lkml.org 
[lkml]   [2012]   [Mar]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 02/15] uaccess: Add new copy_from_user_gup API
    Date
    This brings a get_user_page_fast() based copy_from_user() that can
    do a best effort copy from any context.

    In order to support user stack dump safely in perf samples from
    generic code, rename x86 copy_from_user_nmi to copy_from_user_gup
    and make it generally available. If the arch doesn't provide an
    implementation it will map to copy_from_user_inatomic.

    Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    Signed-off-by: Jiri Olsa <jolsa@redhat.com>
    ---
    arch/x86/include/asm/uaccess.h | 8 +++++---
    arch/x86/kernel/cpu/perf_event.c | 4 ++--
    arch/x86/kernel/cpu/perf_event_intel_ds.c | 3 ++-
    arch/x86/kernel/cpu/perf_event_intel_lbr.c | 2 +-
    arch/x86/lib/usercopy.c | 4 ++--
    arch/x86/oprofile/backtrace.c | 4 ++--
    include/asm-generic/uaccess.h | 4 ++++
    7 files changed, 18 insertions(+), 11 deletions(-)

    diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
    index 8be5f54..e3f5307 100644
    --- a/arch/x86/include/asm/uaccess.h
    +++ b/arch/x86/include/asm/uaccess.h
    @@ -228,6 +228,11 @@ extern void __put_user_2(void);
    extern void __put_user_4(void);
    extern void __put_user_8(void);

    +extern unsigned long
    +__copy_from_user_gup(void *to, const void __user *from, unsigned long n);
    +
    +#define copy_from_user_gup(to, from, n) __copy_from_user_gup(to, from, n)
    +
    #ifdef CONFIG_X86_WP_WORKS_OK

    /**
    @@ -555,9 +560,6 @@ struct __large_struct { unsigned long buf[100]; };

    #endif /* CONFIG_X86_WP_WORKS_OK */

    -extern unsigned long
    -copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
    -
    /*
    * movsl can be slow when source and dest are not both 8-byte aligned
    */
    diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
    index bb8e034..294ad68 100644
    --- a/arch/x86/kernel/cpu/perf_event.c
    +++ b/arch/x86/kernel/cpu/perf_event.c
    @@ -1781,7 +1781,7 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
    frame.next_frame = 0;
    frame.return_address = 0;

    - bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
    + bytes = copy_from_user_gup(&frame, fp, sizeof(frame));
    if (bytes != sizeof(frame))
    break;

    @@ -1827,7 +1827,7 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
    frame.next_frame = NULL;
    frame.return_address = 0;

    - bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
    + bytes = copy_from_user_gup(&frame, fp, sizeof(frame));
    if (bytes != sizeof(frame))
    break;

    diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
    index 7f64df1..77053af 100644
    --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
    +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
    @@ -520,7 +520,8 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
    if (!kernel_ip(ip)) {
    int bytes, size = MAX_INSN_SIZE;

    - bytes = copy_from_user_nmi(buf, (void __user *)to, size);
    + bytes = copy_from_user_gup(buf, (void __user *)to,
    + size);
    if (bytes != size)
    return 0;

    diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
    index 520b426..8f0b9ce 100644
    --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
    +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
    @@ -437,7 +437,7 @@ static int branch_type(unsigned long from, unsigned long to)
    return X86_BR_NONE;

    /* may fail if text not present */
    - bytes = copy_from_user_nmi(buf, (void __user *)from, size);
    + bytes = copy_from_user_gup(buf, (void __user *)from, size);
    if (bytes != size)
    return X86_BR_NONE;

    diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
    index 97be9cb..a03e49a 100644
    --- a/arch/x86/lib/usercopy.c
    +++ b/arch/x86/lib/usercopy.c
    @@ -11,7 +11,7 @@
    * best effort, GUP based copy_from_user() that is NMI-safe
    */
    unsigned long
    -copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
    +__copy_from_user_gup(void *to, const void __user *from, unsigned long n)
    {
    unsigned long offset, addr = (unsigned long)from;
    unsigned long size, len = 0;
    @@ -40,4 +40,4 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)

    return len;
    }
    -EXPORT_SYMBOL_GPL(copy_from_user_nmi);
    +EXPORT_SYMBOL_GPL(__copy_from_user_gup);
    diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
    index d6aa6e8..42511b0 100644
    --- a/arch/x86/oprofile/backtrace.c
    +++ b/arch/x86/oprofile/backtrace.c
    @@ -46,7 +46,7 @@ dump_user_backtrace_32(struct stack_frame_ia32 *head)
    struct stack_frame_ia32 *fp;
    unsigned long bytes;

    - bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
    + bytes = copy_from_user_gup(bufhead, head, sizeof(bufhead));
    if (bytes != sizeof(bufhead))
    return NULL;

    @@ -92,7 +92,7 @@ static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
    struct stack_frame bufhead[2];
    unsigned long bytes;

    - bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
    + bytes = copy_from_user_gup(bufhead, head, sizeof(bufhead));
    if (bytes != sizeof(bufhead))
    return NULL;

    diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
    index 9788568..759339b 100644
    --- a/include/asm-generic/uaccess.h
    +++ b/include/asm-generic/uaccess.h
    @@ -240,6 +240,10 @@ extern int __get_user_bad(void) __attribute__((noreturn));
    #define __copy_to_user_inatomic __copy_to_user
    #endif

    +#ifndef copy_from_user_gup
    +#define copy_from_user_gup __copy_from_user_inatomic
    +#endif
    +
    static inline long copy_from_user(void *to,
    const void __user * from, unsigned long n)
    {
    --
    1.7.1


    \
     
     \ /
      Last update: 2012-03-28 14:39    [W:0.047 / U:92.236 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site