From 385e89d5b20f5a7c33fd7c1904da0e6a8e1b366f Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 28 Nov 2018 17:21:10 +0000 Subject: [PATCH] powerpc/mm: add exec protection on powerpc 603 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 Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- 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 +- .../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 727692fd6bca..49d76adb9bc5 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); @@ -371,7 +371,7 @@ 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) { @@ -438,7 +438,7 @@ 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) @@ -453,7 +453,7 @@ 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 15108b8caf6e..05b08db3901d 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -503,7 +503,7 @@ 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. */