Messages in this thread | | | Date | Sat, 9 Apr 2022 13:36:17 +0200 | Subject | Re: [PATCH V4 2/7] powerpc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT | From | Christophe Leroy <> |
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Le 08/04/2022 à 14:53, Christophe Leroy a écrit : > > > Le 07/04/2022 à 12:32, Anshuman Khandual a écrit : >> This defines and exports a platform specific custom vm_get_page_prot() >> via >> subscribing ARCH_HAS_VM_GET_PAGE_PROT. While here, this also localizes >> arch_vm_get_page_prot() as powerpc_vm_get_page_prot() and moves it near >> vm_get_page_prot(). >> >> Cc: Michael Ellerman <mpe@ellerman.id.au> >> Cc: Paul Mackerras <paulus@samba.org> >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >> --- >> arch/powerpc/Kconfig | 1 + >> arch/powerpc/include/asm/mman.h | 12 ------------ >> arch/powerpc/mm/mmap.c | 26 ++++++++++++++++++++++++++ >> 3 files changed, 27 insertions(+), 12 deletions(-) >> >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >> index 174edabb74fa..eb9b6ddbf92f 100644 >> --- a/arch/powerpc/Kconfig >> +++ b/arch/powerpc/Kconfig >> @@ -140,6 +140,7 @@ config PPC >> select ARCH_HAS_TICK_BROADCAST if >> GENERIC_CLOCKEVENTS_BROADCAST >> select ARCH_HAS_UACCESS_FLUSHCACHE >> select ARCH_HAS_UBSAN_SANITIZE_ALL >> + select ARCH_HAS_VM_GET_PAGE_PROT >> select ARCH_HAVE_NMI_SAFE_CMPXCHG >> select ARCH_KEEP_MEMBLOCK >> select ARCH_MIGHT_HAVE_PC_PARPORT >> diff --git a/arch/powerpc/include/asm/mman.h >> b/arch/powerpc/include/asm/mman.h >> index 7cb6d18f5cd6..1b024e64c8ec 100644 >> --- a/arch/powerpc/include/asm/mman.h >> +++ b/arch/powerpc/include/asm/mman.h >> @@ -24,18 +24,6 @@ static inline unsigned long >> arch_calc_vm_prot_bits(unsigned long prot, >> } >> #define arch_calc_vm_prot_bits(prot, pkey) >> arch_calc_vm_prot_bits(prot, pkey) >> -static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) >> -{ >> -#ifdef CONFIG_PPC_MEM_KEYS >> - return (vm_flags & VM_SAO) ? >> - __pgprot(_PAGE_SAO | vmflag_to_pte_pkey_bits(vm_flags)) : >> - __pgprot(0 | vmflag_to_pte_pkey_bits(vm_flags)); >> -#else >> - return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0); >> -#endif >> -} >> -#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags) >> - >> static inline bool arch_validate_prot(unsigned long prot, unsigned >> long addr) >> { >> if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | >> PROT_SAO)) >> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c >> index c475cf810aa8..cd17bd6fa36b 100644 >> --- a/arch/powerpc/mm/mmap.c >> +++ b/arch/powerpc/mm/mmap.c >> @@ -254,3 +254,29 @@ void arch_pick_mmap_layout(struct mm_struct *mm, >> struct rlimit *rlim_stack) >> mm->get_unmapped_area = arch_get_unmapped_area_topdown; >> } >> } >> + >> +#ifdef CONFIG_PPC64 >> +static pgprot_t powerpc_vm_get_page_prot(unsigned long vm_flags) >> +{ >> +#ifdef CONFIG_PPC_MEM_KEYS >> + return (vm_flags & VM_SAO) ? >> + __pgprot(_PAGE_SAO | vmflag_to_pte_pkey_bits(vm_flags)) : >> + __pgprot(0 | vmflag_to_pte_pkey_bits(vm_flags)); >> +#else >> + return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0); >> +#endif >> +} >> +#else >> +static pgprot_t powerpc_vm_get_page_prot(unsigned long vm_flags) >> +{ >> + return __pgprot(0); >> +} >> +#endif /* CONFIG_PPC64 */ > > Can we reduce this forest of #ifdefs and make it more readable ? > > mm/mmap.c is going away with patch > https://patchwork.ozlabs.org/project/linuxppc-dev/patch/d6d849621f821af253e777a24eda4c648814a76e.1646847562.git.christophe.leroy@csgroup.eu/ > > > So it would be better to add two versions of vm_get_page_prot(), for > instance one in mm/pgtable_64.c and one in mm/pgtable_32.c
Indeed, you don't need anything at all for PPC32. All you need to do is
select ARCH_HAS_VM_GET_PAGE_PROT if PPC64
And in fact it could even be PPC_BOOK3S_64 instead of PPC64 because CONFIG_PPC_MEM_KEYS depends on PPC_BOOK3S_64 and _PAGE_SAO is 0 on nohash/64.
So you can then put it into arch/powerpc/mm/book3s64/pgtable.c
> > >> + >> +pgprot_t vm_get_page_prot(unsigned long vm_flags) >> +{ >> + return __pgprot(pgprot_val(protection_map[vm_flags & >> + (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | >> + pgprot_val(powerpc_vm_get_page_prot(vm_flags))); >> +} >> +EXPORT_SYMBOL(vm_get_page_prot); > > By the way I'm a bit puzzled with the name powerpc_vm_get_page_prot(), > the name suggests that it's just a powerpc replacement of > vm_get_page_prot(). I'd prefer if it was named __vm_get_page_prot(), it > would be clearer that it is a complement to vm_get_page_prot() and not a > remplacement. > > Christophe
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