diff options
| author | Andy Lutomirski <luto@kernel.org> | 2017-11-02 00:58:59 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-11-02 11:04:37 +0100 |
| commit | 26c4ef9c49d8a0341f6d97ce2cfdd55d1236ed29 (patch) | |
| tree | c20569261357d40a9da6357af2488554d3a281ae /arch/x86/entry/entry_64.S | |
| parent | 9da78ba6b47b46428cfdfc0851511ab29c869798 (diff) | |
x86/entry/64: Split the IRET-to-user and IRET-to-kernel paths
These code paths will diverge soon.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/dccf8c7b3750199b4b30383c812d4e2931811509.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index e8ef83df46e6..3eeb1694210c 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -321,7 +321,7 @@ syscall_return_via_sysret: opportunistic_sysret_failed: SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode END(entry_SYSCALL_64) ENTRY(stub_ptregs_64) @@ -423,7 +423,7 @@ ENTRY(ret_from_fork) call syscall_return_slowpath /* returns with IRQs disabled */ TRACE_IRQS_ON /* user mode is traced as IRQS on */ SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode 1: /* kernel thread */ @@ -612,7 +612,20 @@ GLOBAL(retint_user) call prepare_exit_to_usermode TRACE_IRQS_IRETQ SWAPGS - jmp restore_regs_and_iret + +GLOBAL(restore_regs_and_return_to_usermode) +#ifdef CONFIG_DEBUG_ENTRY + /* Assert that pt_regs indicates user mode. */ + testl $3, CS(%rsp) + jnz 1f + ud2 +1: +#endif + RESTORE_EXTRA_REGS + RESTORE_C_REGS + REMOVE_PT_GPREGS_FROM_STACK 8 + INTERRUPT_RETURN + /* Returning to kernel space */ retint_kernel: @@ -632,11 +645,14 @@ retint_kernel: */ TRACE_IRQS_IRETQ -/* - * At this label, code paths which return to kernel and to user, - * which come from interrupts/exception and from syscalls, merge. - */ -GLOBAL(restore_regs_and_iret) +GLOBAL(restore_regs_and_return_to_kernel) +#ifdef CONFIG_DEBUG_ENTRY + /* Assert that pt_regs indicates kernel mode. */ + testl $3, CS(%rsp) + jz 1f + ud2 +1: +#endif RESTORE_EXTRA_REGS RESTORE_C_REGS REMOVE_PT_GPREGS_FROM_STACK 8 @@ -1327,7 +1343,7 @@ ENTRY(nmi) * work, because we don't want to enable interrupts. */ SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode .Lnmi_from_kernel: /* |