diff options
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/book3s64/hash_utils.c | 25 | ||||
| -rw-r--r-- | arch/powerpc/mm/book3s64/pkeys.c | 15 | ||||
| -rw-r--r-- | arch/powerpc/mm/nohash/kaslr_booke.c | 1 |
3 files changed, 33 insertions, 8 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 468169e33c86..9b9f92ad0e7a 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1559,6 +1559,7 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea, pgd_t *pgdir; int rc, ssize, update_flags = 0; unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0); + unsigned long flags; BUG_ON(get_region_id(ea) != USER_REGION_ID); @@ -1592,6 +1593,28 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea, return; #endif /* CONFIG_PPC_64K_PAGES */ + /* + * __hash_page_* must run with interrupts off, as it sets the + * H_PAGE_BUSY bit. It's possible for perf interrupts to hit at any + * time and may take a hash fault reading the user stack, see + * read_user_stack_slow() in the powerpc/perf code. + * + * If that takes a hash fault on the same page as we lock here, it + * will bail out when seeing H_PAGE_BUSY set, and retry the access + * leading to an infinite loop. + * + * Disabling interrupts here does not prevent perf interrupts, but it + * will prevent them taking hash faults (see the NMI test in + * do_hash_page), then read_user_stack's copy_from_user_nofault will + * fail and perf will fall back to read_user_stack_slow(), which + * walks the Linux page tables. + * + * Interrupts must also be off for the duration of the + * mm_is_thread_local test and update, to prevent preempt running the + * mm on another CPU (XXX: this may be racy vs kthread_use_mm). + */ + local_irq_save(flags); + /* Is that local to this CPU ? */ if (mm_is_thread_local(mm)) update_flags |= HPTE_LOCAL_UPDATE; @@ -1614,6 +1637,8 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea, mm_ctx_user_psize(&mm->context), mm_ctx_user_psize(&mm->context), pte_val(*ptep)); + + local_irq_restore(flags); } /* diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c index 1199fc2bfaec..d174106bab67 100644 --- a/arch/powerpc/mm/book3s64/pkeys.c +++ b/arch/powerpc/mm/book3s64/pkeys.c @@ -353,16 +353,15 @@ static bool pkey_access_permitted(int pkey, bool write, bool execute) int pkey_shift; u64 amr; - if (!is_pkey_enabled(pkey)) - return true; - pkey_shift = pkeyshift(pkey); - if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift))) - return true; + if (execute) + return !(read_iamr() & (IAMR_EX_BIT << pkey_shift)); + + amr = read_amr(); + if (write) + return !(amr & (AMR_WR_BIT << pkey_shift)); - amr = read_amr(); /* Delay reading amr until absolutely needed */ - return ((!write && !(amr & (AMR_RD_BIT << pkey_shift))) || - (write && !(amr & (AMR_WR_BIT << pkey_shift)))); + return !(amr & (AMR_RD_BIT << pkey_shift)); } bool arch_pte_access_permitted(u64 pte, bool write, bool execute) diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c index 4a75f2d9bf0e..bce0e5349978 100644 --- a/arch/powerpc/mm/nohash/kaslr_booke.c +++ b/arch/powerpc/mm/nohash/kaslr_booke.c @@ -14,6 +14,7 @@ #include <linux/memblock.h> #include <linux/libfdt.h> #include <linux/crash_core.h> +#include <asm/cacheflush.h> #include <asm/pgalloc.h> #include <asm/prom.h> #include <asm/kdump.h> |