From: Steven Rostedt <[email protected]> In preparation for removing weak functions from available_filter_functions, have the sorttable.c code that sorts the mcount regions during the build modified to take a "nm -S vmlinux" as input, sort it, and any function listed in the mcount_loc section that is not within a boundary of the function list given by nm is considered a weak function and is zeroed out. This will move them all to the beginning of the mcount_loc section. This will allow for the ftrace code to be able to skip them in one go.
Signed-off-by: Steven Rostedt (Google) <[email protected]> --- scripts/link-vmlinux.sh | 4 +- scripts/sorttable.c | 129 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 130 insertions(+), 3 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index d853ddb3b28c..976808c46665 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -177,12 +177,14 @@ mksysmap() sorttable() { - ${objtree}/scripts/sorttable ${1} + ${NM} -S ${1} > .tmp_vmlinux.nm-sort + ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1} } cleanup() { rm -f .btf.* + rm -f .tmp_vmlinux.nm-sort rm -f System.map rm -f vmlinux rm -f vmlinux.map diff --git a/scripts/sorttable.c b/scripts/sorttable.c index c26e71e6ec6b..1a2b420a4929 100644 --- a/scripts/sorttable.c +++ b/scripts/sorttable.c @@ -446,6 +446,98 @@ static void *sort_orctable(void *arg) #endif #ifdef MCOUNT_SORT_ENABLED +struct func_info { + uint64_t addr; + uint64_t size; +}; + +/* List of functions created by: nm -S vmlinux */ +static struct func_info *function_list; +static int function_list_size; + +/* Allocate functions in 1k blocks */ +#define FUNC_BLK_SIZE 1024 +#define FUNC_BLK_MASK (FUNC_BLK_SIZE - 1) + +static int add_field(uint64_t addr, uint64_t size) +{ + struct func_info *fi; + int fsize = function_list_size; + + if (!(fsize & FUNC_BLK_MASK)) { + fsize += FUNC_BLK_SIZE; + fi = realloc(function_list, fsize * sizeof(struct func_info)); + if (!fi) + return -1; + function_list = fi; + } + fi = &function_list[function_list_size++]; + fi->addr = addr; + fi->size = size; + return 0; +} + +/* Only return match if the address lies inside the function size */ +static int cmp_func_addr(const void *K, const void *A) +{ + uint64_t key = *(const uint64_t *)K; + const struct func_info *a = A; + + if (key < a->addr) + return -1; + return key >= a->addr + a->size; +} + +/* Find the function in function list that is bounded by the function size */ +static int find_func(uint64_t key) +{ + return bsearch(&key, function_list, function_list_size, + sizeof(struct func_info), cmp_func_addr) != NULL; +} + +static int cmp_funcs(const void *A, const void *B) +{ + const struct func_info *a = A; + const struct func_info *b = B; + + if (a->addr < b->addr) + return -1; + return a->addr > b->addr; +} + +static int parse_symbols(const char *fname) +{ + FILE *fp; + char addr_str[20]; /* Only need 17, but round up to next int size */ + char size_str[20]; + char type; + + fp = fopen(fname, "r"); + if (!fp) { + perror(fname); + return -1; + } + + while (fscanf(fp, "%16s %16s %c %*s\n", addr_str, size_str, &type) == 3) { + uint64_t addr; + uint64_t size; + + /* Only care about functions */ + if (type != 't' && type != 'T') + continue; + + addr = strtoull(addr_str, NULL, 16); + size = strtoull(size_str, NULL, 16); + if (add_field(addr, size) < 0) + return -1; + } + fclose(fp); + + qsort(function_list, function_list_size, sizeof(struct func_info), cmp_funcs); + + return 0; +} + static pthread_t mcount_sort_thread; struct elf_mcount_loc { @@ -463,6 +555,22 @@ static void *sort_mcount_loc(void *arg) + shdr_offset(emloc->init_data_sec); uint64_t count = emloc->stop_mcount_loc - emloc->start_mcount_loc; unsigned char *start_loc = (void *)emloc->ehdr + offset; + void *end_loc = start_loc + count; + + /* zero out any locations not found by function list */ + if (function_list_size) { + for (void *ptr = start_loc; ptr < end_loc; ptr += long_size) { + uint64_t key; + + key = long_size == 4 ? r((uint32_t *)ptr) : r8((uint64_t *)ptr); + if (!find_func(key)) { + if (long_size == 4) + *(uint32_t *)ptr = 0; + else + *(uint64_t *)ptr = 0; + } + } + } qsort(start_loc, count/long_size, long_size, compare_extable); return NULL; @@ -502,6 +610,8 @@ static void get_mcount_loc(struct elf_mcount_loc *emloc, Elf_Shdr *symtab_sec, return; } } +#else /* MCOUNT_SORT_ENABLED */ +static inline int parse_symbols(const char *fname) { return 0; } #endif static int do_sort(Elf_Ehdr *ehdr, @@ -930,14 +1040,29 @@ int main(int argc, char *argv[]) int i, n_error = 0; /* gcc-4.3.0 false positive complaint */ size_t size = 0; void *addr = NULL; + int c; + + while ((c = getopt(argc, argv, "s:")) >= 0) { + switch (c) { + case 's': + if (parse_symbols(optarg) < 0) { + fprintf(stderr, "Could not parse %s\n", optarg); + return -1; + } + break; + default: + fprintf(stderr, "usage: sorttable [-s nm-file] vmlinux...\n"); + return 0; + } + } - if (argc < 2) { + if ((argc - optind) < 1) { fprintf(stderr, "usage: sorttable vmlinux...\n"); return 0; } /* Process each file in turn, allowing deep failure. */ - for (i = 1; i < argc; i++) { + for (i = optind; i < argc; i++) { addr = mmap_file(argv[i], &size); if (!addr) { ++n_error; -- 2.45.2
