diff options
| -rw-r--r-- | arch/x86/entry/calling.h | 30 | ||||
| -rw-r--r-- | arch/x86/entry/entry_64.S | 4 |
2 files changed, 30 insertions, 4 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 7894e5c0eef7..45a63e00a6af 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -281,8 +281,34 @@ For 32-bit we have the following conventions - kernel is built with .Ldone_\@: .endm -.macro RESTORE_CR3 save_reg:req +.macro RESTORE_CR3 scratch_reg:req save_reg:req ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + + ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID + + /* + * KERNEL pages can always resume with NOFLUSH as we do + * explicit flushes. + */ + bt $X86_CR3_PTI_SWITCH_BIT, \save_reg + jnc .Lnoflush_\@ + + /* + * Check if there's a pending flush for the user ASID we're + * about to set. + */ + movq \save_reg, \scratch_reg + andq $(0x7FF), \scratch_reg + bt \scratch_reg, THIS_CPU_user_pcid_flush_mask + jnc .Lnoflush_\@ + + btr \scratch_reg, THIS_CPU_user_pcid_flush_mask + jmp .Lwrcr3_\@ + +.Lnoflush_\@: + SET_NOFLUSH_BIT \save_reg + +.Lwrcr3_\@: /* * The CR3 write could be avoided when not changing its value, * but would require a CR3 read *and* a scratch register. @@ -301,7 +327,7 @@ For 32-bit we have the following conventions - kernel is built with .endm .macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req .endm -.macro RESTORE_CR3 save_reg:req +.macro RESTORE_CR3 scratch_reg:req save_reg:req .endm #endif diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index fd501844af1f..ed31d00dc5ee 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1288,7 +1288,7 @@ ENTRY(paranoid_exit) testl %ebx, %ebx /* swapgs needed? */ jnz .Lparanoid_exit_no_swapgs TRACE_IRQS_IRETQ - RESTORE_CR3 save_reg=%r14 + RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 SWAPGS_UNSAFE_STACK jmp .Lparanoid_exit_restore .Lparanoid_exit_no_swapgs: @@ -1730,7 +1730,7 @@ end_repeat_nmi: movq $-1, %rsi call do_nmi - RESTORE_CR3 save_reg=%r14 + RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 testl %ebx, %ebx /* swapgs needed? */ jnz nmi_restore |