x86/paravirt: finish change from lazy cpu to context switch start/end

Impact: fix lazy context switch API

Pass the previous and next tasks into the context switch start
end calls, so that the called functions can properly access the
task state (esp in end_context_switch, in which the next task
is not yet completely current).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 58d2481b01a6c81eb0731d8df14d4748c17e1611..dfdee0ca57d3a3328c6ac4dfe1dde729df5fde6b 100644 (file)
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -56,6 +56,7 @@ struct desc_ptr;
 struct tss_struct;
 struct mm_struct;
 struct desc_struct;
+struct task_struct;
 
 /*
  * Wrapper type for pointers to code which uses the non-standard
@@ -203,7 +204,8 @@ struct pv_cpu_ops {
 
        void (*swapgs)(void);
 
-       struct pv_lazy_ops lazy_mode;
+       void (*start_context_switch)(struct task_struct *prev);
+       void (*end_context_switch)(struct task_struct *next);
 };
 
 struct pv_irq_ops {
@@ -1414,20 +1416,21 @@ enum paravirt_lazy_mode {
 };
 
 enum paravirt_lazy_mode paravirt_get_lazy_mode(void);
-void paravirt_enter_lazy_cpu(void);
-void paravirt_leave_lazy_cpu(void);
+void paravirt_start_context_switch(struct task_struct *prev);
+void paravirt_end_context_switch(struct task_struct *next);
+
 void paravirt_enter_lazy_mmu(void);
 void paravirt_leave_lazy_mmu(void);
 
 #define  __HAVE_ARCH_START_CONTEXT_SWITCH
-static inline void arch_start_context_switch(void)
+static inline void arch_start_context_switch(struct task_struct *prev)
 {
-       PVOP_VCALL0(pv_cpu_ops.lazy_mode.enter);
+       PVOP_VCALL1(pv_cpu_ops.start_context_switch, prev);
 }
 
-static inline void arch_end_context_switch(void)
+static inline void arch_end_context_switch(struct task_struct *next)
 {
-       PVOP_VCALL0(pv_cpu_ops.lazy_mode.leave);
+       PVOP_VCALL1(pv_cpu_ops.end_context_switch, next);
 }
 
 #define  __HAVE_ARCH_ENTER_LAZY_MMU_MODE

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index d0812e155f1d60da04c614bee8b97e2e33869876..24e42836e92142f339e068feea1a514f29d593d6 100644 (file)
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -83,6 +83,8 @@ static inline void __init paravirt_pagetable_setup_done(pgd_t *base)
 #define pte_val(x)     native_pte_val(x)
 #define __pte(x)       native_make_pte(x)
 
+#define arch_end_context_switch(prev)  do {} while(0)
+
 #endif /* CONFIG_PARAVIRT */
 
 /*

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 430a0e30577bc8fc59051f526d8c4b5d91d7e6cc..cf1437503bab72e07f8f35bb3c75a57dd7d91715 100644 (file)
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -270,20 +270,20 @@ void paravirt_leave_lazy_mmu(void)
        leave_lazy(PARAVIRT_LAZY_MMU);
 }
 
-void paravirt_enter_lazy_cpu(void)
+void paravirt_start_context_switch(struct task_struct *prev)
 {
        if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
                arch_leave_lazy_mmu_mode();
-               set_thread_flag(TIF_LAZY_MMU_UPDATES);
+               set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
        }
        enter_lazy(PARAVIRT_LAZY_CPU);
 }
 
-void paravirt_leave_lazy_cpu(void)
+void paravirt_end_context_switch(struct task_struct *next)
 {
        leave_lazy(PARAVIRT_LAZY_CPU);
 
-       if (test_and_clear_thread_flag(TIF_LAZY_MMU_UPDATES))
+       if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
                arch_enter_lazy_mmu_mode();
 }
 
@@ -399,10 +399,8 @@ struct pv_cpu_ops pv_cpu_ops = {
        .set_iopl_mask = native_set_iopl_mask,
        .io_delay = native_io_delay,
 
-       .lazy_mode = {
-               .enter = paravirt_nop,
-               .leave = paravirt_nop,
-       },
+       .start_context_switch = paravirt_nop,
+       .end_context_switch = paravirt_nop,
 };
 
 struct pv_apic_ops pv_apic_ops = {

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 57e49a8278a98b2fdaad8c8a963682fbf0cd26f1..d766c7616fd7dc96d9cd2c879371db89d1c0f9bd 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -407,7 +407,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         * done before math_state_restore, so the TS bit is up
         * to date.
         */
-       arch_end_context_switch();
+       arch_end_context_switch(next_p);
 
        /* If the task has used fpu the last 5 timeslices, just do a full
         * restore of the math state immediately to avoid the trap; the

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 7115e6085326c2ac0379170d28e2dba1ba138b69..e8a9aaf9df889ff24661980bcaa06214e2bd24ce 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -428,7 +428,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         * done before math_state_restore, so the TS bit is up
         * to date.
         */
-       arch_end_context_switch();
+       arch_end_context_switch(next_p);
 
        /*
         * Switch FS and GS.

diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 950929c607d353bd8fab0ff51df942a812e52443..55a5d6938e5e7479fe7c4e0870e8b40d811c274e 100644 (file)
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -467,16 +467,16 @@ vmi_startup_ipi_hook(int phys_apicid, unsigned long start_eip,
 }
 #endif
 
-static void vmi_enter_lazy_cpu(void)
+static void vmi_start_context_switch(struct task_struct *prev)
 {
-       paravirt_enter_lazy_cpu();
+       paravirt_start_context_switch(prev);
        vmi_ops.set_lazy_mode(2);
 }
 
-static void vmi_leave_lazy_cpu(void)
+static void vmi_end_context_switch(struct task_struct *next)
 {
        vmi_ops.set_lazy_mode(0);
-       paravirt_leave_lazy_cpu();
+       paravirt_end_context_switch(next);
 }
 
 static void vmi_enter_lazy_mmu(void)
@@ -722,9 +722,9 @@ static inline int __init activate_vmi(void)
        para_fill(pv_cpu_ops.set_iopl_mask, SetIOPLMask);
        para_fill(pv_cpu_ops.io_delay, IODelay);
 
-       para_wrap(pv_cpu_ops.lazy_mode.enter, vmi_enter_lazy_cpu,
+       para_wrap(pv_cpu_ops.start_context_switch, vmi_start_context_switch,
                  set_lazy_mode, SetLazyMode);
-       para_wrap(pv_cpu_ops.lazy_mode.leave, vmi_leave_lazy_cpu,
+       para_wrap(pv_cpu_ops.end_context_switch, vmi_end_context_switch,
                  set_lazy_mode, SetLazyMode);
 
        para_wrap(pv_mmu_ops.lazy_mode.enter, vmi_enter_lazy_mmu,

diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 41a5562e710eded21af3ee082dd595346beb90a6..5287081b356709978183af6aa77d658e1db815c0 100644 (file)
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -153,10 +153,10 @@ static void lguest_leave_lazy_mmu_mode(void)
        paravirt_leave_lazy_mmu();
 }
 
-static void lguest_leave_lazy_cpu_mode(void)
+static void lguest_end_context_switch(struct task_struct *next)
 {
        hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);
-       paravirt_leave_lazy_cpu();
+       paravirt_end_context_switch(next);
 }
 
 /*G:033
@@ -1031,8 +1031,8 @@ __init void lguest_init(void)
        pv_cpu_ops.write_gdt_entry = lguest_write_gdt_entry;
        pv_cpu_ops.write_idt_entry = lguest_write_idt_entry;
        pv_cpu_ops.wbinvd = lguest_wbinvd;
-       pv_cpu_ops.lazy_mode.enter = paravirt_enter_lazy_cpu;
-       pv_cpu_ops.lazy_mode.leave = lguest_leave_lazy_cpu_mode;
+       pv_cpu_ops.start_context_switch = paravirt_start_context_switch;
+       pv_cpu_ops.end_context_switch = lguest_end_context_switch;
 
        /* pagetable management */
        pv_mmu_ops.write_cr3 = lguest_write_cr3;

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index f586e63b9a6323cf7bb291f4c12c0fad36095a45..70b355d3a86c4c62c494c0ba71faf7c6b12da06c 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -203,10 +203,10 @@ static unsigned long xen_get_debugreg(int reg)
        return HYPERVISOR_get_debugreg(reg);
 }
 
-static void xen_leave_lazy_cpu(void)
+static void xen_end_context_switch(struct task_struct *next)
 {
        xen_mc_flush();
-       paravirt_leave_lazy_cpu();
+       paravirt_end_context_switch(next);
 }
 
 static unsigned long xen_store_tr(void)
@@ -817,10 +817,8 @@ static const struct pv_cpu_ops xen_cpu_ops __initdata = {
        /* Xen takes care of %gs when switching to usermode for us */
        .swapgs = paravirt_nop,
 
-       .lazy_mode = {
-               .enter = paravirt_enter_lazy_cpu,
-               .leave = xen_leave_lazy_cpu,
-       },
+       .start_context_switch = paravirt_start_context_switch,
+       .end_context_switch = xen_end_context_switch,
 };
 
 static const struct pv_apic_ops xen_apic_ops __initdata = {

diff --git a/include/asm-frv/pgtable.h b/include/asm-frv/pgtable.h
index 235e34a7a340ba690b83612724e5146749757bb7..09887045d03f092f8e3e06a81b891b7fea655e7a 100644 (file)
--- a/include/asm-frv/pgtable.h
+++ b/include/asm-frv/pgtable.h
@@ -74,7 +74,7 @@ static inline int pte_file(pte_t pte) { return 0; }
 #define arch_enter_lazy_mmu_mode()     do {} while (0)
 #define arch_leave_lazy_mmu_mode()     do {} while (0)
 
-#define arch_start_context_switch()    do {} while (0)
+#define arch_start_context_switch(prev)        do {} while (0)
 
 #else /* !CONFIG_MMU */
 /*****************************************************************************/

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 922f03671dd8cb5102707a45fdc531ae3fefa634..e410f602cab1b31fdd71681708d17049181026d5 100644 (file)
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -291,7 +291,7 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
  * definition.
  */
 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
-#define arch_start_context_switch()    do {} while (0)
+#define arch_start_context_switch(prev)        do {} while (0)
 #endif
 
 #ifndef __HAVE_PFNMAP_TRACKING

diff --git a/kernel/sched.c b/kernel/sched.c
index 7530fdd7c982944be1c83f49eb34ebe2d015bd11..133762aece50e00b76225e5b2fed7124c7694220 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2746,7 +2746,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
         * combine the page table reload and the switch backend into
         * one hypercall.
         */
-       arch_start_context_switch();
+       arch_start_context_switch(prev);
 
        if (unlikely(!mm)) {
                next->active_mm = oldmm;