[XTENSA] Add support for configurable registers and coprocessors
The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.
This patch adds support for these additional states:
- save and restore registers that are used by the compiler upon
interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/include/asm-xtensa/system.h b/include/asm-xtensa/system.h
index e0cb911..62b1e8f 100644
--- a/include/asm-xtensa/system.h
+++ b/include/asm-xtensa/system.h
@@ -46,42 +46,6 @@
return flags & 0xf;
}
-#define RSR_CPENABLE(x) do { \
- __asm__ __volatile__("rsr %0," __stringify(CPENABLE) : "=a" (x)); \
- } while(0);
-#define WSR_CPENABLE(x) do { \
- __asm__ __volatile__("wsr %0," __stringify(CPENABLE)";rsync" \
- :: "a" (x));} while(0);
-
-#define clear_cpenable() __clear_cpenable()
-
-static inline void __clear_cpenable(void)
-{
-#if XCHAL_HAVE_CP
- unsigned long i = 0;
- WSR_CPENABLE(i);
-#endif
-}
-
-static inline void enable_coprocessor(int i)
-{
-#if XCHAL_HAVE_CP
- int cp;
- RSR_CPENABLE(cp);
- cp |= 1 << i;
- WSR_CPENABLE(cp);
-#endif
-}
-
-static inline void disable_coprocessor(int i)
-{
-#if XCHAL_HAVE_CP
- int cp;
- RSR_CPENABLE(cp);
- cp &= ~(1 << i);
- WSR_CPENABLE(cp);
-#endif
-}
#define smp_read_barrier_depends() do { } while(0)
#define read_barrier_depends() do { } while(0)
@@ -111,7 +75,6 @@
#define switch_to(prev,next,last) \
do { \
- clear_cpenable(); \
(last) = _switch_to(prev, next); \
} while(0)
@@ -244,7 +207,7 @@
"wsr a13," __stringify(SAR) "\n\t"
"wsr a14," __stringify(PS) "\n\t"
:: "a" (&a0), "a" (&ps)
- : "a2", "a3", "a12", "a13", "a14", "a15", "memory");
+ : "a2", "a3", "a4", "a7", "a11", "a12", "a13", "a14", "a15", "memory");
}
#define arch_align_stack(x) (x)