[PATCH 9/9] x86/paravirt: finish change from lazy cpu to context switch start/end

Jeremy Fitzhardinge
2009-02-18T22:32:17Z

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>
---
arch/x86/include/asm/paravirt.h | 17 ++++++++++-------
arch/x86/include/asm/pgtable.h | 2 ++
arch/x86/kernel/paravirt.c | 14 ++++++--------
arch/x86/kernel/process_32.c | 2 +-
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/vmi_32.c | 12 ++++++------
arch/x86/lguest/boot.c | 8 ++++----
arch/x86/xen/enlighten.c | 10 ++++------
include/asm-frv/pgtable.h | 2 +-
include/asm-generic/pgtable.h | 2 +-
kernel/sched.c | 2 +-
11 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 58d2481..dfdee0c 100644
--- 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 a00628a..d7dfb89 100644
--- 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 0811730..cb406cb 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -269,24 +269,24 @@ 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)
{
BUG_ON(preemptible());

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)
{
BUG_ON(preemptible());

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();
}

@@ -401,10 +401,8 @@ 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 60d7b18..a846b53 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -578,7 +578,7 @@ __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 d5156e7..64fcb9f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -595,7 +595,7 @@ __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 950929c..55a5d69 100644
--- 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 804c170..d70e80d 100644
--- 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
@@ -1024,8 +1024,8 @@ __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 fc6519a..2af94de 100644
--- 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)
@@ -815,10 +815,8 @@ 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 88bec28..b2107a5 100644
--- 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 922f036..e410f60 100644
--- 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 25d4c6b..2376a90 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2782,7 +2782,7 @@ 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;
--
1.6.0.6