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    Subject[PATCH 3.2 015/104] gcov: add support for gcc 4.7 gcov format
    3.2.101-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Frantisek Hrbata <fhrbata@redhat.com>

    commit 5f41ea0386a53414d688cfcaa321a78310e5f7c1 upstream.

    The gcov in-memory format changed in gcc 4.7. The biggest change, which
    requires this special implementation, is that gcov_info no longer contains
    array of counters for each counter type for all functions and gcov_fn_info
    is not used for mapping of function's counters to these arrays(offset).
    Now each gcov_fn_info contans it's counters, which makes things a little
    bit easier.

    This is heavily based on the previous gcc_3_4.c implementation and patches
    provided by Peter Oberparleiter. Specially the buffer gcda implementation
    for iterator.

    [akpm@linux-foundation.org: use kmemdup() and kcalloc()]
    [oberpar@linux.vnet.ibm.com: gcc_4_7.c needs vmalloc.h]
    Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
    Cc: Jan Stancek <jstancek@redhat.com>
    Cc: Kees Cook <keescook@chromium.org>
    Reviewed-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
    Cc: Rusty Russell <rusty@rustcorp.com.au>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Andy Gospodarek <agospoda@redhat.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    kernel/gcov/base.c | 6 +
    kernel/gcov/gcc_4_7.c | 560 ++++++++++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 566 insertions(+)
    create mode 100644 kernel/gcov/gcc_4_7.c

    --- a/kernel/gcov/base.c
    +++ b/kernel/gcov/base.c
    @@ -79,6 +79,12 @@ void __gcov_merge_delta(gcov_type *count
    }
    EXPORT_SYMBOL(__gcov_merge_delta);

    +void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
    +{
    + /* Unused. */
    +}
    +EXPORT_SYMBOL(__gcov_merge_ior);
    +
    /**
    * gcov_enable_events - enable event reporting through gcov_event()
    *
    --- /dev/null
    +++ b/kernel/gcov/gcc_4_7.c
    @@ -0,0 +1,560 @@
    +/*
    + * This code provides functions to handle gcc's profiling data format
    + * introduced with gcc 4.7.
    + *
    + * This file is based heavily on gcc_3_4.c file.
    + *
    + * For a better understanding, refer to gcc source:
    + * gcc/gcov-io.h
    + * libgcc/libgcov.c
    + *
    + * Uses gcc-internal data definitions.
    + */
    +
    +#include <linux/errno.h>
    +#include <linux/slab.h>
    +#include <linux/string.h>
    +#include <linux/seq_file.h>
    +#include <linux/vmalloc.h>
    +#include "gcov.h"
    +
    +#define GCOV_COUNTERS 8
    +#define GCOV_TAG_FUNCTION_LENGTH 3
    +
    +static struct gcov_info *gcov_info_head;
    +
    +/**
    + * struct gcov_ctr_info - information about counters for a single function
    + * @num: number of counter values for this type
    + * @values: array of counter values for this type
    + *
    + * This data is generated by gcc during compilation and doesn't change
    + * at run-time with the exception of the values array.
    + */
    +struct gcov_ctr_info {
    + unsigned int num;
    + gcov_type *values;
    +};
    +
    +/**
    + * struct gcov_fn_info - profiling meta data per function
    + * @key: comdat key
    + * @ident: unique ident of function
    + * @lineno_checksum: function lineo_checksum
    + * @cfg_checksum: function cfg checksum
    + * @ctrs: instrumented counters
    + *
    + * This data is generated by gcc during compilation and doesn't change
    + * at run-time.
    + *
    + * Information about a single function. This uses the trailing array
    + * idiom. The number of counters is determined from the merge pointer
    + * array in gcov_info. The key is used to detect which of a set of
    + * comdat functions was selected -- it points to the gcov_info object
    + * of the object file containing the selected comdat function.
    + */
    +struct gcov_fn_info {
    + const struct gcov_info *key;
    + unsigned int ident;
    + unsigned int lineno_checksum;
    + unsigned int cfg_checksum;
    + struct gcov_ctr_info ctrs[0];
    +};
    +
    +/**
    + * struct gcov_info - profiling data per object file
    + * @version: gcov version magic indicating the gcc version used for compilation
    + * @next: list head for a singly-linked list
    + * @stamp: uniquifying time stamp
    + * @filename: name of the associated gcov data file
    + * @merge: merge functions (null for unused counter type)
    + * @n_functions: number of instrumented functions
    + * @functions: pointer to pointers to function information
    + *
    + * This data is generated by gcc during compilation and doesn't change
    + * at run-time with the exception of the next pointer.
    + */
    +struct gcov_info {
    + unsigned int version;
    + struct gcov_info *next;
    + unsigned int stamp;
    + const char *filename;
    + void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
    + unsigned int n_functions;
    + struct gcov_fn_info **functions;
    +};
    +
    +/**
    + * gcov_info_filename - return info filename
    + * @info: profiling data set
    + */
    +const char *gcov_info_filename(struct gcov_info *info)
    +{
    + return info->filename;
    +}
    +
    +/**
    + * gcov_info_version - return info version
    + * @info: profiling data set
    + */
    +unsigned int gcov_info_version(struct gcov_info *info)
    +{
    + return info->version;
    +}
    +
    +/**
    + * gcov_info_next - return next profiling data set
    + * @info: profiling data set
    + *
    + * Returns next gcov_info following @info or first gcov_info in the chain if
    + * @info is %NULL.
    + */
    +struct gcov_info *gcov_info_next(struct gcov_info *info)
    +{
    + if (!info)
    + return gcov_info_head;
    +
    + return info->next;
    +}
    +
    +/**
    + * gcov_info_link - link/add profiling data set to the list
    + * @info: profiling data set
    + */
    +void gcov_info_link(struct gcov_info *info)
    +{
    + info->next = gcov_info_head;
    + gcov_info_head = info;
    +}
    +
    +/**
    + * gcov_info_unlink - unlink/remove profiling data set from the list
    + * @prev: previous profiling data set
    + * @info: profiling data set
    + */
    +void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
    +{
    + if (prev)
    + prev->next = info->next;
    + else
    + gcov_info_head = info->next;
    +}
    +
    +/* Symbolic links to be created for each profiling data file. */
    +const struct gcov_link gcov_link[] = {
    + { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
    + { 0, NULL},
    +};
    +
    +/*
    + * Determine whether a counter is active. Doesn't change at run-time.
    + */
    +static int counter_active(struct gcov_info *info, unsigned int type)
    +{
    + return info->merge[type] ? 1 : 0;
    +}
    +
    +/* Determine number of active counters. Based on gcc magic. */
    +static unsigned int num_counter_active(struct gcov_info *info)
    +{
    + unsigned int i;
    + unsigned int result = 0;
    +
    + for (i = 0; i < GCOV_COUNTERS; i++) {
    + if (counter_active(info, i))
    + result++;
    + }
    + return result;
    +}
    +
    +/**
    + * gcov_info_reset - reset profiling data to zero
    + * @info: profiling data set
    + */
    +void gcov_info_reset(struct gcov_info *info)
    +{
    + struct gcov_ctr_info *ci_ptr;
    + unsigned int fi_idx;
    + unsigned int ct_idx;
    +
    + for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
    + ci_ptr = info->functions[fi_idx]->ctrs;
    +
    + for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
    + if (!counter_active(info, ct_idx))
    + continue;
    +
    + memset(ci_ptr->values, 0,
    + sizeof(gcov_type) * ci_ptr->num);
    + ci_ptr++;
    + }
    + }
    +}
    +
    +/**
    + * gcov_info_is_compatible - check if profiling data can be added
    + * @info1: first profiling data set
    + * @info2: second profiling data set
    + *
    + * Returns non-zero if profiling data can be added, zero otherwise.
    + */
    +int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
    +{
    + return (info1->stamp == info2->stamp);
    +}
    +
    +/**
    + * gcov_info_add - add up profiling data
    + * @dest: profiling data set to which data is added
    + * @source: profiling data set which is added
    + *
    + * Adds profiling counts of @source to @dest.
    + */
    +void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
    +{
    + struct gcov_ctr_info *dci_ptr;
    + struct gcov_ctr_info *sci_ptr;
    + unsigned int fi_idx;
    + unsigned int ct_idx;
    + unsigned int val_idx;
    +
    + for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
    + dci_ptr = dst->functions[fi_idx]->ctrs;
    + sci_ptr = src->functions[fi_idx]->ctrs;
    +
    + for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
    + if (!counter_active(src, ct_idx))
    + continue;
    +
    + for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
    + dci_ptr->values[val_idx] +=
    + sci_ptr->values[val_idx];
    +
    + dci_ptr++;
    + sci_ptr++;
    + }
    + }
    +}
    +
    +/**
    + * gcov_info_dup - duplicate profiling data set
    + * @info: profiling data set to duplicate
    + *
    + * Return newly allocated duplicate on success, %NULL on error.
    + */
    +struct gcov_info *gcov_info_dup(struct gcov_info *info)
    +{
    + struct gcov_info *dup;
    + struct gcov_ctr_info *dci_ptr; /* dst counter info */
    + struct gcov_ctr_info *sci_ptr; /* src counter info */
    + unsigned int active;
    + unsigned int fi_idx; /* function info idx */
    + unsigned int ct_idx; /* counter type idx */
    + size_t fi_size; /* function info size */
    + size_t cv_size; /* counter values size */
    +
    + dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
    + if (!dup)
    + return NULL;
    +
    + dup->next = NULL;
    + dup->filename = NULL;
    + dup->functions = NULL;
    +
    + dup->filename = kstrdup(info->filename, GFP_KERNEL);
    + if (!dup->filename)
    + goto err_free;
    +
    + dup->functions = kcalloc(info->n_functions,
    + sizeof(struct gcov_fn_info *), GFP_KERNEL);
    + if (!dup->functions)
    + goto err_free;
    +
    + active = num_counter_active(info);
    + fi_size = sizeof(struct gcov_fn_info);
    + fi_size += sizeof(struct gcov_ctr_info) * active;
    +
    + for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
    + dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
    + if (!dup->functions[fi_idx])
    + goto err_free;
    +
    + *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
    +
    + sci_ptr = info->functions[fi_idx]->ctrs;
    + dci_ptr = dup->functions[fi_idx]->ctrs;
    +
    + for (ct_idx = 0; ct_idx < active; ct_idx++) {
    +
    + cv_size = sizeof(gcov_type) * sci_ptr->num;
    +
    + dci_ptr->values = vmalloc(cv_size);
    +
    + if (!dci_ptr->values)
    + goto err_free;
    +
    + dci_ptr->num = sci_ptr->num;
    + memcpy(dci_ptr->values, sci_ptr->values, cv_size);
    +
    + sci_ptr++;
    + dci_ptr++;
    + }
    + }
    +
    + return dup;
    +err_free:
    + gcov_info_free(dup);
    + return NULL;
    +}
    +
    +/**
    + * gcov_info_free - release memory for profiling data set duplicate
    + * @info: profiling data set duplicate to free
    + */
    +void gcov_info_free(struct gcov_info *info)
    +{
    + unsigned int active;
    + unsigned int fi_idx;
    + unsigned int ct_idx;
    + struct gcov_ctr_info *ci_ptr;
    +
    + if (!info->functions)
    + goto free_info;
    +
    + active = num_counter_active(info);
    +
    + for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
    + if (!info->functions[fi_idx])
    + continue;
    +
    + ci_ptr = info->functions[fi_idx]->ctrs;
    +
    + for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
    + vfree(ci_ptr->values);
    +
    + kfree(info->functions[fi_idx]);
    + }
    +
    +free_info:
    + kfree(info->functions);
    + kfree(info->filename);
    + kfree(info);
    +}
    +
    +#define ITER_STRIDE PAGE_SIZE
    +
    +/**
    + * struct gcov_iterator - specifies current file position in logical records
    + * @info: associated profiling data
    + * @buffer: buffer containing file data
    + * @size: size of buffer
    + * @pos: current position in file
    + */
    +struct gcov_iterator {
    + struct gcov_info *info;
    + void *buffer;
    + size_t size;
    + loff_t pos;
    +};
    +
    +/**
    + * store_gcov_u32 - store 32 bit number in gcov format to buffer
    + * @buffer: target buffer or NULL
    + * @off: offset into the buffer
    + * @v: value to be stored
    + *
    + * Number format defined by gcc: numbers are recorded in the 32 bit
    + * unsigned binary form of the endianness of the machine generating the
    + * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
    + * store anything.
    + */
    +static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
    +{
    + u32 *data;
    +
    + if (buffer) {
    + data = buffer + off;
    + *data = v;
    + }
    +
    + return sizeof(*data);
    +}
    +
    +/**
    + * store_gcov_u64 - store 64 bit number in gcov format to buffer
    + * @buffer: target buffer or NULL
    + * @off: offset into the buffer
    + * @v: value to be stored
    + *
    + * Number format defined by gcc: numbers are recorded in the 32 bit
    + * unsigned binary form of the endianness of the machine generating the
    + * file. 64 bit numbers are stored as two 32 bit numbers, the low part
    + * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
    + * anything.
    + */
    +static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
    +{
    + u32 *data;
    +
    + if (buffer) {
    + data = buffer + off;
    +
    + data[0] = (v & 0xffffffffUL);
    + data[1] = (v >> 32);
    + }
    +
    + return sizeof(*data) * 2;
    +}
    +
    +/**
    + * convert_to_gcda - convert profiling data set to gcda file format
    + * @buffer: the buffer to store file data or %NULL if no data should be stored
    + * @info: profiling data set to be converted
    + *
    + * Returns the number of bytes that were/would have been stored into the buffer.
    + */
    +static size_t convert_to_gcda(char *buffer, struct gcov_info *info)
    +{
    + struct gcov_fn_info *fi_ptr;
    + struct gcov_ctr_info *ci_ptr;
    + unsigned int fi_idx;
    + unsigned int ct_idx;
    + unsigned int cv_idx;
    + size_t pos = 0;
    +
    + /* File header. */
    + pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
    + pos += store_gcov_u32(buffer, pos, info->version);
    + pos += store_gcov_u32(buffer, pos, info->stamp);
    +
    + for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
    + fi_ptr = info->functions[fi_idx];
    +
    + /* Function record. */
    + pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
    + pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
    + pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
    + pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
    + pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
    +
    + ci_ptr = fi_ptr->ctrs;
    +
    + for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
    + if (!counter_active(info, ct_idx))
    + continue;
    +
    + /* Counter record. */
    + pos += store_gcov_u32(buffer, pos,
    + GCOV_TAG_FOR_COUNTER(ct_idx));
    + pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
    +
    + for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
    + pos += store_gcov_u64(buffer, pos,
    + ci_ptr->values[cv_idx]);
    + }
    +
    + ci_ptr++;
    + }
    + }
    +
    + return pos;
    +}
    +
    +/**
    + * gcov_iter_new - allocate and initialize profiling data iterator
    + * @info: profiling data set to be iterated
    + *
    + * Return file iterator on success, %NULL otherwise.
    + */
    +struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
    +{
    + struct gcov_iterator *iter;
    +
    + iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
    + if (!iter)
    + goto err_free;
    +
    + iter->info = info;
    + /* Dry-run to get the actual buffer size. */
    + iter->size = convert_to_gcda(NULL, info);
    + iter->buffer = vmalloc(iter->size);
    + if (!iter->buffer)
    + goto err_free;
    +
    + convert_to_gcda(iter->buffer, info);
    +
    + return iter;
    +
    +err_free:
    + kfree(iter);
    + return NULL;
    +}
    +
    +
    +/**
    + * gcov_iter_get_info - return profiling data set for given file iterator
    + * @iter: file iterator
    + */
    +void gcov_iter_free(struct gcov_iterator *iter)
    +{
    + vfree(iter->buffer);
    + kfree(iter);
    +}
    +
    +/**
    + * gcov_iter_get_info - return profiling data set for given file iterator
    + * @iter: file iterator
    + */
    +struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
    +{
    + return iter->info;
    +}
    +
    +/**
    + * gcov_iter_start - reset file iterator to starting position
    + * @iter: file iterator
    + */
    +void gcov_iter_start(struct gcov_iterator *iter)
    +{
    + iter->pos = 0;
    +}
    +
    +/**
    + * gcov_iter_next - advance file iterator to next logical record
    + * @iter: file iterator
    + *
    + * Return zero if new position is valid, non-zero if iterator has reached end.
    + */
    +int gcov_iter_next(struct gcov_iterator *iter)
    +{
    + if (iter->pos < iter->size)
    + iter->pos += ITER_STRIDE;
    +
    + if (iter->pos >= iter->size)
    + return -EINVAL;
    +
    + return 0;
    +}
    +
    +/**
    + * gcov_iter_write - write data for current pos to seq_file
    + * @iter: file iterator
    + * @seq: seq_file handle
    + *
    + * Return zero on success, non-zero otherwise.
    + */
    +int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
    +{
    + size_t len;
    +
    + if (iter->pos >= iter->size)
    + return -EINVAL;
    +
    + len = ITER_STRIDE;
    + if (iter->pos + len > iter->size)
    + len = iter->size - iter->pos;
    +
    + seq_write(seq, iter->buffer + iter->pos, len);
    +
    + return 0;
    +}
    \
     
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