[PATCH v2 0/3] Makefile: fix support checks that use grep

[Trevor Gamblin]

When building OpenSBI in environments where extensions from the ISA are
used to generate build paths (e.g. Yocto Project), the Makefile checks
which use grep to look for patterns can incorrectly match against the
build paths, rather than the command's exit status. This means a
workaround is needed to handle checking for extensions like zicsr and
zifencei. Instead, make the following variable assignments use the same
exit status pattern as OPENSBI_LD_PIE:

CC_SUPPORT_ZICSR_ZIFENCEI
CC_SUPPORT_STRICT_ALIGN
CC_SUPPORT_SAVE_RESTORE

Tested by building a full image in Yocto including OpenSBI and booting
it in QEMU.

Note that only the first patch (for CC_SUPPORT_ZICSR_ZIFENCEI) is needed
to fix the Yocto QEMU case, but I've submitted the remaining two for
consistency. Also since submitting the first version of this series two
additional uses of grep have appeared in the Makefile, but I've opted
not to change them since they don't appear to result in the same issue
observed in Yocto.

See also: https://bugzilla.yoctoproject.org/show_bug.cgi?id=15897

As an example, in my Yocto build environment, values like CC for OpenSBI
are set like:

|export CC="riscv64-poky-linux-gcc -march=rv64imafdc_zicsr_zifencei -mabi=lp64d -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -Wl,-z,relro,-z,now -fstack-protector-strong  -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security --sysroot=/home/tgamblin/workspace/ypbuilds/poky-qemuriscv64/build/tmp/work/riscv64imafdc_zicsr_zifencei-poky-linux/opensbi/1.9/recipe-sysroot"

and the build error:

| /tmp/ccnpajj3.s: Assembler messages:
| /home/tgamblin/workspace/ypbuilds/poky-qemuriscv64/build/tmp/work/riscv64imafdc_zicsr_zifencei-poky-linux/opensbi/1.9/sources/opensbi-1.9/lib/sbi/sbi_tlb.c:176:
| Error: unrecognized opcode `fence.i', extension `zifencei' required

Checking the exit status directly avoids a positive match as happens
with grep.

Signed-off-by: Trevor Gamblin <tgamblin at baylibre.com>

---
Changes in v2:
- Rebased onto latest master, removed old CC (their changes merged
  already), no functional changes
- Link to v1: https://patch.msgid.link/20260910-makefile_extension_grep-v1-0-b3ae0d456a6e@baylibre.com

---
Trevor Gamblin (3):
      Makefile: don't grep when setting CC_SUPPORT_ZICSR_ZIFENCEI
      Makefile: don't grep when setting CC_SUPPORT_STRICT_ALIGN
      Makefile: don't grep when setting CC_SUPPORT_SAVE_RESTORE

 Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
base-commit: 5a175017261af97e9122fcb9d9012481cdb5aa41
change-id: 20260909-makefile_extension_grep-4f9fcea894cd

Best regards,
--  
Trevor Gamblin <tgamblin at baylibre.com>