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Split kerne timekeep ABI structure vdso_sv_tk out of the struct

Browse source 
sysentvec.  This allows the timekeep data to be shared between similar
ABIs which cannot share sysentvec.

Make the timekeep_push_vdso() tick callback to the timekeep structures
instead of sysentvecs.  If several sysentvec share the vdso_sv_tk
structure, we would update the userspace data several times on each
tick, without the change.

Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when
sysentvec is marked with the new SV_TIMEKEEP flag.  This saves
allocation and update of unneeded vdso_sv_tk for ABIs which do not
provide userspace gettimeofday yet, which are PowerPCs arches right
now.

Make vdso_sv_tk allocator public, namely split out and export
alloc_sv_tk() and alloc_sv_tk_compat32().  ABIs which share timekeep
data now can allocate it manually and share as appropriate.

Requested by:	nwhitehorn
Tested by:	nwhitehorn, pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2015-11-23 07:09:35 +00:00
parent c80e2a5d2b
commit 5e27d79314
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=291171
6 changed files with 95 additions and 53 deletions
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2
sys/amd64/amd64/elf_machdep.c
View file

@ -75,7 +75,7 @@ struct sysentvec elf64_freebsd_sysvec = {
.sv_setregs = exec_setregs,
.sv_fixlimit = NULL,
.sv_maxssiz = NULL,
.sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP,
.sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_TIMEKEEP,
.sv_set_syscall_retval = cpu_set_syscall_retval,
.sv_fetch_syscall_args = cpu_fetch_syscall_args,
.sv_syscallnames = syscallnames,

2
sys/compat/ia32/ia32_sysvec.c
View file

@ -125,7 +125,7 @@ struct sysentvec ia32_freebsd_sysvec = {
.sv_maxssiz = &ia32_maxssiz,
.sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 |
#ifdef __amd64__
SV_SHP
SV_SHP | SV_TIMEKEEP
#else
0
#endif

3
sys/i386/i386/elf_machdep.c
View file

@ -81,7 +81,8 @@ struct sysentvec elf32_freebsd_sysvec = {
.sv_setregs = exec_setregs,
.sv_fixlimit = NULL,
.sv_maxssiz = NULL,
.sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 | SV_SHP,
.sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 | SV_SHP |
SV_TIMEKEEP,
.sv_set_syscall_retval = cpu_set_syscall_retval,
.sv_fetch_syscall_args = cpu_fetch_syscall_args,
.sv_syscallnames = syscallnames,

125
sys/kern/kern_sharedpage.c
View file

@ -1,7 +1,11 @@
/*-
* Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2015 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@ -34,6 +38,7 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/rwlock.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
@ -127,7 +132,7 @@ SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
* calls us after the timehands are updated).
*/
static void
timehands_update(struct sysentvec *sv)
timehands_update(struct vdso_sv_tk *svtk)
{
struct vdso_timehands th;
struct vdso_timekeep *tk;
@ -135,20 +140,20 @@ timehands_update(struct sysentvec *sv)
enabled = tc_fill_vdso_timehands(&th);
th.th_gen = 0;
idx = sv->sv_timekeep_curr;
idx = svtk->sv_timekeep_curr;
if (++idx >= VDSO_TH_NUM)
idx = 0;
sv->sv_timekeep_curr = idx;
if (++sv->sv_timekeep_gen == 0)
sv->sv_timekeep_gen = 1;
svtk->sv_timekeep_curr = idx;
if (++svtk->sv_timekeep_gen == 0)
svtk->sv_timekeep_gen = 1;
tk = (struct vdso_timekeep *)(shared_page_mapping +
sv->sv_timekeep_off);
svtk->sv_timekeep_off);
tk->tk_th[idx].th_gen = 0;
atomic_thread_fence_rel();
if (enabled)
tk->tk_th[idx] = th;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_current, idx);
/*
@ -160,7 +165,7 @@ timehands_update(struct sysentvec *sv)
#ifdef COMPAT_FREEBSD32
static void
timehands_update32(struct sysentvec *sv)
timehands_update32(struct vdso_sv_tk *svtk)
{
struct vdso_timehands32 th;
struct vdso_timekeep32 *tk;
@ -168,20 +173,20 @@ timehands_update32(struct sysentvec *sv)
enabled = tc_fill_vdso_timehands32(&th);
th.th_gen = 0;
idx = sv->sv_timekeep_curr;
idx = svtk->sv_timekeep_curr;
if (++idx >= VDSO_TH_NUM)
idx = 0;
sv->sv_timekeep_curr = idx;
if (++sv->sv_timekeep_gen == 0)
sv->sv_timekeep_gen = 1;
svtk->sv_timekeep_curr = idx;
if (++svtk->sv_timekeep_gen == 0)
svtk->sv_timekeep_gen = 1;
tk = (struct vdso_timekeep32 *)(shared_page_mapping +
sv->sv_timekeep_off);
svtk->sv_timekeep_off);
tk->tk_th[idx].th_gen = 0;
atomic_thread_fence_rel();
if (enabled)
tk->tk_th[idx] = th;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, sv->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_current, idx);
tk->tk_enabled = enabled;
}
@ -192,33 +197,69 @@ timehands_update32(struct sysentvec *sv)
* that needs to be iterated over from the hardclock interrupt
* context.
*/
static struct sysentvec *host_sysentvec;
static struct vdso_sv_tk *host_svtk;
#ifdef COMPAT_FREEBSD32
static struct sysentvec *compat32_sysentvec;
static struct vdso_sv_tk *compat32_svtk;
#endif
void
timekeep_push_vdso(void)
{
if (host_sysentvec != NULL && host_sysentvec->sv_timekeep_base != 0)
timehands_update(host_sysentvec);
if (host_svtk != NULL)
timehands_update(host_svtk);
#ifdef COMPAT_FREEBSD32
if (compat32_sysentvec != NULL &&
compat32_sysentvec->sv_timekeep_base != 0)
timehands_update32(compat32_sysentvec);
if (compat32_svtk != NULL)
timehands_update32(compat32_svtk);
#endif
}
struct vdso_sv_tk *
alloc_sv_tk(void)
{
struct vdso_sv_tk *svtk;
int tk_base;
uint32_t tk_ver;
tk_ver = VDSO_TK_VER_CURR;
svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for native"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep, tk_ver),
sizeof(uint32_t), &tk_ver);
svtk->sv_timekeep_off = tk_base;
timekeep_push_vdso();
return (svtk);
}
#ifdef COMPAT_FREEBSD32
struct vdso_sv_tk *
alloc_sv_tk_compat32(void)
{
struct vdso_sv_tk *svtk;
int tk_base;
uint32_t tk_ver;
svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
tk_ver = VDSO_TK_VER_CURR;
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
tk_ver), sizeof(uint32_t), &tk_ver);
svtk->sv_timekeep_off = tk_base;
timekeep_push_vdso();
return (svtk);
}
#endif
void
exec_sysvec_init(void *param)
{
struct sysentvec *sv;
int tk_base;
uint32_t tk_ver;
sv = (struct sysentvec *)param;
if ((sv->sv_flags & SV_SHP) == 0)
return;
sv->sv_shared_page_obj = shared_page_obj;
@ -226,30 +267,22 @@ exec_sysvec_init(void *param)
shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
return;
tk_ver = VDSO_TK_VER_CURR;
if ((sv->sv_flags & SV_TIMEKEEP) != 0) {
#ifdef COMPAT_FREEBSD32
if ((sv->sv_flags & SV_ILP32) != 0) {
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
tk_ver), sizeof(uint32_t), &tk_ver);
KASSERT(compat32_sysentvec == 0,
("Native compat32 already registered"));
compat32_sysentvec = sv;
} else {
if ((sv->sv_flags & SV_ILP32) != 0) {
KASSERT(compat32_svtk == NULL,
("Compat32 already registered"));
compat32_svtk = alloc_sv_tk_compat32();
sv->sv_timekeep_base = sv->sv_shared_page_base +
compat32_svtk->sv_timekeep_off;
} else {
#endif
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for native"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep,
tk_ver), sizeof(uint32_t), &tk_ver);
KASSERT(host_sysentvec == 0, ("Native already registered"));
host_sysentvec = sv;
KASSERT(host_svtk == NULL, ("Host already registered"));
host_svtk = alloc_sv_tk();
sv->sv_timekeep_base = sv->sv_shared_page_base +
host_svtk->sv_timekeep_off;
#ifdef COMPAT_FREEBSD32
}
#endif
}
#endif
sv->sv_timekeep_base = sv->sv_shared_page_base + tk_base;
sv->sv_timekeep_off = tk_base;
timekeep_push_vdso();
}

7
sys/sys/sysent.h
View file

@ -127,13 +127,10 @@ struct sysentvec {
int (*sv_fetch_syscall_args)(struct thread *, struct
syscall_args *);
const char **sv_syscallnames;
vm_offset_t sv_timekeep_base;
vm_offset_t sv_shared_page_base;
vm_offset_t sv_shared_page_len;
vm_offset_t sv_sigcode_base;
vm_offset_t sv_timekeep_base;
int sv_timekeep_off;
int sv_timekeep_curr;
uint32_t sv_timekeep_gen;
void *sv_shared_page_obj;
void (*sv_schedtail)(struct thread *);
void (*sv_thread_detach)(struct thread *);
@ -145,6 +142,7 @@ struct sysentvec {
#define SV_AOUT 0x008000 /* a.out executable. */
#define SV_SHP 0x010000 /* Shared page. */
#define SV_CAPSICUM 0x020000 /* Force cap_enter() on startup. */
#define SV_TIMEKEEP 0x040000
#define SV_ABI_MASK 0xff
#define SV_PROC_FLAG(p, x) ((p)->p_sysent->sv_flags & (x))
@ -274,6 +272,7 @@ int shared_page_alloc(int size, int align);
int shared_page_fill(int size, int align, const void *data);
void shared_page_write(int base, int size, const void *data);
void exec_sysvec_init(void *param);
void exec_inittk(void);
#define INIT_SYSENTVEC(name, sv) \
SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY, \

9
sys/sys/vdso.h
View file

@ -71,6 +71,12 @@ int __vdso_gettimekeep(struct vdso_timekeep **tk);
struct timecounter;
struct vdso_sv_tk {
int sv_timekeep_off;
int sv_timekeep_curr;
uint32_t sv_timekeep_gen;
};
void timekeep_push_vdso(void);
uint32_t tc_fill_vdso_timehands(struct vdso_timehands *vdso_th);
@ -86,6 +92,8 @@ uint32_t tc_fill_vdso_timehands(struct vdso_timehands *vdso_th);
uint32_t cpu_fill_vdso_timehands(struct vdso_timehands *vdso_th,
struct timecounter *tc);
struct vdso_sv_tk *alloc_sv_tk(void);
#define VDSO_TH_NUM 4
#ifdef COMPAT_FREEBSD32
@ -115,6 +123,7 @@ struct vdso_timekeep32 {
uint32_t tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32);
uint32_t cpu_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32,
struct timecounter *tc);
struct vdso_sv_tk *alloc_sv_tk_compat32(void);
#endif
#endif