6.1-stable review patch. If anyone has any objections, please let me know.
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From: Zhen Lei thunder.leizhen@huawei.com
[ Upstream commit 4dc533e0f2c04174e1ae4aa98e7cffc1c04b9998 ]
Function kallsyms_on_each_symbol() traverses all symbols and submits each symbol to the hook 'fn' for judgment and processing. For some cases, the hook actually only handles the matched symbol, such as livepatch.
Because all symbols are currently sorted by name, all the symbols with the same name are clustered together. Function kallsyms_lookup_names() gets the start and end positions of the set corresponding to the specified name. So we can easily and quickly traverse all the matches.
The test results are as follows (twice): (x86) kallsyms_on_each_match_symbol: 7454, 7984 kallsyms_on_each_symbol : 11733809, 11785803
kallsyms_on_each_match_symbol() consumes only 0.066% of kallsyms_on_each_symbol()'s time. In other words, 1523x better performance.
Signed-off-by: Zhen Lei thunder.leizhen@huawei.com Signed-off-by: Luis Chamberlain mcgrof@kernel.org Stable-dep-of: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/kallsyms.h | 8 ++++++++ kernel/kallsyms.c | 18 ++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 649faac31ddb1..0cd33be7142ad 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -69,6 +69,8 @@ static inline void *dereference_symbol_descriptor(void *ptr) int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, unsigned long), void *data); +int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long), + const char *name, void *data);
/* Lookup the address for a symbol. Returns 0 if not found. */ unsigned long kallsyms_lookup_name(const char *name); @@ -168,6 +170,12 @@ static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct { return -EOPNOTSUPP; } + +static inline int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long), + const char *name, void *data) +{ + return -EOPNOTSUPP; +} #endif /*CONFIG_KALLSYMS*/
static inline void print_ip_sym(const char *loglvl, unsigned long ip) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 32cba13eee6c4..824bcc7b5dbc3 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -303,6 +303,24 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, return 0; }
+int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long), + const char *name, void *data) +{ + int ret; + unsigned int i, start, end; + + ret = kallsyms_lookup_names(name, &start, &end); + if (ret) + return 0; + + for (i = start; !ret && i <= end; i++) { + ret = fn(data, kallsyms_sym_address(get_symbol_seq(i))); + cond_resched(); + } + + return ret; +} + static unsigned long get_symbol_pos(unsigned long addr, unsigned long *symbolsize, unsigned long *offset)