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[PATCH v7 55/64] target/nios2: Update helper_eret for shadow registers
From: |
Richard Henderson |
Subject: |
[PATCH v7 55/64] target/nios2: Update helper_eret for shadow registers |
Date: |
Thu, 21 Apr 2022 08:17:26 -0700 |
When CRS = 0, we restore from estatus; otherwise from sstatus.
Update for the new CRS.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
target/nios2/cpu.h | 1 +
target/nios2/op_helper.c | 10 +++++++---
target/nios2/translate.c | 13 ++++++++-----
3 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index d4d97a159e..c2fedead54 100644
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -82,6 +82,7 @@ enum {
R_FP = 28,
R_EA = 29,
R_BA = 30,
+ R_SSTATUS = 30,
R_RA = 31,
};
diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c
index a3164f5356..94040102f4 100644
--- a/target/nios2/op_helper.c
+++ b/target/nios2/op_helper.c
@@ -73,14 +73,18 @@ void helper_eret(CPUNios2State *env, uint32_t new_status,
uint32_t new_pc)
}
/*
- * Both estatus and bstatus have no constraints on write;
+ * None of estatus, bstatus, or sstatus have constraints on write;
* do not allow reserved fields in status to be set.
- * TODO: more than this is required for shadow registers.
+ * When shadow registers are enabled, eret *does* restore CRS.
+ * Rather than testing eic_present to decide, mask CRS out of
+ * the set of readonly fields.
*/
- new_status &= cpu->cr_state[CR_STATUS].writable;
+ new_status &= cpu->cr_state[CR_STATUS].writable |
+ (cpu->cr_state[CR_STATUS].readonly & R_CR_STATUS_CRS_MASK);
env->ctrl[CR_STATUS] = new_status;
env->pc = new_pc;
+ nios2_update_crs(env);
cpu_loop_exit(cs);
}
diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index fdcc2154f2..29cb610aca 100644
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -491,11 +491,14 @@ static void eret(DisasContext *dc, uint32_t code,
uint32_t flags)
#ifdef CONFIG_USER_ONLY
g_assert_not_reached();
#else
- TCGv tmp = tcg_temp_new();
- tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPUNios2State, ctrl[CR_ESTATUS]));
- gen_helper_eret(cpu_env, tmp, load_gpr(dc, R_EA));
- tcg_temp_free(tmp);
-
+ if (FIELD_EX32(dc->tb_flags, TBFLAGS, CRS0)) {
+ TCGv tmp = tcg_temp_new();
+ tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPUNios2State, ctrl[CR_ESTATUS]));
+ gen_helper_eret(cpu_env, tmp, load_gpr(dc, R_EA));
+ tcg_temp_free(tmp);
+ } else {
+ gen_helper_eret(cpu_env, load_gpr(dc, R_SSTATUS), load_gpr(dc, R_EA));
+ }
dc->base.is_jmp = DISAS_NORETURN;
#endif
}
--
2.34.1
- [PATCH v7 45/64] target/nios2: Introduce dest_gpr, (continued)
- [PATCH v7 45/64] target/nios2: Introduce dest_gpr, Richard Henderson, 2022/04/21
- [PATCH v7 47/64] target/nios2: Enable unaligned traps for system mode, Richard Henderson, 2022/04/21
- [PATCH v7 46/64] target/nios2: Drop CR_STATUS_EH from tb->flags, Richard Henderson, 2022/04/21
- [PATCH v7 49/64] target/nios2: Hoist set of is_jmp into gen_goto_tb, Richard Henderson, 2022/04/21
- [PATCH v7 50/64] target/nios2: Use gen_goto_tb for DISAS_TOO_MANY, Richard Henderson, 2022/04/21
- [PATCH v7 52/64] target/nios2: Implement Misaligned destination exception, Richard Henderson, 2022/04/21
- [PATCH v7 58/64] linux-user/nios2: Handle various SIGILL exceptions, Richard Henderson, 2022/04/21
- [PATCH v7 61/64] hw/nios2: Move memory regions into Nios2Machine, Richard Henderson, 2022/04/21
- [PATCH v7 56/64] target/nios2: Implement EIC interrupt processing, Richard Henderson, 2022/04/21
- [PATCH v7 55/64] target/nios2: Update helper_eret for shadow registers,
Richard Henderson <=
- [PATCH v7 59/64] hw/intc: Vectored Interrupt Controller (VIC), Richard Henderson, 2022/04/21
- [PATCH v7 64/64] tests/tcg/nios2: Add test-shadow-1, Richard Henderson, 2022/04/21
- [PATCH v7 53/64] target/nios2: Introduce shadow register sets, Richard Henderson, 2022/04/21
- [PATCH v7 60/64] hw/nios2: Introduce Nios2MachineState, Richard Henderson, 2022/04/21
- [PATCH v7 54/64] target/nios2: Implement rdprs, wrprs, Richard Henderson, 2022/04/21
- [PATCH v7 57/64] target/nios2: Advance pc when raising exceptions, Richard Henderson, 2022/04/21
- [PATCH v7 62/64] hw/nios2: Machine with a Vectored Interrupt Controller, Richard Henderson, 2022/04/21