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authorMiguel Ojeda <ojeda@kernel.org>2021-04-05 04:58:39 +0200
committerMiguel Ojeda <ojeda@kernel.org>2022-09-28 08:56:08 +0200
commit73bbb94466fd3f8b313eeb0b0467314a262dddb3 (patch)
tree59db1039bae509a80bc1753ce21bbbc8b3e6c7ad /scripts/kallsyms.c
parent6e8c5bbd5e83e649251c198e743c8b9e7c48372b (diff)
kallsyms: support "big" kernel symbols
Rust symbols can become quite long due to namespacing introduced by modules, types, traits, generics, etc. Increasing to 255 is not enough in some cases, therefore introduce longer lengths to the symbol table. In order to avoid increasing all lengths to 2 bytes (since most of them are small, including many Rust ones), use ULEB128 to keep smaller symbols in 1 byte, with the rest in 2 bytes. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'scripts/kallsyms.c')
-rw-r--r--scripts/kallsyms.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 411ff5058b51..6502c4001f01 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -487,12 +487,35 @@ static void write_src(void)
if ((i & 0xFF) == 0)
markers[i >> 8] = off;
- printf("\t.byte 0x%02x", table[i]->len);
+ /* There cannot be any symbol of length zero. */
+ if (table[i]->len == 0) {
+ fprintf(stderr, "kallsyms failure: "
+ "unexpected zero symbol length\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
+ if (table[i]->len > 0x3FFF) {
+ fprintf(stderr, "kallsyms failure: "
+ "unexpected huge symbol length\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Encode length with ULEB128. */
+ if (table[i]->len <= 0x7F) {
+ /* Most symbols use a single byte for the length. */
+ printf("\t.byte 0x%02x", table[i]->len);
+ off += table[i]->len + 1;
+ } else {
+ /* "Big" symbols use two bytes. */
+ printf("\t.byte 0x%02x, 0x%02x",
+ (table[i]->len & 0x7F) | 0x80,
+ (table[i]->len >> 7) & 0x7F);
+ off += table[i]->len + 2;
+ }
for (k = 0; k < table[i]->len; k++)
printf(", 0x%02x", table[i]->sym[k]);
printf("\n");
-
- off += table[i]->len + 1;
}
printf("\n");