diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2022-04-21 08:17:23 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2022-04-26 08:17:05 -0700 |
| commit | 410c6aaa3b44d5bdd1af7c1a465be7d5df2dfbf0 (patch) | |
| tree | 6f4a563e7065afdbc39113f9af2d109466c582fa /target/nios2/op_helper.c | |
| parent | 0e6f22c561a5e9e02dcfa535c4573b0344d4b2ba (diff) | |
target/nios2: Implement Misaligned destination exception
Indirect branches, plus eret and bret optionally raise
an exception when branching to a misaligned address.
The exception is required when an mmu is enabled, but
enable it always because the fallback behaviour is not
documented (though presumably it discards low bits).
For the purposes of the linux-user cpu loop, if EXCP_UNALIGN
(misaligned data) were to arrive, it would be treated the
same as EXCP_UNALIGND (misaligned destination). See the
!defined(CONFIG_NIOS2_ALIGNMENT_TRAP) block in kernel/traps.c.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-53-richard.henderson@linaro.org>
Diffstat (limited to 'target/nios2/op_helper.c')
| -rw-r--r-- | target/nios2/op_helper.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c index a19b504b0e..38a71a1f2d 100644 --- a/target/nios2/op_helper.c +++ b/target/nios2/op_helper.c @@ -64,6 +64,13 @@ uint32_t helper_divu(CPUNios2State *env, uint32_t num, uint32_t den) void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc) { Nios2CPU *cpu = env_archcpu(env); + CPUState *cs = env_cpu(env); + + if (unlikely(new_pc & 3)) { + env->ctrl[CR_BADADDR] = new_pc; + cs->exception_index = EXCP_UNALIGND; + cpu_loop_exit_restore(cs, GETPC()); + } /* * Both estatus and bstatus have no constraints on write; @@ -74,6 +81,6 @@ void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc) env->ctrl[CR_STATUS] = new_status; env->pc = new_pc; - cpu_loop_exit(env_cpu(env)); + cpu_loop_exit(cs); } #endif /* !CONFIG_USER_ONLY */ |