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Message-ID: <20220915111148.409656012@infradead.org>
Date: Thu, 15 Sep 2022 13:11:32 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org, x86@...nel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Josh Poimboeuf <jpoimboe@...nel.org>,
Andrew Cooper <Andrew.Cooper3@...rix.com>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Johannes Wikner <kwikner@...z.ch>,
Alyssa Milburn <alyssa.milburn@...ux.intel.com>,
Jann Horn <jannh@...gle.com>, "H.J. Lu" <hjl.tools@...il.com>,
Joao Moreira <joao.moreira@...el.com>,
Joseph Nuzman <joseph.nuzman@...el.com>,
Steven Rostedt <rostedt@...dmis.org>,
Juergen Gross <jgross@...e.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
K Prateek Nayak <kprateek.nayak@....com>,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v3 53/59] kallsyms: Take callthunks into account
From: Peter Zijlstra <peterz@...radead.org>
Since the pre-symbol function padding is an integral part of the
symbol make kallsyms report it as part of the symbol by reporting it
as sym-x instead of prev_sym+y.
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
kernel/kallsyms.c | 45 ++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 40 insertions(+), 5 deletions(-)
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -292,6 +292,12 @@ static unsigned long get_symbol_pos(unsi
return low;
}
+#ifdef CONFIG_FUNCTION_PADDING_BYTES
+#define PADDING_BYTES CONFIG_FUNCTION_PADDING_BYTES
+#else
+#define PADDING_BYTES 0
+#endif
+
/*
* Lookup an address but don't bother to find any names.
*/
@@ -299,13 +305,25 @@ int kallsyms_lookup_size_offset(unsigned
unsigned long *offset)
{
char namebuf[KSYM_NAME_LEN];
+ int ret;
+
+ addr += PADDING_BYTES;
if (is_ksym_addr(addr)) {
get_symbol_pos(addr, symbolsize, offset);
- return 1;
+ ret = 1;
+ goto found;
}
- return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
- !!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
+
+ ret = !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf);
+ if (!ret) {
+ ret = !!__bpf_address_lookup(addr, symbolsize,
+ offset, namebuf);
+ }
+found:
+ if (ret && offset)
+ *offset -= PADDING_BYTES;
+ return ret;
}
static const char *kallsyms_lookup_buildid(unsigned long addr,
@@ -318,6 +336,8 @@ static const char *kallsyms_lookup_build
namebuf[KSYM_NAME_LEN - 1] = 0;
namebuf[0] = 0;
+ addr += PADDING_BYTES;
+
if (is_ksym_addr(addr)) {
unsigned long pos;
@@ -347,6 +367,8 @@ static const char *kallsyms_lookup_build
found:
cleanup_symbol_name(namebuf);
+ if (ret && offset)
+ *offset -= PADDING_BYTES;
return ret;
}
@@ -373,6 +395,8 @@ int lookup_symbol_name(unsigned long add
symname[0] = '\0';
symname[KSYM_NAME_LEN - 1] = '\0';
+ addr += PADDING_BYTES;
+
if (is_ksym_addr(addr)) {
unsigned long pos;
@@ -400,6 +424,8 @@ int lookup_symbol_attrs(unsigned long ad
name[0] = '\0';
name[KSYM_NAME_LEN - 1] = '\0';
+ addr += PADDING_BYTES;
+
if (is_ksym_addr(addr)) {
unsigned long pos;
@@ -416,6 +442,8 @@ int lookup_symbol_attrs(unsigned long ad
return res;
found:
+ if (offset)
+ *offset -= PADDING_BYTES;
cleanup_symbol_name(name);
return 0;
}
@@ -441,8 +469,15 @@ static int __sprint_symbol(char *buffer,
len = strlen(buffer);
offset -= symbol_offset;
- if (add_offset)
- len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
+ if (add_offset) {
+ char s = '+';
+
+ if ((long)offset < 0) {
+ s = '-';
+ offset = 0UL - offset;
+ }
+ len += sprintf(buffer + len, "%c%#lx/%#lx", s, offset, size);
+ }
if (modname) {
len += sprintf(buffer + len, " [%s", modname);
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