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Peter Anvin" , Thomas Gleixner , Borislav Petkov , Ard Biesheuvel , Uros Bizjak , Brian Gerst Subject: [PATCH v6 15/15] kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU Date: Thu, 23 Jan 2025 14:07:47 -0500 Message-ID: <20250123190747.745588-16-brgerst@gmail.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250123190747.745588-1-brgerst@gmail.com> References: <20250123190747.745588-1-brgerst@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit x86-64 was the only user. Signed-off-by: Brian Gerst Reviewed-by: Ard Biesheuvel --- init/Kconfig | 5 --- kernel/kallsyms.c | 12 ++----- scripts/kallsyms.c | 72 +++++++---------------------------------- scripts/link-vmlinux.sh | 4 --- 4 files changed, 14 insertions(+), 79 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 01d36a84cf66..c2a92fb00a98 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1870,11 +1870,6 @@ 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 - # end of the "standard kernel features (expert users)" menu config ARCH_HAS_MEMBARRIER_CALLBACKS diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index a9a0ca605d4a..4198f30aac3c 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -148,16 +148,8 @@ static unsigned int get_symbol_offset(unsigned long pos) unsigned long kallsyms_sym_address(int 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 unsigned int get_symbol_seq(int index) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 03852da3d249..4b0234e4b12f 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -5,7 +5,7 @@ * 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] in.map > out.S + * Usage: kallsyms [--all-symbols] 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 long long addr; unsigned int len; unsigned int seq; - bool 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 token_profit[0x10000]; @@ -73,7 +67,7 @@ static unsigned char best_table_len[256]; static void usage(void) { - fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] in.map > out.S\n"); + fprintf(stderr, "Usage: kallsyms [--all-symbols] in.map > out.S\n"); exit(1); } @@ -164,7 +158,6 @@ 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 */ @@ -175,7 +168,6 @@ 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 = false; return sym; } @@ -319,11 +311,6 @@ static int expand_symbol(const unsigned char *data, int len, char *result) return total; } -static bool symbol_absolute(const struct sym_entry *s) -{ - return s->percpu_absolute; -} - static int compare_names(const void *a, const void *b) { int ret; @@ -455,22 +442,11 @@ static void write_src(void) */ long long offset; - bool 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", + "relative symbol value %#llx out of range\n", table[i]->addr); exit(EXIT_FAILURE); } @@ -725,36 +701,15 @@ 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 = true; - } -} - /* find the minimum non-absolute 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) @@ -762,7 +717,6 @@ 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}, {}, }; @@ -779,8 +733,6 @@ int main(int argc, char **argv) read_map(argv[optind]); shrink_table(); - if (absolute_percpu) - make_percpus_absolute(); sort_symbols(); record_relative_base(); optimize_token_table(); diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index d853ddb3b28c..8e23066323eb 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -144,10 +144,6 @@ kallsyms() kallsymopt="${kallsymopt} --all-symbols" fi - if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then - kallsymopt="${kallsymopt} --absolute-percpu" - fi - info KSYMS "${2}.S" scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" -- 2.47.1