[PATCH] RISC-V: errata: Use medany for relocatable builds

[Palmer Dabbelt]

We're trying to mix non-PIC/PIE objects into the otherwise-PIE
relocatable kernels, to avoid GOT/PLT references during early boot
alternative resolution (which happens before the GOT/PLT are set up).

riscv64-unknown-linux-gnu-ld: arch/riscv/errata/sifive/errata.o: relocation R_RISCV_HI20 against `tlb_flush_all_threshold' can not be used when making a shared object; recompile with -fPIC
riscv64-unknown-linux-gnu-ld: arch/riscv/errata/thead/errata.o: relocation R_RISCV_HI20 against `riscv_cbom_block_size' can not be used when making a shared object; recompile with -fPIC

Fixes: 8dc2a7e8027f ("riscv: Fix relocatable kernels with early alternatives using -fno-pie")
Signed-off-by: Palmer Dabbelt <palmer at rivosinc.com>
---
I'm not 100% sure it's possible to expose this without Samuel's NOMMU
relocatable builds, see
<https://lore.kernel.org/all/mhng-517c0318-c8fb-4c4a-aa0e-0d08f8d34d78@palmer-ri-x1c9/>
---
 arch/riscv/errata/Makefile | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/errata/Makefile b/arch/riscv/errata/Makefile
index f0da9d7b39c3..bc6c77ba837d 100644
--- a/arch/riscv/errata/Makefile
+++ b/arch/riscv/errata/Makefile
@@ -1,5 +1,9 @@
 ifdef CONFIG_RELOCATABLE
-KBUILD_CFLAGS += -fno-pie
+# We can't use PIC/PIE when handling early-boot errata parsing, as the kernel
+# doesn't have a GOT setup at that point.  So instead just use medany: it's
+# usually position-independent, so it should be good enough for the errata
+# handling.
+KBUILD_CFLAGS += -fno-pie -mcmodel=medany
 endif
 
 ifdef CONFIG_RISCV_ALTERNATIVE_EARLY
-- 
2.45.2