linux-kernel - [PATCH FOR-NEXT] riscv: Add norvc after .option arch in runtime const

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250331-fix_runtime_const_norvc-v1-1-89bc62687ab8@rivosinc.com>
Date: Mon, 31 Mar 2025 11:45:24 -0700
From: Charlie Jenkins <charlie@...osinc.com>
To: Paul Walmsley <paul.walmsley@...ive.com>, 
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
 Alexandre Ghiti <alex@...ti.fr>, Klara Modin <klarasmodin@...il.com>
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Charlie Jenkins <charlie@...osinc.com>
Subject: [PATCH FOR-NEXT] riscv: Add norvc after .option arch in runtime
 const

.option arch clobbers .option norvc. Prevent gas from emitting
compressed instructions in the runtime const alternative blocks by
setting .option norvc after .option arch. This issue starts appearing on
gcc 15, which adds zca to the march.

Reported by: Klara Modin <klarasmodin@...il.com>

Signed-off-by: Charlie Jenkins <charlie@...osinc.com>
Fixes: a44fb5722199 ("riscv: Add runtime constant support")
Closes: https://lore.kernel.org/all/cc8f3525-20b7-445b-877b-2add28a160a2@gmail.com/
---
 arch/riscv/include/asm/runtime-const.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/asm/runtime-const.h
index c07d049fdd5d2999c57d8a90e7363829c5462368..451fd76b881152919f22de8f5c56b51171acbf3c 100644
--- a/arch/riscv/include/asm/runtime-const.h
+++ b/arch/riscv/include/asm/runtime-const.h
@@ -56,6 +56,7 @@
 #define RISCV_RUNTIME_CONST_64_ZBA				\
 	".option push\n\t"					\
 	".option arch,+zba\n\t"					\
+	".option norvc\n\t"					\
 	"slli	%[__tmp],%[__tmp],32\n\t"			\
 	"add.uw %[__ret],%[__ret],%[__tmp]\n\t"			\
 	"nop\n\t"						\
@@ -65,6 +66,7 @@
 #define RISCV_RUNTIME_CONST_64_ZBKB				\
 	".option push\n\t"					\
 	".option arch,+zbkb\n\t"				\
+	".option norvc\n\t"					\
 	"pack	%[__ret],%[__ret],%[__tmp]\n\t"			\
 	"nop\n\t"						\
 	"nop\n\t"						\

---
base-commit: b2117b630c48be69d2782ed79fefe35dcd192ce6
change-id: 20250331-fix_runtime_const_norvc-407af1f24541
-- 
- Charlie