[PATCH 10/24] paravirt hooks at entry functions.

Glauber de Oliveira Costa
2007-11-09T18:42:51Z

Those are the hooks needed for paravirt at entry_64.S
In general, they follow the way of i386.

Signed-off-by: Glauber de Oliveira Costa <gcosta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>
Acked-by: Jeremy Fitzhardinge <jeremy-8XJ3FbD+ij9l57MIdRCFDg@public.gmane.org>
---
arch/x86/kernel/entry_64.S | 108 +++++++++++++++++++++++++++-----------------
1 files changed, 66 insertions(+), 42 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 3a058bb..b6d7008 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -50,6 +50,7 @@
#include <asm/hw_irq.h>
#include <asm/page.h>
#include <asm/irqflags.h>
+#include <asm/paravirt.h>

.code64

@@ -57,6 +58,20 @@
#define retint_kernel retint_restore_args
#endif

+#ifdef CONFIG_PARAVIRT
+ENTRY(native_irq_enable_syscall_ret)
+ movq %gs:pda_oldrsp,%rsp
+ swapgs
+ sysretq
+/*
+ * This could well be defined as a C function, but as it is only used here,
+ * let it be locally defined
+ */
+ENTRY(native_swapgs)
+ swapgs
+ retq
+#endif /* CONFIG_PARAVIRT */
+

.macro TRACE_IRQS_IRETQ offset=ARGOFFSET
#ifdef CONFIG_TRACE_IRQFLAGS
@@ -216,14 +231,21 @@ ENTRY(system_call)
CFI_DEF_CFA rsp,PDA_STACKOFFSET
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
- swapgs
+ SWAPGS_UNSAFE_STACK
+ /*
+ * A hypervisor implementation might want to use a label
+ * after the swapgs, so that it can do the swapgs
+ * for the guest and jump here on syscall.
+ */
+ENTRY(system_call_after_swapgs)
+
movq %rsp,%gs:pda_oldrsp
movq %gs:pda_kernelstack,%rsp
/*
* No need to follow this irqs off/on section - it's straight
* and short:
*/
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_ARGS 8,1
movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
movq %rcx,RIP-ARGOFFSET(%rsp)
@@ -246,7 +268,7 @@ ret_from_sys_call:
sysret_check:
LOCKDEP_SYS_EXIT
GET_THREAD_INFO(%rcx)
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
@@ -260,9 +282,7 @@ sysret_check:
CFI_REGISTER rip,rcx
RESTORE_ARGS 0,-ARG_SKIP,1
/*CFI_REGISTER rflags,r11*/
- movq %gs:pda_oldrsp,%rsp
- swapgs
- sysretq
+ ENABLE_INTERRUPTS_SYSCALL_RET

CFI_RESTORE_STATE
/* Handle reschedules */
@@ -271,7 +291,7 @@ sysret_careful:
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
@@ -282,7 +302,7 @@ sysret_careful:
/* Handle a signal */
sysret_signal:
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
testl $(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
jz 1f

@@ -295,7 +315,7 @@ sysret_signal:
1: movl $_TIF_NEED_RESCHED,%edi
/* Use IRET because user could have changed frame. This
works because ptregscall_common has called FIXUP_TOP_OF_STACK. */
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
jmp int_with_check

@@ -327,7 +347,7 @@ tracesys:
*/
.globl int_ret_from_sys_call
int_ret_from_sys_call:
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl $3,CS-ARGOFFSET(%rsp)
je retint_restore_args
@@ -349,20 +369,20 @@ int_careful:
bt $TIF_NEED_RESCHED,%edx
jnc int_very_careful
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
jmp int_with_check

/* handle signals and tracing -- both require a full stack frame */
int_very_careful:
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_REST
/* Check for syscall exit trace */
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx
@@ -385,7 +405,7 @@ int_signal:
1: movl $_TIF_NEED_RESCHED,%edi
int_restore_rest:
RESTORE_REST
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
jmp int_with_check
CFI_ENDPROC
@@ -506,7 +526,7 @@ END(stub_rt_sigreturn)
CFI_DEF_CFA_REGISTER rbp
testl $3,CS(%rdi)
je 1f
- swapgs
+ SWAPGS
/* irqcount is used to check if a CPU is already on an interrupt
stack or not. While this is essentially redundant with preempt_count
it is a little cheaper to use a separate counter in the PDA
@@ -527,7 +547,7 @@ ENTRY(common_interrupt)
interrupt do_IRQ
/* 0(%rsp): oldrsp-ARGOFFSET */
ret_from_intr:
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
decl %gs:pda_irqcount
leaveq
@@ -556,13 +576,13 @@ retint_swapgs: /* return to user-space */
/*
* The iretq could re-enable interrupts:
*/
- cli
+ DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_IRETQ
- swapgs
+ SWAPGS
jmp restore_args

retint_restore_args: /* return to kernel space */
- cli
+ DISABLE_INTERRUPTS(CLBR_ANY)
/*
* The iretq could re-enable interrupts:
*/
@@ -570,10 +590,14 @@ retint_restore_args: /* return to kernel space */
restore_args:
RESTORE_ARGS 0,8,0
iret_label:
+#ifdef CONFIG_PARAVIRT
+ INTERRUPT_RETURN
+#endif
+ENTRY(native_iret)
iretq

.section __ex_table,"a"
- .quad iret_label,bad_iret
+ .quad native_iret, bad_iret
.previous
.section .fixup,"ax"
/* force a signal here? this matches i386 behaviour */
@@ -581,24 +605,24 @@ iret_label:
bad_iret:
movq $11,%rdi /* SIGSEGV */
TRACE_IRQS_ON
- sti
- jmp do_exit
- .previous
-
+ ENABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI))
+ jmp do_exit
+ .previous
+
/* edi: workmask, edx: work */
retint_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc retint_signal
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
GET_THREAD_INFO(%rcx)
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
jmp retint_check

@@ -606,14 +630,14 @@ retint_signal:
testl $(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
jz retint_swapgs
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_REST
movq $-1,ORIG_RAX(%rsp)
xorl %esi,%esi # oldset
movq %rsp,%rdi # &pt_regs
call do_notify_resume
RESTORE_REST
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
movl $_TIF_NEED_RESCHED,%edi
GET_THREAD_INFO(%rcx)
@@ -731,7 +755,7 @@ END(spurious_interrupt)
rdmsr
testl %edx,%edx
js 1f
- swapgs
+ SWAPGS
xorl %ebx,%ebx
1:
.if \ist
@@ -747,7 +771,7 @@ END(spurious_interrupt)
.if \ist
addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
.endif
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
.if \irqtrace
TRACE_IRQS_OFF
.endif
@@ -776,10 +800,10 @@ paranoid_swapgs\trace:
.if \trace
TRACE_IRQS_IRETQ 0
.endif
- swapgs
+ SWAPGS_UNSAFE_STACK
paranoid_restore\trace:
RESTORE_ALL 8
- iretq
+ INTERRUPT_RETURN
paranoid_userspace\trace:
GET_THREAD_INFO(%rcx)
movl threadinfo_flags(%rcx),%ebx
@@ -794,11 +818,11 @@ paranoid_userspace\trace:
.if \trace
TRACE_IRQS_ON
.endif
- sti
+ ENABLE_INTERRUPTS(CLBR_NONE)
xorl %esi,%esi /* arg2: oldset */
movq %rsp,%rdi /* arg1: &pt_regs */
call do_notify_resume
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
.if \trace
TRACE_IRQS_OFF
.endif
@@ -807,9 +831,9 @@ paranoid_schedule\trace:
.if \trace
TRACE_IRQS_ON
.endif
- sti
+ ENABLE_INTERRUPTS(CLBR_ANY)
call schedule
- cli
+ DISABLE_INTERRUPTS(CLBR_ANY)
.if \trace
TRACE_IRQS_OFF
.endif
@@ -862,7 +886,7 @@ KPROBE_ENTRY(error_entry)
testl $3,CS(%rsp)
je error_kernelspace
error_swapgs:
- swapgs
+ SWAPGS
error_sti:
movq %rdi,RDI(%rsp)
CFI_REL_OFFSET rdi,RDI
@@ -874,7 +898,7 @@ error_sti:
error_exit:
movl %ebx,%eax
RESTORE_REST
- cli
+ DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
GET_THREAD_INFO(%rcx)
testl %eax,%eax
@@ -911,12 +935,12 @@ ENTRY(load_gs_index)
CFI_STARTPROC
pushf
CFI_ADJUST_CFA_OFFSET 8
- cli
- swapgs
+ DISABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI))
+ SWAPGS
gs_change:
movl %edi,%gs
2: mfence /* workaround */
- swapgs
+ SWAPGS
popf
CFI_ADJUST_CFA_OFFSET -8
ret
@@ -930,7 +954,7 @@ ENDPROC(load_gs_index)
.section .fixup,"ax"
/* running with kernelgs */
bad_gs:
- swapgs /* switch back to user gs */
+ SWAPGS /* switch back to user gs */
xorl %eax,%eax
movl %eax,%gs
jmp 2b