[PATCH] RISC-V: fix compile error from decuplicated __ALTERNATIVE_CFG_2

Heiko Stuebner
2023-01-03T21:43:58Z

From: Heiko Stuebner <heiko.stuebner@vrull.eu>

On the non-assembler-side wrapping alternative-macros inside other macros
to prevent duplication of code works, as the end result will just be a
string that gets fed to the asm instruction.

In real assembler code, wrapping .macro blocks inside other .macro blocks
brings more restrictions on usage and the optimization done by
commit 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
results in a compile error like:

../arch/riscv/lib/strcmp.S: Assembler messages:
../arch/riscv/lib/strcmp.S:15: Error: too many positional arguments
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: attempt to move .org backwards

Going back to the original code for the non-assembler-part makes that
code work again. So this reverts the #ifdef ASSEMBLY part of that commit
to the previous variant with duplicated base.

Fixes: 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
---
I was of two minds about either to revert the full patch, or doing just
this partial one for the ASSEMBLY part. I did go with this variant, as I
still like the idea of deduplicating as much as possible :-)

arch/riscv/include/asm/alternative-macros.h | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
index 7226e2462584..e7bdb2a510a4 100644
--- a/arch/riscv/include/asm/alternative-macros.h
+++ b/arch/riscv/include/asm/alternative-macros.h
@@ -44,9 +44,20 @@
ALT_NEW_CONTENT \vendor_id, \errata_id, \enable, \new_c
.endm

+/*
+ * Using ALTERNATIVE_CFG inside ALTERNATIVE_CFG_2 results in compile errors.
+ * So the common code needs to stay duplicated.
+ */
.macro ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
new_c_2, vendor_id_2, errata_id_2, enable_2
- ALTERNATIVE_CFG \old_c, \new_c_1, \vendor_id_1, \errata_id_1, \enable_1
+886 :
+ .option push
+ .option norvc
+ .option norelax
+ \old_c
+ .option pop
+887 :
+ ALT_NEW_CONTENT \vendor_id_1, \errata_id_1, \enable_1, \new_c_1
ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
.endm

--
2.35.1