Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750918AbWHCA0v (ORCPT ); Wed, 2 Aug 2006 20:26:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750900AbWHCAZy (ORCPT ); Wed, 2 Aug 2006 20:25:54 -0400 Received: from 207.47.60.101.static.nextweb.net ([207.47.60.101]:48345 "EHLO mail.goop.org") by vger.kernel.org with ESMTP id S1750918AbWHCAZu (ORCPT ); Wed, 2 Aug 2006 20:25:50 -0400 Message-Id: <20060803002518.298650539@xensource.com> References: <20060803002510.634721860@xensource.com> User-Agent: quilt/0.45-1 Date: Wed, 02 Aug 2006 17:25:14 -0700 From: Jeremy Fitzhardinge To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Jeremy Fitzhardinge , Rusty Russell Subject: [patch 4/8] Replace sensitive instructions with macros. Content-Disposition: inline; filename=004-abstract-asm.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5474 Lines: 195 Abstract sensitive instructions in assembler code, replacing them with macros (which currently are #defined to the native versions). We use long names: assembler is case-insensitive, so if something goes wrong and macros do not expand, it would assemble anyway. Resulting object files are exactly the same as before. Signed-off-by: Rusty Russell Signed-off-by: Jeremy Fitzhardinge --- arch/i386/kernel/entry.S | 38 ++++++++++++++++++++++---------------- include/asm-i386/spinlock.h | 7 +++++-- 2 files changed, 27 insertions(+), 18 deletions(-) =================================================================== --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -76,8 +76,15 @@ NT_MASK = 0x00004000 NT_MASK = 0x00004000 VM_MASK = 0x00020000 +/* These are replaces for paravirtualization */ +#define DISABLE_INTERRUPTS cli +#define ENABLE_INTERRUPTS sti +#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit +#define INTERRUPT_RETURN iret +#define GET_CR0_INTO_EAX movl %cr0, %eax + #ifdef CONFIG_PREEMPT -#define preempt_stop cli; TRACE_IRQS_OFF +#define preempt_stop DISABLE_INTERRUPTS; TRACE_IRQS_OFF #else #define preempt_stop #define resume_kernel restore_nocheck @@ -233,7 +240,7 @@ check_userspace: cmpl $SEGMENT_RPL_MASK, %eax jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) - cli # make sure we don't miss an interrupt + DISABLE_INTERRUPTS # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret movl TI_flags(%ebp), %ecx @@ -244,7 +251,7 @@ ENTRY(resume_userspace) #ifdef CONFIG_PREEMPT ENTRY(resume_kernel) - cli + DISABLE_INTERRUPTS cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ? jnz restore_nocheck need_resched: @@ -272,7 +279,7 @@ sysenter_past_esp: * No need to follow this irqs on/off section: the syscall * disabled irqs and here we enable it straight after entry: */ - sti + ENABLE_INTERRUPTS pushl $(__USER_DS) CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET ss, 0*/ @@ -317,7 +324,7 @@ 1: movl (%ebp),%ebp jae syscall_badsys call *sys_call_table(,%eax,4) movl %eax,EAX(%esp) - cli + DISABLE_INTERRUPTS TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx @@ -327,8 +334,7 @@ 1: movl (%ebp),%ebp movl OLDESP(%esp), %ecx xorl %ebp,%ebp TRACE_IRQS_ON - sti - sysexit + ENABLE_INTERRUPTS_SYSEXIT CFI_ENDPROC @@ -353,7 +359,7 @@ syscall_call: call *sys_call_table(,%eax,4) movl %eax,EAX(%esp) # store the return value syscall_exit: - cli # make sure we don't miss an interrupt + DISABLE_INTERRUPTS # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret TRACE_IRQS_OFF @@ -378,11 +384,11 @@ restore_nocheck_notrace: RESTORE_REGS addl $4, %esp CFI_ADJUST_CFA_OFFSET -4 -1: iret +1: INTERRUPT_RETURN .section .fixup,"ax" iret_exc: TRACE_IRQS_ON - sti + ENABLE_INTERRUPTS pushl $0 # no error code pushl $do_iret_error jmp error_code @@ -406,7 +412,7 @@ ldt_ss: * dosemu and wine happy. */ subl $8, %esp # reserve space for switch16 pointer CFI_ADJUST_CFA_OFFSET 8 - cli + DISABLE_INTERRUPTS TRACE_IRQS_OFF movl %esp, %eax /* Set up the 16bit stack frame with switch32 pointer on top, @@ -416,7 +422,7 @@ ldt_ss: TRACE_IRQS_IRET RESTORE_REGS lss 20+4(%esp), %esp # switch to 16bit stack -1: iret +1: INTERRUPT_RETURN .section __ex_table,"a" .align 4 .long 1b,iret_exc @@ -431,7 +437,7 @@ work_pending: jz work_notifysig work_resched: call schedule - cli # make sure we don't miss an interrupt + DISABLE_INTERRUPTS # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret TRACE_IRQS_OFF @@ -487,7 +493,7 @@ syscall_exit_work: testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl jz work_pending TRACE_IRQS_ON - sti # could let do_syscall_trace() call + ENABLE_INTERRUPTS # could let do_syscall_trace() call # schedule() instead movl %esp, %eax movl $1, %edx @@ -666,7 +672,7 @@ ENTRY(device_not_available) pushl $-1 # mark this as an int CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL - movl %cr0, %eax + GET_CR0_INTO_EAX testl $0x4, %eax # EM (math emulation bit) jne device_not_available_emulate preempt_stop @@ -796,7 +802,7 @@ nmi_16bit_stack: call do_nmi RESTORE_REGS lss 12+4(%esp), %esp # back to 16bit stack -1: iret +1: INTERRUPT_RETURN CFI_ENDPROC .section __ex_table,"a" .align 4 =================================================================== --- a/include/asm-i386/spinlock.h +++ b/include/asm-i386/spinlock.h @@ -16,6 +16,9 @@ * * (the type definitions are in asm/spinlock_types.h) */ + +#define CLI_STRING "cli" +#define STI_STRING "sti" #define __raw_spin_is_locked(x) \ (*(volatile signed char *)(&(x)->slock) <= 0) @@ -43,12 +46,12 @@ "2:\t" \ "testl $0x200, %1\n\t" \ "jz 4f\n\t" \ - "sti\n" \ + STI_STRING "\n" \ "3:\t" \ "rep;nop\n\t" \ "cmpb $0, %0\n\t" \ "jle 3b\n\t" \ - "cli\n\t" \ + CLI_STRING "\n\t" \ "jmp 1b\n" \ "4:\t" \ "rep;nop\n\t" \ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/