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Merge remote-tracking branch 'remotes/vivier/tags/m68k-for-6.1-pull-r…
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…equest' into staging

m68k pull request 20210526

implement m68k "any instruction" trace mode

# gpg: Signature made Wed 26 May 2021 20:56:58 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/m68k-for-6.1-pull-request:
  target/m68k: implement m68k "any instruction" trace mode
  target/m68k: introduce gen_singlestep_exception() function
  target/m68k: call gen_raise_exception() directly if single-stepping in gen_jmp_tb()
  target/m68k: introduce is_singlestepping() function

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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@pm215
pm215 committed May 27, 2021
2 parents c8616fc + 5e50c6c commit 7258034
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Showing 2 changed files with 51 additions and 8 deletions.
8 changes: 8 additions & 0 deletions target/m68k/cpu.h
View file
Expand Up @@ -230,6 +230,9 @@ typedef enum {
#define SR_T_SHIFT 14
#define SR_T 0xc000

#define M68K_SR_TRACE(sr) ((sr & SR_T) >> SR_T_SHIFT)
#define M68K_SR_TRACE_ANY_INS 0x2

#define M68K_SSP 0
#define M68K_USP 1
#define M68K_ISP 2
Expand Down Expand Up @@ -590,6 +593,8 @@ typedef M68kCPU ArchCPU;
#define TB_FLAGS_SFC_S (1 << TB_FLAGS_SFC_S_BIT)
#define TB_FLAGS_DFC_S_BIT 15
#define TB_FLAGS_DFC_S (1 << TB_FLAGS_DFC_S_BIT)
#define TB_FLAGS_TRACE 16
#define TB_FLAGS_TRACE_BIT (1 << TB_FLAGS_TRACE)

static inline void cpu_get_tb_cpu_state(CPUM68KState *env, target_ulong *pc,
target_ulong *cs_base, uint32_t *flags)
Expand All @@ -602,6 +607,9 @@ static inline void cpu_get_tb_cpu_state(CPUM68KState *env, target_ulong *pc,
*flags |= (env->sfc << (TB_FLAGS_SFC_S_BIT - 2)) & TB_FLAGS_SFC_S;
*flags |= (env->dfc << (TB_FLAGS_DFC_S_BIT - 2)) & TB_FLAGS_DFC_S;
}
if (M68K_SR_TRACE(env->sr) == M68K_SR_TRACE_ANY_INS) {
*flags |= TB_FLAGS_TRACE;
}
}

void dump_mmu(CPUM68KState *env);
Expand Down
51 changes: 43 additions & 8 deletions target/m68k/translate.c
View file
Expand Up @@ -124,6 +124,7 @@ typedef struct DisasContext {
#define MAX_TO_RELEASE 8
int release_count;
TCGv release[MAX_TO_RELEASE];
bool ss_active;
} DisasContext;

static void init_release_array(DisasContext *s)
Expand Down Expand Up @@ -194,6 +195,18 @@ static void do_writebacks(DisasContext *s)
}
}

static bool is_singlestepping(DisasContext *s)
{
/*
* Return true if we are singlestepping either because of
* architectural singlestep or QEMU gdbstub singlestep. This does
* not include the command line '-singlestep' mode which is rather
* misnamed as it only means "one instruction per TB" and doesn't
* affect the code we generate.
*/
return s->base.singlestep_enabled || s->ss_active;
}

/* is_jmp field values */
#define DISAS_JUMP DISAS_TARGET_0 /* only pc was modified dynamically */
#define DISAS_EXIT DISAS_TARGET_1 /* cpu state was modified dynamically */
Expand Down Expand Up @@ -308,6 +321,20 @@ static void gen_exception(DisasContext *s, uint32_t dest, int nr)
s->base.is_jmp = DISAS_NORETURN;
}

static void gen_singlestep_exception(DisasContext *s)
{
/*
* Generate the right kind of exception for singlestep, which is
* either the architectural singlestep or EXCP_DEBUG for QEMU's
* gdb singlestepping.
*/
if (s->ss_active) {
gen_raise_exception(EXCP_TRACE);
} else {
gen_raise_exception(EXCP_DEBUG);
}
}

static inline void gen_addr_fault(DisasContext *s)
{
gen_exception(s, s->base.pc_next, EXCP_ADDRESS);
Expand Down Expand Up @@ -1506,8 +1533,10 @@ static inline bool use_goto_tb(DisasContext *s, uint32_t dest)
/* Generate a jump to an immediate address. */
static void gen_jmp_tb(DisasContext *s, int n, uint32_t dest)
{
if (unlikely(s->base.singlestep_enabled)) {
gen_exception(s, dest, EXCP_DEBUG);
if (unlikely(is_singlestepping(s))) {
update_cc_op(s);
tcg_gen_movi_i32(QREG_PC, dest);
gen_singlestep_exception(s);
} else if (use_goto_tb(s, dest)) {
tcg_gen_goto_tb(n);
tcg_gen_movi_i32(QREG_PC, dest);
Expand Down Expand Up @@ -6172,6 +6201,12 @@ static void m68k_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cpu)
dc->done_mac = 0;
dc->writeback_mask = 0;
init_release_array(dc);

dc->ss_active = (M68K_SR_TRACE(env->sr) == M68K_SR_TRACE_ANY_INS);
/* If architectural single step active, limit to 1 */
if (is_singlestepping(dc)) {
dc->base.max_insns = 1;
}
}

static void m68k_tr_tb_start(DisasContextBase *dcbase, CPUState *cpu)
Expand Down Expand Up @@ -6245,17 +6280,17 @@ static void m68k_tr_tb_stop(DisasContextBase *dcbase, CPUState *cpu)
break;
case DISAS_TOO_MANY:
update_cc_op(dc);
if (dc->base.singlestep_enabled) {
if (is_singlestepping(dc)) {
tcg_gen_movi_i32(QREG_PC, dc->pc);
gen_raise_exception(EXCP_DEBUG);
gen_singlestep_exception(dc);
} else {
gen_jmp_tb(dc, 0, dc->pc);
}
break;
case DISAS_JUMP:
/* We updated CC_OP and PC in gen_jmp/gen_jmp_im. */
if (dc->base.singlestep_enabled) {
gen_raise_exception(EXCP_DEBUG);
if (is_singlestepping(dc)) {
gen_singlestep_exception(dc);
} else {
tcg_gen_lookup_and_goto_ptr();
}
Expand All @@ -6265,8 +6300,8 @@ static void m68k_tr_tb_stop(DisasContextBase *dcbase, CPUState *cpu)
* We updated CC_OP and PC in gen_exit_tb, but also modified
* other state that may require returning to the main loop.
*/
if (dc->base.singlestep_enabled) {
gen_raise_exception(EXCP_DEBUG);
if (is_singlestepping(dc)) {
gen_singlestep_exception(dc);
} else {
tcg_gen_exit_tb(NULL, 0);
}
Expand Down

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