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[Qemu-devel] [PATCH 15/15] x86: Debug register emulation
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH 15/15] x86: Debug register emulation |
Date: |
Mon, 23 Jun 2008 16:33:53 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Built on top of previously enhanced breakpoint/watchpoint support, this
patch adds full debug register emulation for the x86 architecture.
Many corner cases were considered, and the result was successfully
tested inside a Linux guest with gdb, but I won't be surprised if one
or two scenarios still behave differently in reality.
Signed-off-by: Jan Kiszka <address@hidden>
---
linux-user/main.c | 4 -
target-i386/cpu.h | 33 +++++++++++++
target-i386/helper.c | 118 ++++++++++++++++++++++++++++++++++++------------
target-i386/op_helper.c | 79 ++++++++++++++++++++++++++++++--
4 files changed, 198 insertions(+), 36 deletions(-)
Index: b/linux-user/main.c
===================================================================
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -403,7 +403,7 @@ void cpu_loop(CPUX86State *env)
queue_signal(env, info.si_signo, &info);
}
break;
- case EXCP01_SSTP:
+ case EXCP01_DB:
case EXCP03_INT3:
#ifndef TARGET_X86_64
if (env->eflags & VM_MASK) {
@@ -413,7 +413,7 @@ void cpu_loop(CPUX86State *env)
{
info.si_signo = SIGTRAP;
info.si_errno = 0;
- if (trapnr == EXCP01_SSTP) {
+ if (trapnr == EXCP01_DB) {
info.si_code = TARGET_TRAP_BRKPT;
info._sifields._sigfault._addr = env->eip;
} else {
Index: b/target-i386/cpu.h
===================================================================
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -199,6 +199,16 @@
#define CR4_OSFXSR_MASK (1 << 9)
#define CR4_OSXMMEXCPT_MASK (1 << 10)
+#define DR6_BD (1 << 13)
+#define DR6_BS (1 << 14)
+#define DR6_BT (1 << 15)
+#define DR6_FIXED_1 0xffff0ff0
+
+#define DR7_GD (1 << 13)
+#define DR7_TYPE_SHIFT 16
+#define DR7_LEN_SHIFT 18
+#define DR7_FIXED_1 0x00000400
+
#define PG_PRESENT_BIT 0
#define PG_RW_BIT 1
#define PG_USER_BIT 2
@@ -334,7 +344,7 @@
#define CPUID_EXT3_SKINIT (1 << 12)
#define EXCP00_DIVZ 0
-#define EXCP01_SSTP 1
+#define EXCP01_DB 1
#define EXCP02_NMI 2
#define EXCP03_INT3 3
#define EXCP04_INTO 4
@@ -566,6 +576,10 @@ typedef struct CPUX86State {
int exception_is_int;
target_ulong exception_next_eip;
target_ulong dr[8]; /* debug registers */
+ union {
+ CPUBreakpoint *cpu_breakpoint[4];
+ CPUWatchpoint *cpu_watchpoint[4];
+ }; /* break/watchpoints for dr[0..3] */
uint32_t smbase;
int interrupt_request;
int user_mode_only; /* user mode only simulation */
@@ -753,6 +767,23 @@ static inline void cpu_clone_regs(CPUSta
}
#endif
+static inline int hw_breakpoint_enabled(unsigned long dr7, int index)
+{
+ return (dr7 >> (index * 2)) & 3;
+}
+
+static inline int hw_breakpoint_type(unsigned long dr7, int index)
+{
+ return (dr7 >> (DR7_TYPE_SHIFT + (index * 2))) & 3;
+}
+
+static inline int hw_breakpoint_len(unsigned long dr7, int index)
+{
+ return ((dr7 >> (DR7_LEN_SHIFT + (index * 2))) & 3) + 1;
+}
+
+int check_hw_breakpoints(CPUState *env, int force_dr6_update);
+
#include "cpu-all.h"
#include "svm.h"
Index: b/target-i386/helper.c
===================================================================
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -32,8 +32,6 @@
//#define DEBUG_MMU
-static int cpu_x86_register (CPUX86State *env, const char *cpu_model);
-
static void add_flagname_to_bitmaps(char *flagname, uint32_t *features,
uint32_t *ext_features,
uint32_t *ext2_features,
@@ -91,33 +89,6 @@ static void add_flagname_to_bitmaps(char
fprintf(stderr, "CPU feature %s not found\n", flagname);
}
-CPUX86State *cpu_x86_init(const char *cpu_model)
-{
- CPUX86State *env;
- static int inited;
-
- env = qemu_mallocz(sizeof(CPUX86State));
- if (!env)
- return NULL;
- cpu_exec_init(env);
- env->cpu_model_str = cpu_model;
-
- /* init various static tables */
- if (!inited) {
- inited = 1;
- optimize_flags_init();
- }
- if (cpu_x86_register(env, cpu_model) < 0) {
- cpu_x86_close(env);
- return NULL;
- }
- cpu_reset(env);
-#ifdef USE_KQEMU
- kqemu_init(env);
-#endif
- return env;
-}
-
typedef struct x86_def_t {
const char *name;
uint32_t level;
@@ -429,6 +400,12 @@ void cpu_reset(CPUX86State *env)
env->fpuc = 0x37f;
env->mxcsr = 0x1f80;
+
+ memset(env->dr, 0, sizeof(env->dr));
+ env->dr[6] = DR6_FIXED_1;
+ env->dr[7] = DR7_FIXED_1;
+ cpu_breakpoint_remove_all(env, BP_CPU);
+ cpu_watchpoint_remove_all(env, BP_CPU);
}
void cpu_x86_close(CPUX86State *env)
@@ -1223,4 +1200,87 @@ target_phys_addr_t cpu_get_phys_page_deb
paddr = (pte & TARGET_PAGE_MASK) + page_offset;
return paddr;
}
+
+int check_hw_breakpoints(CPUState *env, int force_dr6_update)
+{
+ target_ulong dr6;
+ int reg, type;
+ int hit_enabled = 0;
+
+ dr6 = env->dr[6] & ~0xf;
+ for (reg = 0; reg < 4; reg++) {
+ type = hw_breakpoint_type(env->dr[7], reg);
+ if ((type == 0 && env->dr[reg] == env->eip) ||
+ ((type & 1) && env->cpu_watchpoint[reg] &&
+ (env->cpu_watchpoint[reg]->flags & BP_WATCHPOINT_HIT))) {
+ dr6 |= 1 << reg;
+ if (hw_breakpoint_enabled(env->dr[7], reg))
+ hit_enabled = 1;
+ }
+ }
+ if (hit_enabled || force_dr6_update)
+ env->dr[6] = dr6;
+ return hit_enabled;
+}
+
+static CPUDebugExcpHandler *prev_debug_excp_handler;
+
+void raise_exception(int exception_index);
+
+static void breakpoint_handler(CPUState *env)
+{
+ CPUBreakpoint *bp;
+
+ if (env->watchpoint_hit) {
+ if (env->watchpoint_hit->flags & BP_CPU) {
+ env->watchpoint_hit = NULL;
+ if (check_hw_breakpoints(env, 0))
+ raise_exception(EXCP01_DB);
+ else
+ cpu_resume_from_signal(env, NULL);
+ }
+ } else {
+ for (bp = env->breakpoints; bp != NULL; bp = bp->next)
+ if (bp->pc == env->eip) {
+ if (bp->flags & BP_CPU) {
+ check_hw_breakpoints(env, 1);
+ raise_exception(EXCP01_DB);
+ }
+ break;
+ }
+ }
+ if (prev_debug_excp_handler)
+ prev_debug_excp_handler(env);
+}
#endif /* !CONFIG_USER_ONLY */
+
+CPUX86State *cpu_x86_init(const char *cpu_model)
+{
+ CPUX86State *env;
+ static int inited;
+
+ env = qemu_mallocz(sizeof(CPUX86State));
+ if (!env)
+ return NULL;
+ cpu_exec_init(env);
+ env->cpu_model_str = cpu_model;
+
+ /* init various static stuff */
+ if (!inited) {
+ inited = 1;
+ optimize_flags_init();
+#ifndef CONFIG_USER_ONLY
+ prev_debug_excp_handler =
+ cpu_set_debug_excp_handler(breakpoint_handler);
+#endif
+ }
+ if (cpu_x86_register(env, cpu_model) < 0) {
+ cpu_x86_close(env);
+ return NULL;
+ }
+ cpu_reset(env);
+#ifdef USE_KQEMU
+ kqemu_init(env);
+#endif
+ return env;
+}
Index: b/target-i386/op_helper.c
===================================================================
--- a/target-i386/op_helper.c
+++ b/target-i386/op_helper.c
@@ -94,6 +94,53 @@ const CPU86_LDouble f15rk[7] =
3.32192809488736234781L, /*l2t*/
};
+static void hw_breakpoint_insert(int index)
+{
+ int type, err = 0;
+
+ switch (hw_breakpoint_type(env->dr[7], index)) {
+ case 0:
+ if (hw_breakpoint_enabled(env->dr[7], index))
+ err = cpu_breakpoint_insert(env, env->dr[index], BP_CPU,
+ &env->cpu_breakpoint[index]);
+ break;
+ case 1:
+ type = BP_CPU | BP_MEM_WRITE;
+ goto insert_wp;
+ case 2:
+ /* No support for I/O watchpoints yet */
+ break;
+ case 3:
+ type = BP_CPU | BP_MEM_ACCESS;
+ insert_wp:
+ err = cpu_watchpoint_insert(env, env->dr[index],
+ hw_breakpoint_len(env->dr[7], index),
+ type, &env->cpu_watchpoint[index]);
+ break;
+ }
+ if (err)
+ env->cpu_breakpoint[index] = NULL;
+}
+
+static void hw_breakpoint_remove(int index)
+{
+ if (!env->cpu_breakpoint[index])
+ return;
+ switch (hw_breakpoint_type(env->dr[7], index)) {
+ case 0:
+ if (hw_breakpoint_enabled(env->dr[7], index))
+ cpu_breakpoint_remove_by_ref(env, env->cpu_breakpoint[index]);
+ break;
+ case 1:
+ case 3:
+ cpu_watchpoint_remove_by_ref(env, env->cpu_watchpoint[index]);
+ break;
+ case 2:
+ /* No support for I/O watchpoints yet */
+ break;
+ }
+}
+
/* broken thread support */
spinlock_t global_cpu_lock = SPIN_LOCK_UNLOCKED;
@@ -496,6 +543,15 @@ static void switch_tss(int tss_selector,
/* XXX: different exception if CALL ? */
raise_exception_err(EXCP0D_GPF, 0);
}
+
+ /* reset local breakpoints */
+ if (env->dr[7] & 0x55) {
+ for (i = 0; i < 4; i++) {
+ if (hw_breakpoint_enabled(env->dr[7], i) == 0x1)
+ hw_breakpoint_remove(i);
+ }
+ env->dr[7] &= ~0x55;
+ }
}
/* check if Port I/O is allowed in TSS */
@@ -1875,8 +1931,11 @@ void helper_cmpxchg16b(target_ulong a0)
void helper_single_step(void)
{
- env->dr[6] |= 0x4000;
- raise_exception(EXCP01_SSTP);
+#ifndef CONFIG_USER_ONLY
+ check_hw_breakpoints(env, 1);
+#endif
+ env->dr[6] |= DR6_BS;
+ raise_exception(EXCP01_DB);
}
void helper_cpuid(void)
@@ -2991,10 +3050,22 @@ void helper_clts(void)
env->hflags &= ~HF_TS_MASK;
}
-/* XXX: do more */
void helper_movl_drN_T0(int reg, target_ulong t0)
{
- env->dr[reg] = t0;
+ int i;
+
+ if (reg < 4) {
+ hw_breakpoint_remove(reg);
+ env->dr[reg] = t0;
+ hw_breakpoint_insert(reg);
+ } else if (reg == 7) {
+ for (i = 0; i < 4; i++)
+ hw_breakpoint_remove(i);
+ env->dr[7] = t0;
+ for (i = 0; i < 4; i++)
+ hw_breakpoint_insert(i);
+ } else
+ env->dr[reg] = t0;
}
void helper_invlpg(target_ulong addr)
- [Qemu-devel] [PATCH 8/15] Respect length of watchpoints, (continued)
- [Qemu-devel] [PATCH 8/15] Respect length of watchpoints, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 2/15] Introduce SSTEP_INTERNAL, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 12/15] Introduce BP_WATCHPOINT_HIT flag, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 5/15] Return appropriate watch message to gdb, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 6/15] Refactor and enhance break/watchpoint API - v5, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 14/15] Introduce BP_CPU as a breakpoint type, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 1/15] Convert remaining __builtin_expect to likely/unlikely, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 7/15] Extend mem_write_* to mem_access_*, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 13/15] Add debug exception hook, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 3/15] Replace CF_SINGLE_INSN with SSTEP_INTERNAL - v2, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 15/15] x86: Debug register emulation,
Jan Kiszka <=
- [Qemu-devel] [PATCH 10/15] Remove premature memop TB terminations, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 9/15] Restore pc on watchpoint hits, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 11/15] Improve debugging of SMP guests - v2, Jan Kiszka, 2008/06/23
- [Qemu-devel] [PATCH 4/15] Remove unused TB cflags, Jan Kiszka, 2008/06/23