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Subject[PATCH 06/11] x86: entry_64.S: move save_paranoid and ret_from_fork closer to their users
Date
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.

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 3498274..d72e46e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -201,59 +201,6 @@ 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.
*
@@ -623,6 +570,43 @@ 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.
@@ -1256,6 +1240,22 @@ 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


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