diff options
| author | Konstantin Belousov <kib@FreeBSD.org> | 2020-12-25 21:58:43 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2020-12-27 10:59:33 +0000 |
| commit | d39f7430a6e1da419d6e4fb871bca5ba7863f738 (patch) | |
| tree | d04528d9b84a823665eae4b07c8dec5256fef0ab | |
| parent | 9dd48b87e6caa617799700db7f2f5db91b68dbcc (diff) | |
| -rw-r--r-- | sys/amd64/amd64/exception.S | 21 | ||||
| -rw-r--r-- | sys/amd64/amd64/support.S | 3 |
2 files changed, 17 insertions, 7 deletions
diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S index 948f6c40e776..6b56a2c8a50e 100644 --- a/sys/amd64/amd64/exception.S +++ b/sys/amd64/amd64/exception.S @@ -667,9 +667,10 @@ IDTVEC(dbg) jnz dbg_fromuserspace lfence /* - * We've interrupted the kernel. Preserve GS.base in %r12, - * %cr3 in %r13, and possibly lower half of MSR_IA32_SPEC_CTL in %r14d. + * We've interrupted the kernel. See comment in NMI handler about + * registers use. */ + movq %cr2,%r15 movl $MSR_GSBASE,%ecx rdmsr movq %rax,%r12 @@ -710,6 +711,7 @@ IDTVEC(dbg) shrq $32,%rdx wrmsr movq %r13,%cr3 + movq %r15,%cr2 RESTORE_REGS addq $TF_RIP,%rsp jmp doreti_iret @@ -804,10 +806,14 @@ IDTVEC(nmi) testb $SEL_RPL_MASK,TF_CS(%rsp) jnz nmi_fromuserspace /* - * We've interrupted the kernel. Preserve GS.base in %r12, - * %cr3 in %r13, and possibly lower half of MSR_IA32_SPEC_CTL in %r14d. + * We've interrupted the kernel. Preserve in callee-saved regs: + * GS.base in %r12, + * %cr3 in %r13, + * possibly lower half of MSR_IA32_SPEC_CTL in %r14d, + * %cr2 in %r15. */ lfence + movq %cr2,%r15 movl $MSR_GSBASE,%ecx rdmsr movq %rax,%r12 @@ -957,6 +963,7 @@ nocallchain: je 2f call flush_l1d_sw /* bhyve L1TF assist */ 2: movq %r13,%cr3 + movq %r15,%cr2 RESTORE_REGS addq $TF_RIP,%rsp jmp doreti_iret @@ -1011,9 +1018,10 @@ IDTVEC(mchk) testb $SEL_RPL_MASK,TF_CS(%rsp) jnz mchk_fromuserspace /* - * We've interrupted the kernel. Preserve GS.base in %r12, - * %cr3 in %r13, and possibly lower half of MSR_IA32_SPEC_CTL in %r14d. + * We've interrupted the kernel. See comment in NMI handler about + * registers use. */ + movq %cr2,%r15 movl $MSR_GSBASE,%ecx rdmsr movq %rax,%r12 @@ -1071,6 +1079,7 @@ mchk_calltrap: shrq $32,%rdx wrmsr movq %r13,%cr3 + movq %r15,%cr2 RESTORE_REGS addq $TF_RIP,%rsp jmp doreti_iret diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S index 5a25dc1d9695..b0ef54a27ca1 100644 --- a/sys/amd64/amd64/support.S +++ b/sys/amd64/amd64/support.S @@ -1651,7 +1651,8 @@ END(handle_ibrs_exit_rs) * * N.B. The function does not follow ABI calling conventions, it corrupts %rbx. * The vmm.ko caller expects that only %rax, %rdx, %rbx, %rcx, %r9, and %rflags - * registers are clobbered. The NMI handler caller only needs %r13 preserved. + * registers are clobbered. The NMI handler caller only needs %r13 and %r15 + * preserved. */ ENTRY(flush_l1d_sw) #define L1D_FLUSH_SIZE (64 * 1024) |