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[2600:6c4a:4d3f:6d5c::1019]) by smtp.gmail.com with ESMTPSA id j1-20020a37ef01000000b00789e9bbf962sm894901qkk.133.2024.03.22.09.53.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Mar 2024 09:53:07 -0700 (PDT) From: Brian Gerst To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: Ingo Molnar , Thomas Gleixner , Borislav Petkov , "H . Peter Anvin" , Uros Bizjak , David.Laight@aculab.com, Brian Gerst Subject: [PATCH v4 16/16] kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU Date: Fri, 22 Mar 2024 12:52:33 -0400 Message-ID: <20240322165233.71698-17-brgerst@gmail.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240322165233.71698-1-brgerst@gmail.com> References: <20240322165233.71698-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" x86-64 was the only user. Signed-off-by: Brian Gerst --- 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 0f928f82dc7a..0622599ce503 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1781,11 +1781,6 @@ config KALLSYMS_ALL =20 Say N unless you really need all symbols, or kernel live patching. =20 -config KALLSYMS_ABSOLUTE_PERCPU - bool - depends on KALLSYMS - default n - config KALLSYMS_BASE_RELATIVE bool depends on KALLSYMS @@ -1793,11 +1788,7 @@ 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]. =20 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]; =20 - /* 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] >=3D 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]; } =20 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[]; }; =20 @@ -55,14 +54,9 @@ static struct addr_range text_ranges[] =3D { #define text_range_text (&text_ranges[0]) #define text_range_inittext (&text_ranges[1]) =20 -static struct addr_range percpu_range =3D { - "__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; =20 @@ -75,7 +69,7 @@ static unsigned char best_table_len[256]; =20 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 **b= uf, size_t *buf_len) return NULL; =20 check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges)); - check_symbol_range(name, addr, &percpu_range, 1); =20 /* 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 **b= uf, size_t *buf_len) sym->len =3D len; sym->sym[0] =3D type; strcpy(sym_name(sym), name); - sym->percpu_absolute =3D 0; =20 return sym; } @@ -334,11 +326,6 @@ static int expand_symbol(const unsigned char *data, in= t len, char *result) return total; } =20 -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) */ =20 long long offset; - int overflow; - - if (!absolute_percpu) { - offset =3D table[i]->addr - relative_base; - overflow =3D (offset < 0 || offset > UINT_MAX); - } else if (symbol_absolute(table[i])) { - offset =3D table[i]->addr; - overflow =3D (offset < 0 || offset > INT_MAX); - } else { - offset =3D relative_base - table[i]->addr - 1; - overflow =3D (offset < INT_MIN || offset >=3D 0); - } - if (overflow) { + + offset =3D 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); } =20 -static void make_percpus_absolute(void) -{ - unsigned int i; - - for (i =3D 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] =3D 'A'; - table[i]->percpu_absolute =3D 1; - } -} - -/* find the minimum non-absolute symbol address */ +/* find the minimum symbol address */ static void record_relative_base(void) { - unsigned int i; - - for (i =3D 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 =3D table[i]->addr; - return; - } + /* + * The table is sorted by address. + * Take the first symbol value. + */ + if (table_cnt) + relative_base =3D table[0]->addr; } =20 int main(int argc, char **argv) @@ -812,7 +765,6 @@ int main(int argc, char **argv) while (1) { static const struct option long_options[] =3D { {"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) =20 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 7862a8101747..7b0596cd5a80 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -153,10 +153,6 @@ kallsyms() kallsymopt=3D"${kallsymopt} --all-symbols" fi =20 - if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then - kallsymopt=3D"${kallsymopt} --absolute-percpu" - fi - if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then kallsymopt=3D"${kallsymopt} --base-relative" fi --=20 2.44.0