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 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

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-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 2e3f0098bc45f710a2f4cbcc94b80a1fae7a99a1 Mon Sep 17 00:00:00 2001

From: Dominik Brodowski linux@dominikbrodowski.net 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 linux@dominikbrodowski.net

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.

Suggested-by: Linus Torvalds torvalds@linux-foundation.org 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: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180211104949.12992-2-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

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

--- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -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 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -569,8 +569,7 @@ END(irq_entries_start) 1:

ALLOC_PT_GPREGS_ON_STACK - SAVE_C_REGS - SAVE_EXTRA_REGS + SAVE_REGS CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER

@@ -1126,8 +1125,7 @@ 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 @@ -1172,8 +1170,7 @@ 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 @@ -1225,8 +1222,7 @@ 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 linux@dominikbrodowski.net are

queue-4.14/x86-entry-64-interleave-xor-register-clearing-with-push-instructions.patch queue-4.14/x86-entry-64-merge-the-pop_c_regs-and-pop_extra_regs-macros-into-a-single-pop_regs-macro.patch queue-4.14/x86-entry-64-remove-the-unused-icebp-macro.patch queue-4.14/x86-entry-64-use-push_and_clean_regs-in-more-cases.patch queue-4.14/selftests-x86-disable-tests-requiring-32-bit-support-on-pure-64-bit-systems.patch queue-4.14/x86-entry-64-fix-paranoid_entry-frame-pointer-warning.patch queue-4.14/x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch queue-4.14/selftests-x86-do-not-rely-on-int-0x80-in-single_step_syscall.c.patch queue-4.14/selftests-x86-fix-vdso-selftest-segfault-for-vsyscall-none.patch queue-4.14/x86-entry-64-indent-push_and_clear_regs-and-pop_regs-properly.patch queue-4.14/selftests-x86-clean-up-and-document-sscanf-usage.patch queue-4.14/selftests-x86-do-not-rely-on-int-0x80-in-test_mremap_vdso.c.patch queue-4.14/x86-entry-64-get-rid-of-the-alloc_pt_gpregs_on_stack-and-save_and_clear_regs-macros.patch queue-4.14/x86-entry-64-introduce-the-push_and_clean_regs-macro.patch