Messages in this thread | | | Subject | Re: [PATCH v3] powerpc/mm: add exec protection on powerpc 603 | From | Christophe LEROY <> | Date | Thu, 29 Nov 2018 13:13:51 +0100 |
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Le 28/11/2018 à 18:21, Christophe Leroy a écrit : > The 603 doesn't have a HASH table, TLB misses are handled by > software. It is then possible to generate page fault when > _PAGE_EXEC is not set like in nohash/32. > > There is one "reserved" PTE bit available, this patch uses > it for _PAGE_EXEC. > > In order to support it, set_pte_filter() and > set_access_flags_filter() are made common, and the handling > is made dependent on MMU_FTR_HPTE_TABLE > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> --- > v3: Included the _PAGE_EXEC flag in the existing test in TLB handler, no additional insns. > > v2: Amended commit log and removed #ifdef in pagetable dump > > arch/powerpc/include/asm/book3s/32/hash.h | 1 + > arch/powerpc/include/asm/book3s/32/pgtable.h | 18 +++++++++--------- > arch/powerpc/include/asm/cputable.h | 8 ++++---- > arch/powerpc/kernel/head_32.S | 2 +- > arch/powerpc/mm/dump_linuxpagetables-generic.c | 2 -- > arch/powerpc/mm/pgtable.c | 20 +++++++++++--------- > 6 files changed, 26 insertions(+), 25 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/32/hash.h b/arch/powerpc/include/asm/book3s/32/hash.h > index f2892c7ab73e..2a0a467d2985 100644 > --- a/arch/powerpc/include/asm/book3s/32/hash.h > +++ b/arch/powerpc/include/asm/book3s/32/hash.h > @@ -26,6 +26,7 @@ > #define _PAGE_WRITETHRU 0x040 /* W: cache write-through */ > #define _PAGE_DIRTY 0x080 /* C: page changed */ > #define _PAGE_ACCESSED 0x100 /* R: page referenced */ > +#define _PAGE_EXEC 0x200 /* software: exec allowed */ > #define _PAGE_RW 0x400 /* software: user write access allowed */ > #define _PAGE_SPECIAL 0x800 /* software: Special page */ > > diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h > index b849b45429d5..6accf3e686af 100644 > --- a/arch/powerpc/include/asm/book3s/32/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h > @@ -10,9 +10,9 @@ > /* And here we include common definitions */ > > #define _PAGE_KERNEL_RO 0 > -#define _PAGE_KERNEL_ROX 0 > +#define _PAGE_KERNEL_ROX (_PAGE_EXEC) > #define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW) > -#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW) > +#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC) > > #define _PAGE_HPTEFLAGS _PAGE_HASHPTE > > @@ -66,11 +66,11 @@ static inline bool pte_user(pte_t pte) > */ > #define PAGE_NONE __pgprot(_PAGE_BASE) > #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) > -#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) > +#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) > #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) > -#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER) > +#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) > #define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER) > -#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER) > +#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) > > /* Permission masks used for kernel mappings */ > #define PAGE_KERNEL __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW) > @@ -318,7 +318,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma, > int psize) > { > unsigned long set = pte_val(entry) & > - (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW); > + (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC); > > pte_update(ptep, 0, set); > > @@ -384,7 +384,7 @@ static inline int pte_dirty(pte_t pte) { return !!(pte_val(pte) & _PAGE_DIRTY); > static inline int pte_young(pte_t pte) { return !!(pte_val(pte) & _PAGE_ACCESSED); } > static inline int pte_special(pte_t pte) { return !!(pte_val(pte) & _PAGE_SPECIAL); } > static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; } > -static inline bool pte_exec(pte_t pte) { return true; } > +static inline bool pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_EXEC; } > > static inline int pte_present(pte_t pte) > { > @@ -451,7 +451,7 @@ static inline pte_t pte_wrprotect(pte_t pte) > > static inline pte_t pte_exprotect(pte_t pte) > { > - return pte; > + return __pte(pte_val(pte) & ~_PAGE_EXEC); > } > > static inline pte_t pte_mkclean(pte_t pte) > @@ -466,7 +466,7 @@ static inline pte_t pte_mkold(pte_t pte) > > static inline pte_t pte_mkexec(pte_t pte) > { > - return pte; > + return __pte(pte_val(pte) | _PAGE_EXEC); > } > > static inline pte_t pte_mkpte(pte_t pte) > diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h > index 29f49a35d6ee..a0395ccbbe9e 100644 > --- a/arch/powerpc/include/asm/cputable.h > +++ b/arch/powerpc/include/asm/cputable.h > @@ -296,7 +296,7 @@ static inline void cpu_feature_keys_init(void) { } > #define CPU_FTRS_PPC601 (CPU_FTR_COMMON | CPU_FTR_601 | \ > CPU_FTR_COHERENT_ICACHE | CPU_FTR_UNIFIED_ID_CACHE | CPU_FTR_USE_RTC) > #define CPU_FTRS_603 (CPU_FTR_COMMON | CPU_FTR_MAYBE_CAN_DOZE | \ > - CPU_FTR_MAYBE_CAN_NAP | CPU_FTR_PPC_LE) > + CPU_FTR_MAYBE_CAN_NAP | CPU_FTR_PPC_LE | CPU_FTR_NOEXECUTE) > #define CPU_FTRS_604 (CPU_FTR_COMMON | CPU_FTR_PPC_LE) > #define CPU_FTRS_740_NOTAU (CPU_FTR_COMMON | \ > CPU_FTR_MAYBE_CAN_DOZE | CPU_FTR_L2CR | \ > @@ -367,15 +367,15 @@ static inline void cpu_feature_keys_init(void) { } > CPU_FTR_MAYBE_CAN_NAP | CPU_FTR_L2CR | CPU_FTR_ALTIVEC_COMP | \ > CPU_FTR_SPEC7450 | CPU_FTR_NAP_DISABLE_L2_PR | \ > CPU_FTR_PPC_LE | CPU_FTR_NEED_PAIRED_STWCX) > -#define CPU_FTRS_82XX (CPU_FTR_COMMON | CPU_FTR_MAYBE_CAN_DOZE) > +#define CPU_FTRS_82XX (CPU_FTR_COMMON | CPU_FTR_MAYBE_CAN_DOZE | CPU_FTR_NOEXECUTE) > #define CPU_FTRS_G2_LE (CPU_FTR_COMMON | CPU_FTR_MAYBE_CAN_DOZE | \ > CPU_FTR_MAYBE_CAN_NAP) > #define CPU_FTRS_E300 (CPU_FTR_MAYBE_CAN_DOZE | \ > CPU_FTR_MAYBE_CAN_NAP | \ > - CPU_FTR_COMMON) > + CPU_FTR_COMMON | CPU_FTR_NOEXECUTE) > #define CPU_FTRS_E300C2 (CPU_FTR_MAYBE_CAN_DOZE | \ > CPU_FTR_MAYBE_CAN_NAP | \ > - CPU_FTR_COMMON | CPU_FTR_FPU_UNAVAILABLE) > + CPU_FTR_COMMON | CPU_FTR_FPU_UNAVAILABLE | CPU_FTR_NOEXECUTE) > #define CPU_FTRS_CLASSIC32 (CPU_FTR_COMMON) > #define CPU_FTRS_8XX (CPU_FTR_NOEXECUTE) > #define CPU_FTRS_40X (CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE) > diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S > index 118c3b216e60..479017f6a992 100644 > --- a/arch/powerpc/kernel/head_32.S > +++ b/arch/powerpc/kernel/head_32.S > @@ -499,7 +499,7 @@ InstructionTLBMiss: > lis r1,PAGE_OFFSET@h /* check if kernel address */ > cmplw 0,r1,r3 > mfspr r2,SPRN_SPRG_THREAD > - li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */ > + li r1,_PAGE_USER|_PAGE_PRESENT|_PAGE_EXEC /* low addresses tested as user */ > lwz r2,PGDIR(r2) > bge- 112f > mfspr r2,SPRN_SRR1 /* and MSR_PR bit from SRR1 */ > diff --git a/arch/powerpc/mm/dump_linuxpagetables-generic.c b/arch/powerpc/mm/dump_linuxpagetables-generic.c > index 1e3829ec1348..3fe98a0974c6 100644 > --- a/arch/powerpc/mm/dump_linuxpagetables-generic.c > +++ b/arch/powerpc/mm/dump_linuxpagetables-generic.c > @@ -21,13 +21,11 @@ static const struct flag_info flag_array[] = { > .set = "rw", > .clear = "r ", > }, { > -#ifndef CONFIG_PPC_BOOK3S_32 > .mask = _PAGE_EXEC, > .val = _PAGE_EXEC, > .set = " X ", > .clear = " ", > }, { > -#endif > .mask = _PAGE_PRESENT, > .val = _PAGE_PRESENT, > .set = "present", > diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c > index 1e33dccbd176..d3d61d29b4f1 100644 > --- a/arch/powerpc/mm/pgtable.c > +++ b/arch/powerpc/mm/pgtable.c > @@ -74,7 +74,7 @@ static struct page *maybe_pte_to_page(pte_t pte) > * support falls into the same category. > */ > > -static pte_t set_pte_filter(pte_t pte) > +static pte_t set_pte_filter_hash(pte_t pte) > { > if (radix_enabled()) > return pte; > @@ -93,14 +93,12 @@ static pte_t set_pte_filter(pte_t pte) > return pte; > } > > -static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, > - int dirty) > -{ > - return pte; > -} > - > #else /* CONFIG_PPC_BOOK3S */ > > +static pte_t set_pte_filter_hash(pte_t pte) { return pte; } > + > +#endif /* CONFIG_PPC_BOOK3S */ > + > /* Embedded type MMU with HW exec support. This is a bit more complicated > * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so > * instead we "filter out" the exec permission for non clean pages. > @@ -109,6 +107,9 @@ static pte_t set_pte_filter(pte_t pte) > { > struct page *pg; > > + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) > + return set_pte_filter_hash(pte); > + > /* No exec permission in the first place, move on */ > if (!pte_exec(pte) || !pte_looks_normal(pte)) > return pte; > @@ -138,6 +139,9 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, > { > struct page *pg; > > + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) > + return pte; > + > /* So here, we only care about exec faults, as we use them > * to recover lost _PAGE_EXEC and perform I$/D$ coherency > * if necessary. Also if _PAGE_EXEC is already set, same deal, > @@ -172,8 +176,6 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, > return pte_mkexec(pte); > } > > -#endif /* CONFIG_PPC_BOOK3S */ > - > /* > * set_pte stores a linux PTE into the linux page table. > */ >
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