From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Brian Gerst <brgerst@gmail.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>
Subject: [RFC 01/17] x86/asm/64: Remove the restore_c_regs_and_iret label
Date: Wed, 6 Sep 2017 14:36:46 -0700 [thread overview]
Message-ID: <ba61a33873be123a92907862e895f41e5455ce7a.1504733277.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1504733277.git.luto@kernel.org>
In-Reply-To: <cover.1504733277.git.luto@kernel.org>
The only user was the 64-bit opportunistic SYSRET failure path, and
that path didn't really need it. This change makes the
opportunistic SYSRET code a bit more straightforward and gets rid of
the label.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/entry_64.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index e995ea828789..a0ebeeb9d12f 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -240,7 +240,6 @@ entry_SYSCALL64_slow_path:
call do_syscall_64 /* returns with IRQs disabled */
return_from_SYSCALL_64:
- RESTORE_EXTRA_REGS
TRACE_IRQS_IRETQ /* we're about to change IF */
/*
@@ -309,13 +308,14 @@ return_from_SYSCALL_64:
*/
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
+ RESTORE_EXTRA_REGS
RESTORE_C_REGS_EXCEPT_RCX_R11
movq RSP(%rsp), %rsp
USERGS_SYSRET64
opportunistic_sysret_failed:
SWAPGS
- jmp restore_c_regs_and_iret
+ jmp restore_regs_and_iret
END(entry_SYSCALL_64)
ENTRY(stub_ptregs_64)
@@ -550,7 +550,6 @@ retint_kernel:
*/
GLOBAL(restore_regs_and_iret)
RESTORE_EXTRA_REGS
-restore_c_regs_and_iret:
RESTORE_C_REGS
REMOVE_PT_GPREGS_FROM_STACK 8
INTERRUPT_RETURN
--
2.13.5
next prev parent reply other threads:[~2017-09-06 21:41 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 21:36 [RFC 00/17] Pile o' entry stack changes Andy Lutomirski
2017-09-06 21:36 ` Andy Lutomirski [this message]
2017-09-07 9:40 ` [RFC 01/17] x86/asm/64: Remove the restore_c_regs_and_iret label Borislav Petkov
2017-09-07 9:46 ` Ingo Molnar
2017-09-07 9:49 ` Ingo Molnar
2017-09-07 9:57 ` Borislav Petkov
2017-09-07 10:29 ` Ingo Molnar
2017-09-06 21:36 ` [RFC 02/17] x86/asm/64: Split the iret-to-user and iret-to-kernel paths Andy Lutomirski
2017-09-06 21:36 ` [RFC 03/17] x86/asm/64: Move SWAPGS into the common iret-to-usermode path Andy Lutomirski
2017-09-06 21:36 ` [RFC 04/17] x86/asm/64: Simplify reg restore code in the standard IRET paths Andy Lutomirski
2017-09-12 20:05 ` Josh Poimboeuf
2017-09-06 21:36 ` [RFC 05/17] x86/asm/64: Shrink paranoid_exit_restore and make labels local Andy Lutomirski
2017-09-06 21:36 ` [RFC 06/17] x86/asm/64: Use pop instead of movq in syscall_return_via_sysret Andy Lutomirski
2017-09-06 21:36 ` [RFC 07/17] x86/asm/64: Merge the fast and slow SYSRET paths Andy Lutomirski
2017-09-06 21:36 ` [RFC 08/17] x86/asm/64: De-Xen-ify our NMI code Andy Lutomirski
2017-09-07 9:34 ` Juergen Gross
2017-09-07 18:38 ` Andy Lutomirski
2017-09-08 4:26 ` Juergen Gross
2017-09-06 21:36 ` [RFC 09/17] x86/asm/32: Pull MSR_IA32_SYSENTER_CS update code out of native_load_sp0() Andy Lutomirski
2017-09-12 20:06 ` Josh Poimboeuf
2017-09-06 21:36 ` [RFC 10/17] x86/asm/64: Pass sp0 directly to load_sp0() Andy Lutomirski
2017-09-06 21:36 ` [RFC 11/17] x86/asm: Add task_top_of_stack() to find the top of a task's stack Andy Lutomirski
2017-09-06 21:36 ` [RFC 12/17] x86/xen/64: Clean up SP code in cpu_initialize_context() Andy Lutomirski
2017-09-12 20:09 ` Josh Poimboeuf
2017-09-06 21:36 ` [RFC 13/17] x86/boot/64: Stop initializing TSS.sp0 at boot Andy Lutomirski
2017-09-06 21:36 ` [RFC 14/17] x86/asm/64: Remove all remaining direct thread_struct::sp0 reads Andy Lutomirski
2017-09-06 21:37 ` [RFC 15/17] x86/boot/32: Fix cpu_current_top_of_stack initialization at boot Andy Lutomirski
2017-09-06 21:37 ` [RFC 16/17] x86/asm/64: Remove thread_struct::sp0 Andy Lutomirski
2017-09-06 21:37 ` [RFC 17/17] x86/traps: Use a new on_thread_stack() helper to clean up an assertion Andy Lutomirski
2017-09-12 20:11 ` Josh Poimboeuf
2017-09-12 20:25 ` Andrew Cooper
2017-09-06 22:16 ` [RFC 00/17] Pile o' entry stack changes Andi Kleen
2017-09-07 0:01 ` Andy Lutomirski
2017-09-07 7:04 ` Ingo Molnar
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