6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
[ Upstream commit 19bd8981dc2ee35fdc81ab1b0104b607c917d470 ]
kallsyms_seqs_of_names[] records the symbol index sorted by address, the
maximum value in kallsyms_seqs_of_names[] is the number of symbols. And
2^24 = 16777216, which means that three bytes are enough to store the
index. This can help us save (1 * kallsyms_num_syms) bytes of memory.
Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Stable-dep-of: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/kallsyms.c | 18 ++++++++++++++----
kernel/kallsyms_internal.h | 2 +-
scripts/kallsyms.c | 5 ++++-
3 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index ad3cccb0970f8..32cba13eee6c4 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -197,6 +197,16 @@ static int compare_symbol_name(const char *name, char *namebuf)
return strcmp(name, namebuf);
}
+static unsigned int get_symbol_seq(int index)
+{
+ unsigned int i, seq = 0;
+
+ for (i = 0; i < 3; i++)
+ seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];
+
+ return seq;
+}
+
static int kallsyms_lookup_names(const char *name,
unsigned int *start,
unsigned int *end)
@@ -211,7 +221,7 @@ static int kallsyms_lookup_names(const char *name,
while (low <= high) {
mid = low + (high - low) / 2;
- seq = kallsyms_seqs_of_names[mid];
+ seq = get_symbol_seq(mid);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
ret = compare_symbol_name(name, namebuf);
@@ -228,7 +238,7 @@ static int kallsyms_lookup_names(const char *name,
low = mid;
while (low) {
- seq = kallsyms_seqs_of_names[low - 1];
+ seq = get_symbol_seq(low - 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
@@ -240,7 +250,7 @@ static int kallsyms_lookup_names(const char *name,
if (end) {
high = mid;
while (high < kallsyms_num_syms - 1) {
- seq = kallsyms_seqs_of_names[high + 1];
+ seq = get_symbol_seq(high + 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
@@ -265,7 +275,7 @@ unsigned long kallsyms_lookup_name(const char *name)
ret = kallsyms_lookup_names(name, &i, NULL);
if (!ret)
- return kallsyms_sym_address(kallsyms_seqs_of_names[i]);
+ return kallsyms_sym_address(get_symbol_seq(i));
return module_kallsyms_lookup_name(name);
}
diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h
index a04b7a5cb1e3e..27fabdcc40f57 100644
--- a/kernel/kallsyms_internal.h
+++ b/kernel/kallsyms_internal.h
@@ -26,6 +26,6 @@ extern const char kallsyms_token_table[] __weak;
extern const u16 kallsyms_token_index[] __weak;
extern const unsigned int kallsyms_markers[] __weak;
-extern const unsigned int kallsyms_seqs_of_names[] __weak;
+extern const u8 kallsyms_seqs_of_names[] __weak;
#endif // LINUX_KALLSYMS_INTERNAL_H_
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 80aab2aa72246..ff8cce1757849 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -602,7 +602,10 @@ static void write_src(void)
sort_symbols_by_name();
output_label("kallsyms_seqs_of_names");
for (i = 0; i < table_cnt; i++)
- printf("\t.long\t%u\n", table[i]->seq);
+ printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n",
+ (unsigned char)(table[i]->seq >> 16),
+ (unsigned char)(table[i]->seq >> 8),
+ (unsigned char)(table[i]->seq >> 0));
printf("\n");
output_label("kallsyms_token_table");
--
2.42.0
