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| author | Andy Lutomirski <luto@kernel.org> | 2017-11-02 10:58:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-25 16:26:16 +0300 |
| commit | 65236abc42b068506720f4a5168e5e63636138dd (patch) | |
| tree | 4763900f5be57a65acb936a15e8b8c5a2779ea8d /arch/x86/entry/entry_64.S | |
| parent | b7ee7fcca8a525c9bc636fab23779f18d3de9e80 (diff) | |
| download | linux-65236abc42b068506720f4a5168e5e63636138dd.tar.xz | |
x86/entry/64: Split the IRET-to-user and IRET-to-kernel paths
commit 26c4ef9c49d8a0341f6d97ce2cfdd55d1236ed29 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 33eb2127eac8..9e262c8ccc2d 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -322,7 +322,7 @@ 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) @@ -424,7 +424,7 @@ 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 */ @@ -613,7 +613,20 @@ 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: @@ -633,11 +646,14 @@ 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 @@ -1328,7 +1344,7 @@ 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: /* |