GCC 12 objects to pointers derived from a constant:
util.c: In function 'find_rsdp':
util.c:429:16: error: array subscript 0 is outside array bounds of 'uint16_t[0]' {aka 'short unsigned int[]'} [-Werror=array-bounds]
429 | ebda_seg = *(uint16_t *)ADDR_FROM_SEG_OFF(0x40, 0xe);
cc1: all warnings being treated as errors
This is a GCC bug, but work around it rather than turning array-bounds
checking off generally.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>
This only manifests in release builds, presumably a side effect of neediung
some constant-folding to notice the ADDR_FROM_SEG_OFF() expression.
We don't see this in CI because debug isn't configured correctly for the
tools/ part of the build
---
tools/firmware/rombios/32bit/util.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/firmware/rombios/32bit/util.c b/tools/firmware/rombios/32bit/util.c
index 6c1c4805144b..a47e000a2629 100644
--- a/tools/firmware/rombios/32bit/util.c
+++ b/tools/firmware/rombios/32bit/util.c
@@ -424,10 +424,10 @@ static struct acpi_20_rsdp *__find_rsdp(const void *start, unsigned int len)
struct acpi_20_rsdp *find_rsdp(void)
{
struct acpi_20_rsdp *rsdp;
- uint16_t ebda_seg;
+ uint16_t *volatile /* GCC issue 99578 */ ebda_seg =
+ ADDR_FROM_SEG_OFF(0x40, 0xe);
- ebda_seg = *(uint16_t *)ADDR_FROM_SEG_OFF(0x40, 0xe);
- rsdp = __find_rsdp((void *)(ebda_seg << 16), 1024);
+ rsdp = __find_rsdp((void *)(*ebda_seg << 16), 1024);
if (!rsdp)
rsdp = __find_rsdp((void *)0xE0000, 0x20000);
base-commit: d0eabe3eaf0db5b78843095a2918d50961e99e96
--
2.30.2