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From: Dominik Brodowski <linux@dominikbrodowski.net>
To: Ingo Molnar <mingo@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
	tglx@linutronix.de, Andi Kleen <ak@linux.intel.com>,
	torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
	luto@kernel.org, x86@kernel.org
Subject: [PATCH tip-pti 1/2] x86/entry: remove SAVE_C_REGS_EXCEPT_* macros
Date: Tue, 6 Feb 2018 22:25:46 +0100	[thread overview]
Message-ID: <20180206212546.GA2026@light.dominikbrodowski.net> (raw)
In-Reply-To: <20180206105139.nwlg3fwdxyhhrtc4@gmail.com>

The macros which save all but specific registers have been unused for
a long time. Remove them and the SAVE_C_REGS_HELPER macro, but
instead provide the SAVE_C_REGS macro directly.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index f4b129d4af42..75a237c95ff7 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -101,41 +101,18 @@ For 32-bit we have the following conventions - kernel is built with
 	addq	$-(15*8), %rsp
 	.endm
 
-	.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
-	.if \r11
+	.macro SAVE_C_REGS offset=0
 	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)
 	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)

  parent reply	other threads:[~2018-02-06 21:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-06  1:18 [PATCH v3 0/3] x86/entry: Clear registers to sanitize speculative usages Dan Williams
2018-02-06  1:18 ` [PATCH v3 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels Dan Williams
2018-02-06 11:52   ` [tip:x86/pti] x86/entry/64: Clear extra registers beyond syscall arguments, to reduce speculation attack surface tip-bot for Dan Williams
2018-02-06  1:18 ` [PATCH v3 2/3] x86/entry: Clear registers for 64bit exceptions/interrupts Dan Williams
2018-02-06  9:04   ` Dominik Brodowski
2018-02-06 10:48     ` Ingo Molnar
2018-02-06  9:17   ` Dominik Brodowski
2018-02-06 10:51     ` Ingo Molnar
2018-02-06 10:57       ` Dominik Brodowski
2018-02-06 21:25       ` Dominik Brodowski [this message]
2018-02-06 22:56         ` [PATCH tip-pti 1/2] x86/entry: remove SAVE_C_REGS_EXCEPT_* macros Linus Torvalds
2018-02-06 21:32       ` [PATCH tip-pti 2/2] x86/entry: interleave XOR register clearing with PUSH/MOV instructions Dominik Brodowski
2018-02-06 22:30         ` Dan Williams
2018-02-06 22:48         ` Linus Torvalds
2018-02-06 23:05           ` Andy Lutomirski
2018-02-06 23:54           ` Andi Kleen
2018-02-07  1:30             ` Linus Torvalds
2018-02-07 15:18               ` Andi Kleen
2018-02-07 17:05                 ` Linus Torvalds
2018-02-07 17:37                   ` Linus Torvalds
2018-02-06 12:00   ` [tip:x86/pti] x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface tip-bot for Dan Williams
2018-02-06  1:18 ` [PATCH v3 3/3] x86/entry: Clear registers for compat syscalls Dan Williams
2018-02-06  7:26   ` Ingo Molnar
2018-02-06  7:53     ` Dan Williams
2018-02-06 12:00   ` [tip:x86/pti] x86/entry/64/compat: Clear registers for compat syscalls, to reduce speculation attack surface tip-bot for Dan Williams

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