diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 46 | ||||
| -rw-r--r-- | arch/x86/include/asm/kaiser.h | 8 |
2 files changed, 36 insertions, 18 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index efd96f02ac9e..59d9e5d8c05b 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1025,7 +1025,11 @@ idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vec /* * Save all registers in pt_regs, and switch gs if needed. * Use slow, but surefire "are we in kernel?" check. - * Return: ebx=0: need swapgs on exit, ebx=1: otherwise + * + * Return: ebx=0: needs swapgs but not SWITCH_USER_CR3 in paranoid_exit + * ebx=1: needs neither swapgs nor SWITCH_USER_CR3 in paranoid_exit + * ebx=2: needs both swapgs and SWITCH_USER_CR3 in paranoid_exit + * ebx=3: needs SWITCH_USER_CR3 but not swapgs in paranoid_exit */ ENTRY(paranoid_entry) cld @@ -1037,9 +1041,26 @@ ENTRY(paranoid_entry) testl %edx, %edx js 1f /* negative -> in kernel */ SWAPGS - SWITCH_KERNEL_CR3 xorl %ebx, %ebx -1: ret +1: +#ifdef CONFIG_KAISER + /* + * We might have come in between a swapgs and a SWITCH_KERNEL_CR3 + * on entry, or between a SWITCH_USER_CR3 and a swapgs on exit. + * Do a conditional SWITCH_KERNEL_CR3: this could safely be done + * unconditionally, but we need to find out whether the reverse + * should be done on return (conveyed to paranoid_exit in %ebx). + */ + movq %cr3, %rax + testl $KAISER_SHADOW_PGD_OFFSET, %eax + jz 2f + orl $2, %ebx + andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax + orq x86_cr3_pcid_noflush, %rax + movq %rax, %cr3 +2: +#endif + ret END(paranoid_entry) /* @@ -1052,20 +1073,25 @@ END(paranoid_entry) * be complicated. Fortunately, we there's no good reason * to try to handle preemption here. * - * On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) + * On entry: ebx=0: needs swapgs but not SWITCH_USER_CR3 + * ebx=1: needs neither swapgs nor SWITCH_USER_CR3 + * ebx=2: needs both swapgs and SWITCH_USER_CR3 + * ebx=3: needs SWITCH_USER_CR3 but not swapgs */ ENTRY(paranoid_exit) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF_DEBUG - testl %ebx, %ebx /* swapgs needed? */ + TRACE_IRQS_IRETQ_DEBUG +#ifdef CONFIG_KAISER + testl $2, %ebx /* SWITCH_USER_CR3 needed? */ + jz paranoid_exit_no_switch + SWITCH_USER_CR3 +paranoid_exit_no_switch: +#endif + testl $1, %ebx /* swapgs needed? */ jnz paranoid_exit_no_swapgs - TRACE_IRQS_IRETQ - SWITCH_USER_CR3_NO_STACK SWAPGS_UNSAFE_STACK - jmp paranoid_exit_restore paranoid_exit_no_swapgs: - TRACE_IRQS_IRETQ_DEBUG -paranoid_exit_restore: RESTORE_EXTRA_REGS RESTORE_C_REGS REMOVE_PT_GPREGS_FROM_STACK 8 diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h index 48d8d70dd8c7..3dc5f4c39b3e 100644 --- a/arch/x86/include/asm/kaiser.h +++ b/arch/x86/include/asm/kaiser.h @@ -63,20 +63,12 @@ _SWITCH_TO_KERNEL_CR3 %rax movq PER_CPU_VAR(unsafe_stack_register_backup), %rax .endm -.macro SWITCH_USER_CR3_NO_STACK -movq %rax, PER_CPU_VAR(unsafe_stack_register_backup) -_SWITCH_TO_USER_CR3 %rax %al -movq PER_CPU_VAR(unsafe_stack_register_backup), %rax -.endm - #else /* CONFIG_KAISER */ .macro SWITCH_KERNEL_CR3 reg .endm .macro SWITCH_USER_CR3 reg regb .endm -.macro SWITCH_USER_CR3_NO_STACK -.endm .macro SWITCH_KERNEL_CR3_NO_STACK .endm |