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

amluto · Ingo Molnar · commit 150ac78d63af · 2015-10-09T09:41:10.000+02:00
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>
diff --git 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
