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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: [PATCH] x86_64 entry.S cleanup
Chris Wright wrote:
> This patch cleans up x86_64 entry.S. Namely, it updates the Xen
> relevant
> macros to be the simpler version that's found in i386. This means
> that:
>
> - XEN_[UN]BLOCK_EVENTS interface now takes care of dealing with
> SMP issues and is no longer conditionally defined
> - XEN_LOCKED_[UN]BLOCK_EVENTS is identical in both cases (SMP and UP)
> and no longer needs to be conditionally defined
> - XEN_[UN]LOCK_VPCU_INFO_SMP is dropped in favor of
> XEN_GET/PUT_VCPU_INFO
>
> This cleans up the code, minimizes the differences with i386 code, and
> lays the groundwork for SMP support (the real reason I did this ;-).
> It's booting, executing syscalls, taking interrupts, etc (it's what
> I'm
> using to send this e-mail). There's some questionable logic left
> behind
> in error_call_handler, however. Jun, would you mind reviewing this
> patch to see if I made any obvious errors?
>
Looks good.
I think you are talking about the different code path for
do_hypervisor_callback, which does not do
XEN_SAVE_UPCALL_MASK(%r11,%cl,EVENT_MASK. Looks like we don't need to do
that any more. See Changes for
linux-2.6.11-xen-sparse/arch/xen/i386/kernel/entry.S@xxxxx So we can
remove that extra checking and the code saving the mask. Can you please
update the patch?
error_call_handler:
movq %rdi, RDI(%rsp)
movq %rsp,%rdi
movq ORIG_RAX(%rsp),%rsi # get error code
movq $-1,ORIG_RAX(%rsp)
leaq do_hypervisor_callback,%rcx
cmpq %rax,%rcx
je 0f # don't save event mask for
callbacks
XEN_GET_VCPU_INFO(%r11)
XEN_SAVE_UPCALL_MASK(%r11,%cl,EVENT_MASK)
0:
call *%rax
Thanks,
Jun
---
Intel Open Source Technology Center
> Signed-off-by: Chris Wright <chrisw@xxxxxxxx>
>
> ===== linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S 1.9 vs
> edited ===== ---
> 1.9/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S
2005-06-10
> 02:10:17 -07:00 +++
> edited/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S
2005-06-13
> 09:21:50 -07:00 @@ -63,42 +63,28 @@ VGCF_IN_SYSCALL = (1<<8) #define
> sizeof_vcpu_shift 3
>
> #ifdef CONFIG_SMP
> -#define XEN_GET_VCPU_INFO(reg)
> -#define preempt_disable(reg) incl TI_preempt_count(reg)
> -#define preempt_enable(reg) decl TI_preempt_count(reg)
> -#define XEN_LOCK_VCPU_INFO_SMP(reg) preempt_disable(%rbp)
; \
> - movl TI_cpu(%rbp),reg
; \
> +#define preempt_disable(reg) incl threadinfo_preempt_count(reg)
> +#define preempt_enable(reg) decl threadinfo_preempt_count(reg)
> +#define XEN_GET_VCPU_INFO(reg) preempt_disable(%rbp)
; \
> + movq %gs:pda_cpunumber,reg
; \
> shl $sizeof_vcpu_shift,reg
; \
> - addl HYPERVISOR_shared_info,reg
> -#define XEN_UNLOCK_VCPU_INFO_SMP(reg) preempt_enable(%rbp)
> -#define XEN_UNLOCK_VCPU_INFO_SMP_fixup .byte 0xff,0xff,0xff
> -#define Ux00 0xff
> -#define XEN_LOCKED_BLOCK_EVENTS(reg) movb $1,evtchn_upcall_mask(reg)
> -#define XEN_BLOCK_EVENTS(reg) XEN_LOCK_VCPU_INFO_SMP(reg)
; \
> - XEN_LOCKED_BLOCK_EVENTS(reg)
; \
> - XEN_UNLOCK_VCPU_INFO_SMP(reg)
> -#define XEN_UNBLOCK_EVENTS(reg) XEN_LOCK_VCPU_INFO_SMP(reg)
; \
> - movb $0,evtchn_upcall_mask(reg)
; \
> - XEN_UNLOCK_VCPU_INFO_SMP(reg)
> -#define XEN_SAVE_UPCALL_MASK(reg,tmp,off) GET_THREAD_INFO(%ebp)
; \
> - XEN_LOCK_VCPU_INFO_SMP(reg)
; \
> - movb evtchn_upcall_mask(reg), tmp
; \
> - movb tmp, off(%rsp)
; \
> - XEN_UNLOCK_VCPU_INFO_SMP(reg)
> + addq HYPERVISOR_shared_info,reg
> +#define XEN_PUT_VCPU_INFO(reg) preempt_enable(%rbp)
; \
> +#define XEN_PUT_VCPU_INFO_fixup .byte 0xff,0xff,0xff
> #else
> #define XEN_GET_VCPU_INFO(reg) movq HYPERVISOR_shared_info,reg
> -#define XEN_LOCK_VCPU_INFO_SMP(reg) movq HYPERVISOR_shared_info,reg
> -#define XEN_UNLOCK_VCPU_INFO_SMP(reg)
> -#define XEN_UNLOCK_VCPU_INFO_SMP_fixup
> -#define Ux00 0x00
> -#define XEN_LOCKED_BLOCK_EVENTS(reg) movb $1,evtchn_upcall_mask(reg)
> -#define XEN_BLOCK_EVENTS(reg) XEN_LOCKED_BLOCK_EVENTS(reg)
> -#define XEN_UNBLOCK_EVENTS(reg) movb $0,evtchn_upcall_mask(reg)
> -#define XEN_SAVE_UPCALL_MASK(reg,tmp,off) \
> - movb evtchn_upcall_mask(reg), tmp; \
> - movb tmp, off(%rsp)
> +#define XEN_PUT_VCPU_INFO(reg)
> +#define XEN_PUT_VCPU_INFO_fixup
> #endif
>
> +#define XEN_LOCKED_BLOCK_EVENTS(reg) movb $1,evtchn_upcall_mask(reg)
> +#define XEN_LOCKED_UNBLOCK_EVENTS(reg) movb
> $0,evtchn_upcall_mask(reg) +#define
> XEN_BLOCK_EVENTS(reg) XEN_GET_VCPU_INFO(reg) ; \
> + XEN_LOCKED_BLOCK_EVENTS(reg)
; \ + XEN_PUT_VCPU_INFO(reg)
> +#define XEN_UNBLOCK_EVENTS(reg) XEN_GET_VCPU_INFO(reg)
; \
> + XEN_LOCKED_UNBLOCK_EVENTS(reg)
; \
> + XEN_PUT_VCPU_INFO(reg)
> #define XEN_TEST_PENDING(reg) testb
$0xFF,evtchn_upcall_pending(reg)
>
> .code64
> @@ -256,8 +242,6 @@ ENTRY(system_call)
> CFI_STARTPROC
> SAVE_ARGS -8,0
> movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
> - XEN_GET_VCPU_INFO(%r11)
> - XEN_SAVE_UPCALL_MASK(%r11,%cl,EVENT_MASK-ARGOFFSET) #
> saved %rcx XEN_UNBLOCK_EVENTS(%r11)
> GET_THREAD_INFO(%rcx)
> testl
> $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx) @@
> -277,7 +261,6 @@ ret_from_sys_call: /* edi: flagmask */
> sysret_check:
> GET_THREAD_INFO(%rcx)
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> movl threadinfo_flags(%rcx),%edx
> andl %edi,%edx
> @@ -291,7 +274,6 @@ sysret_check:
> sysret_careful:
> bt $TIF_NEED_RESCHED,%edx
> jnc sysret_signal
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> pushq %rdi
> call schedule
> @@ -301,7 +283,6 @@ sysret_careful:
> /* Handle a signal */
> sysret_signal:
> /* sti */
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
> jz 1f
> @@ -345,7 +326,6 @@ badsys:
> * Has correct top of stack, but partial stack frame.
> */
> ENTRY(int_ret_from_sys_call)
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> testb $3,CS-ARGOFFSET(%rsp)
> jnz 1f
> @@ -369,7 +349,6 @@ int_careful:
> bt $TIF_NEED_RESCHED,%edx
> jnc int_very_careful
> /* sti */
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> pushq %rdi
> call schedule
> @@ -379,7 +358,6 @@ int_careful:
> /* handle signals and tracing -- both require a full stack frame
*/
> int_very_careful:
> /* sti */
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> SAVE_REST
> /* Check for syscall exit trace */
> @@ -529,11 +507,11 @@ retint_check:
> retint_restore_args:
> movb EVENT_MASK-REST_SKIP(%rsp), %al
> notb %al # %al == ~saved_mask
> - XEN_LOCK_VCPU_INFO_SMP(%rsi)
> + XEN_GET_VCPU_INFO(%rsi)
> andb evtchn_upcall_mask(%rsi),%al
> andb $1,%al # %al == mask & ~saved_mask
> jnz restore_all_enable_events # != 0 => reenable event
delivery
> - XEN_UNLOCK_VCPU_INFO_SMP(%rsi)
> + XEN_PUT_VCPU_INFO(%rsi)
>
> RESTORE_ARGS 0,8,0
> testb $3,8(%rsp) # check CS
> @@ -548,13 +526,11 @@ user_mode:
> retint_careful:
> bt $TIF_NEED_RESCHED,%edx
> jnc retint_signal
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> /* sti */
> pushq %rdi
> call schedule
> popq %rdi
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> GET_THREAD_INFO(%rcx)
> /* cli */
> @@ -563,7 +539,6 @@ retint_careful:
> retint_signal:
> testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
> jz retint_restore_args
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> SAVE_REST
> movq $-1,ORIG_RAX(%rsp)
> @@ -571,7 +546,6 @@ retint_signal:
> movq %rsp,%rdi # &pt_regs
> call do_notify_resume
> RESTORE_REST
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> movl $_TIF_NEED_RESCHED,%edi
> GET_THREAD_INFO(%rcx)
> @@ -590,10 +564,8 @@ retint_kernel:
> jc retint_restore_args
> movl $PREEMPT_ACTIVE,threadinfo_preempt_count(%rcx)
> /* sti */
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_UNBLOCK_EVENTS(%rsi)
> call schedule
> - XEN_GET_VCPU_INFO(%rsi) /* %esi can be different */
> XEN_BLOCK_EVENTS(%rsi)
> /* cli */
> GET_THREAD_INFO(%rcx)
> @@ -731,14 +703,11 @@ error_call_handler:
> leaq do_hypervisor_callback,%rcx
> cmpq %rax,%rcx
> je 0f # don't save event mask for
> callbacks
> - XEN_GET_VCPU_INFO(%r11)
> - XEN_SAVE_UPCALL_MASK(%r11,%cl,EVENT_MASK)
> 0:
> call *%rax
> error_exit:
> RESTORE_REST
> /* cli */
> - XEN_GET_VCPU_INFO(%rsi)
> XEN_BLOCK_EVENTS(%rsi)
> GET_THREAD_INFO(%rcx)
> testb $3,CS-ARGOFFSET(%rsp)
> @@ -807,7 +776,7 @@ restore_all_enable_events:
> scrit: /**** START OF CRITICAL REGION ****/
> XEN_TEST_PENDING(%rsi)
> jnz 14f # process more events if
necessary...
> - XEN_UNLOCK_VCPU_INFO_SMP(%rsi)
> + XEN_PUT_VCPU_INFO(%rsi)
> RESTORE_ARGS 0,8,0
> testb $3,8(%rsp) # check CS
> jnz crit_user_mode
> @@ -817,7 +786,7 @@ crit_user_mode:
> SWITCH_TO_USER 0
>
> 14: XEN_LOCKED_BLOCK_EVENTS(%rsi)
> - XEN_UNLOCK_VCPU_INFO_SMP(%rsi)
> + XEN_PUT_VCPU_INFO(%rsi)
> SAVE_REST
> movq %rsp,%rdi # set the argument again
> jmp 11b
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