diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/pgtable-3level.h | 30 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 6 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten.c | 3 |
4 files changed, 24 insertions, 21 deletions
diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h index 43876f16caf..cb00ccc7d57 100644 --- a/arch/x86/include/asm/pgtable-3level.h +++ b/arch/x86/include/asm/pgtable-3level.h @@ -47,16 +47,26 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte) * they can run pmd_offset_map_lock or pmd_trans_huge or other pmd * operations. * - * Without THP if the mmap_sem is hold for reading, the - * pmd can only transition from null to not null while pmd_read_atomic runs. - * So there's no need of literally reading it atomically. + * Without THP if the mmap_sem is hold for reading, the pmd can only + * transition from null to not null while pmd_read_atomic runs. So + * we can always return atomic pmd values with this function. * * With THP if the mmap_sem is hold for reading, the pmd can become - * THP or null or point to a pte (and in turn become "stable") at any - * time under pmd_read_atomic, so it's mandatory to read it atomically - * with cmpxchg8b. + * trans_huge or none or point to a pte (and in turn become "stable") + * at any time under pmd_read_atomic. We could read it really + * atomically here with a atomic64_read for the THP enabled case (and + * it would be a whole lot simpler), but to avoid using cmpxchg8b we + * only return an atomic pmdval if the low part of the pmdval is later + * found stable (i.e. pointing to a pte). And we're returning a none + * pmdval if the low part of the pmd is none. In some cases the high + * and low part of the pmdval returned may not be consistent if THP is + * enabled (the low part may point to previously mapped hugepage, + * while the high part may point to a more recently mapped hugepage), + * but pmd_none_or_trans_huge_or_clear_bad() only needs the low part + * of the pmd to be read atomically to decide if the pmd is unstable + * or not, with the only exception of when the low part of the pmd is + * zero in which case we return a none pmd. */ -#ifndef CONFIG_TRANSPARENT_HUGEPAGE static inline pmd_t pmd_read_atomic(pmd_t *pmdp) { pmdval_t ret; @@ -74,12 +84,6 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp) return (pmd_t) { ret }; } -#else /* CONFIG_TRANSPARENT_HUGEPAGE */ -static inline pmd_t pmd_read_atomic(pmd_t *pmdp) -{ - return (pmd_t) { atomic64_read((atomic64_t *)pmdp) }; -} -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte) { diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 47acaf31916..32856fa4384 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -491,14 +491,16 @@ static inline void nmi_nesting_preprocess(struct pt_regs *regs) */ if (unlikely(is_debug_stack(regs->sp))) { debug_stack_set_zero(); - __get_cpu_var(update_debug_stack) = 1; + this_cpu_write(update_debug_stack, 1); } } static inline void nmi_nesting_postprocess(void) { - if (unlikely(__get_cpu_var(update_debug_stack))) + if (unlikely(this_cpu_read(update_debug_stack))) { debug_stack_reset(); + this_cpu_write(update_debug_stack, 0); + } } #endif diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 685845cf16e..cf1178332bc 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1211,12 +1211,6 @@ static long x32_arch_ptrace(struct task_struct *child, 0, sizeof(struct user_i387_struct), datap); - /* normal 64bit interface to access TLS data. - Works just like arch_prctl, except that the arguments - are reversed. */ - case PTRACE_ARCH_PRCTL: - return do_arch_prctl(child, data, addr); - default: return compat_ptrace_request(child, request, addr, data); } diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index cf759609c9b..34cc627f18f 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1107,7 +1107,10 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { .wbinvd = native_wbinvd, .read_msr = native_read_msr_safe, + .rdmsr_regs = native_rdmsr_safe_regs, .write_msr = xen_write_msr_safe, + .wrmsr_regs = native_wrmsr_safe_regs, + .read_tsc = native_read_tsc, .read_pmc = native_read_pmc, |