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linux-user/nios2: Properly emulate EXCP_TRAP

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The real kernel has to load the instruction and extract
the imm5 field; for qemu, modify the translator to do this.

The use of R_AT for this in cpu_loop was a bug.  Handle
the other trap numbers as per the kernel's trap_table.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211221025012.1057923-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson 2021-12-20 18:50:06 -08:00 • committed by Laurent Vivier
parent e13685a6e5
commit 87d7bfdba1
3 changed files with 39 additions and 20 deletions
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17
target/nios2/translate.c
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@ -636,6 +636,21 @@ static void divu(DisasContext *dc, uint32_t code, uint32_t flags)
tcg_temp_free(t0);
}
static void trap(DisasContext *dc, uint32_t code, uint32_t flags)
{
#ifdef CONFIG_USER_ONLY
/*
* The imm5 field is not stored anywhere on real hw; the kernel
* has to load the insn and extract the field. But we can make
* things easier for cpu_loop if we pop this into env->error_code.
*/
R_TYPE(instr, code);
tcg_gen_st_i32(tcg_constant_i32(instr.imm5), cpu_env,
offsetof(CPUNios2State, error_code));
#endif
t_gen_helper_raise_exception(dc, EXCP_TRAP);
}
static const Nios2Instruction r_type_instructions[] = {
INSTRUCTION_ILLEGAL(),
INSTRUCTION(eret), /* eret */
@ -682,7 +697,7 @@ static const Nios2Instruction r_type_instructions[] = {
INSTRUCTION_ILLEGAL(),
INSTRUCTION_ILLEGAL(),
INSTRUCTION_ILLEGAL(),
INSTRUCTION_FLG(gen_excp, EXCP_TRAP), /* trap */
INSTRUCTION(trap), /* trap */
INSTRUCTION(wrctl), /* wrctl */
INSTRUCTION_ILLEGAL(),
INSTRUCTION_FLG(gen_cmpxx, TCG_COND_LTU), /* cmpltu */