[08/10] hurd: Fix setting up pthreads
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Commit Message
On x86_64, we have to pass function arguments in registers, not on the
stack. We also have to align the stack pointer in a specific way. Since
sharing the logic with i386 does not bring much benefit, split the file
back into i386- and x86_64-specific versions, and fix the x86_64 version
to set up the thread properly.
Bonus: i386 keeps doing the extra RPC inside __thread_set_pcsptp to
fetch the state of the thread before setting it; but x86_64 no lnoger
does that.
Checked on x86_64-gnu and i686-gnu.
Fixes be6d002ca277ffc90058d382396150cb0e785b9c
"hurd: Set up the basic tree for x86_64-gnu"
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
__thread_set_pcsptp is also used by pthread_cancel (), which suffers
from the same issue. Eventually I'd like to remove __thread_set_pcsptp
entirely.
.../mach/hurd/{x86 => i386}/htl/pt-setup.c | 2 +-
sysdeps/mach/hurd/x86_64/htl/pt-setup.c | 93 +++++++++++++++++++
2 files changed, 94 insertions(+), 1 deletion(-)
rename sysdeps/mach/hurd/{x86 => i386}/htl/pt-setup.c (98%)
create mode 100644 sysdeps/mach/hurd/x86_64/htl/pt-setup.c
Comments
Applied, thanks!
Sergey Bugaev, le mer. 17 mai 2023 22:14:34 +0300, a ecrit:
> On x86_64, we have to pass function arguments in registers, not on the
> stack. We also have to align the stack pointer in a specific way. Since
> sharing the logic with i386 does not bring much benefit, split the file
> back into i386- and x86_64-specific versions, and fix the x86_64 version
> to set up the thread properly.
>
> Bonus: i386 keeps doing the extra RPC inside __thread_set_pcsptp to
> fetch the state of the thread before setting it; but x86_64 no lnoger
> does that.
>
> Checked on x86_64-gnu and i686-gnu.
>
> Fixes be6d002ca277ffc90058d382396150cb0e785b9c
> "hurd: Set up the basic tree for x86_64-gnu"
>
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
> __thread_set_pcsptp is also used by pthread_cancel (), which suffers
> from the same issue. Eventually I'd like to remove __thread_set_pcsptp
> entirely.
>
> .../mach/hurd/{x86 => i386}/htl/pt-setup.c | 2 +-
> sysdeps/mach/hurd/x86_64/htl/pt-setup.c | 93 +++++++++++++++++++
> 2 files changed, 94 insertions(+), 1 deletion(-)
> rename sysdeps/mach/hurd/{x86 => i386}/htl/pt-setup.c (98%)
> create mode 100644 sysdeps/mach/hurd/x86_64/htl/pt-setup.c
>
> diff --git a/sysdeps/mach/hurd/x86/htl/pt-setup.c b/sysdeps/mach/hurd/i386/htl/pt-setup.c
> similarity index 98%
> rename from sysdeps/mach/hurd/x86/htl/pt-setup.c
> rename to sysdeps/mach/hurd/i386/htl/pt-setup.c
> index 686124d7..ba108b96 100644
> --- a/sysdeps/mach/hurd/x86/htl/pt-setup.c
> +++ b/sysdeps/mach/hurd/i386/htl/pt-setup.c
> @@ -1,4 +1,4 @@
> -/* Setup thread stack. Hurd/x86 version.
> +/* Setup thread stack. Hurd/i386 version.
> Copyright (C) 2000-2023 Free Software Foundation, Inc.
> This file is part of the GNU C Library.
>
> diff --git a/sysdeps/mach/hurd/x86_64/htl/pt-setup.c b/sysdeps/mach/hurd/x86_64/htl/pt-setup.c
> new file mode 100644
> index 00000000..7dc62912
> --- /dev/null
> +++ b/sysdeps/mach/hurd/x86_64/htl/pt-setup.c
> @@ -0,0 +1,93 @@
> +/* Setup thread stack. Hurd/x86_64 version.
> + Copyright (C) 2000-2023 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C 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.
> +
> + The GNU C 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 the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <stdint.h>
> +#include <assert.h>
> +#include <mach.h>
> +#include <hurd.h>
> +
> +#include <thread_state.h>
> +#include <pt-internal.h>
> +
> +/* Set up the stack for THREAD. Return the stack pointer
> + for the new thread. */
> +static void *
> +stack_setup (struct __pthread *thread)
> +{
> + error_t err;
> + uintptr_t bottom, top;
> +
> + /* Calculate the top of the new stack. */
> + bottom = (uintptr_t) thread->stackaddr;
> + top = bottom + thread->stacksize + round_page (thread->guardsize);
> +
> + if (thread->guardsize)
> + {
> + err = __vm_protect (__mach_task_self (), (vm_address_t) bottom,
> + thread->guardsize, 0, 0);
> + assert_perror (err);
> + }
> +
> + return (void *) PTR_ALIGN_DOWN_8_16 (top);
> +}
> +
> +int
> +__pthread_setup (struct __pthread *thread,
> + void (*entry_point) (struct __pthread *, void *(*)(void *),
> + void *), void *(*start_routine) (void *),
> + void *arg)
> +{
> + error_t err;
> + struct i386_thread_state state;
> + struct i386_fsgs_base_state fsgs_state;
> +
> + if (thread->kernel_thread == hurd_thread_self ())
> + /* Fix up the TCB for the main thread. The C library has already
> + installed a TCB, which we want to keep using. This TCB must not
> + be freed so don't register it in the thread structure. On the
> + other hand, it's not yet possible to reliably release a TCB.
> + Leave the unused one registered so that it doesn't leak. */
> + return 0;
> +
> +
> + thread->mcontext.pc = entry_point;
> + thread->mcontext.sp = stack_setup (thread);
> +
> + /* Set up the state to call entry_point (thread, start_routine, arg) */
> + memset (&state, 0, sizeof (state));
> + state.ursp = (uintptr_t) thread->mcontext.sp;
> + state.rip = (uintptr_t) thread->mcontext.pc;
> + state.rdi = (uintptr_t) thread;
> + state.rsi = (uintptr_t) start_routine;
> + state.rdx = (uintptr_t) arg;
> +
> + err = __thread_set_state (thread->kernel_thread, i386_THREAD_STATE,
> + (thread_state_t) &state,
> + i386_THREAD_STATE_COUNT);
> + assert_perror (err);
> +
> + /* Set fs_base to the TCB pointer for the thread. */
> + memset (&fsgs_state, 0, sizeof (fsgs_state));
> + fsgs_state.fs_base = (uintptr_t) thread->tcb;
> + err = __thread_set_state (thread->kernel_thread, i386_FSGS_BASE_STATE,
> + (thread_state_t) &fsgs_state,
> + i386_FSGS_BASE_STATE_COUNT);
> + assert_perror (err);
> +
> + return 0;
> +}
> --
> 2.40.1
>
>
similarity index 98%
rename from sysdeps/mach/hurd/x86/htl/pt-setup.c
rename to sysdeps/mach/hurd/i386/htl/pt-setup.c
@@ -1,4 +1,4 @@
-/* Setup thread stack. Hurd/x86 version.
+/* Setup thread stack. Hurd/i386 version.
Copyright (C) 2000-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
new file mode 100644
@@ -0,0 +1,93 @@
+/* Setup thread stack. Hurd/x86_64 version.
+ Copyright (C) 2000-2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C 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.
+
+ The GNU C 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <stdint.h>
+#include <assert.h>
+#include <mach.h>
+#include <hurd.h>
+
+#include <thread_state.h>
+#include <pt-internal.h>
+
+/* Set up the stack for THREAD. Return the stack pointer
+ for the new thread. */
+static void *
+stack_setup (struct __pthread *thread)
+{
+ error_t err;
+ uintptr_t bottom, top;
+
+ /* Calculate the top of the new stack. */
+ bottom = (uintptr_t) thread->stackaddr;
+ top = bottom + thread->stacksize + round_page (thread->guardsize);
+
+ if (thread->guardsize)
+ {
+ err = __vm_protect (__mach_task_self (), (vm_address_t) bottom,
+ thread->guardsize, 0, 0);
+ assert_perror (err);
+ }
+
+ return (void *) PTR_ALIGN_DOWN_8_16 (top);
+}
+
+int
+__pthread_setup (struct __pthread *thread,
+ void (*entry_point) (struct __pthread *, void *(*)(void *),
+ void *), void *(*start_routine) (void *),
+ void *arg)
+{
+ error_t err;
+ struct i386_thread_state state;
+ struct i386_fsgs_base_state fsgs_state;
+
+ if (thread->kernel_thread == hurd_thread_self ())
+ /* Fix up the TCB for the main thread. The C library has already
+ installed a TCB, which we want to keep using. This TCB must not
+ be freed so don't register it in the thread structure. On the
+ other hand, it's not yet possible to reliably release a TCB.
+ Leave the unused one registered so that it doesn't leak. */
+ return 0;
+
+
+ thread->mcontext.pc = entry_point;
+ thread->mcontext.sp = stack_setup (thread);
+
+ /* Set up the state to call entry_point (thread, start_routine, arg) */
+ memset (&state, 0, sizeof (state));
+ state.ursp = (uintptr_t) thread->mcontext.sp;
+ state.rip = (uintptr_t) thread->mcontext.pc;
+ state.rdi = (uintptr_t) thread;
+ state.rsi = (uintptr_t) start_routine;
+ state.rdx = (uintptr_t) arg;
+
+ err = __thread_set_state (thread->kernel_thread, i386_THREAD_STATE,
+ (thread_state_t) &state,
+ i386_THREAD_STATE_COUNT);
+ assert_perror (err);
+
+ /* Set fs_base to the TCB pointer for the thread. */
+ memset (&fsgs_state, 0, sizeof (fsgs_state));
+ fsgs_state.fs_base = (uintptr_t) thread->tcb;
+ err = __thread_set_state (thread->kernel_thread, i386_FSGS_BASE_STATE,
+ (thread_state_t) &fsgs_state,
+ i386_FSGS_BASE_STATE_COUNT);
+ assert_perror (err);
+
+ return 0;
+}