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-rw-r--r--arch/i386/kernel/entry.S110
1 files changed, 74 insertions, 36 deletions
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 87f9f60b803b..5a63d6fdb70e 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -76,8 +76,15 @@ DF_MASK = 0x00000400
NT_MASK = 0x00004000
VM_MASK = 0x00020000
+/* These are replaces for paravirtualization */
+#define DISABLE_INTERRUPTS cli
+#define ENABLE_INTERRUPTS sti
+#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
+#define INTERRUPT_RETURN iret
+#define GET_CR0_INTO_EAX movl %cr0, %eax
+
#ifdef CONFIG_PREEMPT
-#define preempt_stop cli; TRACE_IRQS_OFF
+#define preempt_stop DISABLE_INTERRUPTS; TRACE_IRQS_OFF
#else
#define preempt_stop
#define resume_kernel restore_nocheck
@@ -176,18 +183,21 @@ VM_MASK = 0x00020000
#define RING0_INT_FRAME \
CFI_STARTPROC simple;\
+ CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, 3*4;\
/*CFI_OFFSET cs, -2*4;*/\
CFI_OFFSET eip, -3*4
#define RING0_EC_FRAME \
CFI_STARTPROC simple;\
+ CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, 4*4;\
/*CFI_OFFSET cs, -2*4;*/\
CFI_OFFSET eip, -3*4
#define RING0_PTREGS_FRAME \
CFI_STARTPROC simple;\
+ CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, OLDESP-EBX;\
/*CFI_OFFSET cs, CS-OLDESP;*/\
CFI_OFFSET eip, EIP-OLDESP;\
@@ -233,10 +243,11 @@ ret_from_intr:
check_userspace:
movl EFLAGS(%esp), %eax # mix EFLAGS and CS
movb CS(%esp), %al
- testl $(VM_MASK | 3), %eax
- jz resume_kernel
+ andl $(VM_MASK | SEGMENT_RPL_MASK), %eax
+ cmpl $USER_RPL, %eax
+ jb resume_kernel # not returning to v8086 or userspace
ENTRY(resume_userspace)
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
@@ -247,7 +258,7 @@ ENTRY(resume_userspace)
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
- cli
+ DISABLE_INTERRUPTS
cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
jnz restore_nocheck
need_resched:
@@ -267,6 +278,7 @@ need_resched:
# sysenter call handler stub
ENTRY(sysenter_entry)
CFI_STARTPROC simple
+ CFI_SIGNAL_FRAME
CFI_DEF_CFA esp, 0
CFI_REGISTER esp, ebp
movl TSS_sysenter_esp0(%esp),%esp
@@ -275,7 +287,7 @@ sysenter_past_esp:
* No need to follow this irqs on/off section: the syscall
* disabled irqs and here we enable it straight after entry:
*/
- sti
+ ENABLE_INTERRUPTS
pushl $(__USER_DS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET ss, 0*/
@@ -320,7 +332,7 @@ sysenter_past_esp:
jae syscall_badsys
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp)
- cli
+ DISABLE_INTERRUPTS
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx
@@ -330,8 +342,7 @@ sysenter_past_esp:
movl OLDESP(%esp), %ecx
xorl %ebp,%ebp
TRACE_IRQS_ON
- sti
- sysexit
+ ENABLE_INTERRUPTS_SYSEXIT
CFI_ENDPROC
@@ -356,7 +367,7 @@ syscall_call:
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@@ -371,8 +382,8 @@ restore_all:
# See comments in process.c:copy_thread() for details.
movb OLDSS(%esp), %ah
movb CS(%esp), %al
- andl $(VM_MASK | (4 << 8) | 3), %eax
- cmpl $((4 << 8) | 3), %eax
+ andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
+ cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
CFI_REMEMBER_STATE
je ldt_ss # returning to user-space with LDT SS
restore_nocheck:
@@ -381,11 +392,11 @@ restore_nocheck_notrace:
RESTORE_REGS
addl $4, %esp
CFI_ADJUST_CFA_OFFSET -4
-1: iret
+1: INTERRUPT_RETURN
.section .fixup,"ax"
iret_exc:
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS
pushl $0 # no error code
pushl $do_iret_error
jmp error_code
@@ -409,7 +420,7 @@ ldt_ss:
* dosemu and wine happy. */
subl $8, %esp # reserve space for switch16 pointer
CFI_ADJUST_CFA_OFFSET 8
- cli
+ DISABLE_INTERRUPTS
TRACE_IRQS_OFF
movl %esp, %eax
/* Set up the 16bit stack frame with switch32 pointer on top,
@@ -419,7 +430,7 @@ ldt_ss:
TRACE_IRQS_IRET
RESTORE_REGS
lss 20+4(%esp), %esp # switch to 16bit stack
-1: iret
+1: INTERRUPT_RETURN
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
@@ -434,7 +445,7 @@ work_pending:
jz work_notifysig
work_resched:
call schedule
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@@ -490,7 +501,7 @@ syscall_exit_work:
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
TRACE_IRQS_ON
- sti # could let do_syscall_trace() call
+ ENABLE_INTERRUPTS # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
@@ -591,11 +602,9 @@ ENTRY(name) \
/* The include is where all of the SMP etc. interrupts come from */
#include "entry_arch.h"
-ENTRY(divide_error)
- RING0_INT_FRAME
- pushl $0 # no error code
- CFI_ADJUST_CFA_OFFSET 4
- pushl $do_divide_error
+KPROBE_ENTRY(page_fault)
+ RING0_EC_FRAME
+ pushl $do_page_fault
CFI_ADJUST_CFA_OFFSET 4
ALIGN
error_code:
@@ -645,6 +654,7 @@ error_code:
call *%edi
jmp ret_from_exception
CFI_ENDPROC
+KPROBE_END(page_fault)
ENTRY(coprocessor_error)
RING0_INT_FRAME
@@ -669,7 +679,7 @@ ENTRY(device_not_available)
pushl $-1 # mark this as an int
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
- movl %cr0, %eax
+ GET_CR0_INTO_EAX
testl $0x4, %eax # EM (math emulation bit)
jne device_not_available_emulate
preempt_stop
@@ -702,9 +712,15 @@ device_not_available_emulate:
jne ok; \
label: \
movl TSS_sysenter_esp0+offset(%esp),%esp; \
+ CFI_DEF_CFA esp, 0; \
+ CFI_UNDEFINED eip; \
pushfl; \
+ CFI_ADJUST_CFA_OFFSET 4; \
pushl $__KERNEL_CS; \
- pushl $sysenter_past_esp
+ CFI_ADJUST_CFA_OFFSET 4; \
+ pushl $sysenter_past_esp; \
+ CFI_ADJUST_CFA_OFFSET 4; \
+ CFI_REL_OFFSET eip, 0
KPROBE_ENTRY(debug)
RING0_INT_FRAME
@@ -720,7 +736,8 @@ debug_stack_correct:
call do_debug
jmp ret_from_exception
CFI_ENDPROC
- .previous .text
+KPROBE_END(debug)
+
/*
* NMI is doubly nasty. It can happen _while_ we're handling
* a debug fault, and the debug fault hasn't yet been able to
@@ -729,7 +746,7 @@ debug_stack_correct:
* check whether we got an NMI on the debug path where the debug
* fault happened on the sysenter path.
*/
-ENTRY(nmi)
+KPROBE_ENTRY(nmi)
RING0_INT_FRAME
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
@@ -754,6 +771,7 @@ ENTRY(nmi)
cmpl $sysenter_entry,12(%esp)
je nmi_debug_stack_check
nmi_stack_correct:
+ /* We have a RING0_INT_FRAME here */
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
@@ -764,9 +782,12 @@ nmi_stack_correct:
CFI_ENDPROC
nmi_stack_fixup:
+ RING0_INT_FRAME
FIX_STACK(12,nmi_stack_correct, 1)
jmp nmi_stack_correct
+
nmi_debug_stack_check:
+ /* We have a RING0_INT_FRAME here */
cmpw $__KERNEL_CS,16(%esp)
jne nmi_stack_correct
cmpl $debug,(%esp)
@@ -777,8 +798,10 @@ nmi_debug_stack_check:
jmp nmi_stack_correct
nmi_16bit_stack:
- RING0_INT_FRAME
- /* create the pointer to lss back */
+ /* We have a RING0_INT_FRAME here.
+ *
+ * create the pointer to lss back
+ */
pushl %ss
CFI_ADJUST_CFA_OFFSET 4
pushl %esp
@@ -799,12 +822,13 @@ nmi_16bit_stack:
call do_nmi
RESTORE_REGS
lss 12+4(%esp), %esp # back to 16bit stack
-1: iret
+1: INTERRUPT_RETURN
CFI_ENDPROC
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
.previous
+KPROBE_END(nmi)
KPROBE_ENTRY(int3)
RING0_INT_FRAME
@@ -816,7 +840,7 @@ KPROBE_ENTRY(int3)
call do_int3
jmp ret_from_exception
CFI_ENDPROC
- .previous .text
+KPROBE_END(int3)
ENTRY(overflow)
RING0_INT_FRAME
@@ -881,7 +905,7 @@ KPROBE_ENTRY(general_protection)
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
- .previous .text
+KPROBE_END(general_protection)
ENTRY(alignment_check)
RING0_EC_FRAME
@@ -890,13 +914,14 @@ ENTRY(alignment_check)
jmp error_code
CFI_ENDPROC
-KPROBE_ENTRY(page_fault)
- RING0_EC_FRAME
- pushl $do_page_fault
+ENTRY(divide_error)
+ RING0_INT_FRAME
+ pushl $0 # no error code
+ CFI_ADJUST_CFA_OFFSET 4
+ pushl $do_divide_error
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
- .previous .text
#ifdef CONFIG_X86_MCE
ENTRY(machine_check)
@@ -949,6 +974,19 @@ ENTRY(arch_unwind_init_running)
ENDPROC(arch_unwind_init_running)
#endif
+ENTRY(kernel_thread_helper)
+ pushl $0 # fake return address for unwinder
+ CFI_STARTPROC
+ movl %edx,%eax
+ push %edx
+ CFI_ADJUST_CFA_OFFSET 4
+ call *%ebx
+ push %eax
+ CFI_ADJUST_CFA_OFFSET 4
+ call do_exit
+ CFI_ENDPROC
+ENDPROC(kernel_thread_helper)
+
.section .rodata,"a"
#include "syscall_table.S"
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.