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Subject[tip:x86/asm] x86/entry/32: Switch INT80 to the new C syscall path
Commit-ID:  150ac78d63afb96360dab448b7b4d33c98c8266c
Gitweb: http://git.kernel.org/tip/150ac78d63afb96360dab448b7b4d33c98c8266c
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Mon, 5 Oct 2015 17:48:14 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 9 Oct 2015 09:41:10 +0200

x86/entry/32: Switch INT80 to the new C syscall path

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/a7e8d8df96838eae3208dd0441023f3ce7a81831.1444091585.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_32.S | 34 +++++++++++++---------------------
1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 36b6beb..02881e5 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -153,13 +153,13 @@

#endif /* CONFIG_X86_32_LAZY_GS */

-.macro SAVE_ALL
+.macro SAVE_ALL pt_regs_ax=%eax
cld
PUSH_GS
pushl %fs
pushl %es
pushl %ds
- pushl %eax
+ pushl \pt_regs_ax
pushl %ebp
pushl %edi
pushl %esi
@@ -370,20 +370,17 @@ ENDPROC(entry_SYSENTER_32)
# system call handler stub
ENTRY(entry_INT80_32)
ASM_CLAC
- pushl %eax # save orig_eax
- SAVE_ALL
- GET_THREAD_INFO(%ebp)
- # system call tracing in operation / emulation
- testl $_TIF_WORK_SYSCALL_ENTRY, TI_flags(%ebp)
- jnz syscall_trace_entry
- cmpl $(NR_syscalls), %eax
- jae syscall_badsys
-syscall_call:
- call *sys_call_table(, %eax, 4)
-syscall_after_call:
- movl %eax, PT_EAX(%esp) # store the return value
-syscall_exit:
- jmp syscall_exit_work
+ pushl %eax /* pt_regs->orig_ax */
+ SAVE_ALL pt_regs_ax=$-ENOSYS /* save rest, load -ENOSYS into ax */
+
+ /*
+ * User mode is traced as though IRQs are on, and the interrupt gate
+ * turned them off.
+ */
+ TRACE_IRQS_OFF
+
+ movl %esp, %eax
+ call do_int80_syscall_32

restore_all:
TRACE_IRQS_IRET
@@ -491,11 +488,6 @@ syscall_fault:
jmp resume_userspace
END(syscall_fault)

-syscall_badsys:
- movl $-ENOSYS, %eax
- jmp syscall_after_call
-END(syscall_badsys)
-
sysenter_badsys:
movl $-ENOSYS, %eax
jmp sysenter_after_call

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