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perf: Fix arch_perf_out_copy_user default

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The arch_perf_output_copy_user() default of
__copy_from_user_inatomic() returns bytes not copied, while all other
argument functions given DEFINE_OUTPUT_COPY() return bytes copied.

Since copy_from_user_nmi() is the odd duck out by returning bytes
copied where all other *copy_{to,from}* functions return bytes not
copied, change it over and ammend DEFINE_OUTPUT_COPY() to expect bytes
not copied.

Oddly enough DEFINE_OUTPUT_COPY() already returned bytes not copied
while expecting its worker functions to return bytes copied.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: will.deacon@arm.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131030201622.GR16117@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2013-10-30 21:16:22 +01:00 committed by Ingo Molnar
parent 394570b793
commit 0a196848ca
6 changed files with 33 additions and 16 deletions
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4
arch/x86/kernel/cpu/perf_event.c
View File

@ -1989,7 +1989,7 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
frame.return_address = 0;
bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
if (bytes != sizeof(frame))
if (bytes != 0)
break;
if (!valid_user_frame(fp, sizeof(frame)))
@ -2041,7 +2041,7 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
frame.return_address = 0;
bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
if (bytes != sizeof(frame))
if (bytes != 0)
break;
if (!valid_user_frame(fp, sizeof(frame)))

2
arch/x86/kernel/cpu/perf_event_intel_ds.c
View File

@ -789,7 +789,7 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
size = ip - to; /* Must fit our buffer, see above */
bytes = copy_from_user_nmi(buf, (void __user *)to, size);
if (bytes != size)
if (bytes != 0)
return 0;
kaddr = buf;

2
arch/x86/kernel/cpu/perf_event_intel_lbr.c
View File

@ -491,7 +491,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
/* may fail if text not present */
bytes = copy_from_user_nmi(buf, (void __user *)from, size);
if (bytes != size)
if (bytes != 0)
return X86_BR_NONE;
addr = buf;

2
arch/x86/lib/usercopy.c
View File

@ -31,6 +31,6 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
ret = __copy_from_user_inatomic(to, from, n);
pagefault_enable();
return n - ret;
return ret;
}
EXPORT_SYMBOL_GPL(copy_from_user_nmi);

4
arch/x86/oprofile/backtrace.c
View File

@ -47,7 +47,7 @@ dump_user_backtrace_32(struct stack_frame_ia32 *head)
unsigned long bytes;
bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
if (bytes != sizeof(bufhead))
if (bytes != 0)
return NULL;
fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
@ -93,7 +93,7 @@ static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
unsigned long bytes;
bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
if (bytes != sizeof(bufhead))
if (bytes != 0)
return NULL;
oprofile_add_trace(bufhead[0].return_address);

35
kernel/events/internal.h
View File

@ -82,16 +82,16 @@ static inline unsigned long perf_data_size(struct ring_buffer *rb)
}
#define DEFINE_OUTPUT_COPY(func_name, memcpy_func) \
static inline unsigned int \
static inline unsigned long \
func_name(struct perf_output_handle *handle, \
const void *buf, unsigned int len) \
const void *buf, unsigned long len) \
{ \
unsigned long size, written; \
\
do { \
size = min_t(unsigned long, handle->size, len); \
\
size = min(handle->size, len); \
written = memcpy_func(handle->addr, buf, size); \
written = size - written; \
\
len -= written; \
handle->addr += written; \
@ -110,20 +110,37 @@ func_name(struct perf_output_handle *handle, \
return len; \
}
static inline int memcpy_common(void *dst, const void *src, size_t n)
static inline unsigned long
memcpy_common(void *dst, const void *src, unsigned long n)
{
memcpy(dst, src, n);
return n;
return 0;
}
DEFINE_OUTPUT_COPY(__output_copy, memcpy_common)
#define MEMCPY_SKIP(dst, src, n) (n)
static inline unsigned long
memcpy_skip(void *dst, const void *src, unsigned long n)
{
return 0;
}
DEFINE_OUTPUT_COPY(__output_skip, MEMCPY_SKIP)
DEFINE_OUTPUT_COPY(__output_skip, memcpy_skip)
#ifndef arch_perf_out_copy_user
#define arch_perf_out_copy_user __copy_from_user_inatomic
#define arch_perf_out_copy_user arch_perf_out_copy_user
static inline unsigned long
arch_perf_out_copy_user(void *dst, const void *src, unsigned long n)
{
unsigned long ret;
pagefault_disable();
ret = __copy_from_user_inatomic(dst, src, n);
pagefault_enable();
return ret;
}
#endif
DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)