diff options
Diffstat (limited to 'arch/x86/xen/xen-asm.S')
| -rw-r--r-- | arch/x86/xen/xen-asm.S | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 220dd9678494..e730e6200e64 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -20,6 +20,7 @@ #include <linux/init.h> #include <linux/linkage.h> +#include <../entry/calling.h> .pushsection .noinstr.text, "ax" /* @@ -28,7 +29,7 @@ */ SYM_FUNC_START(xen_irq_disable_direct) movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask - ret + RET SYM_FUNC_END(xen_irq_disable_direct) /* @@ -57,7 +58,7 @@ SYM_FUNC_START(check_events) pop %rcx pop %rax FRAME_END - ret + RET SYM_FUNC_END(check_events) /* @@ -83,7 +84,7 @@ SYM_FUNC_START(xen_irq_enable_direct) call check_events 1: FRAME_END - ret + RET SYM_FUNC_END(xen_irq_enable_direct) /* @@ -99,7 +100,7 @@ SYM_FUNC_START(xen_save_fl_direct) testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask setz %ah addb %ah, %ah - ret + RET SYM_FUNC_END(xen_save_fl_direct) SYM_FUNC_START(xen_read_cr2) @@ -107,14 +108,14 @@ SYM_FUNC_START(xen_read_cr2) _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX FRAME_END - ret + RET SYM_FUNC_END(xen_read_cr2); SYM_FUNC_START(xen_read_cr2_direct) FRAME_BEGIN _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX FRAME_END - ret + RET SYM_FUNC_END(xen_read_cr2_direct); .popsection @@ -193,6 +194,25 @@ SYM_CODE_START(xen_iret) SYM_CODE_END(xen_iret) /* + * XEN pv doesn't use trampoline stack, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is + * also the kernel stack. Reusing swapgs_restore_regs_and_return_to_usermode() + * in XEN pv would cause %rsp to move up to the top of the kernel stack and + * leave the IRET frame below %rsp, which is dangerous to be corrupted if #NMI + * interrupts. And swapgs_restore_regs_and_return_to_usermode() pushing the IRET + * frame at the same address is useless. + */ +SYM_CODE_START(xenpv_restore_regs_and_return_to_usermode) + UNWIND_HINT_REGS + POP_REGS + + /* stackleak_erase() can work safely on the kernel stack. */ + STACKLEAK_ERASE_NOCLOBBER + + addq $8, %rsp /* skip regs->orig_ax */ + jmp xen_iret +SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode) + +/* * Xen handles syscall callbacks much like ordinary exceptions, which * means we have: * - kernel gs |