diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index c40f89ab1b4c..a19ed151a813 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -161,6 +161,7 @@ syscall_return_via_sysret: SYM_INNER_LABEL(entry_SYSRETQ_unsafe_stack, SYM_L_GLOBAL) ANNOTATE_NOENDBR swapgs + CLEAR_CPU_BUFFERS sysretq SYM_INNER_LABEL(entry_SYSRETQ_end, SYM_L_GLOBAL) ANNOTATE_NOENDBR @@ -247,7 +248,13 @@ SYM_CODE_START(ret_from_fork_asm) * and unwind should work normally. */ UNWIND_HINT_REGS + +#ifdef CONFIG_X86_FRED + ALTERNATIVE "jmp swapgs_restore_regs_and_return_to_usermode", \ + "jmp asm_fred_exit_user", X86_FEATURE_FRED +#else jmp swapgs_restore_regs_and_return_to_usermode +#endif SYM_CODE_END(ret_from_fork_asm) .popsection @@ -370,14 +377,6 @@ SYM_CODE_END(\asmsym) idtentry \vector asm_\cfunc \cfunc has_error_code=1 .endm -/* - * System vectors which invoke their handlers directly and are not - * going through the regular common device interrupt handling code. - */ -.macro idtentry_sysvec vector cfunc - idtentry \vector asm_\cfunc \cfunc has_error_code=0 -.endm - /** * idtentry_mce_db - Macro to generate entry stubs for #MC and #DB * @vector: Vector number @@ -573,6 +572,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL) .Lswapgs_and_iret: swapgs + CLEAR_CPU_BUFFERS /* Assert that the IRET frame indicates user mode. */ testb $3, 8(%rsp) jnz .Lnative_iret @@ -723,6 +723,8 @@ native_irq_return_ldt: */ popq %rax /* Restore user RAX */ + CLEAR_CPU_BUFFERS + /* * RSP now points to an ordinary IRET frame, except that the page * is read-only and RSP[31:16] are preloaded with the userspace @@ -968,14 +970,14 @@ SYM_CODE_START_LOCAL(paranoid_exit) IBRS_EXIT save_reg=%r15 /* - * The order of operations is important. RESTORE_CR3 requires + * The order of operations is important. PARANOID_RESTORE_CR3 requires * kernel GSBASE. * * NB to anyone to try to optimize this code: this code does * not execute at all for exceptions from user mode. Those * exceptions go through error_return instead. */ - RESTORE_CR3 scratch_reg=%rax save_reg=%r14 + PARANOID_RESTORE_CR3 scratch_reg=%rax save_reg=%r14 /* Handle the three GSBASE cases */ ALTERNATIVE "jmp .Lparanoid_exit_checkgs", "", X86_FEATURE_FSGSBASE @@ -1404,8 +1406,7 @@ end_repeat_nmi: /* Always restore stashed SPEC_CTRL value (see paranoid_entry) */ IBRS_EXIT save_reg=%r15 - /* Always restore stashed CR3 value (see paranoid_entry) */ - RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 + PARANOID_RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 /* * The above invocation of paranoid_entry stored the GSBASE @@ -1450,6 +1451,12 @@ nmi_restore: movq $0, 5*8(%rsp) /* clear "NMI executing" */ /* + * Skip CLEAR_CPU_BUFFERS here, since it only helps in rare cases like + * NMI in kernel after user state is restored. For an unprivileged user + * these conditions are hard to meet. + */ + + /* * iretq reads the "iret" frame and exits the NMI stack in a * single instruction. We are returning to kernel mode, so this * cannot result in a fault. Similarly, we don't need to worry @@ -1466,6 +1473,7 @@ SYM_CODE_START(entry_SYSCALL32_ignore) UNWIND_HINT_END_OF_STACK ENDBR mov $-ENOSYS, %eax + CLEAR_CPU_BUFFERS sysretl SYM_CODE_END(entry_SYSCALL32_ignore) |