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s390x/tcg: Implement MONITOR CALL 

Recent upstream Linux uses the MONITOR CALL instruction for things like
BUG_ON() and WARN_ON(). We currently inject an operation exception when
we hit a MONITOR CALL instruction - which is wrong, as the instruction
is not glued to specific CPU features.

Doing a simple WARN_ON_ONCE() currently results in a panic:
  [   18.162801] illegal operation: 0001 ilc:2 [#1] SMP
  [   18.162889] Modules linked in:
  [...]
  [   18.165476] Kernel panic - not syncing: Fatal exception: panic_on_oops

With a proper implementation, we now get:
  [   18.242754] ------------[ cut here ]------------
  [   18.242855] WARNING: CPU: 7 PID: 1 at init/main.c:1534 [...]
  [   18.242919] Modules linked in:
  [...]
  [   18.246262] ---[ end trace a420477d71dc97b4 ]---
  [   18.259014] Freeing unused kernel memory: 4220K

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200918085122.26132-1-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
master
David Hildenbrand 2020-09-18 10:51:22 +02:00 committed by Cornelia Huck
parent fabdada935
commit 20d143e2ca
4 changed files with 48 additions and 0 deletions
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23
target/s390x/excp_helper.c
View File

@ -610,4 +610,27 @@ void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
tcg_s390_program_interrupt(env, PGM_SPECIFICATION, retaddr);
}
static void QEMU_NORETURN monitor_event(CPUS390XState *env,
uint64_t monitor_code,
uint8_t monitor_class, uintptr_t ra)
{
/* Store the Monitor Code and the Monitor Class Number into the lowcore */
stq_phys(env_cpu(env)->as,
env->psa + offsetof(LowCore, monitor_code), monitor_code);
stw_phys(env_cpu(env)->as,
env->psa + offsetof(LowCore, mon_class_num), monitor_class);
tcg_s390_program_interrupt(env, PGM_MONITOR, ra);
}
void HELPER(monitor_call)(CPUS390XState *env, uint64_t monitor_code,
uint32_t monitor_class)
{
g_assert(monitor_class <= 0xff);
if (env->cregs[8] & (0x8000 >> monitor_class)) {
monitor_event(env, monitor_code, monitor_class, GETPC());
}
}
#endif /* CONFIG_USER_ONLY */

1
target/s390x/helper.h
View File

@ -349,4 +349,5 @@ DEF_HELPER_3(sic, void, env, i64, i64)
DEF_HELPER_3(rpcit, void, env, i32, i32)
DEF_HELPER_5(pcistb, void, env, i32, i32, i64, i32)
DEF_HELPER_4(mpcifc, void, env, i32, i64, i32)
DEF_HELPER_3(monitor_call, void, env, i64, i32)
#endif

3
target/s390x/insn-data.def
View File

@ -617,6 +617,9 @@
C(0x9a00, LAM, RS_a, Z, 0, a2, 0, 0, lam, 0)
C(0xeb9a, LAMY, RSY_a, LD, 0, a2, 0, 0, lam, 0)
/* MONITOR CALL */
C(0xaf00, MC, SI, Z, la1, 0, 0, 0, mc, 0)
/* MOVE */
C(0xd200, MVC, SS_a, Z, la1, a2, 0, 0, mvc, 0)
C(0xe544, MVHHI, SIL, GIE, la1, i2, 0, m1_16, mov2, 0)

21
target/s390x/translate.c
View File

@ -3302,6 +3302,27 @@ static DisasJumpType op_lcbb(DisasContext *s, DisasOps *o)
return DISAS_NEXT;
}
static DisasJumpType op_mc(DisasContext *s, DisasOps *o)
{
#if !defined(CONFIG_USER_ONLY)
TCGv_i32 i2;
#endif
const uint16_t monitor_class = get_field(s, i2);
if (monitor_class & 0xff00) {
gen_program_exception(s, PGM_SPECIFICATION);
return DISAS_NORETURN;
}
#if !defined(CONFIG_USER_ONLY)
i2 = tcg_const_i32(monitor_class);
gen_helper_monitor_call(cpu_env, o->addr1, i2);
tcg_temp_free_i32(i2);
#endif
/* Defaults to a NOP. */
return DISAS_NEXT;
}
static DisasJumpType op_mov2(DisasContext *s, DisasOps *o)
{
o->out = o->in2;