diff options
Diffstat (limited to 'arch/powerpc/mm/hash_utils_64.c')
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 83 |
1 files changed, 69 insertions, 14 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 9326a6962b42..7b4cacb0d4ba 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -637,7 +637,7 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap) * For now this makes the whole process use 4k pages. */ #ifdef CONFIG_PPC_64K_PAGES -static void demote_segment_4k(struct mm_struct *mm, unsigned long addr) +void demote_segment_4k(struct mm_struct *mm, unsigned long addr) { if (mm->context.user_psize == MMU_PAGE_4K) return; @@ -645,13 +645,62 @@ static void demote_segment_4k(struct mm_struct *mm, unsigned long addr) #ifdef CONFIG_SPU_BASE spu_flush_all_slbs(mm); #endif + if (get_paca()->context.user_psize != MMU_PAGE_4K) { + get_paca()->context = mm->context; + slb_flush_and_rebolt(); + } } #endif /* CONFIG_PPC_64K_PAGES */ +#ifdef CONFIG_PPC_SUBPAGE_PROT +/* + * This looks up a 2-bit protection code for a 4k subpage of a 64k page. + * Userspace sets the subpage permissions using the subpage_prot system call. + * + * Result is 0: full permissions, _PAGE_RW: read-only, + * _PAGE_USER or _PAGE_USER|_PAGE_RW: no access. + */ +static int subpage_protection(pgd_t *pgdir, unsigned long ea) +{ + struct subpage_prot_table *spt = pgd_subpage_prot(pgdir); + u32 spp = 0; + u32 **sbpm, *sbpp; + + if (ea >= spt->maxaddr) + return 0; + if (ea < 0x100000000) { + /* addresses below 4GB use spt->low_prot */ + sbpm = spt->low_prot; + } else { + sbpm = spt->protptrs[ea >> SBP_L3_SHIFT]; + if (!sbpm) + return 0; + } + sbpp = sbpm[(ea >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)]; + if (!sbpp) + return 0; + spp = sbpp[(ea >> PAGE_SHIFT) & (SBP_L1_COUNT - 1)]; + + /* extract 2-bit bitfield for this 4k subpage */ + spp >>= 30 - 2 * ((ea >> 12) & 0xf); + + /* turn 0,1,2,3 into combination of _PAGE_USER and _PAGE_RW */ + spp = ((spp & 2) ? _PAGE_USER : 0) | ((spp & 1) ? _PAGE_RW : 0); + return spp; +} + +#else /* CONFIG_PPC_SUBPAGE_PROT */ +static inline int subpage_protection(pgd_t *pgdir, unsigned long ea) +{ + return 0; +} +#endif + /* Result code is: * 0 - handled * 1 - normal page fault * -1 - critical hash insertion error + * -2 - access not permitted by subpage protection mechanism */ int hash_page(unsigned long ea, unsigned long access, unsigned long trap) { @@ -802,7 +851,14 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap) rc = __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize); else #endif /* CONFIG_PPC_HAS_HASH_64K */ - rc = __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize); + { + int spp = subpage_protection(pgdir, ea); + if (access & spp) + rc = -2; + else + rc = __hash_page_4K(ea, access, vsid, ptep, trap, + local, ssize, spp); + } #ifndef CONFIG_PPC_64K_PAGES DBG_LOW(" o-pte: %016lx\n", pte_val(*ptep)); @@ -874,7 +930,8 @@ void hash_preload(struct mm_struct *mm, unsigned long ea, __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize); else #endif /* CONFIG_PPC_HAS_HASH_64K */ - __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize); + __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize, + subpage_protection(pgdir, ea)); local_irq_restore(flags); } @@ -919,19 +976,17 @@ void flush_hash_range(unsigned long number, int local) * low_hash_fault is called when we the low level hash code failed * to instert a PTE due to an hypervisor error */ -void low_hash_fault(struct pt_regs *regs, unsigned long address) +void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc) { if (user_mode(regs)) { - siginfo_t info; - - info.si_signo = SIGBUS; - info.si_errno = 0; - info.si_code = BUS_ADRERR; - info.si_addr = (void __user *)address; - force_sig_info(SIGBUS, &info, current); - return; - } - bad_page_fault(regs, address, SIGBUS); +#ifdef CONFIG_PPC_SUBPAGE_PROT + if (rc == -2) + _exception(SIGSEGV, regs, SEGV_ACCERR, address); + else +#endif + _exception(SIGBUS, regs, BUS_ADRERR, address); + } else + bad_page_fault(regs, address, SIGBUS); } #ifdef CONFIG_DEBUG_PAGEALLOC |