Messages in this thread Patch in this message | | | From | Brian Gerst <> | Subject | [PATCH 9/9] kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU | Date | Mon, 23 Oct 2023 17:17:30 -0400 |
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x86-64 was the only user.
Signed-off-by: Brian Gerst <brgerst@gmail.com> --- init/Kconfig | 11 +----- kernel/kallsyms.c | 12 ++----- scripts/kallsyms.c | 80 ++++++++--------------------------------- scripts/link-vmlinux.sh | 4 --- 4 files changed, 18 insertions(+), 89 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig index 1af31b23e376..4d91c5632aaf 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1715,11 +1715,6 @@ config KALLSYMS_ALL Say N unless you really need all symbols, or kernel live patching. -config KALLSYMS_ABSOLUTE_PERCPU - bool - depends on KALLSYMS - default n - config KALLSYMS_BASE_RELATIVE bool depends on KALLSYMS @@ -1727,11 +1722,7 @@ config KALLSYMS_BASE_RELATIVE help Instead of emitting them as absolute values in the native word size, emit the symbol references in the kallsyms table as 32-bit entries, - each containing a relative value in the range [base, base + U32_MAX] - or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either - an absolute value in the range [0, S32_MAX] or a relative value in the - range [base, base + S32_MAX], where base is the lowest relative symbol - address encountered in the image. + each containing a relative value in the range [base, base + U32_MAX]. On 64-bit builds, this reduces the size of the address table by 50%, but more importantly, it results in entries whose values are build diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 18edd57b5fe8..f4e8e531052a 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -151,16 +151,8 @@ unsigned long kallsyms_sym_address(int idx) if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) return kallsyms_addresses[idx]; - /* values are unsigned offsets if --absolute-percpu is not in effect */ - if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU)) - return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; - - /* ...otherwise, positive offsets are absolute values */ - if (kallsyms_offsets[idx] >= 0) - return kallsyms_offsets[idx]; - - /* ...and negative offsets are relative to kallsyms_relative_base - 1 */ - return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; + /* values are unsigned offsets */ + return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; } static void cleanup_symbol_name(char *s) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 653b92f6d4c8..501f978abf4b 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -5,8 +5,8 @@ * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * - * Usage: kallsyms [--all-symbols] [--absolute-percpu] - * [--base-relative] [--lto-clang] in.map > out.S + * Usage: kallsyms [--all-symbols] [--base-relative] [--lto-clang] + * in.map > out.S * * Table compression uses all the unused char codes on the symbols and * maps these to the most used substrings (tokens). For instance, it might @@ -37,7 +37,6 @@ struct sym_entry { unsigned int len; unsigned int seq; unsigned int start_pos; - unsigned int percpu_absolute; unsigned char sym[]; }; @@ -55,14 +54,9 @@ static struct addr_range text_ranges[] = { #define text_range_text (&text_ranges[0]) #define text_range_inittext (&text_ranges[1]) -static struct addr_range percpu_range = { - "__per_cpu_start", "__per_cpu_end", -1ULL, 0 -}; - static struct sym_entry **table; static unsigned int table_size, table_cnt; static int all_symbols; -static int absolute_percpu; static int base_relative; static int lto_clang; @@ -75,7 +69,7 @@ static unsigned char best_table_len[256]; static void usage(void) { - fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] " + fprintf(stderr, "Usage: kallsyms [--all-symbols] " "[--base-relative] [--lto-clang] in.map > out.S\n"); exit(1); } @@ -167,7 +161,6 @@ static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) return NULL; check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges)); - check_symbol_range(name, addr, &percpu_range, 1); /* include the type field in the symbol name, so that it gets * compressed together */ @@ -183,7 +176,6 @@ static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) sym->len = len; sym->sym[0] = type; strcpy(sym_name(sym), name); - sym->percpu_absolute = 0; return sym; } @@ -334,11 +326,6 @@ static int expand_symbol(const unsigned char *data, int len, char *result) return total; } -static int symbol_absolute(const struct sym_entry *s) -{ - return s->percpu_absolute; -} - static void cleanup_symbol_name(char *s) { char *p; @@ -499,30 +486,17 @@ static void write_src(void) */ long long offset; - int overflow; - - if (!absolute_percpu) { - offset = table[i]->addr - relative_base; - overflow = (offset < 0 || offset > UINT_MAX); - } else if (symbol_absolute(table[i])) { - offset = table[i]->addr; - overflow = (offset < 0 || offset > INT_MAX); - } else { - offset = relative_base - table[i]->addr - 1; - overflow = (offset < INT_MIN || offset >= 0); - } - if (overflow) { + + offset = table[i]->addr - relative_base; + if (offset < 0 || offset > UINT_MAX) { fprintf(stderr, "kallsyms failure: " - "%s symbol value %#llx out of range in relative mode\n", - symbol_absolute(table[i]) ? "absolute" : "relative", + "symbol value %#llx out of range in relative mode\n", table[i]->addr); exit(EXIT_FAILURE); } printf("\t.long\t%#x /* %s */\n", (int)offset, table[i]->sym); - } else if (!symbol_absolute(table[i])) { - output_address(table[i]->addr); } else { - printf("\tPTR\t%#llx\n", table[i]->addr); + output_address(table[i]->addr); } } printf("\n"); @@ -775,36 +749,15 @@ static void sort_symbols(void) qsort(table, table_cnt, sizeof(table[0]), compare_symbols); } -static void make_percpus_absolute(void) -{ - unsigned int i; - - for (i = 0; i < table_cnt; i++) - if (symbol_in_range(table[i], &percpu_range, 1)) { - /* - * Keep the 'A' override for percpu symbols to - * ensure consistent behavior compared to older - * versions of this tool. - */ - table[i]->sym[0] = 'A'; - table[i]->percpu_absolute = 1; - } -} - -/* find the minimum non-absolute symbol address */ +/* find the minimum symbol address */ static void record_relative_base(void) { - unsigned int i; - - for (i = 0; i < table_cnt; i++) - if (!symbol_absolute(table[i])) { - /* - * The table is sorted by address. - * Take the first non-absolute symbol value. - */ - relative_base = table[i]->addr; - return; - } + /* + * The table is sorted by address. + * Take the first symbol value. + */ + if (table_cnt) + relative_base = table[0]->addr; } int main(int argc, char **argv) @@ -812,7 +765,6 @@ int main(int argc, char **argv) while (1) { static const struct option long_options[] = { {"all-symbols", no_argument, &all_symbols, 1}, - {"absolute-percpu", no_argument, &absolute_percpu, 1}, {"base-relative", no_argument, &base_relative, 1}, {"lto-clang", no_argument, <o_clang, 1}, {}, @@ -831,8 +783,6 @@ int main(int argc, char **argv) read_map(argv[optind]); shrink_table(); - if (absolute_percpu) - make_percpus_absolute(); sort_symbols(); if (base_relative) record_relative_base(); diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index a432b171be82..d25b6d5de45e 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -148,10 +148,6 @@ kallsyms() kallsymopt="${kallsymopt} --all-symbols" fi - if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then - kallsymopt="${kallsymopt} --absolute-percpu" - fi - if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then kallsymopt="${kallsymopt} --base-relative" fi -- 2.41.0
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