[Xen-ia64-devel] [PATCH 02/28] ia64/xen: introduce ia64_get_psr_i() to make kernel paravirtualization friendly.

[yamahata@xxxxxxxxxxxxx]

__local_irq_save() and local_save_flags() are used to mask interruptions.
They read all psr bits that requres whole bit emulation.
On the other hand, reading only psr.i, the single bit, can be virtualized
cheaply.

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
---
 include/asm-ia64/intrinsics.h |    2 ++
 include/asm-ia64/system.h     |    4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/asm-ia64/intrinsics.h b/include/asm-ia64/intrinsics.h
index c206755..5800ad0 100644
--- a/include/asm-ia64/intrinsics.h
+++ b/include/asm-ia64/intrinsics.h
@@ -18,6 +18,8 @@
 # include <asm/gcc_intrin.h>
 #endif
 
+#define ia64_get_psr_i()       (ia64_getreg(_IA64_REG_PSR) & IA64_PSR_I)
+
 #define ia64_set_rr0_to_rr4(val0, val1, val2, val3, val4)      \
 do {                                                           \
        ia64_set_rr(0x0000000000000000UL, (val0));              \
diff --git a/include/asm-ia64/system.h b/include/asm-ia64/system.h
index 595112b..2bca73e 100644
--- a/include/asm-ia64/system.h
+++ b/include/asm-ia64/system.h
@@ -125,7 +125,7 @@ extern struct ia64_boot_param {
 #define __local_irq_save(x)                    \
 do {                                           \
        ia64_stop();                            \
-       (x) = ia64_getreg(_IA64_REG_PSR);       \
+       (x) = ia64_get_psr_i();                 \
        ia64_stop();                            \
        ia64_rsm(IA64_PSR_I);                   \
 } while (0)
@@ -173,7 +173,7 @@ do {                                                        
        \
 #endif /* !CONFIG_IA64_DEBUG_IRQ */
 
 #define local_irq_enable()     ({ ia64_stop(); ia64_ssm(IA64_PSR_I); 
ia64_srlz_d(); })
-#define local_save_flags(flags)        ({ ia64_stop(); (flags) = 
ia64_getreg(_IA64_REG_PSR); })
+#define local_save_flags(flags)        ({ ia64_stop(); (flags) = 
ia64_get_psr_i(); })
 
 #define irqs_disabled()                                \
 ({                                             \
-- 
1.5.3

-- 
yamahata

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