diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3f5a978a02a7..b7c3ea4cb19d 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -519,7 +519,7 @@ ENTRY(interrupt_entry) testb $3, CS-ORIG_RAX+8(%rsp) jz 1f SWAPGS - + FENCE_SWAPGS_USER_ENTRY /* * Switch to the thread stack. The IRET frame and orig_ax are * on the stack, as well as the return address. RDI..R12 are @@ -549,8 +549,10 @@ ENTRY(interrupt_entry) UNWIND_HINT_FUNC movq (%rdi), %rdi + jmp 2f 1: - + FENCE_SWAPGS_KERNEL_ENTRY +2: PUSH_AND_CLEAR_REGS save_ret=1 ENCODE_FRAME_POINTER 8 @@ -662,7 +664,7 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode) /* Returning to kernel space */ retint_kernel: -#ifdef CONFIG_PREEMPT +#ifdef CONFIG_PREEMPTION /* Interrupts are off */ /* Check if we need preemption */ btl $9, EFLAGS(%rsp) /* were interrupts off? */ @@ -1056,10 +1058,10 @@ ENTRY(native_load_gs_index) ENDPROC(native_load_gs_index) EXPORT_SYMBOL(native_load_gs_index) - _ASM_EXTABLE(.Lgs_change, bad_gs) + _ASM_EXTABLE(.Lgs_change, .Lbad_gs) .section .fixup, "ax" /* running with kernelgs */ -bad_gs: +.Lbad_gs: SWAPGS /* switch back to user gs */ .macro ZAP_GS /* This can't be a string because the preprocessor needs to see it. */ @@ -1113,7 +1115,7 @@ ENTRY(xen_do_hypervisor_callback) /* do_hypervisor_callback(struct *pt_regs) */ call xen_evtchn_do_upcall LEAVE_IRQ_STACK -#ifndef CONFIG_PREEMPT +#ifndef CONFIG_PREEMPTION call xen_maybe_preempt_hcall #endif jmp error_exit @@ -1238,6 +1240,13 @@ ENTRY(paranoid_entry) */ SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 + /* + * The above SAVE_AND_SWITCH_TO_KERNEL_CR3 macro doesn't do an + * unconditional CR3 write, even in the PTI case. So do an lfence + * to prevent GS speculation, regardless of whether PTI is enabled. + */ + FENCE_SWAPGS_KERNEL_ENTRY + ret END(paranoid_entry) @@ -1288,6 +1297,7 @@ ENTRY(error_entry) * from user mode due to an IRET fault. */ SWAPGS + FENCE_SWAPGS_USER_ENTRY /* We have user CR3. Change to kernel CR3. */ SWITCH_TO_KERNEL_CR3 scratch_reg=%rax @@ -1301,6 +1311,8 @@ ENTRY(error_entry) pushq %r12 ret +.Lerror_entry_done_lfence: + FENCE_SWAPGS_KERNEL_ENTRY .Lerror_entry_done: ret @@ -1318,7 +1330,7 @@ ENTRY(error_entry) cmpq %rax, RIP+8(%rsp) je .Lbstep_iret cmpq $.Lgs_change, RIP+8(%rsp) - jne .Lerror_entry_done + jne .Lerror_entry_done_lfence /* * hack: .Lgs_change can fail with user gsbase. If this happens, fix up @@ -1326,6 +1338,7 @@ ENTRY(error_entry) * .Lgs_change's error handler with kernel gsbase. */ SWAPGS + FENCE_SWAPGS_USER_ENTRY SWITCH_TO_KERNEL_CR3 scratch_reg=%rax jmp .Lerror_entry_done @@ -1340,6 +1353,7 @@ ENTRY(error_entry) * gsbase and CR3. Switch to kernel gsbase and CR3: */ SWAPGS + FENCE_SWAPGS_USER_ENTRY SWITCH_TO_KERNEL_CR3 scratch_reg=%rax /* @@ -1431,6 +1445,7 @@ ENTRY(nmi) swapgs cld + FENCE_SWAPGS_USER_ENTRY SWITCH_TO_KERNEL_CR3 scratch_reg=%rdx movq %rsp, %rdx movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp |