| Message ID | 20220603101411.488970-3-anshuman.khandual@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | mm/mmap: Enable more platforms with ARCH_HAS_VM_GET_PAGE_PROT | expand |
Le 03/06/2022 à 12:14, Anshuman Khandual a écrit : > This defines and exports a platform specific custom vm_get_page_prot() via > subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX > macros can be dropped which are no longer needed. > > Cc: Heiko Carstens <hca@linux.ibm.com> > Cc: Vasily Gorbik <gor@linux.ibm.com> > Cc: linux-s390@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Acked-by: Sven Schnelle <svens@linux.ibm.com> > Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > arch/s390/Kconfig | 1 + > arch/s390/include/asm/pgtable.h | 17 ----------------- > arch/s390/mm/mmap.c | 33 +++++++++++++++++++++++++++++++++ > 3 files changed, 34 insertions(+), 17 deletions(-) > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index b17239ae7bd4..cdcf678deab1 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -81,6 +81,7 @@ config S390 > select ARCH_HAS_SYSCALL_WRAPPER > select ARCH_HAS_UBSAN_SANITIZE_ALL > select ARCH_HAS_VDSO_DATA > + select ARCH_HAS_VM_GET_PAGE_PROT > select ARCH_HAVE_NMI_SAFE_CMPXCHG > select ARCH_INLINE_READ_LOCK > select ARCH_INLINE_READ_LOCK_BH > diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h > index a397b072a580..c63a05b5368a 100644 > --- a/arch/s390/include/asm/pgtable.h > +++ b/arch/s390/include/asm/pgtable.h > @@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr) > * implies read permission. > */ > /*xwr*/ > -#define __P000 PAGE_NONE > -#define __P001 PAGE_RO > -#define __P010 PAGE_RO > -#define __P011 PAGE_RO > -#define __P100 PAGE_RX > -#define __P101 PAGE_RX > -#define __P110 PAGE_RX > -#define __P111 PAGE_RX > - > -#define __S000 PAGE_NONE > -#define __S001 PAGE_RO > -#define __S010 PAGE_RW > -#define __S011 PAGE_RW > -#define __S100 PAGE_RX > -#define __S101 PAGE_RX > -#define __S110 PAGE_RWX > -#define __S111 PAGE_RWX > > /* > * Segment entry (large page) protection definitions. > diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c > index d545f5c39f7e..11d75b8d5ec0 100644 > --- a/arch/s390/mm/mmap.c > +++ b/arch/s390/mm/mmap.c > @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) > mm->get_unmapped_area = arch_get_unmapped_area_topdown; > } > } > + > +pgprot_t vm_get_page_prot(unsigned long vm_flags) > +{ > + switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) { > + case VM_NONE: > + return PAGE_NONE; > + case VM_READ: > + case VM_WRITE: > + case VM_WRITE | VM_READ: > + return PAGE_RO; > + case VM_EXEC: > + case VM_EXEC | VM_READ: > + case VM_EXEC | VM_WRITE: > + case VM_EXEC | VM_WRITE | VM_READ: > + return PAGE_RX; > + case VM_SHARED: > + return PAGE_NONE; > + case VM_SHARED | VM_READ: > + return PAGE_RO; > + case VM_SHARED | VM_WRITE: > + case VM_SHARED | VM_WRITE | VM_READ: > + return PAGE_RW; > + case VM_SHARED | VM_EXEC: > + case VM_SHARED | VM_EXEC | VM_READ: > + return PAGE_RX; > + case VM_SHARED | VM_EXEC | VM_WRITE: > + case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ: > + return PAGE_RWX; > + default: > + BUILD_BUG(); > + } > +} > +EXPORT_SYMBOL(vm_get_page_prot); Wasn't it demonstrated in previous discussions that a switch/case is suboptimal compared to a table cell read ? In order to get rid of the _Sxxx/_Pxxx macros, my preference would go to having architectures provide their own protection_map[] table, and keep the generic vm_get_page_prot() for the architectures would don't need a specific version of it. This comment applies to all following patches as well.
On 6/3/22 17:55, Christophe Leroy wrote: > > > Le 03/06/2022 à 12:14, Anshuman Khandual a écrit : >> This defines and exports a platform specific custom vm_get_page_prot() via >> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX >> macros can be dropped which are no longer needed. >> >> Cc: Heiko Carstens <hca@linux.ibm.com> >> Cc: Vasily Gorbik <gor@linux.ibm.com> >> Cc: linux-s390@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> Acked-by: Sven Schnelle <svens@linux.ibm.com> >> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >> --- >> arch/s390/Kconfig | 1 + >> arch/s390/include/asm/pgtable.h | 17 ----------------- >> arch/s390/mm/mmap.c | 33 +++++++++++++++++++++++++++++++++ >> 3 files changed, 34 insertions(+), 17 deletions(-) >> >> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig >> index b17239ae7bd4..cdcf678deab1 100644 >> --- a/arch/s390/Kconfig >> +++ b/arch/s390/Kconfig >> @@ -81,6 +81,7 @@ config S390 >> select ARCH_HAS_SYSCALL_WRAPPER >> select ARCH_HAS_UBSAN_SANITIZE_ALL >> select ARCH_HAS_VDSO_DATA >> + select ARCH_HAS_VM_GET_PAGE_PROT >> select ARCH_HAVE_NMI_SAFE_CMPXCHG >> select ARCH_INLINE_READ_LOCK >> select ARCH_INLINE_READ_LOCK_BH >> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h >> index a397b072a580..c63a05b5368a 100644 >> --- a/arch/s390/include/asm/pgtable.h >> +++ b/arch/s390/include/asm/pgtable.h >> @@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr) >> * implies read permission. >> */ >> /*xwr*/ >> -#define __P000 PAGE_NONE >> -#define __P001 PAGE_RO >> -#define __P010 PAGE_RO >> -#define __P011 PAGE_RO >> -#define __P100 PAGE_RX >> -#define __P101 PAGE_RX >> -#define __P110 PAGE_RX >> -#define __P111 PAGE_RX >> - >> -#define __S000 PAGE_NONE >> -#define __S001 PAGE_RO >> -#define __S010 PAGE_RW >> -#define __S011 PAGE_RW >> -#define __S100 PAGE_RX >> -#define __S101 PAGE_RX >> -#define __S110 PAGE_RWX >> -#define __S111 PAGE_RWX >> >> /* >> * Segment entry (large page) protection definitions. >> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c >> index d545f5c39f7e..11d75b8d5ec0 100644 >> --- a/arch/s390/mm/mmap.c >> +++ b/arch/s390/mm/mmap.c >> @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) >> mm->get_unmapped_area = arch_get_unmapped_area_topdown; >> } >> } >> + >> +pgprot_t vm_get_page_prot(unsigned long vm_flags) >> +{ >> + switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) { >> + case VM_NONE: >> + return PAGE_NONE; >> + case VM_READ: >> + case VM_WRITE: >> + case VM_WRITE | VM_READ: >> + return PAGE_RO; >> + case VM_EXEC: >> + case VM_EXEC | VM_READ: >> + case VM_EXEC | VM_WRITE: >> + case VM_EXEC | VM_WRITE | VM_READ: >> + return PAGE_RX; >> + case VM_SHARED: >> + return PAGE_NONE; >> + case VM_SHARED | VM_READ: >> + return PAGE_RO; >> + case VM_SHARED | VM_WRITE: >> + case VM_SHARED | VM_WRITE | VM_READ: >> + return PAGE_RW; >> + case VM_SHARED | VM_EXEC: >> + case VM_SHARED | VM_EXEC | VM_READ: >> + return PAGE_RX; >> + case VM_SHARED | VM_EXEC | VM_WRITE: >> + case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ: >> + return PAGE_RWX; >> + default: >> + BUILD_BUG(); >> + } >> +} >> +EXPORT_SYMBOL(vm_get_page_prot); > > Wasn't it demonstrated in previous discussions that a switch/case is > suboptimal compared to a table cell read ? Right but all these platform patches here were acked from respective platform folks. I assumed that they might have valued the simplicity in switch case statements, while also dropping off the __SXXX/__PXXX macros, which is the final objective. Looks like that assumption was not accurate. > > In order to get rid of the _Sxxx/_Pxxx macros, my preference would go to > having architectures provide their own protection_map[] table, and keep > the generic vm_get_page_prot() for the architectures would don't need a > specific version of it. I will try and rework the patches as suggested. > > This comment applies to all following patches as well.
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b17239ae7bd4..cdcf678deab1 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -81,6 +81,7 @@ config S390 select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_UBSAN_SANITIZE_ALL select ARCH_HAS_VDSO_DATA + select ARCH_HAS_VM_GET_PAGE_PROT select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK select ARCH_INLINE_READ_LOCK_BH diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index a397b072a580..c63a05b5368a 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr) * implies read permission. */ /*xwr*/ -#define __P000 PAGE_NONE -#define __P001 PAGE_RO -#define __P010 PAGE_RO -#define __P011 PAGE_RO -#define __P100 PAGE_RX -#define __P101 PAGE_RX -#define __P110 PAGE_RX -#define __P111 PAGE_RX - -#define __S000 PAGE_NONE -#define __S001 PAGE_RO -#define __S010 PAGE_RW -#define __S011 PAGE_RW -#define __S100 PAGE_RX -#define __S101 PAGE_RX -#define __S110 PAGE_RWX -#define __S111 PAGE_RWX /* * Segment entry (large page) protection definitions. diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index d545f5c39f7e..11d75b8d5ec0 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } + +pgprot_t vm_get_page_prot(unsigned long vm_flags) +{ + switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) { + case VM_NONE: + return PAGE_NONE; + case VM_READ: + case VM_WRITE: + case VM_WRITE | VM_READ: + return PAGE_RO; + case VM_EXEC: + case VM_EXEC | VM_READ: + case VM_EXEC | VM_WRITE: + case VM_EXEC | VM_WRITE | VM_READ: + return PAGE_RX; + case VM_SHARED: + return PAGE_NONE; + case VM_SHARED | VM_READ: + return PAGE_RO; + case VM_SHARED | VM_WRITE: + case VM_SHARED | VM_WRITE | VM_READ: + return PAGE_RW; + case VM_SHARED | VM_EXEC: + case VM_SHARED | VM_EXEC | VM_READ: + return PAGE_RX; + case VM_SHARED | VM_EXEC | VM_WRITE: + case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ: + return PAGE_RWX; + default: + BUILD_BUG(); + } +} +EXPORT_SYMBOL(vm_get_page_prot);