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-rw-r--r--i386/i386/db_trace.c2
-rw-r--r--i386/i386/debug_i386.c2
-rw-r--r--i386/i386/i386asm.sym2
-rw-r--r--i386/i386/pcb.c12
-rw-r--r--i386/i386/thread.h22
-rw-r--r--x86_64/locore.S228
6 files changed, 108 insertions, 160 deletions
diff --git a/i386/i386/db_trace.c b/i386/i386/db_trace.c
index 2b6ad741..8bd86fa5 100644
--- a/i386/i386/db_trace.c
+++ b/i386/i386/db_trace.c
@@ -78,8 +78,6 @@ struct db_variable db_regs[] = {
{ "r13",(long *)&ddb_regs.r13, db_i386_reg_value },
{ "r14",(long *)&ddb_regs.r14, db_i386_reg_value },
{ "r15",(long *)&ddb_regs.r15, db_i386_reg_value },
- { "fsb",(long *)&ddb_regs.fsbase,db_i386_reg_value },
- { "gsb",(long *)&ddb_regs.gsbase,db_i386_reg_value },
#endif
};
struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
diff --git a/i386/i386/debug_i386.c b/i386/i386/debug_i386.c
index b5465796..41d032e3 100644
--- a/i386/i386/debug_i386.c
+++ b/i386/i386/debug_i386.c
@@ -40,8 +40,6 @@ void dump_ss(const struct i386_saved_state *st)
st->r8, st->r9, st->r10, st->r11);
printf("R12 %016lx R13 %016lx R14 %016lx R15 %016lx\n",
st->r12, st->r13, st->r14, st->r15);
- printf("FSBASE %016lx GSBASE %016lx\n",
- st->fsbase, st->gsbase);
printf("RIP %016lx EFLAGS %08lx\n", st->eip, st->efl);
#else
printf("EAX %08lx EBX %08lx ECX %08lx EDX %08lx\n",
diff --git a/i386/i386/i386asm.sym b/i386/i386/i386asm.sym
index fd0be557..1b9b40bb 100644
--- a/i386/i386/i386asm.sym
+++ b/i386/i386/i386asm.sym
@@ -108,8 +108,6 @@ offset i386_saved_state r r12
offset i386_saved_state r r13
offset i386_saved_state r r14
offset i386_saved_state r r15
-offset i386_saved_state r fsbase
-offset i386_saved_state r gsbase
#endif
offset i386_interrupt_state i eip
diff --git a/i386/i386/pcb.c b/i386/i386/pcb.c
index d1c5fb50..1cf87eb1 100644
--- a/i386/i386/pcb.c
+++ b/i386/i386/pcb.c
@@ -229,8 +229,8 @@ void switch_ktss(pcb_t pcb)
#endif /* MACH_PV_DESCRIPTORS */
#if defined(__x86_64__) && !defined(USER32)
- wrmsr(MSR_REG_FSBASE, pcb->iss.fsbase);
- wrmsr(MSR_REG_GSBASE, pcb->iss.gsbase);
+ wrmsr(MSR_REG_FSBASE, pcb->ims.sbs.fsbase);
+ wrmsr(MSR_REG_GSBASE, pcb->ims.sbs.gsbase);
#endif
db_load_context(pcb);
@@ -687,8 +687,8 @@ kern_return_t thread_setstatus(
return KERN_INVALID_ARGUMENT;
state = (struct i386_fsgs_base_state *) tstate;
- thread->pcb->iss.fsbase = state->fs_base;
- thread->pcb->iss.gsbase = state->gs_base;
+ thread->pcb->ims.sbs.fsbase = state->fs_base;
+ thread->pcb->ims.sbs.gsbase = state->gs_base;
if (thread == current_thread()) {
wrmsr(MSR_REG_FSBASE, state->fs_base);
wrmsr(MSR_REG_GSBASE, state->gs_base);
@@ -889,8 +889,8 @@ kern_return_t thread_getstatus(
return KERN_INVALID_ARGUMENT;
state = (struct i386_fsgs_base_state *) tstate;
- state->fs_base = thread->pcb->iss.fsbase;
- state->gs_base = thread->pcb->iss.gsbase;
+ state->fs_base = thread->pcb->ims.sbs.fsbase;
+ state->gs_base = thread->pcb->ims.sbs.gsbase;
*count = i386_FSGS_BASE_STATE_COUNT;
break;
}
diff --git a/i386/i386/thread.h b/i386/i386/thread.h
index 2378154f..86a44098 100644
--- a/i386/i386/thread.h
+++ b/i386/i386/thread.h
@@ -51,10 +51,6 @@
*/
struct i386_saved_state {
-#ifdef __x86_64__
- unsigned long fsbase;
- unsigned long gsbase;
-#endif
unsigned long gs;
unsigned long fs;
unsigned long es;
@@ -162,6 +158,13 @@ struct v86_assist_state {
#define V86_IF_PENDING 0x8000 /* unused bit */
#endif
+#if defined(__x86_64__) && !defined(USER32)
+struct i386_segment_base_state {
+ unsigned long fsbase;
+ unsigned long gsbase;
+};
+#endif
+
/*
* i386_interrupt_state:
*
@@ -206,14 +209,23 @@ struct i386_machine_state {
#endif
struct real_descriptor user_gdt[USER_GDT_SLOTS];
struct i386_debug_state ids;
+#if defined(__x86_64__) && !defined(USER32)
+ struct i386_segment_base_state sbs;
+#endif
};
typedef struct pcb {
+ /* START of the exception stack.
+ * NOTE: this area is used as exception stack when switching
+ * CPL, and it MUST be big enough to save the thread state and
+ * switch to a proper stack area, even considering recursive
+ * exceptions, otherwise it could corrupt nearby memory */
struct i386_interrupt_state iis[2]; /* interrupt and NMI */
#ifdef __x86_64__
- unsigned long pad; /* ensure exception stack is aligned to 16 */
+ unsigned long pad; /* ensure exception stack is aligned to 16 */
#endif
struct i386_saved_state iss;
+ /* END of exception stack*/
struct i386_machine_state ims;
decl_simple_lock_data(, lock)
unsigned short init_control; /* Initial FPU control to set */
diff --git a/x86_64/locore.S b/x86_64/locore.S
index 7127957b..66a9436a 100644
--- a/x86_64/locore.S
+++ b/x86_64/locore.S
@@ -39,6 +39,10 @@
#include <i386/i386/cpu_number.h>
#include <i386/i386/xen.h>
+
+/*
+ * Helpers for thread state as saved in the pcb area, during trap or irq handling
+ */
#define pusha \
pushq %rax ;\
pushq %rcx ;\
@@ -75,45 +79,74 @@
popq %rcx ;\
popq %rax
+/*
+ * Note that we have to load the kernel segment registers even if this
+ * is a trap from the kernel, because the kernel uses user segment
+ * registers for copyin/copyout.
+ * (XXX Would it be smarter just to use fs or gs for that?)
+ */
#ifdef USER32
-#define PUSH_FSGS \
+#define PUSH_SEGMENTS(reg) \
+ movq %ds,reg ;\
+ pushq reg ;\
+ movq %es,reg ;\
+ pushq reg ;\
pushq %fs ;\
- pushq %gs ;\
- subq $16,%rsp
+ pushq %gs
#else
-#define PUSH_FSGS \
+#define PUSH_SEGMENTS(reg) \
subq $32,%rsp
#endif
#ifdef USER32
-#define POP_FSGS \
+#define POP_SEGMENTS(reg) \
popq %gs ;\
popq %fs ;\
- addq $16,%rsp
+ popq reg ;\
+ movq reg,%es ;\
+ popq reg ;\
+ movq reg,%ds
#else
-#define POP_FSGS \
+#define POP_SEGMENTS(reg) \
addq $32,%rsp
#endif
#ifdef USER32
-#define PUSH_FSGS_ISR \
+#define PUSH_SEGMENTS_ISR(reg) \
+ movq %ds,reg ;\
+ pushq reg ;\
+ movq %es,reg ;\
+ pushq reg ;\
pushq %fs ;\
pushq %gs
#else
-#define PUSH_FSGS_ISR \
- subq $16,%rsp
+#define PUSH_SEGMENTS_ISR(reg) \
+ subq $32,%rsp
#endif
#ifdef USER32
-#define POP_FSGS_ISR \
+#define POP_SEGMENTS_ISR(reg) \
popq %gs ;\
- popq %fs
+ popq %fs ;\
+ popq reg ;\
+ movq reg,%es ;\
+ popq reg ;\
+ movq reg,%ds
#else
-#define POP_FSGS_ISR \
- addq $16,%rsp
+#define POP_SEGMENTS_ISR(reg) \
+ addq $32,%rsp
#endif
-
+#ifdef USER32
+#define SET_KERNEL_SEGMENTS \
+ mov %ss,%dx /* switch to kernel segments */ ;\
+ mov %dx,%ds ;\
+ mov %dx,%es ;\
+ mov %dx,%fs ;\
+ mov %dx,%gs
+#else
+#define SET_KERNEL_SEGMENTS
+#endif
/*
* Fault recovery.
@@ -350,32 +383,17 @@ ENTRY(start_timer)
/*
* Trap/interrupt entry points.
*
- * All traps must create the following save area on the kernel stack:
- *
- * gs
- * fs
- * es
- * ds
- * edi
- * esi
- * ebp
- * cr2 if page fault - otherwise unused
- * ebx
- * edx
- * ecx
- * eax
- * trap number
- * error code
- * eip
- * cs
- * eflags
- * user rsp - if from user
- * user ss - if from user
- * es - if from V86 thread
- * ds - if from V86 thread
- * fs - if from V86 thread
- * gs - if from V86 thread
+ * All traps must create the i386_saved_state struct on the stack on
+ * entry. Note that:
+ * - CR2 is only used if the trap is a page fault
+ * - user_rsp/user_ss are only used if entering from user space
+ * - v86_regs are used only from V86 threads
+ * (TODO check if V86 is still used with USER32)
*
+ * Depending the CPL before entry, the stack might be switched or not;
+ * if entering from user-space the CPU loads TSS->RSP0 in RSP,
+ * otherwise RSP is unchanged. After this, the cpu pushes
+ * SS/RSP/RFLAFS/CS/RIP and optionally ErrorCode and executes the handler.
*/
/* Try to save/show some information when a double fault happens
@@ -426,16 +444,16 @@ trap_check_kernel_exit:
/* check for the kernel exit sequence */
cmpq $_kret_iret,16(%rsp) /* on IRET? */
je fault_iret
-#if 0
+#ifdef USER32
cmpq $_kret_popl_ds,16(%rsp) /* popping DS? */
je fault_popl_ds
cmpq $_kret_popl_es,16(%rsp) /* popping ES? */
je fault_popl_es
-#endif
cmpq $_kret_popl_fs,16(%rsp) /* popping FS? */
je fault_popl_fs
cmpq $_kret_popl_gs,16(%rsp) /* popping GS? */
je fault_popl_gs
+#endif
take_fault: /* if none of the above: */
jmp EXT(alltraps) /* treat as normal trap. */
@@ -464,6 +482,7 @@ fault_iret:
popq %rax /* restore eax */
jmp EXT(alltraps) /* take fault */
+#ifdef USER32
/*
* Fault restoring a segment register. The user's registers are still
* saved on the stack. The offending segment register has not been
@@ -499,6 +518,7 @@ push_gs:
push_gsbase:
pushq $0
pushq $0
+#endif
push_segregs:
movq %rax,R_TRAPNO(%rsp) /* set trap number */
movq %rdx,R_ERR(%rsp) /* set error code */
@@ -562,23 +582,8 @@ ENTRY(t_page_fault)
ENTRY(alltraps)
pusha /* save the general registers */
trap_push_segs:
- movq %ds,%rax /* and the segment registers */
- pushq %rax
- movq %es,%rax /* and the segment registers */
- pushq %rax
- PUSH_FSGS
-
- /* Note that we have to load the segment registers
- even if this is a trap from the kernel,
- because the kernel uses user segment registers for copyin/copyout.
- (XXX Would it be smarter just to use fs or gs for that?) */
- mov %ss,%ax /* switch to kernel data segment */
- mov %ax,%ds /* (same as kernel stack segment) */
- mov %ax,%es
-#ifdef USER32
- mov %ax,%fs
- mov %ax,%gs
-#endif
+ PUSH_SEGMENTS(%rax)
+ SET_KERNEL_SEGMENTS
trap_set_segs:
cld /* clear direction flag */
#ifdef USER32
@@ -634,23 +639,20 @@ _return_to_user:
*/
_return_from_kernel:
- addq $16,%rsp /* skip FS/GS base */
#ifndef USER32
-_kret_popl_gs:
-_kret_popl_fs:
- addq $16,%rsp /* skip FS/GS selector */
+ addq $32,%rsp /* skip FS/GS selector */
#else
_kret_popl_gs:
popq %gs /* restore segment registers */
_kret_popl_fs:
popq %fs
-#endif
_kret_popl_es:
popq %rax
movq %rax,%es
_kret_popl_ds:
popq %rax
movq %rax,%ds
+#endif
popa /* restore general registers */
addq $16,%rsp /* discard trap number and error code */
_kret_iret:
@@ -777,8 +779,11 @@ INTERRUPT(255)
/* XXX handle NMI - at least print a warning like Linux does. */
/*
- * All interrupts enter here.
- * old %eax on stack; interrupt number in %eax.
+ * All interrupts enter here. The cpu might have loaded a new RSP,
+ * depending on the previous CPL, as in alltraps.
+ * Old %eax on stack, interrupt number in %eax; we need to fill the remaining
+ * fields of struct i386_interrupt_state, which might be in the pcb or in the
+ * interrupt stack.
*/
ENTRY(all_intrs)
pushq %rcx /* save registers */
@@ -791,24 +796,15 @@ ENTRY(all_intrs)
pushq %r11
cld /* clear direction flag */
- movq %ds,%rdx /* save segment registers */
- pushq %rdx
- movq %es,%rdx
- pushq %rdx
- PUSH_FSGS_ISR
+ PUSH_SEGMENTS_ISR(%rdx)
movq %rsp,%rdx /* on an interrupt stack? */
and $(~(INTSTACK_SIZE-1)),%rdx
cmpq %ss:EXT(int_stack_base),%rdx
je int_from_intstack /* if not: */
- mov %ss,%dx /* switch to kernel segments */
- mov %dx,%ds
- mov %dx,%es
-#ifdef USER32
- mov %dx,%fs
- mov %dx,%gs
-#endif
+ SET_KERNEL_SEGMENTS
+
CPU_NUMBER(%edx)
movq CX(EXT(int_stack_top),%edx),%rcx
@@ -849,11 +845,7 @@ LEXT(return_to_iret) /* ( label for kdb_kintr and hardclock) */
cmpq $0,CX(EXT(need_ast),%edx)
jnz ast_from_interrupt /* take it if so */
1:
- POP_FSGS_ISR
- pop %rdx
- mov %rdx,%es
- pop %rdx
- mov %rdx,%ds
+ POP_SEGMENTS_ISR(%rdx)
pop %r11
pop %r10
pop %r9
@@ -871,12 +863,7 @@ int_from_intstack:
jb stack_overflowed /* if not: */
call EXT(interrupt) /* call interrupt routine */
_return_to_iret_i: /* ( label for kdb_kintr) */
- POP_FSGS_ISR
- pop %rdx
- mov %rdx,%es
- pop %rdx
- mov %rdx,%ds
-
+ POP_SEGMENTS_ISR(%rdx)
pop %r11
pop %r10
pop %r9
@@ -909,11 +896,7 @@ stack_overflowed:
* ss
*/
ast_from_interrupt:
- POP_FSGS_ISR
- pop %rdx
- mov %rdx,%es
- pop %rdx
- mov %rdx,%ds
+ POP_SEGMENTS_ISR(%rdx)
popq %r11
popq %r10
popq %r9
@@ -926,19 +909,8 @@ ast_from_interrupt:
pushq $0 /* zero code */
pushq $0 /* zero trap number */
pusha /* save general registers */
- mov %ds,%rdx /* save segment registers */
- push %rdx
- mov %es,%rdx
- push %rdx
- PUSH_FSGS_ISR
-
- mov %ss,%dx /* switch to kernel segments */
- mov %dx,%ds
- mov %dx,%es
-#ifdef USER32
- mov %dx,%fs
- mov %dx,%gs
-#endif
+ PUSH_SEGMENTS_ISR(%rdx)
+ SET_KERNEL_SEGMENTS
CPU_NUMBER(%edx)
TIME_TRAP_UENTRY
@@ -1056,20 +1028,12 @@ kdb_from_iret_i: /* on interrupt stack */
pushq $0 /* zero error code */
pushq $0 /* zero trap number */
pusha /* save general registers */
- mov %ds,%rdx /* save segment registers */
- push %rdx
- mov %es,%rdx
- push %rdx
- PUSH_FSGS
+ PUSH_SEGMENTS(%rdx)
movq %rsp,%rdx /* pass regs, */
movq $0,%rsi /* code, */
movq $-1,%rdi /* type to kdb */
call EXT(kdb_trap)
- POP_FSGS
- pop %rdx
- mov %rdx,%es
- pop %rdx
- mov %rdx,%ds
+ POP_SEGMENTS(%rdx)
popa /* restore general registers */
addq $16,%rsp
@@ -1144,23 +1108,13 @@ ttd_from_iret_i: /* on interrupt stack */
pushq $0 /* zero error code */
pushq $0 /* zero trap number */
pusha /* save general registers */
- mov %ds,%rdx /* save segment registers */
- push %rdx
- mov %es,%rdx
- push %rdx
- push %fs
- push %gs
+ PUSH_SEGMENTS_ISR(%rdx)
ud2 // TEST it
movq %rsp,%rdx /* pass regs, */
movq $0,%rsi /* code, */
movq $-1,%rdi /* type to kdb */
call _kttd_trap
- pop %gs /* restore segment registers */
- pop %fs
- pop %rdx
- mov %rdx,%es
- pop %rdx
- mov %rdx,%ds
+ POP_SEGMENTS_ISR(%rdx)
popa /* restore general registers */
addq $16,%rsp
@@ -1193,20 +1147,8 @@ syscall_entry_2:
pushq $0 /* clear trap number slot */
pusha /* save the general registers */
- movq %ds,%rdx /* and the segment registers */
- pushq %rdx
- movq %es,%rdx
- pushq %rdx
- pushq %fs
- pushq %gs
- pushq $0 // gsbase
- pushq $0 // fsbase
-
- mov %ss,%dx /* switch to kernel data segment */
- mov %dx,%ds
- mov %dx,%es
- mov %dx,%fs
- mov %dx,%gs
+ PUSH_SEGMENTS(%rdx)
+ SET_KERNEL_SEGMENTS
/*
* Shuffle eflags,eip,cs into proper places
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-18 11:53:07 +0000