prctl_get_tagged_addr_ctrl do_prctl_inval0
> #endif
> +#ifndef do_prctl_get_unalign
> +#define do_prctl_get_unalign do_prctl_inval1
> +#endif
> +#ifndef do_prctl_set_unalign
> +#define do_prctl_set_unalign do_prctl_inval1
> +#endif
>
> static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
> abi_long arg3, abi_long arg4, abi_long arg5)
> @@ -6440,6 +6446,11 @@ static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
> }
> return do_prctl_get_tagged_addr_ctrl(env);
>
> + case PR_GET_UNALIGN:
> + return do_prctl_get_unalign(env, arg2);
> + case PR_SET_UNALIGN:
> + return do_prctl_set_unalign(env, arg2);
> +
> case PR_GET_DUMPABLE:
> case PR_SET_DUMPABLE:
> case PR_GET_KEEPCAPS:
> @@ -6482,8 +6493,6 @@ static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
> case PR_SET_THP_DISABLE:
> case PR_GET_TSC:
> case PR_SET_TSC:
> - case PR_GET_UNALIGN:
> - case PR_SET_UNALIGN:
> default:
> /* Disable to prevent the target disabling stuff we need. */
> return -TARGET_EINVAL;
On 1/9/24 04:15, Philippe Mathieu-Daudé wrote:
>> +/*
>> + * This can't go in hw/core/cpu.c because that file is compiled only
>> + * once for both user-mode and system builds.
>> + */
>> static Property cpu_common_props[] = {
>> -#ifndef CONFIG_USER_ONLY
>> +#ifdef CONFIG_USER_ONLY
>> /*
>> - * Create a memory property for softmmu CPU object,
>> - * so users can wire up its memory. (This can't go in hw/core/cpu.c
>> - * because that file is compiled only once for both user-mode
>> - * and system builds.) The default if no link is set up is to use
>> + * Create a property for the user-only object, so users can
>> + * adjust prctl(PR_SET_UNALIGN) from the command-line.
>
> How can I test this per-thread property?
-cpu foo,prctl-unalign-sigbus=true
> Shouldn't this be an accel (TCG/user) property, for all threads?
There is always one cpu at user-only startup, and it is copied on clone.
Logically it would be a kernel property, since it's something the kernel does, not the
cpu. But cpu vs accel makes no difference to me; it was just easy here.
IIRC, this is simply a proxy for not really being able to inherit this bit across
fork+exec like you can with the real kernel.
r~
On 8/1/24 22:13, Richard Henderson wrote:
> On 1/9/24 04:15, Philippe Mathieu-Daudé wrote:
>>> +/*
>>> + * This can't go in hw/core/cpu.c because that file is compiled only
>>> + * once for both user-mode and system builds.
>>> + */
>>> static Property cpu_common_props[] = {
>>> -#ifndef CONFIG_USER_ONLY
>>> +#ifdef CONFIG_USER_ONLY
>>> /*
>>> - * Create a memory property for softmmu CPU object,
>>> - * so users can wire up its memory. (This can't go in hw/core/cpu.c
>>> - * because that file is compiled only once for both user-mode
>>> - * and system builds.) The default if no link is set up is to use
>>> + * Create a property for the user-only object, so users can
>>> + * adjust prctl(PR_SET_UNALIGN) from the command-line.
>>
>> How can I test this per-thread property?
>
> -cpu foo,prctl-unalign-sigbus=true
>
>
>> Shouldn't this be an accel (TCG/user) property, for all threads?
>
> There is always one cpu at user-only startup, and it is copied on clone.
>
> Logically it would be a kernel property, since it's something the kernel
> does, not the cpu. But cpu vs accel makes no difference to me; it was
> just easy here.
Can a process started with prctl(PR_SET_UNALIGN) unset it before
forking?
"kernel property" as "accel property" works for me.
> IIRC, this is simply a proxy for not really being able to inherit this
> bit across fork+exec like you can with the real kernel.
>
>
> r~
On 1/9/24 10:21, Philippe Mathieu-Daudé wrote:
> On 8/1/24 22:13, Richard Henderson wrote:
>> On 1/9/24 04:15, Philippe Mathieu-Daudé wrote:
>>>> +/*
>>>> + * This can't go in hw/core/cpu.c because that file is compiled only
>>>> + * once for both user-mode and system builds.
>>>> + */
>>>> static Property cpu_common_props[] = {
>>>> -#ifndef CONFIG_USER_ONLY
>>>> +#ifdef CONFIG_USER_ONLY
>>>> /*
>>>> - * Create a memory property for softmmu CPU object,
>>>> - * so users can wire up its memory. (This can't go in hw/core/cpu.c
>>>> - * because that file is compiled only once for both user-mode
>>>> - * and system builds.) The default if no link is set up is to use
>>>> + * Create a property for the user-only object, so users can
>>>> + * adjust prctl(PR_SET_UNALIGN) from the command-line.
>>>
>>> How can I test this per-thread property?
>>
>> -cpu foo,prctl-unalign-sigbus=true
>>
>>
>>> Shouldn't this be an accel (TCG/user) property, for all threads?
>>
>> There is always one cpu at user-only startup, and it is copied on clone.
>>
>> Logically it would be a kernel property, since it's something the kernel does, not the
>> cpu. But cpu vs accel makes no difference to me; it was just easy here.
>
> Can a process started with prctl(PR_SET_UNALIGN) unset it before
> forking?
Yes.
> "kernel property" as "accel property" works for me.
Does it really matter though, especially now that the cpu property has been present for
two years now.
r~
On 12/20/21 22:41, Richard Henderson wrote:
> This requires extra work for each target, but adds the
> common syscall code, and the necessary flag in CPUState.
>
> Reviewed-by: Warner Losh <imp@bsdimp.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> include/hw/core/cpu.h | 3 +++
> linux-user/generic/target_prctl_unalign.h | 27 +++++++++++++++++++++++
> cpu.c | 20 ++++++++++++-----
> linux-user/syscall.c | 13 +++++++++--
> 4 files changed, 56 insertions(+), 7 deletions(-)
> create mode 100644 linux-user/generic/target_prctl_unalign.h
>
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index e948e81f1a..76ab3b851c 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -413,6 +413,9 @@ struct CPUState {
>
> bool ignore_memory_transaction_failures;
>
> + /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */
> + bool prctl_unalign_sigbus;
Could we forward-declare a UserEmuCPUState structure in this file,
use it here:
struct UserEmuCPUState *user_cpu;
and declare it in include/hw/core/useremu-cpu.h (or better name)
restricted to user emulation?
I'd rather not mix sys/user emu specific fields in CPUState.
Can be done later of course, so:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
On 12/20/21 2:31 PM, Philippe Mathieu-Daudé wrote: >> + /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */ >> + bool prctl_unalign_sigbus; > > Could we forward-declare a UserEmuCPUState structure in this file, > use it here: > > struct UserEmuCPUState *user_cpu; > > and declare it in include/hw/core/useremu-cpu.h (or better name) > restricted to user emulation? Eh. I suppose we could, but at the moment it's one byte in an existing padding hole. > I'd rather not mix sys/user emu specific fields in CPUState. There are *lots* of system specific fields in CPUState. r~
Le 20/12/2021 à 22:41, Richard Henderson a écrit : > This requires extra work for each target, but adds the > common syscall code, and the necessary flag in CPUState. > > Reviewed-by: Warner Losh <imp@bsdimp.com> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/hw/core/cpu.h | 3 +++ > linux-user/generic/target_prctl_unalign.h | 27 +++++++++++++++++++++++ > cpu.c | 20 ++++++++++++----- > linux-user/syscall.c | 13 +++++++++-- > 4 files changed, 56 insertions(+), 7 deletions(-) > create mode 100644 linux-user/generic/target_prctl_unalign.h > Reviewed-by: Laurent Vivier <laurent@vivier.eu>
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