[PATCH bpf-next] riscv, bpf: Fix RV32 broken build, and silence RV64 warning

[Björn Töpel]

Commit 252c765bd764 ("riscv, bpf: Add BPF exception tables") only
addressed RV64, and broke the RV32 build [1]. Fix by gating the exception
tables code with CONFIG_ARCH_RV64I.

Further, silence a "-Wmissing-prototypes" warning [2] in the RV64 BPF
JIT.

[1] https://lore.kernel.org/llvm/202111020610.9oy9Rr0G-lkp@intel.com/
[2] https://lore.kernel.org/llvm/202110290334.2zdMyRq4-lkp@intel.com/

Fixes: 252c765bd764 ("riscv, bpf: Add BPF exception tables")
Signed-off-by: Björn Töpel <bjorn at kernel.org>
---
Tong/Daniel: The RV32 build has been broken since Thursday. I'll try
to fast-track a bit, and commit a quick-fix for it. Hope that's OK
with you, Tong!

I've verified the build on my machine using riscv32 GCC 9.3.0 and
riscv64 GCC 11.2.0.


Björn
---
arch/riscv/mm/extable.c         | 4 ++--
 arch/riscv/net/bpf_jit_comp64.c | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/extable.c b/arch/riscv/mm/extable.c
index 18bf338303b6..ddb7d3b99e89 100644
--- a/arch/riscv/mm/extable.c
+++ b/arch/riscv/mm/extable.c
@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include <linux/uaccess.h>
 
-#ifdef CONFIG_BPF_JIT
+#if defined(CONFIG_BPF_JIT) && defined(CONFIG_ARCH_RV64I)
 int rv_bpf_fixup_exception(const struct exception_table_entry *ex, struct pt_regs *regs);
 #endif
 
@@ -23,7 +23,7 @@ int fixup_exception(struct pt_regs *regs)
 	if (!fixup)
 		return 0;
 
-#ifdef CONFIG_BPF_JIT
+#if defined(CONFIG_BPF_JIT) && defined(CONFIG_ARCH_RV64I)
 	if (regs->epc >= BPF_JIT_REGION_START && regs->epc < BPF_JIT_REGION_END)
 		return rv_bpf_fixup_exception(fixup, regs);
 #endif
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 2ca345c7b0bf..f2a779c7e225 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -459,6 +459,8 @@ static int emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx)
 #define BPF_FIXUP_OFFSET_MASK   GENMASK(26, 0)
 #define BPF_FIXUP_REG_MASK      GENMASK(31, 27)
 
+int rv_bpf_fixup_exception(const struct exception_table_entry *ex,
+				struct pt_regs *regs);
 int rv_bpf_fixup_exception(const struct exception_table_entry *ex,
 				struct pt_regs *regs)
 {

base-commit: cc0356d6a02e064387c16a83cb96fe43ef33181e
-- 
2.32.0