diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 8 | ||||
| -rw-r--r-- | arch/powerpc/kernel/head_64.S | 1 | ||||
| -rw-r--r-- | arch/powerpc/mm/Makefile | 1 | ||||
| -rw-r--r-- | arch/powerpc/mm/hash_low_64.S | 16 | ||||
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 83 | ||||
| -rw-r--r-- | arch/powerpc/mm/subpage-prot.c | 213 | ||||
| -rw-r--r-- | include/asm-powerpc/mmu-hash64.h | 3 | ||||
| -rw-r--r-- | include/asm-powerpc/pgalloc-64.h | 5 | ||||
| -rw-r--r-- | include/asm-powerpc/pgtable-64k.h | 39 | ||||
| -rw-r--r-- | include/asm-powerpc/systbl.h | 1 | ||||
| -rw-r--r-- | include/asm-powerpc/unistd.h | 3 | ||||
| -rw-r--r-- | kernel/sys_ni.c | 1 |
12 files changed, 353 insertions, 21 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 66a3d8cee5c..53d0955abf1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -342,6 +342,14 @@ config PPC_64K_PAGES while on hardware with such support, it will be used to map normal application pages. +config PPC_SUBPAGE_PROT + bool "Support setting protections for 4k subpages" + depends on PPC_64K_PAGES + help + This option adds support for a system call to allow user programs + to set access permissions (read/write, readonly, or no access) + on the 4k subpages of each 64k page. + config SCHED_SMT bool "SMT (Hyperthreading) scheduler support" depends on PPC64 && SMP diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index c34986835a4..11b4f6d9ffc 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -903,6 +903,7 @@ handle_page_fault: * the PTE insertion */ 12: bl .save_nvgprs + mr r5,r3 addi r3,r1,STACK_FRAME_OVERHEAD ld r4,_DAR(r1) bl .low_hash_fault diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index 20629ae95c5..41649a5d360 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -22,3 +22,4 @@ obj-$(CONFIG_FSL_BOOKE) += fsl_booke_mmu.o obj-$(CONFIG_NEED_MULTIPLE_NODES) += numa.o obj-$(CONFIG_PPC_MM_SLICES) += slice.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_PPC_SUBPAGE_PROT) += subpage-prot.o diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S index e935edd6b72..21d24848647 100644 --- a/arch/powerpc/mm/hash_low_64.S +++ b/arch/powerpc/mm/hash_low_64.S @@ -331,7 +331,8 @@ htab_pte_insert_failure: *****************************************************************************/ /* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, - * pte_t *ptep, unsigned long trap, int local, int ssize) + * pte_t *ptep, unsigned long trap, int local, int ssize, + * int subpg_prot) */ /* @@ -429,12 +430,19 @@ END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT) xor r28,r28,r0 /* hash */ /* Convert linux PTE bits into HW equivalents */ -4: andi. r3,r30,0x1fe /* Get basic set of flags */ - xori r3,r3,HPTE_R_N /* _PAGE_EXEC -> NOEXEC */ +4: +#ifdef CONFIG_PPC_SUBPAGE_PROT + andc r10,r30,r10 + andi. r3,r10,0x1fe /* Get basic set of flags */ + rlwinm r0,r10,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */ +#else + andi. r3,r30,0x1fe /* Get basic set of flags */ rlwinm r0,r30,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */ +#endif + xori r3,r3,HPTE_R_N /* _PAGE_EXEC -> NOEXEC */ rlwinm r4,r30,32-7+1,30,30 /* _PAGE_DIRTY -> _PAGE_USER (r4) */ and r0,r0,r4 /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/ - andc r0,r30,r0 /* r0 = pte & ~r0 */ + andc r0,r3,r0 /* r0 = pte & ~r0 */ rlwimi r3,r0,32-1,31,31 /* Insert result into PP lsb */ ori r3,r3,HPTE_R_C /* Always add "C" bit for perf. */ diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 9326a6962b4..7b4cacb0d4b 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 diff --git a/arch/powerpc/mm/subpage-prot.c b/arch/powerpc/mm/subpage-prot.c new file mode 100644 index 00000000000..4cafc0c33d0 --- /dev/null +++ b/arch/powerpc/mm/subpage-prot.c @@ -0,0 +1,213 @@ +/* + * Copyright 2007-2008 Paul Mackerras, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> + +#include <asm/pgtable.h> +#include <asm/uaccess.h> +#include <asm/tlbflush.h> + +/* + * Free all pages allocated for subpage protection maps and pointers. + * Also makes sure that the subpage_prot_table structure is + * reinitialized for the next user. + */ +void subpage_prot_free(pgd_t *pgd) +{ + struct subpage_prot_table *spt = pgd_subpage_prot(pgd); + unsigned long i, j, addr; + u32 **p; + + for (i = 0; i < 4; ++i) { + if (spt->low_prot[i]) { + free_page((unsigned long)spt->low_prot[i]); + spt->low_prot[i] = NULL; + } + } + addr = 0; + for (i = 0; i < 2; ++i) { + p = spt->protptrs[i]; + if (!p) + continue; + spt->protptrs[i] = NULL; + for (j = 0; j < SBP_L2_COUNT && addr < spt->maxaddr; + ++j, addr += PAGE_SIZE) + if (p[j]) + free_page((unsigned long)p[j]); + free_page((unsigned long)p); + } + spt->maxaddr = 0; +} + +static void hpte_flush_range(struct mm_struct *mm, unsigned long addr, + int npages) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + spinlock_t *ptl; + + pgd = pgd_offset(mm, addr); + if (pgd_none(*pgd)) + return; + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return; + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return; + pte = pte_offset_map_lock(mm, pmd, addr, &ptl); + arch_enter_lazy_mmu_mode(); + for (; npages > 0; --npages) { + pte_update(mm, addr, pte, 0, 0); + addr += PAGE_SIZE; + ++pte; + } + arch_leave_lazy_mmu_mode(); + pte_unmap_unlock(pte - 1, ptl); +} + +/* + * Clear the subpage protection map for an address range, allowing + * all accesses that are allowed by the pte permissions. + */ +static void subpage_prot_clear(unsigned long addr, unsigned long len) +{ + struct mm_struct *mm = current->mm; + struct subpage_prot_table *spt = pgd_subpage_prot(mm->pgd); + u32 **spm, *spp; + int i, nw; + unsigned long next, limit; + + down_write(&mm->mmap_sem); + limit = addr + len; + if (limit > spt->maxaddr) + limit = spt->maxaddr; + for (; addr < limit; addr = next) { + next = pmd_addr_end(addr, limit); + if (addr < 0x100000000) { + spm = spt->low_prot; + } else { + spm = spt->protptrs[addr >> SBP_L3_SHIFT]; + if (!spm) + continue; + } + spp = spm[(addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)]; + if (!spp) + continue; + spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1); + + i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); + nw = PTRS_PER_PTE - i; + if (addr + (nw << PAGE_SHIFT) > next) + nw = (next - addr) >> PAGE_SHIFT; + + memset(spp, 0, nw * sizeof(u32)); + + /* now flush any existing HPTEs for the range */ + hpte_flush_range(mm, addr, nw); + } + up_write(&mm->mmap_sem); +} + +/* + * Copy in a subpage protection map for an address range. + * The map has 2 bits per 4k subpage, so 32 bits per 64k page. + * Each 2-bit field is 0 to allow any access, 1 to prevent writes, + * 2 or 3 to prevent all accesses. + * Note that the normal page protections also apply; the subpage + * protection mechanism is an additional constraint, so putting 0 + * in a 2-bit field won't allow writes to a page that is otherwise + * write-protected. + */ +long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map) +{ + struct mm_struct *mm = current->mm; + struct subpage_prot_table *spt = pgd_subpage_prot(mm->pgd); + u32 **spm, *spp; + int i, nw; + unsigned long next, limit; + int err; + + /* Check parameters */ + if ((addr & ~PAGE_MASK) || (len & ~PAGE_MASK) || + addr >= TASK_SIZE || len >= TASK_SIZE || addr + len > TASK_SIZE) + return -EINVAL; + + if (is_hugepage_only_range(mm, addr, len)) + return -EINVAL; + + if (!map) { + /* Clear out the protection map for the address range */ + subpage_prot_clear(addr, len); + return 0; + } + + if (!access_ok(VERIFY_READ, map, (len >> PAGE_SHIFT) * sizeof(u32))) + return -EFAULT; + + down_write(&mm->mmap_sem); + for (limit = addr + len; addr < limit; addr = next) { + next = pmd_addr_end(addr, limit); + err = -ENOMEM; + if (addr < 0x100000000) { + spm = spt->low_prot; + } else { + spm = spt->protptrs[addr >> SBP_L3_SHIFT]; + if (!spm) { + spm = (u32 **)get_zeroed_page(GFP_KERNEL); + if (!spm) + goto out; + spt->protptrs[addr >> SBP_L3_SHIFT] = spm; + } + } + spm += (addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1); + spp = *spm; + if (!spp) { + spp = (u32 *)get_zeroed_page(GFP_KERNEL); + if (!spp) + goto out; + *spm = spp; + } + spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1); + + local_irq_disable(); + demote_segment_4k(mm, addr); + local_irq_enable(); + + i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); + nw = PTRS_PER_PTE - i; + if (addr + (nw << PAGE_SHIFT) > next) + nw = (next - addr) >> PAGE_SHIFT; + + up_write(&mm->mmap_sem); + err = -EFAULT; + if (__copy_from_user(spp, map, nw * sizeof(u32))) + goto out2; + map += nw; + down_write(&mm->mmap_sem); + + /* now flush any existing HPTEs for the range */ + hpte_flush_range(mm, addr, nw); + } + if (limit > spt->maxaddr) + spt->maxaddr = limit; + err = 0; + out: + up_write(&mm->mmap_sem); + out2: + return err; +} diff --git a/include/asm-powerpc/mmu-hash64.h b/include/asm-powerpc/mmu-hash64.h index 2a1b4040e20..2864fa3989e 100644 --- a/include/asm-powerpc/mmu-hash64.h +++ b/include/asm-powerpc/mmu-hash64.h @@ -265,7 +265,7 @@ static inline unsigned long hpt_hash(unsigned long va, unsigned int shift, extern int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, pte_t *ptep, unsigned long trap, - unsigned int local, int ssize); + unsigned int local, int ssize, int subpage_prot); extern int __hash_page_64K(unsigned long ea, unsigned long access, unsigned long vsid, pte_t *ptep, unsigned long trap, unsigned int local, int ssize); @@ -279,6 +279,7 @@ extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend, unsigned long pstart, unsigned long mode, int psize, int ssize); extern void set_huge_psize(int psize); +extern void demote_segment_4k(struct mm_struct *mm, unsigned long addr); extern void htab_initialize(void); extern void htab_initialize_secondary(void); diff --git a/include/asm-powerpc/pgalloc-64.h b/include/asm-powerpc/pgalloc-64.h index 94d0294341d..43214c8085b 100644 --- a/include/asm-powerpc/pgalloc-64.h +++ b/include/asm-powerpc/pgalloc-64.h @@ -12,6 +12,10 @@ #include <linux/cpumask.h> #include <linux/percpu.h> +#ifndef CONFIG_PPC_SUBPAGE_PROT +static inline void subpage_prot_free(pgd_t *pgd) {} +#endif + extern struct kmem_cache *pgtable_cache[]; #define PGD_CACHE_NUM 0 @@ -27,6 +31,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm) static inline void pgd_free(pgd_t *pgd) { + subpage_prot_free(pgd); kmem_cache_free(pgtable_cache[PGD_CACHE_NUM], pgd); } diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h index bd54b772fbc..1cbd6b377ee 100644 --- a/include/asm-powerpc/pgtable-64k.h +++ b/include/asm-powerpc/pgtable-64k.h @@ -13,12 +13,49 @@ #define PTE_TABLE_SIZE (sizeof(real_pte_t) << PTE_INDEX_SIZE) #define PMD_TABLE_SIZE (sizeof(pmd_t) << PMD_INDEX_SIZE) #define PGD_TABLE_SIZE (sizeof(pgd_t) << PGD_INDEX_SIZE) -#endif /* __ASSEMBLY__ */ #define PTRS_PER_PTE (1 << PTE_INDEX_SIZE) #define PTRS_PER_PMD (1 << PMD_INDEX_SIZE) #define PTRS_PER_PGD (1 << PGD_INDEX_SIZE) +#ifdef CONFIG_PPC_SUBPAGE_PROT +/* + * For the sub-page protection option, we extend the PGD with one of + * these. Basically we have a 3-level tree, with the top level being + * the protptrs array. To optimize speed and memory consumption when + * only addresses < 4GB are being protected, pointers to the first + * four pages of sub-page protection words are stored in the low_prot + * array. + * Each page of sub-page protection words protects 1GB (4 bytes + * protects 64k). For the 3-level tree, each page of pointers then + * protects 8TB. + */ +struct subpage_prot_table { + unsigned long maxaddr; /* only addresses < this are protected */ + unsigned int **protptrs[2]; + unsigned int *low_prot[4]; +}; + +#undef PGD_TABLE_SIZE +#define PGD_TABLE_SIZE ((sizeof(pgd_t) << PGD_INDEX_SIZE) + \ + sizeof(struct subpage_prot_table)) + +#define SBP_L1_BITS (PAGE_SHIFT - 2) +#define SBP_L2_BITS (PAGE_SHIFT - 3) +#define SBP_L1_COUNT (1 << SBP_L1_BITS) +#define SBP_L2_COUNT (1 << SBP_L2_BITS) +#define SBP_L2_SHIFT (PAGE_SHIFT + SBP_L1_BITS) +#define SBP_L3_SHIFT (SBP_L2_SHIFT + SBP_L2_BITS) + +extern void subpage_prot_free(pgd_t *pgd); + +static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd) +{ + return (struct subpage_prot_table *)(pgd + PTRS_PER_PGD); +} +#endif /* CONFIG_PPC_SUBPAGE_PROT */ +#endif /* __ASSEMBLY__ */ + /* With 4k base page size, hugepage PTEs go at the PMD level */ #define MIN_HUGEPTE_SHIFT PAGE_SHIFT diff --git a/include/asm-powerpc/systbl.h b/include/asm-powerpc/systbl.h index 11d5383b2f0..0c8b0d67913 100644 --- a/include/asm-powerpc/systbl.h +++ b/include/asm-powerpc/systbl.h @@ -313,3 +313,4 @@ COMPAT_SYS_SPU(timerfd) SYSCALL_SPU(eventfd) COMPAT_SYS_SPU(sync_file_range2) COMPAT_SYS(fallocate) +SYSCALL(subpage_prot) diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h index 97d82b6a940..fedc4b8e49e 100644 --- a/include/asm-powerpc/unistd.h +++ b/include/asm-powerpc/unistd.h @@ -332,10 +332,11 @@ #define __NR_eventfd 307 #define __NR_sync_file_range2 308 #define __NR_fallocate 309 +#define __NR_subpage_prot 310 #ifdef __KERNEL__ -#define __NR_syscalls 310 +#define __NR_syscalls 311 #define __NR__exit __NR_exit #define NR_syscalls __NR_syscalls diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 56cb009a4b3..beee5b3b68a 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -131,6 +131,7 @@ cond_syscall(sys32_sysctl); cond_syscall(ppc_rtas); cond_syscall(sys_spu_run); cond_syscall(sys_spu_create); +cond_syscall(sys_subpage_prot); /* mmu depending weak syscall entries */ cond_syscall(sys_mprotect); |