Patch "x86/entry/64: Merge SAVE_C_REGS and SAVE_EXTRA_REGS, remove unused extensions" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

x86/entry/64: Merge SAVE_C_REGS and SAVE_EXTRA_REGS, remove unused extensions

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dominik Brodowski <[email protected]>
Date: Sun, 11 Feb 2018 11:49:42 +0100
Subject: x86/entry/64: Merge SAVE_C_REGS and SAVE_EXTRA_REGS, remove unused extensions

From: Dominik Brodowski <[email protected]>

commit 2e3f0098bc45f710a2f4cbcc94b80a1fae7a99a1 upstream.

All current code paths call SAVE_C_REGS and then immediately SAVE_EXTRA_REGS. Therefore, merge these two macros and order the MOV sequeneces properly.

While at it, remove the macros to save all except specific registers, as these macros have been unused for a long time.

---
 arch/x86/entry/calling.h  |   57 ++++++++++++----------------------------------
 arch/x86/entry/entry_64.S |   12 +++------
 2 files changed, 19 insertions(+), 50 deletions(-)

@@ -101,49 +101,22 @@ For 32-bit we have the following convent
 	addq	$-(15*8), %rsp
 	.endm
 
-	.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
-	.if \r11
-	movq %r11, 6*8+\offset(%rsp)
-	.endif
-	.if \r8910
-	movq %r10, 7*8+\offset(%rsp)
-	movq %r9,  8*8+\offset(%rsp)
-	movq %r8,  9*8+\offset(%rsp)
-	.endif
-	.if \rax
-	movq %rax, 10*8+\offset(%rsp)
-	.endif
-	.if \rcx
-	movq %rcx, 11*8+\offset(%rsp)
-	.endif
-	movq %rdx, 12*8+\offset(%rsp)
-	movq %rsi, 13*8+\offset(%rsp)
+	.macro SAVE_REGS offset=0
 	movq %rdi, 14*8+\offset(%rsp)
-	UNWIND_HINT_REGS offset=\offset extra=0
-	.endm
-	.macro SAVE_C_REGS offset=0
-	SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1
-	.endm
-	.macro SAVE_C_REGS_EXCEPT_RAX_RCX offset=0
-	SAVE_C_REGS_HELPER \offset, 0, 0, 1, 1
-	.endm
-	.macro SAVE_C_REGS_EXCEPT_R891011
-	SAVE_C_REGS_HELPER 0, 1, 1, 0, 0
-	.endm
-	.macro SAVE_C_REGS_EXCEPT_RCX_R891011
-	SAVE_C_REGS_HELPER 0, 1, 0, 0, 0
-	.endm
-	.macro SAVE_C_REGS_EXCEPT_RAX_RCX_R11
-	SAVE_C_REGS_HELPER 0, 0, 0, 1, 0
-	.endm
-
-	.macro SAVE_EXTRA_REGS offset=0
-	movq %r15, 0*8+\offset(%rsp)
-	movq %r14, 1*8+\offset(%rsp)
-	movq %r13, 2*8+\offset(%rsp)
-	movq %r12, 3*8+\offset(%rsp)
-	movq %rbp, 4*8+\offset(%rsp)
+	movq %rsi, 13*8+\offset(%rsp)
+	movq %rdx, 12*8+\offset(%rsp)
+	movq %rcx, 11*8+\offset(%rsp)
+	movq %rax, 10*8+\offset(%rsp)
+	movq %r8,  9*8+\offset(%rsp)
+	movq %r9,  8*8+\offset(%rsp)
+	movq %r10, 7*8+\offset(%rsp)
+	movq %r11, 6*8+\offset(%rsp)
 	movq %rbx, 5*8+\offset(%rsp)
+	movq %rbp, 4*8+\offset(%rsp)
+	movq %r12, 3*8+\offset(%rsp)
+	movq %r13, 2*8+\offset(%rsp)
+	movq %r14, 1*8+\offset(%rsp)
+	movq %r15, 0*8+\offset(%rsp)
 	UNWIND_HINT_REGS offset=\offset
 	.endm
 

@@ -197,7 +170,7 @@ For 32-bit we have the following convent
  * is just setting the LSB, which makes it an invalid stack address and is also
  * a signal to the unwinder that it's a pt_regs pointer in disguise.
  *
- * NOTE: This macro must be used *after* SAVE_EXTRA_REGS because it corrupts
+ * NOTE: This macro must be used *after* SAVE_REGS because it corrupts
  * the original rbp.
  */
 .macro ENCODE_FRAME_POINTER ptregs_offset=0

@@ -573,8 +573,7 @@ END(irq_entries_start)
 1:
 
 	ALLOC_PT_GPREGS_ON_STACK
-	SAVE_C_REGS
-	SAVE_EXTRA_REGS
+	SAVE_REGS
 	CLEAR_REGS_NOSPEC
 	ENCODE_FRAME_POINTER
 

@@ -1132,8 +1131,7 @@ ENTRY(xen_failsafe_callback)
 	UNWIND_HINT_IRET_REGS
 	pushq	$-1 /* orig_ax = -1 => not a system call */
 	ALLOC_PT_GPREGS_ON_STACK
-	SAVE_C_REGS
-	SAVE_EXTRA_REGS
+	SAVE_REGS
 	CLEAR_REGS_NOSPEC
 	ENCODE_FRAME_POINTER
 	jmp	error_exit

@@ -1178,8 +1176,7 @@ idtentry machine_check		do_mce			has_err
 ENTRY(paranoid_entry)
 	UNWIND_HINT_FUNC
 	cld
-	SAVE_C_REGS 8
-	SAVE_EXTRA_REGS 8
+	SAVE_REGS 8
 	CLEAR_REGS_NOSPEC
 	ENCODE_FRAME_POINTER 8
 	movl	$1, %ebx

@@ -1231,8 +1228,7 @@ END(paranoid_exit)
 ENTRY(error_entry)
 	UNWIND_HINT_FUNC
 	cld
-	SAVE_C_REGS 8
-	SAVE_EXTRA_REGS 8
+	SAVE_REGS 8
 	CLEAR_REGS_NOSPEC
 	ENCODE_FRAME_POINTER 8
 	testb	$3, CS+8(%rsp)

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/selftests-x86-fix-build-bug-caused-by-the-5lvl-test-which-has-been-moved-to-the-vm-directory.patch queue-4.15/x86-entry-64-interleave-xor-register-clearing-with-push-instructions.patch queue-4.15/x86-entry-64-merge-the-pop_c_regs-and-pop_extra_regs-macros-into-a-single-pop_regs-macro.patch queue-4.15/x86-entry-64-remove-the-unused-icebp-macro.patch queue-4.15/x86-entry-64-use-push_and_clean_regs-in-more-cases.patch queue-4.15/selftests-x86-disable-tests-requiring-32-bit-support-on-pure-64-bit-systems.patch queue-4.15/x86-entry-64-fix-paranoid_entry-frame-pointer-warning.patch queue-4.15/x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch queue-4.15/selftests-x86-do-not-rely-on-int-0x80-in-single_step_syscall.c.patch queue-4.15/selftests-x86-fix-vdso-selftest-segfault-for-vsyscall-none.patch queue-4.15/x86-entry-64-indent-push_and_clear_regs-and-pop_regs-properly.patch queue-4.15/selftests-x86-clean-up-and-document-sscanf-usage.patch queue-4.15/selftests-x86-do-not-rely-on-int-0x80-in-test_mremap_vdso.c.patch queue-4.15/x86-entry-64-get-rid-of-the-alloc_pt_gpregs_on_stack-and-save_and_clear_regs-macros.patch queue-4.15/x86-entry-64-introduce-the-push_and_clean_regs-macro.patch