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authorSteven Rostedt <rostedt@goodmis.org>2025-02-25 13:20:08 -0500
committerSteven Rostedt (Google) <rostedt@goodmis.org>2025-02-25 13:25:13 -0500
commitdc208c69c033d3caba0509da1ae065d2b5ff165f (patch)
tree42b0609203c09008865a93438b55df7e3a7e83f0 /scripts
parent46514b3c2c17c67cefe84b0c1a59e0aaf6093131 (diff)
scripts/sorttable: Allow matches to functions before function entry
ARM 64 uses -fpatchable-function-entry=4,2 which adds padding before the function and the addresses in the mcount_loc point there instead of the function entry that is returned by nm. In order to find a function from nm to make sure it's not an unused weak function, the entries in the mcount_loc section needs to match the entries from nm. Since it can be an instruction before the entry, add a before_func variable that ARM 64 can set to 8, and if the mcount_loc entry is within 8 bytes of the nm function entry, then it will be considered a match. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: "Arnd Bergmann" <arnd@arndb.de> Cc: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/20250225182054.815536219@goodmis.org Fixes: ef378c3b82338 ("scripts/sorttable: Zero out weak functions in mcount_loc table") Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/sorttable.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/scripts/sorttable.c b/scripts/sorttable.c
index 07ad8116bc8d..7b4b3714b1af 100644
--- a/scripts/sorttable.c
+++ b/scripts/sorttable.c
@@ -611,13 +611,16 @@ static int add_field(uint64_t addr, uint64_t size)
return 0;
}
+/* Used for when mcount/fentry is before the function entry */
+static int before_func;
+
/* Only return match if the address lies inside the function size */
static int cmp_func_addr(const void *K, const void *A)
{
uint64_t key = *(const uint64_t *)K;
const struct func_info *a = A;
- if (key < a->addr)
+ if (key + before_func < a->addr)
return -1;
return key >= a->addr + a->size;
}
@@ -1253,6 +1256,8 @@ static int do_file(char const *const fname, void *addr)
#ifdef MCOUNT_SORT_ENABLED
sort_reloc = true;
rela_type = 0x403;
+ /* arm64 uses patchable function entry placing before function */
+ before_func = 8;
#endif
/* fallthrough */
case EM_386: