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scripts/sorttable: Allow matches to functions before function entry

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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>
This commit is contained in:
Steven Rostedt 2025-02-25 13:20:08 -05:00 committed by Steven Rostedt (Google)
parent 46514b3c2c
commit dc208c69c0
1 changed files with 6 additions and 1 deletions
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7
scripts/sorttable.c
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@ -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: