From e52a2122cb1574723c7c8181ba751cc0ff37648e Mon Sep 17 00:00:00 2001
From: Zhang Jiao <zhangjiao2_yewu@cmss.chinamobile.com>
Date: Thu, 12 Dec 2024 09:46:18 +0800
Subject: [PATCH] target/riscv: Avoid bad shift in riscv_cpu_do_interrupt()
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cheery-pick from 5311599cdc48337f2f27b1b51a80d46d75b05ed0

In riscv_cpu_do_interrupt() we use the 'cause' value we got out of
cs->exception as a shift value.  However this value can be larger
than 31, which means that "1 << cause" is undefined behaviour,
because we do the shift on an 'int' type.

This causes the undefined behaviour sanitizer to complain
on one of the check-tcg tests:

$ UBSAN_OPTIONS=print_stacktrace=1:abort_on_error=1:halt_on_error=1 ./build/clang/qemu-system-riscv64 -M virt -semihosting -display none -device loader,file=build/clang/tests/tcg/riscv64-softmmu/issue1060
../../target/riscv/cpu_helper.c:1805:38: runtime error: shift exponent 63 is too large for 32-bit type 'int'
    #0 0x55f2dc026703 in riscv_cpu_do_interrupt /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/clang/../../target/riscv/cpu_helper.c:1805:38
    #1 0x55f2dc3d170e in cpu_handle_exception /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/clang/../../accel/tcg/cpu-exec.c:752:9

In this case cause is RISCV_EXCP_SEMIHOST, which is 0x3f.

Use 1ULL instead to ensure that the shift is in range.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fixes: 1697837ed9 ("target/riscv: Add M-mode virtual interrupt and IRQ filtering support.")
Fixes: 40336d5b1d ("target/riscv: Add HS-mode virtual interrupt and IRQ filtering support.")
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20241128103831.3452572-1-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Zhang Jiao <zhangjiao2_yewu@cmss.chinamobile.com>
---
 target/riscv/cpu_helper.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index e7e23b34f4..4d8f1248dd 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -1644,10 +1644,10 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     bool async = !!(cs->exception_index & RISCV_EXCP_INT_FLAG);
     target_ulong cause = cs->exception_index & RISCV_EXCP_INT_MASK;
     uint64_t deleg = async ? env->mideleg : env->medeleg;
-    bool s_injected = env->mvip & (1 << cause) & env->mvien &&
-        !(env->mip & (1 << cause));
-    bool vs_injected = env->hvip & (1 << cause) & env->hvien &&
-        !(env->mip & (1 << cause));
+    bool s_injected = env->mvip & (1ULL << cause) & env->mvien &&
+        !(env->mip & (1ULL << cause));
+    bool vs_injected = env->hvip & (1ULL << cause) & env->hvien &&
+        !(env->mip & (1ULL << cause));
     target_ulong tval = 0;
     target_ulong tinst = 0;
     target_ulong htval = 0;
-- 
2.41.0.windows.1