tree 7724ab855bc0266b61f3c14d9f55a78f4a00b9fa
parent 1c13f8d85c7306213cd525308ee8973e5663a3f8
author Paul Menzel <pmenzel@molgen.mpg.de> 1664734624 +0200
committer Felix Singer <service+coreboot-gerrit@felixsinger.de> 1712850510 +0000

Makefile.inc: Decrease minimal pagesize from 4 kB to 1 kB

GCC 12 incorrectly warns about an array out of bounds issue:

```
$ make V=1 # emulation/qemu-i440fx
[…]
    CC         ramstage/arch/x86/ebda.o
x86_64-linux-gnu-gcc-12 -MMD -Isrc -Isrc/include -Isrc/commonlib/include -Isrc/commonlib/bsd/include -Ibuild -I3rdparty/vboot/firmware/include -include src/include/kconfig.h -include src/include/rules.h -include src/commonlib/bsd/include/commonlib/bsd/compiler.h -I3rdparty -D__BUILD_DIR__=\"build\" -Isrc/arch/x86/include -D__ARCH_x86_32__ -pipe -g -nostdinc -std=gnu11 -nostdlib -Wall -Wundef -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wredundant-decls -Wno-trigraphs -Wimplicit-fallthrough -Wshadow -Wdate-time -Wtype-limits -Wvla -Wdangling-else -fno-common -ffreestanding -fno-builtin -fomit-frame-pointer -fstrict-aliasing -ffunction-sections -fdata-sections -fno-pie -Wno-packed-not-aligned -fconserve-stack -Wnull-dereference -Wreturn-type -Wlogical-op -Wduplicated-cond -Wno-unused-but-set-variable -Werror -Os -Wno-address-of-packed-member -m32 -Wl,-b,elf32-i386 -Wl,-melf_i386 -m32  -fuse-ld=bfd -fno-stack-protector -Wl,--build-id=none -fno-delete-null-pointer-checks -Wlogical-op -march=i686 -mno-mmx -MT build/ramstage/arch/x86/ebda.o -D__RAMSTAGE__ -c -o build/ramstage/arch/x86/ebda.o src/arch/x86/ebda.c
In file included from src/arch/x86/ebda.c:6:
In function 'write_ble8',
    inlined from 'write_le8' at src/commonlib/include/commonlib/endian.h:155:2,
    inlined from 'write_le16' at src/commonlib/include/commonlib/endian.h:178:2,
    inlined from 'setup_ebda' at src/arch/x86/ebda.c:35:2,
    inlined from 'setup_default_ebda' at src/arch/x86/ebda.c:48:2:
src/commonlib/include/commonlib/endian.h:27:26: error: array subscript 0 is outside array bounds of 'void[0]' [-Werror=array-bounds]
   27 |         *(uint8_t *)dest = val;
      |         ~~~~~~~~~~~~~~~~~^~~~~
[…]
```

[In GCC 12 the new parameter `min-pagesize` is added and defaults 4 kB.][1]
It treats INTEGER_CST addresses smaller than that as assumed results of
pointer arithmetics from NULL while addresses equal or larger than that
as expected user constant addresses. For GCC 13 we can represent results
from pointer arithmetics on NULL using &MEM[(void*)0 + offset] instead
of (void*)offset INTEGER_CSTs.

[1]: https://web.archive.org/web/20220711061810/https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578

TEST=No compile error with gcc (Debian 12.2.0-3) 12.2.0
Change-Id: I6e36633f42cb4dc5af53212c10c919a86e451ee0
Original-Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Original-Reviewed-on: https://review.coreboot.org/c/coreboot/+/62830
Original-Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81785
Tested-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>