mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-29 15:43:59 +08:00
b23e5844df
Commit 7457c0da02 ("x86/alternatives: Add int3_emulate_call()
selftest") is used to ensure there is a gap setup in int3 exception stack
which could be used for inserting call return address.
This gap is missed in XEN PV int3 exception entry path, then below panic
triggered:
[ 0.772876] general protection fault: 0000 [#1] SMP NOPTI
[ 0.772886] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0+ #11
[ 0.772893] RIP: e030:int3_magic+0x0/0x7
[ 0.772905] RSP: 3507:ffffffff82203e98 EFLAGS: 00000246
[ 0.773334] Call Trace:
[ 0.773334] alternative_instructions+0x3d/0x12e
[ 0.773334] check_bugs+0x7c9/0x887
[ 0.773334] ? __get_locked_pte+0x178/0x1f0
[ 0.773334] start_kernel+0x4ff/0x535
[ 0.773334] ? set_init_arg+0x55/0x55
[ 0.773334] xen_start_kernel+0x571/0x57a
For 64bit PV guests, Xen's ABI enters the kernel with using SYSRET, with
%rcx/%r11 on the stack. To convert back to "normal" looking exceptions,
the xen thunks do 'xen_*: pop %rcx; pop %r11; jmp *'.
E.g. Extracting 'xen_pv_trap xenint3' we have:
xen_xenint3:
pop %rcx;
pop %r11;
jmp xenint3
As xenint3 and int3 entry code are same except xenint3 doesn't generate
a gap, we can fix it by using int3 and drop useless xenint3.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
180 lines
3.8 KiB
ArmAsm
180 lines
3.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Asm versions of Xen pv-ops, suitable for direct use.
|
|
*
|
|
* We only bother with direct forms (ie, vcpu in pda) of the
|
|
* operations here; the indirect forms are better handled in C.
|
|
*/
|
|
|
|
#include <asm/errno.h>
|
|
#include <asm/percpu.h>
|
|
#include <asm/processor-flags.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/asm.h>
|
|
|
|
#include <xen/interface/xen.h>
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/linkage.h>
|
|
|
|
.macro xen_pv_trap name
|
|
ENTRY(xen_\name)
|
|
pop %rcx
|
|
pop %r11
|
|
jmp \name
|
|
END(xen_\name)
|
|
_ASM_NOKPROBE(xen_\name)
|
|
.endm
|
|
|
|
xen_pv_trap divide_error
|
|
xen_pv_trap debug
|
|
xen_pv_trap xendebug
|
|
xen_pv_trap int3
|
|
xen_pv_trap xennmi
|
|
xen_pv_trap overflow
|
|
xen_pv_trap bounds
|
|
xen_pv_trap invalid_op
|
|
xen_pv_trap device_not_available
|
|
xen_pv_trap double_fault
|
|
xen_pv_trap coprocessor_segment_overrun
|
|
xen_pv_trap invalid_TSS
|
|
xen_pv_trap segment_not_present
|
|
xen_pv_trap stack_segment
|
|
xen_pv_trap general_protection
|
|
xen_pv_trap page_fault
|
|
xen_pv_trap spurious_interrupt_bug
|
|
xen_pv_trap coprocessor_error
|
|
xen_pv_trap alignment_check
|
|
#ifdef CONFIG_X86_MCE
|
|
xen_pv_trap machine_check
|
|
#endif /* CONFIG_X86_MCE */
|
|
xen_pv_trap simd_coprocessor_error
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
xen_pv_trap entry_INT80_compat
|
|
#endif
|
|
xen_pv_trap hypervisor_callback
|
|
|
|
__INIT
|
|
ENTRY(xen_early_idt_handler_array)
|
|
i = 0
|
|
.rept NUM_EXCEPTION_VECTORS
|
|
pop %rcx
|
|
pop %r11
|
|
jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
|
|
i = i + 1
|
|
.fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
|
|
.endr
|
|
END(xen_early_idt_handler_array)
|
|
__FINIT
|
|
|
|
hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
|
|
/*
|
|
* Xen64 iret frame:
|
|
*
|
|
* ss
|
|
* rsp
|
|
* rflags
|
|
* cs
|
|
* rip <-- standard iret frame
|
|
*
|
|
* flags
|
|
*
|
|
* rcx }
|
|
* r11 }<-- pushed by hypercall page
|
|
* rsp->rax }
|
|
*/
|
|
ENTRY(xen_iret)
|
|
pushq $0
|
|
jmp hypercall_iret
|
|
|
|
ENTRY(xen_sysret64)
|
|
/*
|
|
* We're already on the usermode stack at this point, but
|
|
* still with the kernel gs, so we can easily switch back.
|
|
*
|
|
* tss.sp2 is scratch space.
|
|
*/
|
|
movq %rsp, PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
|
|
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
|
|
|
|
pushq $__USER_DS
|
|
pushq PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
|
|
pushq %r11
|
|
pushq $__USER_CS
|
|
pushq %rcx
|
|
|
|
pushq $VGCF_in_syscall
|
|
jmp hypercall_iret
|
|
|
|
/*
|
|
* Xen handles syscall callbacks much like ordinary exceptions, which
|
|
* means we have:
|
|
* - kernel gs
|
|
* - kernel rsp
|
|
* - an iret-like stack frame on the stack (including rcx and r11):
|
|
* ss
|
|
* rsp
|
|
* rflags
|
|
* cs
|
|
* rip
|
|
* r11
|
|
* rsp->rcx
|
|
*/
|
|
|
|
/* Normal 64-bit system call target */
|
|
ENTRY(xen_syscall_target)
|
|
popq %rcx
|
|
popq %r11
|
|
|
|
/*
|
|
* Neither Xen nor the kernel really knows what the old SS and
|
|
* CS were. The kernel expects __USER_DS and __USER_CS, so
|
|
* report those values even though Xen will guess its own values.
|
|
*/
|
|
movq $__USER_DS, 4*8(%rsp)
|
|
movq $__USER_CS, 1*8(%rsp)
|
|
|
|
jmp entry_SYSCALL_64_after_hwframe
|
|
ENDPROC(xen_syscall_target)
|
|
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
|
|
/* 32-bit compat syscall target */
|
|
ENTRY(xen_syscall32_target)
|
|
popq %rcx
|
|
popq %r11
|
|
|
|
/*
|
|
* Neither Xen nor the kernel really knows what the old SS and
|
|
* CS were. The kernel expects __USER32_DS and __USER32_CS, so
|
|
* report those values even though Xen will guess its own values.
|
|
*/
|
|
movq $__USER32_DS, 4*8(%rsp)
|
|
movq $__USER32_CS, 1*8(%rsp)
|
|
|
|
jmp entry_SYSCALL_compat_after_hwframe
|
|
ENDPROC(xen_syscall32_target)
|
|
|
|
/* 32-bit compat sysenter target */
|
|
ENTRY(xen_sysenter_target)
|
|
mov 0*8(%rsp), %rcx
|
|
mov 1*8(%rsp), %r11
|
|
mov 5*8(%rsp), %rsp
|
|
jmp entry_SYSENTER_compat
|
|
ENDPROC(xen_sysenter_target)
|
|
|
|
#else /* !CONFIG_IA32_EMULATION */
|
|
|
|
ENTRY(xen_syscall32_target)
|
|
ENTRY(xen_sysenter_target)
|
|
lea 16(%rsp), %rsp /* strip %rcx, %r11 */
|
|
mov $-ENOSYS, %rax
|
|
pushq $0
|
|
jmp hypercall_iret
|
|
ENDPROC(xen_syscall32_target)
|
|
ENDPROC(xen_sysenter_target)
|
|
|
|
#endif /* CONFIG_IA32_EMULATION */
|