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From: Denys Vlasenko <dvlasenk@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Frederic Weisbecker <fweisbec@gmail.com>, X86 ML <x86@kernel.org>,
	Alexei Starovoitov <ast@plumgrid.com>,
	Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] x86: entry_64.S: move save_paranoid and ret_from_fork closer to their users
Date: Tue, 24 Feb 2015 01:12:20 +0100	[thread overview]
Message-ID: <1424736744-13414-2-git-send-email-dvlasenk@redhat.com> (raw)
In-Reply-To: <1424736744-13414-1-git-send-email-dvlasenk@redhat.com>

For some odd reason, these two functions are at the very top of the file.
save_paranoid's caller is approximately in the middle of it, move it there.
Move ret_from_fork to be right after fork/exec helpers.

This is a pure block move, nothing is changed in the function bodies.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: X86 ML <x86@kernel.org>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: linux-kernel@vger.kernel.org
---
 arch/x86/kernel/entry_64.S | 106 ++++++++++++++++++++++-----------------------
 1 file changed, 53 insertions(+), 53 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 63e7ccd..71b549a 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -202,59 +202,6 @@ ENDPROC(native_usergs_sysret64)
 	CFI_REL_OFFSET r15, R15+\offset
 	.endm
 
-ENTRY(save_paranoid)
-	XCPT_FRAME 1 RDI+8
-	cld
-	SAVE_C_REGS 8
-	SAVE_EXTRA_REGS 8
-	movl $1,%ebx
-	movl $MSR_GS_BASE,%ecx
-	rdmsr
-	testl %edx,%edx
-	js 1f	/* negative -> in kernel */
-	SWAPGS
-	xorl %ebx,%ebx
-1:	ret
-	CFI_ENDPROC
-END(save_paranoid)
-
-/*
- * A newly forked process directly context switches into this address.
- *
- * rdi: prev task we switched from
- */
-ENTRY(ret_from_fork)
-	DEFAULT_FRAME
-
-	LOCK ; btr $TIF_FORK,TI_flags(%r8)
-
-	pushq_cfi $0x0002
-	popfq_cfi				# reset kernel eflags
-
-	call schedule_tail			# rdi: 'prev' task parameter
-
-	GET_THREAD_INFO(%rcx)
-
-	RESTORE_EXTRA_REGS
-
-	testl $3,CS(%rsp)			# from kernel_thread?
-	jz   1f
-
-	testl $_TIF_IA32, TI_flags(%rcx)	# 32-bit compat task needs IRET
-	jnz  int_ret_from_sys_call
-
-	RESTORE_TOP_OF_STACK %rdi
-	jmp ret_from_sys_call			# go to the SYSRET fastpath
-
-1:
-	movq %rbp, %rdi
-	call *%rbx
-	movl $0, RAX(%rsp)
-	RESTORE_EXTRA_REGS
-	jmp int_ret_from_sys_call
-	CFI_ENDPROC
-END(ret_from_fork)
-
 /*
  * 64bit SYSCALL instruction entry. Up to 6 arguments in registers.
  *
@@ -581,6 +528,43 @@ END(stub_x32_execveat)
 #endif
 
 /*
+ * A newly forked process directly context switches into this address.
+ *
+ * rdi: prev task we switched from
+ */
+ENTRY(ret_from_fork)
+	DEFAULT_FRAME
+
+	LOCK ; btr $TIF_FORK,TI_flags(%r8)
+
+	pushq_cfi $0x0002
+	popfq_cfi				# reset kernel eflags
+
+	call schedule_tail			# rdi: 'prev' task parameter
+
+	GET_THREAD_INFO(%rcx)
+
+	RESTORE_EXTRA_REGS
+
+	testl $3,CS(%rsp)			# from kernel_thread?
+	jz   1f
+
+	testl $_TIF_IA32, TI_flags(%rcx)	# 32-bit compat task needs IRET
+	jnz  int_ret_from_sys_call
+
+	RESTORE_TOP_OF_STACK %rdi
+	jmp ret_from_sys_call			# go to the SYSRET fastpath
+
+1:
+	movq %rbp, %rdi
+	call *%rbx
+	movl $0, RAX(%rsp)
+	RESTORE_EXTRA_REGS
+	jmp int_ret_from_sys_call
+	CFI_ENDPROC
+END(ret_from_fork)
+
+/*
  * Build the entry stubs and pointer table with some assembler magic.
  * We pack 7 stubs into a single 32-byte chunk, which will fit in a
  * single cache line on all modern x86 implementations.
@@ -1269,6 +1253,22 @@ idtentry async_page_fault do_async_page_fault has_error_code=1
 idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
 #endif
 
+ENTRY(save_paranoid)
+	XCPT_FRAME 1 RDI+8
+	cld
+	SAVE_C_REGS 8
+	SAVE_EXTRA_REGS 8
+	movl $1,%ebx
+	movl $MSR_GS_BASE,%ecx
+	rdmsr
+	testl %edx,%edx
+	js 1f	/* negative -> in kernel */
+	SWAPGS
+	xorl %ebx,%ebx
+1:	ret
+	CFI_ENDPROC
+END(save_paranoid)
+
 	/*
 	 * "Paranoid" exit path from exception stack.  This is invoked
 	 * only on return from non-NMI IST interrupts that came
-- 
1.8.1.4


  reply	other threads:[~2015-02-24  0:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-24  0:12 [PATCH 1/6] x86: add comments about various syscall instructions, no code changes Denys Vlasenko
2015-02-24  0:12 ` Denys Vlasenko [this message]
2015-02-24  0:37   ` [PATCH 2/6] x86: entry_64.S: move save_paranoid and ret_from_fork closer to their users Andy Lutomirski
2015-02-24  0:12 ` [PATCH 3/6] x86: entry_64.S: rename save_paranoid to paranoid_entry, no code changes Denys Vlasenko
2015-02-24  0:37   ` Andy Lutomirski
2015-02-24  0:12 ` [PATCH 4/6] x86: entry_64.S: fold test_in_nmi macro into its only user Denys Vlasenko
2015-02-24  0:34   ` Andy Lutomirski
2015-02-24  0:12 ` [PATCH 5/6] x86: ia32entry.S: fold IA32_ARG_FIXUP macro into its callers Denys Vlasenko
2015-02-24  0:35   ` Andy Lutomirski
2015-02-24  0:12 ` [PATCH 6/6] x86: entry_64.S: use more understandable constants Denys Vlasenko
2015-02-24  0:37   ` Andy Lutomirski
2015-02-24  0:37 ` [PATCH 1/6] x86: add comments about various syscall instructions, no code changes Andy Lutomirski

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