| Message ID | 20230625231751.404120-1-bugaevc@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/5] htl: Let Mach place thread stacks | expand |
Applied, thanks! Sergey Bugaev, le lun. 26 juin 2023 02:17:47 +0300, a ecrit: > Instead of trying to allocate a thread stack at a specific address, > looping over the address space, just set the ANYWHERE flag in > vm_allocate (). The previous behavior: > > - defeats ASLR (for Mach versions that support ASLR), > - is particularly slow if the lower 4 GB of the address space are mapped > inaccessible, as we're planning to do on 64-bit Hurd, > - is just silly. > > Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> > --- > sysdeps/mach/htl/pt-stack-alloc.c | 35 ++++++------------------------- > 1 file changed, 6 insertions(+), 29 deletions(-) > > diff --git a/sysdeps/mach/htl/pt-stack-alloc.c b/sysdeps/mach/htl/pt-stack-alloc.c > index 429ac2d9..97e6b445 100644 > --- a/sysdeps/mach/htl/pt-stack-alloc.c > +++ b/sysdeps/mach/htl/pt-stack-alloc.c > @@ -19,14 +19,9 @@ > #include <errno.h> > > #include <mach.h> > -#include <mach/machine/vm_param.h> > > #include <pt-internal.h> > > -/* The next address to use for stack allocation. */ > -static vm_address_t next_stack_base = VM_MIN_ADDRESS; > - > - > /* Allocate a new stack of size STACKSIZE. If successful, store the > address of the newly allocated stack in *STACKADDR and return 0. > Otherwise return an error code (EINVAL for an invalid stack size, > @@ -35,30 +30,12 @@ static vm_address_t next_stack_base = VM_MIN_ADDRESS; > int > __pthread_stack_alloc (void **stackaddr, size_t stacksize) > { > - vm_offset_t base; > - int i = 0; > - > -get_stack: > - i++; > - for (base = next_stack_base; > - base < VM_MAX_ADDRESS > - && __vm_allocate (__mach_task_self (), &base, > - stacksize, FALSE) != KERN_SUCCESS; base += stacksize) > - ; > - > - if (base >= VM_MAX_ADDRESS) > - { > - if (i == 1) > - { > - next_stack_base = VM_MIN_ADDRESS; > - goto get_stack; > - } > - else > - return EAGAIN; > - } > + error_t err; > > - next_stack_base = base + stacksize; > + err = __vm_allocate (__mach_task_self (), (vm_offset_t *) stackaddr, > + stacksize, TRUE); > > - (*stackaddr) = (void *) base; > - return 0; > + if (err == KERN_NO_SPACE) > + err = EAGAIN; > + return err; > } > -- > 2.41.0 > >
diff --git a/sysdeps/mach/htl/pt-stack-alloc.c b/sysdeps/mach/htl/pt-stack-alloc.c index 429ac2d9..97e6b445 100644 --- a/sysdeps/mach/htl/pt-stack-alloc.c +++ b/sysdeps/mach/htl/pt-stack-alloc.c @@ -19,14 +19,9 @@ #include <errno.h> #include <mach.h> -#include <mach/machine/vm_param.h> #include <pt-internal.h> -/* The next address to use for stack allocation. */ -static vm_address_t next_stack_base = VM_MIN_ADDRESS; - - /* Allocate a new stack of size STACKSIZE. If successful, store the address of the newly allocated stack in *STACKADDR and return 0. Otherwise return an error code (EINVAL for an invalid stack size, @@ -35,30 +30,12 @@ static vm_address_t next_stack_base = VM_MIN_ADDRESS; int __pthread_stack_alloc (void **stackaddr, size_t stacksize) { - vm_offset_t base; - int i = 0; - -get_stack: - i++; - for (base = next_stack_base; - base < VM_MAX_ADDRESS - && __vm_allocate (__mach_task_self (), &base, - stacksize, FALSE) != KERN_SUCCESS; base += stacksize) - ; - - if (base >= VM_MAX_ADDRESS) - { - if (i == 1) - { - next_stack_base = VM_MIN_ADDRESS; - goto get_stack; - } - else - return EAGAIN; - } + error_t err; - next_stack_base = base + stacksize; + err = __vm_allocate (__mach_task_self (), (vm_offset_t *) stackaddr, + stacksize, TRUE); - (*stackaddr) = (void *) base; - return 0; + if (err == KERN_NO_SPACE) + err = EAGAIN; + return err; }
Instead of trying to allocate a thread stack at a specific address, looping over the address space, just set the ANYWHERE flag in vm_allocate (). The previous behavior: - defeats ASLR (for Mach versions that support ASLR), - is particularly slow if the lower 4 GB of the address space are mapped inaccessible, as we're planning to do on 64-bit Hurd, - is just silly. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> --- sysdeps/mach/htl/pt-stack-alloc.c | 35 ++++++------------------------- 1 file changed, 6 insertions(+), 29 deletions(-)