#include <asm/errno.h>
#include <asm/segment.h>
#include <asm/smp.h>
-#include <asm/page.h>
-#include <asm/desc.h>
+#include <asm/page_types.h>
#include <asm/percpu.h>
#include <asm/dwarf2.h>
#include <asm/processor-flags.h>
#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
#define preempt_stop(clobbers)
-#define resume_kernel restore_nocheck
+#define resume_kernel restore_all
#endif
.macro TRACE_IRQS_IRET
/*CFI_REL_OFFSET gs, PT_GS*/
.endm
.macro SET_KERNEL_GS reg
- xorl \reg, \reg
+ movl $(__KERNEL_STACK_CANARY), \reg
movl \reg, %gs
.endm
END(ret_from_fork)
/*
+ * Interrupt exit functions should be protected against kprobes
+ */
+ .pushsection .kprobes.text, "ax"
+/*
* Return to user mode is not as complex as all this looks,
* but we want the default path for a system call return to
* go as quickly as possible which is why some of this is
ENTRY(resume_kernel)
DISABLE_INTERRUPTS(CLBR_ANY)
cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
- jnz restore_nocheck
+ jnz restore_all
need_resched:
movl TI_flags(%ebp), %ecx # need_resched set ?
testb $_TIF_NEED_RESCHED, %cl
END(resume_kernel)
#endif
CFI_ENDPROC
+/*
+ * End of kprobes section
+ */
+ .popsection
/* SYSENTER_RETURN points to after the "sysenter" instruction in
the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
GET_THREAD_INFO(%ebp)
- /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
- testw $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
jnz sysenter_audit
sysenter_do_call:
cmpl $(nr_syscalls), %eax
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
- testw $_TIF_ALLWORK_MASK, %cx
+ testl $_TIF_ALLWORK_MASK, %ecx
jne sysexit_audit
sysenter_exit:
/* if something modifies registers it must also disable sysexit */
#ifdef CONFIG_AUDITSYSCALL
sysenter_audit:
- testw $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
jnz syscall_trace_entry
addl $4,%esp
CFI_ADJUST_CFA_OFFSET -4
jmp sysenter_do_call
sysexit_audit:
- testw $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %cx
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
jne syscall_exit_work
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY)
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
- testw $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %cx
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
jne syscall_exit_work
movl PT_EAX(%esp),%eax /* reload syscall return value */
jmp sysenter_exit
PTGS_TO_GS_EX
ENDPROC(ia32_sysenter_target)
+/*
+ * syscall stub including irq exit should be protected against kprobes
+ */
+ .pushsection .kprobes.text, "ax"
# system call handler stub
ENTRY(system_call)
RING0_INT_FRAME # can't unwind into user space anyway
SAVE_ALL
GET_THREAD_INFO(%ebp)
# system call tracing in operation / emulation
- /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
- testw $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
jnz syscall_trace_entry
cmpl $(nr_syscalls), %eax
jae syscall_badsys
# between sampling and the iret
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
- testw $_TIF_ALLWORK_MASK, %cx # current->work
+ testl $_TIF_ALLWORK_MASK, %ecx # current->work
jne syscall_exit_work
restore_all:
+ TRACE_IRQS_IRET
+restore_all_notrace:
movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
# Warning: PT_OLDSS(%esp) contains the wrong/random values if we
# are returning to the kernel.
CFI_REMEMBER_STATE
je ldt_ss # returning to user-space with LDT SS
restore_nocheck:
- TRACE_IRQS_IRET
-restore_nocheck_notrace:
RESTORE_REGS 4 # skip orig_eax/error_code
CFI_ADJUST_CFA_OFFSET -4
irq_return:
jne restore_nocheck
#endif
- /* If returning to userspace with 16bit stack,
- * try to fix the higher word of ESP, as the CPU
- * won't restore it.
- * This is an "official" bug of all the x86-compatible
- * CPUs, which we can try to work around to make
- * dosemu and wine happy. */
- movl PT_OLDESP(%esp), %eax
- movl %esp, %edx
- call patch_espfix_desc
+/*
+ * Setup and switch to ESPFIX stack
+ *
+ * We're returning to userspace with a 16 bit stack. The CPU will not
+ * restore the high word of ESP for us on executing iret... This is an
+ * "official" bug of all the x86-compatible CPUs, which we can work
+ * around to make dosemu and wine happy. We do this by preloading the
+ * high word of ESP with the high word of the userspace ESP while
+ * compensating for the offset by changing to the ESPFIX segment with
+ * a base address that matches for the difference.
+ */
+ mov %esp, %edx /* load kernel esp */
+ mov PT_OLDESP(%esp), %eax /* load userspace esp */
+ mov %dx, %ax /* eax: new kernel esp */
+ sub %eax, %edx /* offset (low word is 0) */
+ PER_CPU(gdt_page, %ebx)
+ shr $16, %edx
+ mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
+ mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
pushl $__ESPFIX_SS
CFI_ADJUST_CFA_OFFSET 4
- pushl %eax
+ push %eax /* new kernel esp */
CFI_ADJUST_CFA_OFFSET 4
+ /* Disable interrupts, but do not irqtrace this section: we
+ * will soon execute iret and the tracer was already set to
+ * the irqstate after the iret */
DISABLE_INTERRUPTS(CLBR_EAX)
- TRACE_IRQS_OFF
- lss (%esp), %esp
+ lss (%esp), %esp /* switch to espfix segment */
CFI_ADJUST_CFA_OFFSET -8
jmp restore_nocheck
CFI_ENDPROC
# perform syscall exit tracing
ALIGN
syscall_exit_work:
- testb $_TIF_WORK_SYSCALL_EXIT, %cl
+ testl $_TIF_WORK_SYSCALL_EXIT, %ecx
jz work_pending
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
jmp resume_userspace
END(syscall_badsys)
CFI_ENDPROC
+/*
+ * End of kprobes section
+ */
+ .popsection
+
+/*
+ * System calls that need a pt_regs pointer.
+ */
+#define PTREGSCALL0(name) \
+ ALIGN; \
+ptregs_##name: \
+ leal 4(%esp),%eax; \
+ jmp sys_##name;
+
+#define PTREGSCALL1(name) \
+ ALIGN; \
+ptregs_##name: \
+ leal 4(%esp),%edx; \
+ movl (PT_EBX+4)(%esp),%eax; \
+ jmp sys_##name;
+
+#define PTREGSCALL2(name) \
+ ALIGN; \
+ptregs_##name: \
+ leal 4(%esp),%ecx; \
+ movl (PT_ECX+4)(%esp),%edx; \
+ movl (PT_EBX+4)(%esp),%eax; \
+ jmp sys_##name;
+
+#define PTREGSCALL3(name) \
+ ALIGN; \
+ptregs_##name: \
+ leal 4(%esp),%eax; \
+ pushl %eax; \
+ movl PT_EDX(%eax),%ecx; \
+ movl PT_ECX(%eax),%edx; \
+ movl PT_EBX(%eax),%eax; \
+ call sys_##name; \
+ addl $4,%esp; \
+ ret
+
+PTREGSCALL1(iopl)
+PTREGSCALL0(fork)
+PTREGSCALL0(vfork)
+PTREGSCALL3(execve)
+PTREGSCALL2(sigaltstack)
+PTREGSCALL0(sigreturn)
+PTREGSCALL0(rt_sigreturn)
+PTREGSCALL2(vm86)
+PTREGSCALL1(vm86old)
+
+/* Clone is an oddball. The 4th arg is in %edi */
+ ALIGN;
+ptregs_clone:
+ leal 4(%esp),%eax
+ pushl %eax
+ pushl PT_EDI(%eax)
+ movl PT_EDX(%eax),%ecx
+ movl PT_ECX(%eax),%edx
+ movl PT_EBX(%eax),%eax
+ call sys_clone
+ addl $8,%esp
+ ret
.macro FIXUP_ESPFIX_STACK
- /* since we are on a wrong stack, we cant make it a C code :( */
+/*
+ * Switch back for ESPFIX stack to the normal zerobased stack
+ *
+ * We can't call C functions using the ESPFIX stack. This code reads
+ * the high word of the segment base from the GDT and swiches to the
+ * normal stack and adjusts ESP with the matching offset.
+ */
+ /* fixup the stack */
PER_CPU(gdt_page, %ebx)
- GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
- addl %esp, %eax
+ mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
+ mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
+ shl $16, %eax
+ addl %esp, %eax /* the adjusted stack pointer */
pushl $__KERNEL_DS
CFI_ADJUST_CFA_OFFSET 4
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
- lss (%esp), %esp
+ lss (%esp), %esp /* switch to the normal stack segment */
CFI_ADJUST_CFA_OFFSET -8
.endm
.macro UNWIND_ESPFIX_STACK
ENDPROC(common_interrupt)
CFI_ENDPROC
+/*
+ * Irq entries should be protected against kprobes
+ */
+ .pushsection .kprobes.text, "ax"
#define BUILD_INTERRUPT3(name, nr, fn) \
ENTRY(name) \
RING0_INT_FRAME; \
#define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
/* The include is where all of the SMP etc. interrupts come from */
-#include "entry_arch.h"
+#include <asm/entry_arch.h>
ENTRY(coprocessor_error)
RING0_INT_FRAME
jmp error_code
CFI_ENDPROC
END(spurious_interrupt_bug)
+/*
+ * End of kprobes section
+ */
+ .popsection
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
+ movl %edi,%eax
+ call *%esi
call do_exit
ud2 # padding for call trace
CFI_ENDPROC
pushl %edx
movl 0xc(%esp), %edx
lea 0x4(%ebp), %eax
+ movl (%ebp), %ecx
subl $MCOUNT_INSN_SIZE, %edx
call prepare_ftrace_return
popl %edx
.globl return_to_handler
return_to_handler:
- pushl $0
pushl %eax
- pushl %ecx
pushl %edx
+ movl %ebp, %eax
call ftrace_return_to_handler
- movl %eax, 0xc(%esp)
+ movl %eax, %ecx
popl %edx
- popl %ecx
popl %eax
- ret
+ jmp *%ecx
#endif
.section .rodata,"a"
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_nmi
- jmp restore_nocheck_notrace
+ jmp restore_all_notrace
CFI_ENDPROC
nmi_stack_fixup:
CFI_ADJUST_CFA_OFFSET 4
pushl %esp
CFI_ADJUST_CFA_OFFSET 4
- addw $4, (%esp)
+ addl $4, (%esp)
/* copy the iret frame of 12 bytes */
.rept 3
pushl 16(%esp)
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