[PATCH 1/1] ACPI: Fix building with GCC 15
From: Brahmajit Das
Date: Mon Apr 14 2025 - 12:18:04 EST
Since the Linux kernel initializes many non-C-string char arrays with
literals. While it would be possible to convert initializers from:
{ "BOOP", ... }
to something like:
{ { 'B', 'O', 'O', 'P' }, ... }
that is annoying.
Making -Wunterminated-string-initialization stay silent about char
arrays marked with nonstring would be much better.
Without the __attribute__((nonstring)) we would get the following build
error:
...
drivers/acpi/acpica/acpredef.h:903:11: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (5 chars into 4 available) [-Werror=unterminated-string-initialization]
903 | {{"_S3D", METHOD_0ARGS,
| ^~~~~~
drivers/acpi/acpica/acpredef.h:906:11: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (5 chars into 4 available) [-Werror=unterminated-string-initialization]
906 | {{"_S4D", METHOD_0ARGS,
| ^~~~~~
and,
...
drivers/acpi/acpica/nsrepair2.c:115:10: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (5 chars into 4 available) [-Werror=unterminated-string-initialization]
115 | {"_ALR", acpi_ns_repair_ALR},
| ^~~~~~
drivers/acpi/acpica/nsrepair2.c:116:10: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (5 chars into 4 available) [-Werror=unterminated-string-initialization]
116 | {"_CID", acpi_ns_repair_CID},
...
Upstream GCC has added this commit
622968990beee7499e951590258363545b4a3b57[0][1] which silences warning
about truncating NUL char when initializing nonstring arrays.
[0]: https://gcc.gnu.org/cgit/gcc/commit/?id=622968990beee7499e951590258363545b4a3b57
[1]: https://gcc.gnu.org/cgit/gcc/commit/?id=afb46540d3921e96c4cd7ba8fa2c8b0901759455
Thanks to Jakub Jelinek <jakub@xxxxxxxxxxx> for the gcc patch.
Signed-off-by: Brahmajit Das <listout@xxxxxxxxxxx>
---
drivers/acpi/acpica/aclocal.h | 4 ++--
drivers/acpi/acpica/nsrepair2.c | 2 +-
drivers/acpi/tables.c | 28 +++++++++++++++-------------
include/acpi/actbl.h | 3 ++-
4 files changed, 20 insertions(+), 17 deletions(-)
diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h
index 6f4fe47c955b..d2cda1b35e59 100644
--- a/drivers/acpi/acpica/aclocal.h
+++ b/drivers/acpi/acpica/aclocal.h
@@ -293,7 +293,7 @@ acpi_status (*acpi_internal_method) (struct acpi_walk_state * walk_state);
* expected_return_btypes - Allowed type(s) for the return value
*/
struct acpi_name_info {
- char name[ACPI_NAMESEG_SIZE];
+ char name[ACPI_NAMESEG_SIZE] __attribute__((nonstring));
u16 argument_list;
u8 expected_btypes;
};
@@ -370,7 +370,7 @@ typedef acpi_status (*acpi_object_converter) (struct acpi_namespace_node *
converted_object);
struct acpi_simple_repair_info {
- char name[ACPI_NAMESEG_SIZE];
+ char name[ACPI_NAMESEG_SIZE] __attribute__((nonstring));
u32 unexpected_btypes;
u32 package_index;
acpi_object_converter object_converter;
diff --git a/drivers/acpi/acpica/nsrepair2.c b/drivers/acpi/acpica/nsrepair2.c
index 1bb7b71f07f1..a28b1fa2b1ea 100644
--- a/drivers/acpi/acpica/nsrepair2.c
+++ b/drivers/acpi/acpica/nsrepair2.c
@@ -25,7 +25,7 @@ acpi_status (*acpi_repair_function) (struct acpi_evaluate_info * info,
return_object_ptr);
typedef struct acpi_repair_info {
- char name[ACPI_NAMESEG_SIZE];
+ char name[ACPI_NAMESEG_SIZE] __attribute__((nonstring));
acpi_repair_function repair_function;
} acpi_repair_info;
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 2295abbecd14..27104cbb48b5 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -396,19 +396,21 @@ static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
}
/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
-static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst = {
- ACPI_SIG_BERT, ACPI_SIG_BGRT, ACPI_SIG_CPEP, ACPI_SIG_ECDT,
- ACPI_SIG_EINJ, ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT,
- ACPI_SIG_MSCT, ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT,
- ACPI_SIG_ASF, ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR,
- ACPI_SIG_HPET, ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG,
- ACPI_SIG_MCHI, ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI,
- ACPI_SIG_TCPA, ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT,
- ACPI_SIG_WDDT, ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT,
- ACPI_SIG_PSDT, ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT,
- ACPI_SIG_IORT, ACPI_SIG_NFIT, ACPI_SIG_HMAT, ACPI_SIG_PPTT,
- ACPI_SIG_NHLT, ACPI_SIG_AEST, ACPI_SIG_CEDT, ACPI_SIG_AGDI,
- ACPI_SIG_NBFT };
+static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst
+ __attribute__((nonstring)) = {
+ ACPI_SIG_BERT, ACPI_SIG_BGRT, ACPI_SIG_CPEP, ACPI_SIG_ECDT,
+ ACPI_SIG_EINJ, ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT,
+ ACPI_SIG_MSCT, ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT,
+ ACPI_SIG_ASF, ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR,
+ ACPI_SIG_HPET, ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG,
+ ACPI_SIG_MCHI, ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI,
+ ACPI_SIG_TCPA, ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT,
+ ACPI_SIG_WDDT, ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT,
+ ACPI_SIG_PSDT, ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT,
+ ACPI_SIG_IORT, ACPI_SIG_NFIT, ACPI_SIG_HMAT, ACPI_SIG_PPTT,
+ ACPI_SIG_NHLT, ACPI_SIG_AEST, ACPI_SIG_CEDT, ACPI_SIG_AGDI,
+ ACPI_SIG_NBFT
+ };
#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h
index 451f6276da49..88ba1b978053 100644
--- a/include/acpi/actbl.h
+++ b/include/acpi/actbl.h
@@ -66,7 +66,8 @@
******************************************************************************/
struct acpi_table_header {
- char signature[ACPI_NAMESEG_SIZE]; /* ASCII table signature */
+ char signature[ACPI_NAMESEG_SIZE]
+ __attribute__((nonstring)); /* ASCII table signature */
u32 length; /* Length of table in bytes, including this header */
u8 revision; /* ACPI Specification minor version number */
u8 checksum; /* To make sum of entire table == 0 */
--
2.49.0