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kernel-fxtec-pro1x/include/asm-sparc64/system.h
David S. Miller 56fb4df6da [SPARC64]: Elminate all usage of hard-coded trap globals. 
UltraSPARC has special sets of global registers which are switched to
for certain trap types.  There is one set for MMU related traps, one
set of Interrupt Vector processing, and another set (called the
Alternate globals) for all other trap types.

For what seems like forever we've hard coded the values in some of
these trap registers.  Some examples include:

1) Interrupt Vector global %g6 holds current processors interrupt
   work struct where received interrupts are managed for IRQ handler
   dispatch.

2) MMU global %g7 holds the base of the page tables of the currently
   active address space.

3) Alternate global %g6 held the current_thread_info() value.

Such hardcoding has resulted in some serious issues in many areas.
There are some code sequences where having another register available
would help clean up the implementation.  Taking traps such as
cross-calls from the OBP firmware requires some trick code sequences
wherein we have to save away and restore all of the special sets of
global registers when we enter/exit OBP.

We were also using the IMMU TSB register on SMP to hold the per-cpu
area base address, which doesn't work any longer now that we actually
use the TSB facility of the cpu.

The implementation is pretty straight forward.  One tricky bit is
getting the current processor ID as that is different on different cpu
variants.  We use a stub with a fancy calling convention which we
patch at boot time.  The calling convention is that the stub is
branched to and the (PC - 4) to return to is in register %g1.  The cpu
number is left in %g6.  This stub can be invoked by using the
__GET_CPUID macro.

We use an array of per-cpu trap state to store the current thread and
physical address of the current address space's page tables.  The
TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this
table, it uses __GET_CPUID and also clobbers %g1.

TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load
the current processor's IRQ software state into %g6.  It also uses
__GET_CPUID and clobbers %g1.

Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the
current address space's page tables into %g7, it clobbers %g1 and uses
__GET_CPUID.

Many refinements are possible, as well as some tuning, with this stuff
in place.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:16 -08:00

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/* $Id: system.h,v 1.69 2002/02/09 19:49:31 davem Exp $ */
#ifndef __SPARC64_SYSTEM_H
#define __SPARC64_SYSTEM_H
#include <linux/config.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/visasm.h>
#ifndef __ASSEMBLY__
/*
* Sparc (general) CPU types
*/
enum sparc_cpu {
sun4 = 0x00,
sun4c = 0x01,
sun4m = 0x02,
sun4d = 0x03,
sun4e = 0x04,
sun4u = 0x05, /* V8 ploos ploos */
sun_unknown = 0x06,
ap1000 = 0x07, /* almost a sun4m */
};
#define sparc_cpu_model sun4u
/* This cannot ever be a sun4c nor sun4 :) That's just history. */
#define ARCH_SUN4C_SUN4 0
#define ARCH_SUN4 0
/* These are here in an effort to more fully work around Spitfire Errata
* #51. Essentially, if a memory barrier occurs soon after a mispredicted
* branch, the chip can stop executing instructions until a trap occurs.
* Therefore, if interrupts are disabled, the chip can hang forever.
*
* It used to be believed that the memory barrier had to be right in the
* delay slot, but a case has been traced recently wherein the memory barrier
* was one instruction after the branch delay slot and the chip still hung.
* The offending sequence was the following in sym_wakeup_done() of the
* sym53c8xx_2 driver:
*
* call sym_ccb_from_dsa, 0
* movge %icc, 0, %l0
* brz,pn %o0, .LL1303
* mov %o0, %l2
* membar #LoadLoad
*
* The branch has to be mispredicted for the bug to occur. Therefore, we put
* the memory barrier explicitly into a "branch always, predicted taken"
* delay slot to avoid the problem case.
*/
#define membar_safe(type) \
do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \
" membar " type "\n" \
"1:\n" \
: : : "memory"); \
} while (0)
#define mb() \
membar_safe("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")
#define rmb() \
membar_safe("#LoadLoad")
#define wmb() \
membar_safe("#StoreStore")
#define membar_storeload() \
membar_safe("#StoreLoad")
#define membar_storeload_storestore() \
membar_safe("#StoreLoad | #StoreStore")
#define membar_storeload_loadload() \
membar_safe("#StoreLoad | #LoadLoad")
#define membar_storestore_loadstore() \
membar_safe("#StoreStore | #LoadStore")
#endif
#define setipl(__new_ipl) \
__asm__ __volatile__("wrpr %0, %%pil" : : "r" (__new_ipl) : "memory")
#define local_irq_disable() \
__asm__ __volatile__("wrpr 15, %%pil" : : : "memory")
#define local_irq_enable() \
__asm__ __volatile__("wrpr 0, %%pil" : : : "memory")
#define getipl() \
({ unsigned long retval; __asm__ __volatile__("rdpr %%pil, %0" : "=r" (retval)); retval; })
#define swap_pil(__new_pil) \
({ unsigned long retval; \
__asm__ __volatile__("rdpr %%pil, %0\n\t" \
"wrpr %1, %%pil" \
: "=&r" (retval) \
: "r" (__new_pil) \
: "memory"); \
retval; \
})
#define read_pil_and_cli() \
({ unsigned long retval; \
__asm__ __volatile__("rdpr %%pil, %0\n\t" \
"wrpr 15, %%pil" \
: "=r" (retval) \
: : "memory"); \
retval; \
})
#define local_save_flags(flags) ((flags) = getipl())
#define local_irq_save(flags) ((flags) = read_pil_and_cli())
#define local_irq_restore(flags) setipl((flags))
/* On sparc64 IRQ flags are the PIL register. A value of zero
* means all interrupt levels are enabled, any other value means
* only IRQ levels greater than that value will be received.
* Consequently this means that the lowest IRQ level is one.
*/
#define irqs_disabled() \
({ unsigned long flags; \
local_save_flags(flags);\
(flags > 0); \
})
#define nop() __asm__ __volatile__ ("nop")
#define read_barrier_depends() do { } while(0)
#define set_mb(__var, __value) \
do { __var = __value; membar_storeload_storestore(); } while(0)
#define set_wmb(__var, __value) \
do { __var = __value; wmb(); } while(0)
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() __asm__ __volatile__("":::"memory")
#define smp_rmb() __asm__ __volatile__("":::"memory")
#define smp_wmb() __asm__ __volatile__("":::"memory")
#define smp_read_barrier_depends() do { } while(0)
#endif
#define flushi(addr) __asm__ __volatile__ ("flush %0" : : "r" (addr) : "memory")
#define flushw_all() __asm__ __volatile__("flushw")
/* Performance counter register access. */
#define read_pcr(__p) __asm__ __volatile__("rd %%pcr, %0" : "=r" (__p))
#define write_pcr(__p) __asm__ __volatile__("wr %0, 0x0, %%pcr" : : "r" (__p))
#define read_pic(__p) __asm__ __volatile__("rd %%pic, %0" : "=r" (__p))
/* Blackbird errata workaround. See commentary in
* arch/sparc64/kernel/smp.c:smp_percpu_timer_interrupt()
* for more information.
*/
#define reset_pic() \
__asm__ __volatile__("ba,pt %xcc, 99f\n\t" \
".align 64\n" \
"99:wr %g0, 0x0, %pic\n\t" \
"rd %pic, %g0")
#ifndef __ASSEMBLY__
extern void sun_do_break(void);
extern int serial_console;
extern int stop_a_enabled;
static __inline__ int con_is_present(void)
{
return serial_console ? 0 : 1;
}
extern void synchronize_user_stack(void);
extern void __flushw_user(void);
#define flushw_user() __flushw_user()
#define flush_user_windows flushw_user
#define flush_register_windows flushw_all
/* Don't hold the runqueue lock over context switch */
#define __ARCH_WANT_UNLOCKED_CTXSW
#define prepare_arch_switch(next) \
do { \
flushw_all(); \
} while (0)
/* See what happens when you design the chip correctly?
*
* We tell gcc we clobber all non-fixed-usage registers except
* for l0/l1. It will use one for 'next' and the other to hold
* the output value of 'last'. 'next' is not referenced again
* past the invocation of switch_to in the scheduler, so we need
* not preserve it's value. Hairy, but it lets us remove 2 loads
* and 2 stores in this critical code path. -DaveM
*/
#define EXTRA_CLOBBER ,"%l1"
#define switch_to(prev, next, last) \
do { if (test_thread_flag(TIF_PERFCTR)) { \
unsigned long __tmp; \
read_pcr(__tmp); \
current_thread_info()->pcr_reg = __tmp; \
read_pic(__tmp); \
current_thread_info()->kernel_cntd0 += (unsigned int)(__tmp);\
current_thread_info()->kernel_cntd1 += ((__tmp) >> 32); \
} \
flush_tlb_pending(); \
save_and_clear_fpu(); \
/* If you are tempted to conditionalize the following */ \
/* so that ASI is only written if it changes, think again. */ \
__asm__ __volatile__("wr %%g0, %0, %%asi" \
: : "r" (__thread_flag_byte_ptr(task_thread_info(next))[TI_FLAG_BYTE_CURRENT_DS]));\
trap_block[current_thread_info()->cpu].thread = \
task_thread_info(next); \
__asm__ __volatile__( \
"mov %%g4, %%g7\n\t" \
"wrpr %%g0, 0x95, %%pstate\n\t" \
"stx %%i6, [%%sp + 2047 + 0x70]\n\t" \
"stx %%i7, [%%sp + 2047 + 0x78]\n\t" \
"rdpr %%wstate, %%o5\n\t" \
"stx %%o6, [%%g6 + %3]\n\t" \
"stb %%o5, [%%g6 + %2]\n\t" \
"rdpr %%cwp, %%o5\n\t" \
"stb %%o5, [%%g6 + %5]\n\t" \
"mov %1, %%g6\n\t" \
"ldub [%1 + %5], %%g1\n\t" \
"wrpr %%g1, %%cwp\n\t" \
"ldx [%%g6 + %3], %%o6\n\t" \
"ldub [%%g6 + %2], %%o5\n\t" \
"ldub [%%g6 + %4], %%o7\n\t" \
"mov %%g6, %%l2\n\t" \
"wrpr %%o5, 0x0, %%wstate\n\t" \
"ldx [%%sp + 2047 + 0x70], %%i6\n\t" \
"ldx [%%sp + 2047 + 0x78], %%i7\n\t" \
"wrpr %%g0, 0x94, %%pstate\n\t" \
"mov %%l2, %%g6\n\t" \
"ldx [%%g6 + %6], %%g4\n\t" \
"wrpr %%g0, 0x96, %%pstate\n\t" \
"brz,pt %%o7, 1f\n\t" \
" mov %%g7, %0\n\t" \
"b,a ret_from_syscall\n\t" \
"1:\n\t" \
: "=&r" (last) \
: "0" (task_thread_info(next)), \
"i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_NEW_CHILD), \
"i" (TI_CWP), "i" (TI_TASK) \
: "cc", \
"g1", "g2", "g3", "g7", \
"l2", "l3", "l4", "l5", "l6", "l7", \
"i0", "i1", "i2", "i3", "i4", "i5", \
"o0", "o1", "o2", "o3", "o4", "o5", "o7" EXTRA_CLOBBER);\
/* If you fuck with this, update ret_from_syscall code too. */ \
if (test_thread_flag(TIF_PERFCTR)) { \
write_pcr(current_thread_info()->pcr_reg); \
reset_pic(); \
} \
} while(0)
/*
* On SMP systems, when the scheduler does migration-cost autodetection,
* it needs a way to flush as much of the CPU's caches as possible.
*
* TODO: fill this in!
*/
static inline void sched_cacheflush(void)
{
}
static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__(
" membar #StoreLoad | #LoadLoad\n"
" mov %0, %1\n"
"1: lduw [%4], %2\n"
" cas [%4], %2, %0\n"
" cmp %2, %0\n"
" bne,a,pn %%icc, 1b\n"
" mov %1, %0\n"
" membar #StoreLoad | #StoreStore\n"
: "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
: "0" (val), "r" (m)
: "cc", "memory");
return val;
}
static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long val)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__(
" membar #StoreLoad | #LoadLoad\n"
" mov %0, %1\n"
"1: ldx [%4], %2\n"
" casx [%4], %2, %0\n"
" cmp %2, %0\n"
" bne,a,pn %%xcc, 1b\n"
" mov %1, %0\n"
" membar #StoreLoad | #StoreStore\n"
: "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
: "0" (val), "r" (m)
: "cc", "memory");
return val;
}
#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define tas(ptr) (xchg((ptr),1))
extern void __xchg_called_with_bad_pointer(void);
static __inline__ unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
int size)
{
switch (size) {
case 4:
return xchg32(ptr, x);
case 8:
return xchg64(ptr, x);
};
__xchg_called_with_bad_pointer();
return x;
}
extern void die_if_kernel(char *str, struct pt_regs *regs) __attribute__ ((noreturn));
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/
#define __HAVE_ARCH_CMPXCHG 1
static __inline__ unsigned long
__cmpxchg_u32(volatile int *m, int old, int new)
{
__asm__ __volatile__("membar #StoreLoad | #LoadLoad\n"
"cas [%2], %3, %0\n\t"
"membar #StoreLoad | #StoreStore"
: "=&r" (new)
: "0" (new), "r" (m), "r" (old)
: "memory");
return new;
}
static __inline__ unsigned long
__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
{
__asm__ __volatile__("membar #StoreLoad | #LoadLoad\n"
"casx [%2], %3, %0\n\t"
"membar #StoreLoad | #StoreStore"
: "=&r" (new)
: "0" (new), "r" (m), "r" (old)
: "memory");
return new;
}
/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);
static __inline__ unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
{
switch (size) {
case 4:
return __cmpxchg_u32(ptr, old, new);
case 8:
return __cmpxchg_u64(ptr, old, new);
}
__cmpxchg_called_with_bad_pointer();
return old;
}
#define cmpxchg(ptr,o,n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
(unsigned long)_n_, sizeof(*(ptr))); \
})
#endif /* !(__ASSEMBLY__) */
#define arch_align_stack(x) (x)
#endif /* !(__SPARC64_SYSTEM_H) */
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