| Message ID | 20190606200646.3951-19-yu-cheng.yu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Control-flow Enforcement: Shadow Stack | expand |
On Thu, Jun 06, 2019 at 01:06:37PM -0700, Yu-cheng Yu wrote: > There are a few places that need do_mmap() with mm->mmap_sem held. > Create an in-line function for that. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > --- > include/linux/mm.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 398f1e1c35e5..7cf014604848 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr, unsigned long len) > static inline void mm_populate(unsigned long addr, unsigned long len) {} > #endif > > +static inline unsigned long do_mmap_locked(unsigned long addr, > + unsigned long len, unsigned long prot, unsigned long flags, > + vm_flags_t vm_flags) > +{ > + struct mm_struct *mm = current->mm; > + unsigned long populate; > + > + down_write(&mm->mmap_sem); > + addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0, > + &populate, NULL); Funny thing how do_mmap() takes a file pointer as first argument and this thing explicitly NULLs that. That more or less invalidates the name do_mmap_locked(). > + up_write(&mm->mmap_sem); > + > + if (populate) > + mm_populate(addr, populate); > + > + return addr; > +}
On Fri, Jun 07, 2019 at 09:43:22AM +0200, Peter Zijlstra wrote: > On Thu, Jun 06, 2019 at 01:06:37PM -0700, Yu-cheng Yu wrote: > > There are a few places that need do_mmap() with mm->mmap_sem held. > > Create an in-line function for that. > > > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > > --- > > include/linux/mm.h | 18 ++++++++++++++++++ > > 1 file changed, 18 insertions(+) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 398f1e1c35e5..7cf014604848 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr, unsigned long len) > > static inline void mm_populate(unsigned long addr, unsigned long len) {} > > #endif > > > > +static inline unsigned long do_mmap_locked(unsigned long addr, > > + unsigned long len, unsigned long prot, unsigned long flags, > > + vm_flags_t vm_flags) > > +{ > > + struct mm_struct *mm = current->mm; > > + unsigned long populate; > > + > > + down_write(&mm->mmap_sem); > > + addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0, > > + &populate, NULL); > > Funny thing how do_mmap() takes a file pointer as first argument and > this thing explicitly NULLs that. That more or less invalidates the name > do_mmap_locked(). > > > + up_write(&mm->mmap_sem); > > + > > + if (populate) > > + mm_populate(addr, populate); > > + > > + return addr; > > +} You also don't retain that last @uf argument. I'm thikning you're better off adding a helper to the cet.c file; call it cet_mmap() or whatever.
On Fri, 2019-06-07 at 09:47 +0200, Peter Zijlstra wrote: > On Fri, Jun 07, 2019 at 09:43:22AM +0200, Peter Zijlstra wrote: > > On Thu, Jun 06, 2019 at 01:06:37PM -0700, Yu-cheng Yu wrote: > > > There are a few places that need do_mmap() with mm->mmap_sem held. > > > Create an in-line function for that. > > > > > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > > > --- > > > include/linux/mm.h | 18 ++++++++++++++++++ > > > 1 file changed, 18 insertions(+) > > > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > > index 398f1e1c35e5..7cf014604848 100644 > > > --- a/include/linux/mm.h > > > +++ b/include/linux/mm.h > > > @@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr, > > > unsigned long len) > > > static inline void mm_populate(unsigned long addr, unsigned long len) {} > > > #endif > > > > > > +static inline unsigned long do_mmap_locked(unsigned long addr, > > > + unsigned long len, unsigned long prot, unsigned long flags, > > > + vm_flags_t vm_flags) > > > +{ > > > + struct mm_struct *mm = current->mm; > > > + unsigned long populate; > > > + > > > + down_write(&mm->mmap_sem); > > > + addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0, > > > + &populate, NULL); > > > > Funny thing how do_mmap() takes a file pointer as first argument and > > this thing explicitly NULLs that. That more or less invalidates the name > > do_mmap_locked(). > > > > > + up_write(&mm->mmap_sem); > > > + > > > + if (populate) > > > + mm_populate(addr, populate); > > > + > > > + return addr; > > > +} > > You also don't retain that last @uf argument. > > I'm thikning you're better off adding a helper to the cet.c file; call > it cet_mmap() or whatever. Ok, I will fix that. Yu-cheng
diff --git a/include/linux/mm.h b/include/linux/mm.h index 398f1e1c35e5..7cf014604848 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr, unsigned long len) static inline void mm_populate(unsigned long addr, unsigned long len) {} #endif +static inline unsigned long do_mmap_locked(unsigned long addr, + unsigned long len, unsigned long prot, unsigned long flags, + vm_flags_t vm_flags) +{ + struct mm_struct *mm = current->mm; + unsigned long populate; + + down_write(&mm->mmap_sem); + addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0, + &populate, NULL); + up_write(&mm->mmap_sem); + + if (populate) + mm_populate(addr, populate); + + return addr; +} + /* These take the mm semaphore themselves */ extern int __must_check vm_brk(unsigned long, unsigned long); extern int __must_check vm_brk_flags(unsigned long, unsigned long, unsigned long);
There are a few places that need do_mmap() with mm->mmap_sem held. Create an in-line function for that. Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> --- include/linux/mm.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)