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target/microblaze: Collected fixes for env->iflags 

There are several problems here that can result in soft lockup,
depending on exactly where an interrupt or exception is delivered:

Include BIMM_FLAG in IFLAGS_TB_MASK, since it needs to follow D_FLAG.
Ensure that iflags is 0 when entering an interrupt/exception handler.
Add mb_cpu_synchronize_from_tb to restore iflags from tb->flags.
The change to t_sync_flags is cosmetic, but makes the code clearer.

This fixes the reported regression in acceptance/replay_kernel.py.

Fixes: 683a247ed7 ("target/microblaze: Store "current" iflags in insn_start")
Tested-by: Thomas Huth <thuth@redhat.com>
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200904190842.2282109-2-richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Richard Henderson 2020-09-04 12:08:24 -07:00 committed by Thomas Huth
parent cc9962d8ea
commit 88e74b6122
4 changed files with 26 additions and 9 deletions
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11
target/microblaze/cpu.c
View File

@ -80,6 +80,16 @@ static void mb_cpu_set_pc(CPUState *cs, vaddr value)
MicroBlazeCPU *cpu = MICROBLAZE_CPU(cs);
cpu->env.pc = value;
/* Ensure D_FLAG and IMM_FLAG are clear for the new PC */
cpu->env.iflags = 0;
}
static void mb_cpu_synchronize_from_tb(CPUState *cs, TranslationBlock *tb)
{
MicroBlazeCPU *cpu = MICROBLAZE_CPU(cs);
cpu->env.pc = tb->pc;
cpu->env.iflags = tb->flags & IFLAGS_TB_MASK;
}
static bool mb_cpu_has_work(CPUState *cs)
@ -321,6 +331,7 @@ static void mb_cpu_class_init(ObjectClass *oc, void *data)
cc->cpu_exec_interrupt = mb_cpu_exec_interrupt;
cc->dump_state = mb_cpu_dump_state;
cc->set_pc = mb_cpu_set_pc;
cc->synchronize_from_tb = mb_cpu_synchronize_from_tb;
cc->gdb_read_register = mb_cpu_gdb_read_register;
cc->gdb_write_register = mb_cpu_gdb_write_register;
cc->tlb_fill = mb_cpu_tlb_fill;

3
target/microblaze/cpu.h
View File

@ -270,7 +270,8 @@ struct CPUMBState {
#define D_FLAG (1 << 19) /* Bit in ESR. */
/* TB dependent CPUMBState. */
#define IFLAGS_TB_MASK (D_FLAG | IMM_FLAG | DRTI_FLAG | DRTE_FLAG | DRTB_FLAG)
#define IFLAGS_TB_MASK (D_FLAG | BIMM_FLAG | IMM_FLAG | \
DRTI_FLAG | DRTE_FLAG | DRTB_FLAG)
#define MSR_TB_MASK (MSR_UM | MSR_VM | MSR_EE)
uint32_t iflags;

17
target/microblaze/helper.c
View File

@ -113,7 +113,10 @@ void mb_cpu_do_interrupt(CPUState *cs)
uint32_t t, msr = mb_cpu_read_msr(env);
/* IMM flag cannot propagate across a branch and into the dslot. */
assert(!((env->iflags & D_FLAG) && (env->iflags & IMM_FLAG)));
assert((env->iflags & (D_FLAG | IMM_FLAG)) != (D_FLAG | IMM_FLAG));
/* BIMM flag cannot be set without D_FLAG. */
assert((env->iflags & (D_FLAG | BIMM_FLAG)) != BIMM_FLAG);
/* RTI flags are private to translate. */
assert(!(env->iflags & (DRTI_FLAG | DRTE_FLAG | DRTB_FLAG)));
env->res_addr = RES_ADDR_NONE;
switch (cs->exception_index) {
@ -146,7 +149,7 @@ void mb_cpu_do_interrupt(CPUState *cs)
env->pc, env->ear,
env->esr, env->iflags);
log_cpu_state_mask(CPU_LOG_INT, cs, 0);
env->iflags &= ~(IMM_FLAG | D_FLAG);
env->iflags = 0;
env->pc = cpu->cfg.base_vectors + 0x20;
break;
@ -186,14 +189,14 @@ void mb_cpu_do_interrupt(CPUState *cs)
"exception at pc=%x ear=%" PRIx64 " iflags=%x\n",
env->pc, env->ear, env->iflags);
log_cpu_state_mask(CPU_LOG_INT, cs, 0);
env->iflags &= ~(IMM_FLAG | D_FLAG);
env->iflags = 0;
env->pc = cpu->cfg.base_vectors + 0x20;
break;
case EXCP_IRQ:
assert(!(msr & (MSR_EIP | MSR_BIP)));
assert(msr & MSR_IE);
assert(!(env->iflags & D_FLAG));
assert(!(env->iflags & (D_FLAG | IMM_FLAG)));
t = (msr & (MSR_VM | MSR_UM)) << 1;
@ -226,13 +229,14 @@ void mb_cpu_do_interrupt(CPUState *cs)
mb_cpu_write_msr(env, msr);
env->regs[14] = env->pc;
env->iflags = 0;
env->pc = cpu->cfg.base_vectors + 0x10;
//log_cpu_state_mask(CPU_LOG_INT, cs, 0);
break;
case EXCP_HW_BREAK:
assert(!(env->iflags & IMM_FLAG));
assert(!(env->iflags & D_FLAG));
assert(!(env->iflags & (D_FLAG | IMM_FLAG)));
t = (msr & (MSR_VM | MSR_UM)) << 1;
qemu_log_mask(CPU_LOG_INT,
"break at pc=%x msr=%x %x iflags=%x\n",
@ -242,6 +246,7 @@ void mb_cpu_do_interrupt(CPUState *cs)
msr |= t;
msr |= MSR_BIP;
env->regs[16] = env->pc;
env->iflags = 0;
env->pc = cpu->cfg.base_vectors + 0x18;
mb_cpu_write_msr(env, msr);
break;

4
target/microblaze/translate.c
View File

@ -91,8 +91,8 @@ static int typeb_imm(DisasContext *dc, int x)
static void t_sync_flags(DisasContext *dc)
{
/* Synch the tb dependent flags between translator and runtime. */
if ((dc->tb_flags ^ dc->base.tb->flags) & ~MSR_TB_MASK) {
tcg_gen_movi_i32(cpu_iflags, dc->tb_flags & ~MSR_TB_MASK);
if ((dc->tb_flags ^ dc->base.tb->flags) & IFLAGS_TB_MASK) {
tcg_gen_movi_i32(cpu_iflags, dc->tb_flags & IFLAGS_TB_MASK);
}
}