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Subject[PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference
Date
From: Ira Weiny <ira.weiny@intel.com>

In preparation for adding PKS information to struct irqentry_state_t
change all call sites and usages to pass the struct by reference
instead of by value.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
arch/x86/entry/common.c | 16 +++++++---------
arch/x86/include/asm/idtentry.h | 29 +++++++++++++++++------------
arch/x86/kernel/kvm.c | 4 ++--
arch/x86/kernel/nmi.c | 7 ++++---
arch/x86/kernel/traps.c | 21 +++++++++++++--------
arch/x86/mm/fault.c | 4 ++--
include/linux/entry-common.h | 7 ++++---
kernel/entry/common.c | 20 ++++++++------------
8 files changed, 57 insertions(+), 51 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 870efeec8bda..305da13770b6 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -209,9 +209,9 @@ SYSCALL_DEFINE0(ni_syscall)
return -ENOSYS;
}

-noinstr bool idtentry_enter_nmi(struct pt_regs *regs)
+noinstr void idtentry_enter_nmi(struct pt_regs *regs, irqentry_state_t *irq_state)
{
- bool irq_state = lockdep_hardirqs_enabled();
+ irq_state->exit_rcu = lockdep_hardirqs_enabled();

__nmi_enter();
lockdep_hardirqs_off(CALLER_ADDR0);
@@ -222,15 +222,13 @@ noinstr bool idtentry_enter_nmi(struct pt_regs *regs)
trace_hardirqs_off_finish();
ftrace_nmi_enter();
instrumentation_end();
-
- return irq_state;
}

-noinstr void idtentry_exit_nmi(struct pt_regs *regs, bool restore)
+noinstr void idtentry_exit_nmi(struct pt_regs *regs, irqentry_state_t *irq_state)
{
instrumentation_begin();
ftrace_nmi_exit();
- if (restore) {
+ if (irq_state->exit_rcu) {
trace_hardirqs_on_prepare();
lockdep_hardirqs_on_prepare(CALLER_ADDR0);
}
@@ -238,7 +236,7 @@ noinstr void idtentry_exit_nmi(struct pt_regs *regs, bool restore)

rcu_nmi_exit();
lockdep_hardirq_exit();
- if (restore)
+ if (irq_state->exit_rcu)
lockdep_hardirqs_on(CALLER_ADDR0);
__nmi_exit();
}
@@ -295,7 +293,7 @@ __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
bool inhcall;
irqentry_state_t state;

- state = irqentry_enter(regs);
+ irqentry_enter(regs, &state);
old_regs = set_irq_regs(regs);

instrumentation_begin();
@@ -311,7 +309,7 @@ __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
instrumentation_end();
restore_inhcall(inhcall);
} else {
- irqentry_exit(regs, state);
+ irqentry_exit(regs, &state);
}
}
#endif /* CONFIG_XEN_PV */
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index a0638640f1ed..622889ba21d0 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -11,8 +11,8 @@

#include <asm/irq_stack.h>

-bool idtentry_enter_nmi(struct pt_regs *regs);
-void idtentry_exit_nmi(struct pt_regs *regs, bool irq_state);
+void idtentry_enter_nmi(struct pt_regs *regs, irqentry_state_t *irq_state);
+void idtentry_exit_nmi(struct pt_regs *regs, irqentry_state_t *irq_state);

/**
* DECLARE_IDTENTRY - Declare functions for simple IDT entry points
@@ -52,12 +52,13 @@ static __always_inline void __##func(struct pt_regs *regs); \
\
__visible noinstr void func(struct pt_regs *regs) \
{ \
- irqentry_state_t state = irqentry_enter(regs); \
+ irqentry_state_t state; \
\
+ irqentry_enter(regs, &state); \
instrumentation_begin(); \
__##func (regs); \
instrumentation_end(); \
- irqentry_exit(regs, state); \
+ irqentry_exit(regs, &state); \
} \
\
static __always_inline void __##func(struct pt_regs *regs)
@@ -99,12 +100,13 @@ static __always_inline void __##func(struct pt_regs *regs, \
__visible noinstr void func(struct pt_regs *regs, \
unsigned long error_code) \
{ \
- irqentry_state_t state = irqentry_enter(regs); \
+ irqentry_state_t state; \
\
+ irqentry_enter(regs, &state); \
instrumentation_begin(); \
__##func (regs, error_code); \
instrumentation_end(); \
- irqentry_exit(regs, state); \
+ irqentry_exit(regs, &state); \
} \
\
static __always_inline void __##func(struct pt_regs *regs, \
@@ -195,15 +197,16 @@ static __always_inline void __##func(struct pt_regs *regs, u8 vector); \
__visible noinstr void func(struct pt_regs *regs, \
unsigned long error_code) \
{ \
- irqentry_state_t state = irqentry_enter(regs); \
+ irqentry_state_t state; \
\
+ irqentry_enter(regs, &state); \
instrumentation_begin(); \
irq_enter_rcu(); \
kvm_set_cpu_l1tf_flush_l1d(); \
__##func (regs, (u8)error_code); \
irq_exit_rcu(); \
instrumentation_end(); \
- irqentry_exit(regs, state); \
+ irqentry_exit(regs, &state); \
} \
\
static __always_inline void __##func(struct pt_regs *regs, u8 vector)
@@ -237,15 +240,16 @@ static void __##func(struct pt_regs *regs); \
\
__visible noinstr void func(struct pt_regs *regs) \
{ \
- irqentry_state_t state = irqentry_enter(regs); \
+ irqentry_state_t state; \
\
+ irqentry_enter(regs, &state); \
instrumentation_begin(); \
irq_enter_rcu(); \
kvm_set_cpu_l1tf_flush_l1d(); \
run_sysvec_on_irqstack_cond(__##func, regs); \
irq_exit_rcu(); \
instrumentation_end(); \
- irqentry_exit(regs, state); \
+ irqentry_exit(regs, &state); \
} \
\
static noinline void __##func(struct pt_regs *regs)
@@ -266,15 +270,16 @@ static __always_inline void __##func(struct pt_regs *regs); \
\
__visible noinstr void func(struct pt_regs *regs) \
{ \
- irqentry_state_t state = irqentry_enter(regs); \
+ irqentry_state_t state; \
\
+ irqentry_enter(regs, &state); \
instrumentation_begin(); \
__irq_enter_raw(); \
kvm_set_cpu_l1tf_flush_l1d(); \
__##func (regs); \
__irq_exit_raw(); \
instrumentation_end(); \
- irqentry_exit(regs, state); \
+ irqentry_exit(regs, &state); \
} \
\
static __always_inline void __##func(struct pt_regs *regs)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 9663ba31347c..c6be0a54236f 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -241,7 +241,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
if (!flags)
return false;

- state = irqentry_enter(regs);
+ irqentry_enter(regs, &state);
instrumentation_begin();

/*
@@ -262,7 +262,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
}

instrumentation_end();
- irqentry_exit(regs, state);
+ irqentry_exit(regs, &state);
return true;
}

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 4fc9954a9560..68c07cad0150 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -33,6 +33,7 @@
#include <asm/reboot.h>
#include <asm/cache.h>
#include <asm/nospec-branch.h>
+#include <asm/idtentry.h>

#define CREATE_TRACE_POINTS
#include <trace/events/nmi.h>
@@ -475,7 +476,7 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7);

DEFINE_IDTENTRY_RAW(exc_nmi)
{
- bool irq_state;
+ irqentry_state_t irq_state = { };

if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id()))
return;
@@ -490,14 +491,14 @@ DEFINE_IDTENTRY_RAW(exc_nmi)

this_cpu_write(nmi_dr7, local_db_save());

- irq_state = idtentry_enter_nmi(regs);
+ idtentry_enter_nmi(regs, &irq_state);

inc_irq_stat(__nmi_count);

if (!ignore_nmis)
default_do_nmi(regs);

- idtentry_exit_nmi(regs, irq_state);
+ idtentry_exit_nmi(regs, &irq_state);

local_db_restore(this_cpu_read(nmi_dr7));

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 81a2fb711091..daf7bc02fc99 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -254,11 +254,11 @@ DEFINE_IDTENTRY_RAW(exc_invalid_op)
if (!user_mode(regs) && handle_bug(regs))
return;

- state = irqentry_enter(regs);
+ irqentry_enter(regs, &state);
instrumentation_begin();
handle_invalid_op(regs);
instrumentation_end();
- irqentry_exit(regs, state);
+ irqentry_exit(regs, &state);
}

DEFINE_IDTENTRY(exc_coproc_segment_overrun)
@@ -342,6 +342,7 @@ __visible void __noreturn handle_stack_overflow(const char *message,
*/
DEFINE_IDTENTRY_DF(exc_double_fault)
{
+ irqentry_state_t irq_state;
static const char str[] = "double fault";
struct task_struct *tsk = current;

@@ -404,7 +405,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault)
}
#endif

- idtentry_enter_nmi(regs);
+ idtentry_enter_nmi(regs, &irq_state);
instrumentation_begin();
notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);

@@ -650,12 +651,15 @@ DEFINE_IDTENTRY_RAW(exc_int3)
instrumentation_end();
irqentry_exit_to_user_mode(regs);
} else {
- bool irq_state = idtentry_enter_nmi(regs);
+ irqentry_state_t irq_state;
+
+ idtentry_enter_nmi(regs, &irq_state);
+
instrumentation_begin();
if (!do_int3(regs))
die("int3", regs, 0);
instrumentation_end();
- idtentry_exit_nmi(regs, irq_state);
+ idtentry_exit_nmi(regs, &irq_state);
}
}

@@ -861,7 +865,9 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
* includes the entry stack is excluded for everything.
*/
unsigned long dr7 = local_db_save();
- bool irq_state = idtentry_enter_nmi(regs);
+ irqentry_state_t irq_state;
+
+ idtentry_enter_nmi(regs, &irq_state);
instrumentation_begin();

/*
@@ -880,8 +886,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
handle_debug(regs, dr6, false);

instrumentation_end();
- idtentry_exit_nmi(regs, irq_state);
-
+ idtentry_exit_nmi(regs, &irq_state);
local_db_restore(dr7);
}

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 6e3e8a124903..e55bc4bff389 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1476,11 +1476,11 @@ DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault)
* code reenabled RCU to avoid subsequent wreckage which helps
* debugability.
*/
- state = irqentry_enter(regs);
+ irqentry_enter(regs, &state);

instrumentation_begin();
handle_page_fault(regs, error_code, address);
instrumentation_end();

- irqentry_exit(regs, state);
+ irqentry_exit(regs, &state);
}
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 159c7476b11b..de4f24c554ee 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -349,6 +349,7 @@ typedef struct irqentry_state {
/**
* irqentry_enter - Handle state tracking on ordinary interrupt entries
* @regs: Pointer to pt_regs of interrupted context
+ * @state: Pointer to an object to store the irq state
*
* Invokes:
* - lockdep irqflag state tracking as low level ASM entry disabled
@@ -377,7 +378,7 @@ typedef struct irqentry_state {
*
* Returns: An opaque object that must be passed to idtentry_exit()
*/
-irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs);
+void noinstr irqentry_enter(struct pt_regs *regs, irqentry_state_t *state);

/**
* irqentry_exit_cond_resched - Conditionally reschedule on return from interrupt
@@ -389,7 +390,7 @@ void irqentry_exit_cond_resched(void);
/**
* irqentry_exit - Handle return from exception that used irqentry_enter()
* @regs: Pointer to pt_regs (exception entry regs)
- * @state: Return value from matching call to irqentry_enter()
+ * @state: Reference to the value saved in irqentry_enter()
*
* Depending on the return target (kernel/user) this runs the necessary
* preemption and work checks if possible and reguired and returns to
@@ -400,6 +401,6 @@ void irqentry_exit_cond_resched(void);
*
* Counterpart to irqentry_enter().
*/
-void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state);
+void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t *state);

#endif
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 6fdb6105e6d6..21601993ad1b 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -282,15 +282,13 @@ noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
exit_to_user_mode();
}

-noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
+noinstr void irqentry_enter(struct pt_regs *regs, irqentry_state_t *state)
{
- irqentry_state_t ret = {
- .exit_rcu = false,
- };
+ state->exit_rcu = false;

if (user_mode(regs)) {
irqentry_enter_from_user_mode(regs);
- return ret;
+ return;
}

/*
@@ -328,8 +326,8 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
trace_hardirqs_off_finish();
instrumentation_end();

- ret.exit_rcu = true;
- return ret;
+ state->exit_rcu = true;
+ return;
}

/*
@@ -343,8 +341,6 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
/* Use the combo lockdep/tracing function */
trace_hardirqs_off();
instrumentation_end();
-
- return ret;
}

void irqentry_exit_cond_resched(void)
@@ -359,7 +355,7 @@ void irqentry_exit_cond_resched(void)
}
}

-noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
+noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t *state)
{
lockdep_assert_irqs_disabled();

@@ -372,7 +368,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
* carefully and needs the same ordering of lockdep/tracing
* and RCU as the return to user mode path.
*/
- if (state.exit_rcu) {
+ if (state->exit_rcu) {
instrumentation_begin();
/* Tell the tracer that IRET will enable interrupts */
trace_hardirqs_on_prepare();
@@ -394,7 +390,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
* IRQ flags state is correct already. Just tell RCU if it
* was not watching on entry.
*/
- if (state.exit_rcu)
+ if (state->exit_rcu)
rcu_irq_exit();
}
}
--
2.28.0.rc0.12.gb6a658bd00c9
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