From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn@kernel.org>
Date: Wed, 3 Nov 2021 12:54:53 +0100
Subject: riscv, bpf: Fix RV32 broken build, and silence RV64 warning
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Patch-mainline: v5.16-rc1
Git-commit: f47d4ffe3a84ae11fc4bddc37939b9719467042c
References: jsc#PED-1377

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@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Tong Tiangen <tongtiangen@huawei.com>
Link: https://lore.kernel.org/bpf/20211103115453.397209-1-bjorn@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 arch/riscv/mm/extable.c         |    4 ++--
 arch/riscv/net/bpf_jit_comp64.c |    2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

--- 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
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -460,6 +460,8 @@ static int emit_call(bool fixed, u64 add
 #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)
 {
 	off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);