freebsd-dev/sys/i386/include/pcpu.h

186 lines
5.9 KiB
C
Raw Normal View History

/*-
* Copyright (c) Peter Wemm
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
1999-08-28 01:08:13 +00:00
* $FreeBSD$
*/
#ifndef _MACHINE_PCPU_H_
#define _MACHINE_PCPU_H_
#ifndef _SYS_CDEFS_H_
#error "sys/cdefs.h is a prerequisite for this file"
#endif
#ifdef _KERNEL
#include <machine/segments.h>
#include <machine/tss.h>
/*
* The SMP parts are setup in pmap.c and locore.s for the BSP, and
* mp_machdep.c sets up the data for the AP's to "see" when they awake.
* The reason for doing it via a struct is so that an array of pointers
* to each CPU's data can be set up for things like "check curproc on all
* other processors"
*/
#define PCPU_MD_FIELDS \
struct pcpu *pc_prvspace; /* Self-reference */ \
struct pmap *pc_curpmap; \
struct i386tss pc_common_tss; \
struct segment_descriptor pc_common_tssd; \
struct segment_descriptor *pc_tss_gdt; \
Change the segment limits to 4GB, we set the user accessible bit on all of the kernel address space already. Intel recommend this anyway, because using a non-4GB limit adds an additional clock cycle to address generation. We were able to install 4GB segments into the LDT, so any limits we imposed on %cs and %ds were academic anyway. More importantly, this allows us to make a page in the kernel readable to user applications, for holding things like the signal trampoline and other fun things. Move the user %cs/%ds segments from the LDT to the GDT. There was no good reason for them to be there anyway. The old LDT entries are still there but we can now relax the restriction that prevented users from emptying the default LDT entries. Putting user and kernel %cs and %ds together allows us to access the fast sysenter/sysexit/syscall/sysret instructions. syscall/sysret in particular require that the user/kernel segments be laid out this way. Reserve a slot specifically for NDIS while here. Create two user controllable slots in the GDT that are context switched with the (kernel) thread. This allows user applications to set two user privilige selectors to arbitary values. Create i386_set_fsbase(void *base) and friends. (get/set, fs/gs). For i386, %gs is used by tls and the thread libraries and this means that user processes no longer have to have the cost of having a custom LDT, and we will no longer to do a ldt switch when activating a kthread/ithread in the usual case any more. In other words, we can now set the base address for %fs and %gs to arbitary addresses without the pain of messing with ldt segments.
2005-04-13 22:57:17 +00:00
struct segment_descriptor *pc_fsgs_gdt; \
int pc_currentldt; \
u_int pc_acpi_id; /* ACPI CPU id */ \
u_int pc_apic_id; \
int pc_private_tss /* Flag indicating private tss */
#ifdef lint
extern struct pcpu *pcpup;
#define PCPU_GET(member) (pcpup->pc_ ## member)
#define PCPU_LAZY_INC(member) (++pcpup->pc_ ## member)
#define PCPU_PTR(member) (&pcpup->pc_ ## member)
#define PCPU_SET(member, val) (pcpup->pc_ ## member = (val))
#elif defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE___TYPEOF)
/*
* Evaluates to the byte offset of the per-cpu variable name.
*/
#define __pcpu_offset(name) \
__offsetof(struct pcpu, name)
/*
* Evaluates to the type of the per-cpu variable name.
*/
#define __pcpu_type(name) \
__typeof(((struct pcpu *)0)->name)
/*
* Evaluates to the address of the per-cpu variable name.
*/
#define __PCPU_PTR(name) __extension__ ({ \
__pcpu_type(name) *__p; \
\
__asm __volatile("movl %%fs:%1,%0; addl %2,%0" \
: "=r" (__p) \
: "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace))), \
"i" (__pcpu_offset(name))); \
\
__p; \
})
/*
* Evaluates to the value of the per-cpu variable name.
*/
#define __PCPU_GET(name) __extension__ ({ \
__pcpu_type(name) __res; \
struct __s { \
u_char __b[MIN(sizeof(__pcpu_type(name)), 4)]; \
} __s; \
\
if (sizeof(__res) == 1 || sizeof(__res) == 2 || \
sizeof(__res) == 4) { \
Simplified PCPU_GET() and PCPU_SET(). We must copy through a temporary variable to avoid invalid constraints in dead code. Use an array of u_char's (inside a struct) instead of a char/short/int/long variable so that the variable and its accesses can be spelled in the same way in all cases and code doesn't need to be cloned just to hold the spelling differences. Fixed strict-aliasing errors in PCPU_SET() and in the amd64 PCPU_GET(). Cast to (void *) as in rev.1.37 of the i386 version where the errors were fixed for the i386 PCPU_GET() only. It would be more correct to copy to and from the temp. variable using memcpy(), but then an ifdef tangle would be required to ensure using the builtin memcpy(). We depend on fairly aggressive optimization to put the temp. variable only in a register despite it being copied using *(type *)(void *)&anothertype and could depend on this when using memcpy() too. This seems to work right even for -O0, but the -O0 case has not been completely tested. This change gives identical object code for all object files in LINT on amd64 (except for one file with a __TIME__ stamp). For LINT on i386 it gives unimportant differences in instruction order and padding in a few object files. This was only tested for -O. This change (actually a previous version of it) gives the following reductions in the number of object files in LINT that fail to compile with -O2 but without the -fno-strict-aliasing kludge: - amd64: 29 (down from 211) - i386: 36 (down from 47) gcc-3.4.6 actually allows the invalid constraints that result from not using the temp. variable, at least with -O[1-2], but gcc-3.3.3 crashes on them and I don't want to depend on compiler bugs.
2007-02-06 16:21:09 +00:00
__asm __volatile("mov %%fs:%1,%0" \
: "=r" (__s) \
: "m" (*(struct __s *)(__pcpu_offset(name)))); \
*(struct __s *)(void *)&__res = __s; \
} else { \
__res = *__PCPU_PTR(name); \
} \
__res; \
})
/*
* Increments the value of the per-cpu counter name. The implementation
* must be atomic with respect to interrupts.
*/
#define __PCPU_LAZY_INC(name) do { \
CTASSERT(sizeof(__pcpu_type(name)) == 1 || \
sizeof(__pcpu_type(name)) == 2 || \
sizeof(__pcpu_type(name)) == 4); \
if (sizeof(__pcpu_type(name)) == 1) { \
__asm __volatile("incb %%fs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} else if (sizeof(__pcpu_type(name)) == 2) { \
__asm __volatile("incw %%fs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} else if (sizeof(__pcpu_type(name)) == 4) { \
__asm __volatile("incl %%fs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} \
} while (0)
/*
* Sets the value of the per-cpu variable name to value val.
*/
#define __PCPU_SET(name, val) { \
__pcpu_type(name) __val; \
struct __s { \
u_char __b[MIN(sizeof(__pcpu_type(name)), 4)]; \
} __s; \
\
__val = (val); \
Simplified PCPU_GET() and PCPU_SET(). We must copy through a temporary variable to avoid invalid constraints in dead code. Use an array of u_char's (inside a struct) instead of a char/short/int/long variable so that the variable and its accesses can be spelled in the same way in all cases and code doesn't need to be cloned just to hold the spelling differences. Fixed strict-aliasing errors in PCPU_SET() and in the amd64 PCPU_GET(). Cast to (void *) as in rev.1.37 of the i386 version where the errors were fixed for the i386 PCPU_GET() only. It would be more correct to copy to and from the temp. variable using memcpy(), but then an ifdef tangle would be required to ensure using the builtin memcpy(). We depend on fairly aggressive optimization to put the temp. variable only in a register despite it being copied using *(type *)(void *)&anothertype and could depend on this when using memcpy() too. This seems to work right even for -O0, but the -O0 case has not been completely tested. This change gives identical object code for all object files in LINT on amd64 (except for one file with a __TIME__ stamp). For LINT on i386 it gives unimportant differences in instruction order and padding in a few object files. This was only tested for -O. This change (actually a previous version of it) gives the following reductions in the number of object files in LINT that fail to compile with -O2 but without the -fno-strict-aliasing kludge: - amd64: 29 (down from 211) - i386: 36 (down from 47) gcc-3.4.6 actually allows the invalid constraints that result from not using the temp. variable, at least with -O[1-2], but gcc-3.3.3 crashes on them and I don't want to depend on compiler bugs.
2007-02-06 16:21:09 +00:00
if (sizeof(__val) == 1 || sizeof(__val) == 2 || \
sizeof(__val) == 4) { \
__s = *(struct __s *)(void *)&__val; \
__asm __volatile("mov %1,%%fs:%0" \
: "=m" (*(struct __s *)(__pcpu_offset(name))) \
: "r" (__s)); \
} else { \
*__PCPU_PTR(name) = __val; \
} \
}
#define PCPU_GET(member) __PCPU_GET(pc_ ## member)
#define PCPU_LAZY_INC(member) __PCPU_LAZY_INC(pc_ ## member)
#define PCPU_PTR(member) __PCPU_PTR(pc_ ## member)
#define PCPU_SET(member, val) __PCPU_SET(pc_ ## member, val)
static __inline struct thread *
__curthread(void)
{
struct thread *td;
__asm __volatile("movl %%fs:0,%0" : "=r" (td));
return (td);
}
#define curthread (__curthread())
#else /* !lint || defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE___TYPEOF) */
#error "this file needs to be ported to your compiler"
#endif /* lint, etc. */
#endif /* _KERNEL */
#endif /* !_MACHINE_PCPU_H_ */