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Subject[tip:x86/pti] x86/entry/64: Merge the POP_C_REGS and POP_EXTRA_REGS macros into a single POP_REGS macro
Commit-ID:  502af0d70843c2a9405d7ba1f79b4b0305aaf5f5
Gitweb: https://git.kernel.org/tip/502af0d70843c2a9405d7ba1f79b4b0305aaf5f5
Author: Dominik Brodowski <linux@dominikbrodowski.net>
AuthorDate: Sun, 11 Feb 2018 11:49:43 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 09:04:52 +0100

x86/entry/64: Merge the POP_C_REGS and POP_EXTRA_REGS macros into a single POP_REGS macro

The two special, opencoded cases for POP_C_REGS can be handled by ASM
macros.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180211104949.12992-3-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/calling.h | 15 +++++++++++----
arch/x86/entry/entry_64.S | 26 ++++----------------------
2 files changed, 15 insertions(+), 26 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 8907a65..3bda317 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -139,25 +139,32 @@ For 32-bit we have the following conventions - kernel is built with
xorq %r15, %r15
.endm

- .macro POP_EXTRA_REGS
+ .macro POP_REGS pop_rdi=1 skip_r11rcx=0
popq %r15
popq %r14
popq %r13
popq %r12
popq %rbp
popq %rbx
- .endm
-
- .macro POP_C_REGS
+ .if \skip_r11rcx
+ popq %rsi
+ .else
popq %r11
+ .endif
popq %r10
popq %r9
popq %r8
popq %rax
+ .if \skip_r11rcx
+ popq %rsi
+ .else
popq %rcx
+ .endif
popq %rdx
popq %rsi
+ .if \pop_rdi
popq %rdi
+ .endif
.endm

.macro icebp
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 1a6fc01..7351c91 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -334,15 +334,7 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
UNWIND_HINT_EMPTY
- POP_EXTRA_REGS
- popq %rsi /* skip r11 */
- popq %r10
- popq %r9
- popq %r8
- popq %rax
- popq %rsi /* skip rcx */
- popq %rdx
- popq %rsi
+ POP_REGS pop_rdi=0 skip_r11rcx=1

/*
* Now all regs are restored except RSP and RDI.
@@ -635,15 +627,7 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode)
ud2
1:
#endif
- POP_EXTRA_REGS
- popq %r11
- popq %r10
- popq %r9
- popq %r8
- popq %rax
- popq %rcx
- popq %rdx
- popq %rsi
+ POP_REGS pop_rdi=0

/*
* The stack is now user RDI, orig_ax, RIP, CS, EFLAGS, RSP, SS.
@@ -701,8 +685,7 @@ GLOBAL(restore_regs_and_return_to_kernel)
ud2
1:
#endif
- POP_EXTRA_REGS
- POP_C_REGS
+ POP_REGS
addq $8, %rsp /* skip regs->orig_ax */
INTERRUPT_RETURN

@@ -1661,8 +1644,7 @@ end_repeat_nmi:
nmi_swapgs:
SWAPGS_UNSAFE_STACK
nmi_restore:
- POP_EXTRA_REGS
- POP_C_REGS
+ POP_REGS

/*
* Skip orig_ax and the "outermost" frame to point RSP at the "iret"
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