target/riscv: do not call GETPC() in check_ret_from_m_mode()

target/riscv: do not call GETPC() in check_ret_from_m_mode()

GETPC() should always be called from the top level helper, e.g. the
first helper that is called by the translation code. We stopped doing
that in commit 3157a553ec, and then we introduced problems when
unwinding the exceptions being thrown by helper_mret(), as reported by
[1].

Call GETPC() at the top level helper and pass the value along.

[1] https://gitlab.com/qemu-project/qemu/-/issues/3020

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: 3157a553ec ("target/riscv: Add Smrnmi mnret instruction")
Closes: https://gitlab.com/qemu-project/qemu/-/issues/3020
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250714133739.1248296-1-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
(cherry picked from commit 16aa7771afeac422dcf7be2833d5426da6b814fa)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>