From: Jason Chien <jason.chien@sifive.com>
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: "Jason Chien" <jason.chien@sifive.com>,
"Frank Chang" <frank.chang@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Alistair Francis" <alistair.francis@wdc.com>,
"Bin Meng" <bin.meng@windriver.com>,
"Weiwei Li" <liwei1518@gmail.com>,
"Daniel Henrique Barboza" <dbarboza@ventanamicro.com>,
"Liu Zhiwei" <zhiwei_liu@linux.alibaba.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Junqiang Wang" <wangjunqiang@iscas.ac.cn>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [PATCH v2] target/riscv: Update $ra with current $pc in trans_cm_jalt()
Date: Wed, 7 Feb 2024 16:18:08 +0800 [thread overview]
Message-ID: <20240207081820.28559-1-jason.chien@sifive.com> (raw)
The original implementation sets $pc to the address read from the jump
vector table first and links $ra with the address of the next instruction
after the updated $pc. After jumping to the updated $pc and executing the
next ret instruction, the program jumps to $ra, which is in the same
function currently executing, which results in an infinite loop.
This commit stores the jump address in a temporary, updates $ra with the
current $pc, and copies the temporary to $pc.
Signed-off-by: Jason Chien <jason.chien@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
---
target/riscv/insn_trans/trans_rvzce.c.inc | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/target/riscv/insn_trans/trans_rvzce.c.inc b/target/riscv/insn_trans/trans_rvzce.c.inc
index 2d992e14c4..cd234ad960 100644
--- a/target/riscv/insn_trans/trans_rvzce.c.inc
+++ b/target/riscv/insn_trans/trans_rvzce.c.inc
@@ -293,12 +293,14 @@ static bool trans_cm_jalt(DisasContext *ctx, arg_cm_jalt *a)
{
REQUIRE_ZCMT(ctx);
+ TCGv addr = tcg_temp_new();
+
/*
* Update pc to current for the non-unwinding exception
* that might come from cpu_ld*_code() in the helper.
*/
gen_update_pc(ctx, 0);
- gen_helper_cm_jalt(cpu_pc, tcg_env, tcg_constant_i32(a->index));
+ gen_helper_cm_jalt(addr, tcg_env, tcg_constant_i32(a->index));
/* c.jt vs c.jalt depends on the index. */
if (a->index >= 32) {
@@ -307,6 +309,8 @@ static bool trans_cm_jalt(DisasContext *ctx, arg_cm_jalt *a)
gen_set_gpr(ctx, xRA, succ_pc);
}
+ tcg_gen_mov_tl(cpu_pc, addr);
+
tcg_gen_lookup_and_goto_ptr();
ctx->base.is_jmp = DISAS_NORETURN;
return true;
--
2.43.0
next reply other threads:[~2024-02-07 8:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 8:18 Jason Chien [this message]
2024-02-08 19:31 ` [PATCH v2] target/riscv: Update $ra with current $pc in trans_cm_jalt() Richard Henderson
2024-02-15 9:53 ` Alistair Francis
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