On 2022-02-10 18:27, Victor Erminpour wrote:
On 2/10/22 10:06 AM, Robin Murphy wrote:
On 2022-02-10 00:32, Victor Erminpour wrote:
When building with automatic stack variable initialization, GCC 12
complains about variables defined outside of switch case statements.
Move the variable into the case that uses it, which silences the
warning:
./drivers/acpi/arm64/iort.c:1670:59: error: statement will never be
executed [-Werror=switch-unreachable]
1670 | struct acpi_iort_named_component
*ncomp;
| ^~~~~
Notwithstanding the fact that that warning is nonsensical, this patch
changes valid C code into invalid C code that doesn't even compile:
drivers/acpi/arm64/iort.c: In function
‘acpi_iort_dma_get_max_cpu_address’:
drivers/acpi/arm64/iort.c:1669:4: error: a label can only be part of a
statement and a declaration is not a statement
1669 | struct acpi_iort_named_component *ncomp;
| ^~~~~~
drivers/acpi/arm64/iort.c:1676:4: error: a label can only be part of a
statement and a declaration is not a statement
1676 | struct acpi_iort_root_complex *rc;
| ^~~~~~
Robin.
Hi Robin,
Thank you for your constructive criticism.
Could the solution be enclosing the case statement in curly braces?
I know this isn't a big issue for you, but this is a legitimate error
for people
building the kernel with GCC 12 and CONFIG_INIT_STACK_ALL_ZERO enabled.
As Ard pointed out first, it is not a legitimate error, it is a spurious
error. The fact that you seemingly didn't get the label errors above,
nor even "ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]", implies that GCC 12 currently has a
completely broken notion of declarations vs. statements with that option
enabled, so GCC 12 needs fixing.
Robin.
Regards,
--Victor
Signed-off-by: Victor Erminpour <victor.erminpour@xxxxxxxxxx>
---
drivers/acpi/arm64/iort.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 3b23fb775ac4..5c5d2e56d756 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1645,7 +1645,7 @@ void __init acpi_iort_init(void)
*/
phys_addr_t __init acpi_iort_dma_get_max_cpu_address(void)
{
- phys_addr_t limit = PHYS_ADDR_MAX;
+ phys_addr_t local_limit, limit = PHYS_ADDR_MAX;
struct acpi_iort_node *node, *end;
struct acpi_table_iort *iort;
acpi_status status;
@@ -1667,17 +1667,15 @@ phys_addr_t __init
acpi_iort_dma_get_max_cpu_address(void)
break;
switch (node->type) {
- struct acpi_iort_named_component *ncomp;
- struct acpi_iort_root_complex *rc;
- phys_addr_t local_limit;
-
case ACPI_IORT_NODE_NAMED_COMPONENT:
+ struct acpi_iort_named_component *ncomp;
ncomp = (struct acpi_iort_named_component
*)node->node_data;
local_limit = DMA_BIT_MASK(ncomp->memory_address_limit);
limit = min_not_zero(limit, local_limit);
break;
case ACPI_IORT_NODE_PCI_ROOT_COMPLEX:
+ struct acpi_iort_root_complex *rc;
if (node->revision < 1)
break;
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