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[XTENSA] Add support for configurable registers and coprocessors

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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>
This commit is contained in:
Chris Zankel
2008-02-12 13:17:07 -08:00
parent 71d28e6c28
commit c658eac628
17 changed files with 1076 additions and 885 deletions
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39
include/asm-xtensa/system.h
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@@ -46,42 +46,6 @@ static inline int irqs_disabled(void)
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 @@ extern void *_switch_to(void *last, void *next);
#define switch_to(prev,next,last) \
do { \
clear_cpenable(); \
(last) = _switch_to(prev, next); \
} while(0)
@@ -244,7 +207,7 @@ static inline void spill_registers(void)
"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)