From 0da5db313317e3195482d3e660a1074857374a89 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 26 Sep 2006 10:52:39 +0200 Subject: [PATCH] [PATCH] i386: Abstract sensitive instructions 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 Signed-off-by: Andrew Morton Signed-off-by: Andi Kleen --- arch/i386/kernel/entry.S | 38 +++++++++++++++++++++---------------- include/asm-i386/spinlock.h | 7 +++++-- 2 files changed, 27 insertions(+), 18 deletions(-) diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index 4b08452492..3872fca5c7 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -76,8 +76,15 @@ DF_MASK = 0x00000400 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 @@ -236,7 +243,7 @@ check_userspace: testl $(VM_MASK | 3), %eax jz resume_kernel 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 @@ -247,7 +254,7 @@ 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: @@ -275,7 +282,7 @@ 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*/ @@ -320,7 +327,7 @@ sysenter_past_esp: 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 @@ -330,8 +337,7 @@ sysenter_past_esp: movl OLDESP(%esp), %ecx xorl %ebp,%ebp TRACE_IRQS_ON - sti - sysexit + ENABLE_INTERRUPTS_SYSEXIT CFI_ENDPROC @@ -356,7 +362,7 @@ 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 @@ -381,11 +387,11 @@ 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 @@ -409,7 +415,7 @@ 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, @@ -419,7 +425,7 @@ 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 @@ -434,7 +440,7 @@ 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 @@ -490,7 +496,7 @@ 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 @@ -668,7 +674,7 @@ 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 @@ -811,7 +817,7 @@ 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 diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h index 324329313a..b0b3043f05 100644 --- a/include/asm-i386/spinlock.h +++ b/include/asm-i386/spinlock.h @@ -7,6 +7,9 @@ #include #include +#define CLI_STRING "cli" +#define STI_STRING "sti" + /* * Your basic SMP spinlocks, allowing only a single CPU anywhere * @@ -55,12 +58,12 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla "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" -- 2.39.5