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Create shared (readonly) page. Each ABI may specify the use of page by

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setting SV_SHP flag and providing pointer to the vm object and mapping
address. Provide simple allocator to carve space in the page, tailored
to put the code with alignment restrictions.

Enable shared page use for amd64, both native and 32bit FreeBSD
binaries.  Page is private mapped at the top of the user address
space, moving a start of the stack one page down. Move signal
trampoline code from the top of the stack to the shared page.

Reviewed by:	 alc
This commit is contained in:
Konstantin Belousov 2011-01-08 16:13:44 +00:00
parent ed167eaa80
commit 6297a3d843
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=217151
10 changed files with 132 additions and 18 deletions
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6
sys/amd64/amd64/elf_machdep.c
View File

@ -75,11 +75,14 @@ struct sysentvec elf64_freebsd_sysvec = {
.sv_setregs = exec_setregs,
.sv_fixlimit = NULL,
.sv_maxssiz = NULL,
.sv_flags = SV_ABI_FREEBSD | SV_LP64,
.sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP,
.sv_set_syscall_retval = cpu_set_syscall_retval,
.sv_fetch_syscall_args = cpu_fetch_syscall_args,
.sv_syscallnames = syscallnames,
.sv_shared_page_base = SHAREDPAGE,
.sv_shared_page_len = PAGE_SIZE,
};
INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);
static Elf64_Brandinfo freebsd_brand_info = {
.brand = ELFOSABI_FREEBSD,
@ -129,7 +132,6 @@ SYSINIT(kelf64, SI_SUB_EXEC, SI_ORDER_ANY,
(sysinit_cfunc_t) elf64_insert_brand_entry,
&kfreebsd_brand_info);
void
elf64_dump_thread(struct thread *td __unused, void *dst __unused,
size_t *off __unused)

2
sys/amd64/amd64/machdep.c
View File

@ -386,7 +386,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
}
regs->tf_rsp = (long)sfp;
regs->tf_rip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
regs->tf_rip = p->p_sysent->sv_sigcode_base;
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;

5
sys/amd64/ia32/ia32_signal.c
View File

@ -393,7 +393,8 @@ freebsd4_ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
}
regs->tf_rsp = (uintptr_t)sfp;
regs->tf_rip = p->p_sysent->sv_psstrings - sz_freebsd4_ia32_sigcode;
regs->tf_rip = p->p_sysent->sv_sigcode_base + sz_ia32_sigcode -
sz_freebsd4_ia32_sigcode;
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;
@ -514,7 +515,7 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
}
regs->tf_rsp = (uintptr_t)sfp;
regs->tf_rip = p->p_sysent->sv_psstrings - *(p->p_sysent->sv_szsigcode);
regs->tf_rip = p->p_sysent->sv_sigcode_base;
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;

3
sys/amd64/include/vmparam.h
View File

@ -186,7 +186,8 @@
#define VM_MAXUSER_ADDRESS UVADDR(NUPML4E, 0, 0, 0)
#define USRSTACK VM_MAXUSER_ADDRESS
#define SHAREDPAGE (VM_MAXUSER_ADDRESS - PAGE_SIZE)
#define USRSTACK SHAREDPAGE
#define VM_MAX_ADDRESS UPT_MAX_ADDRESS
#define VM_MIN_ADDRESS (0)

7
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -2546,7 +2546,10 @@ freebsd32_copyout_strings(struct image_params *imgp)
execpath_len = 0;
arginfo = (struct freebsd32_ps_strings *)curproc->p_sysent->
sv_psstrings;
szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
if (imgp->proc->p_sysent->sv_sigcode_base == 0)
szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
else
szsigcode = 0;
destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
roundup(execpath_len, sizeof(char *)) -
roundup(sizeof(canary), sizeof(char *)) -
@ -2556,7 +2559,7 @@ freebsd32_copyout_strings(struct image_params *imgp)
/*
* install sigcode
*/
if (szsigcode)
if (szsigcode != 0)
copyout(imgp->proc->p_sysent->sv_sigcode,
((caddr_t)arginfo - szsigcode), szsigcode);

15
sys/compat/ia32/ia32_sysvec.c
View File

@ -129,7 +129,7 @@ struct sysentvec ia32_freebsd_sysvec = {
.sv_minsigstksz = MINSIGSTKSZ,
.sv_pagesize = IA32_PAGE_SIZE,
.sv_minuser = 0,
.sv_maxuser = FREEBSD32_USRSTACK,
.sv_maxuser = FREEBSD32_MAXUSER,
.sv_usrstack = FREEBSD32_USRSTACK,
.sv_psstrings = FREEBSD32_PS_STRINGS,
.sv_stackprot = VM_PROT_ALL,
@ -137,12 +137,20 @@ struct sysentvec ia32_freebsd_sysvec = {
.sv_setregs = ia32_setregs,
.sv_fixlimit = ia32_fixlimit,
.sv_maxssiz = &ia32_maxssiz,
.sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32,
.sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 |
#ifdef __amd64__
SV_SHP
#else
0
#endif
,
.sv_set_syscall_retval = ia32_set_syscall_retval,
.sv_fetch_syscall_args = ia32_fetch_syscall_args,
.sv_syscallnames = freebsd32_syscallnames,
.sv_shared_page_base = FREEBSD32_SHAREDPAGE,
.sv_shared_page_len = PAGE_SIZE,
};
INIT_SYSENTVEC(elf_ia32_sysvec, &ia32_freebsd_sysvec);
static Elf32_Brandinfo ia32_brand_info = {
.brand = ELFOSABI_FREEBSD,
@ -191,7 +199,6 @@ SYSINIT(kia32, SI_SUB_EXEC, SI_ORDER_ANY,
(sysinit_cfunc_t) elf32_insert_brand_entry,
&kia32_brand_info);
void
elf32_dump_thread(struct thread *td __unused, void *dst __unused,
size_t *off __unused)

8
sys/compat/ia32/ia32_util.h
View File

@ -41,9 +41,13 @@
#include <sys/cdefs.h>
#ifdef __ia64__
#define FREEBSD32_USRSTACK ((1ul << 32) - IA32_PAGE_SIZE * 2)
#define FREEBSD32_MAXUSER ((1ul << 32) - IA32_PAGE_SIZE * 2)
#define FREEBSD32_SHAREDPAGE 0
#define FREEBSD32_USRSTACK FREEBSD32_MAXUSER
#else
#define FREEBSD32_USRSTACK ((1ul << 32) - IA32_PAGE_SIZE)
#define FREEBSD32_MAXUSER ((1ul << 32) - IA32_PAGE_SIZE)
#define FREEBSD32_SHAREDPAGE (FREEBSD32_MAXUSER - IA32_PAGE_SIZE)
#define FREEBSD32_USRSTACK FREEBSD32_SHAREDPAGE
#endif
#define IA32_PAGE_SIZE 4096

89
sys/kern/kern_exec.c
View File

@ -389,6 +389,7 @@ do_execve(td, args, mac_p)
imgp->canarylen = 0;
imgp->pagesizes = 0;
imgp->pagesizeslen = 0;
imgp->stack_prot = 0;
#ifdef MAC
error = mac_execve_enter(imgp, mac_p);
@ -996,6 +997,7 @@ exec_new_vmspace(imgp, sv)
int error;
struct proc *p = imgp->proc;
struct vmspace *vmspace = p->p_vmspace;
vm_object_t obj;
vm_offset_t sv_minuser, stack_addr;
vm_map_t map;
u_long ssiz;
@ -1029,6 +1031,20 @@ exec_new_vmspace(imgp, sv)
map = &vmspace->vm_map;
}
/* Map a shared page */
obj = sv->sv_shared_page_obj;
if (obj != NULL) {
vm_object_reference(obj);
error = vm_map_fixed(map, obj, 0,
sv->sv_shared_page_base, sv->sv_shared_page_len,
VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
MAP_COPY_ON_WRITE | MAP_ACC_NO_CHARGE);
if (error) {
vm_object_deallocate(obj);
return (error);
}
}
/* Allocate a new stack */
if (sv->sv_maxssiz != NULL)
ssiz = *sv->sv_maxssiz;
@ -1036,7 +1052,9 @@ exec_new_vmspace(imgp, sv)
ssiz = maxssiz;
stack_addr = sv->sv_usrstack - ssiz;
error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
sv->sv_stackprot,
VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
if (error)
return (error);
@ -1208,8 +1226,10 @@ exec_copyout_strings(imgp)
p = imgp->proc;
szsigcode = 0;
arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
if (p->p_sysent->sv_szsigcode != NULL)
szsigcode = *(p->p_sysent->sv_szsigcode);
if (p->p_sysent->sv_sigcode_base == 0) {
if (p->p_sysent->sv_szsigcode != NULL)
szsigcode = *(p->p_sysent->sv_szsigcode);
}
destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
roundup(execpath_len, sizeof(char *)) -
roundup(sizeof(canary), sizeof(char *)) -
@ -1219,7 +1239,7 @@ exec_copyout_strings(imgp)
/*
* install sigcode
*/
if (szsigcode)
if (szsigcode != 0)
copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
szsigcode), szsigcode);
@ -1459,3 +1479,64 @@ exec_unregister(execsw_arg)
execsw = newexecsw;
return (0);
}
static vm_object_t shared_page_obj;
static int shared_page_free;
int
shared_page_fill(int size, int align, const char *data)
{
vm_page_t m;
struct sf_buf *s;
vm_offset_t sk;
int res;
VM_OBJECT_LOCK(shared_page_obj);
m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY);
res = roundup(shared_page_free, align);
if (res + size >= IDX_TO_OFF(shared_page_obj->size))
res = -1;
else {
VM_OBJECT_UNLOCK(shared_page_obj);
s = sf_buf_alloc(m, SFB_DEFAULT);
sk = sf_buf_kva(s);
bcopy(data, (void *)(sk + res), size);
shared_page_free = res + size;
sf_buf_free(s);
VM_OBJECT_LOCK(shared_page_obj);
}
vm_page_wakeup(m);
VM_OBJECT_UNLOCK(shared_page_obj);
return (res);
}
static void
shared_page_init(void *dummy __unused)
{
vm_page_t m;
shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
VM_PROT_DEFAULT, 0, NULL);
VM_OBJECT_LOCK(shared_page_obj);
m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_RETRY | VM_ALLOC_NOBUSY |
VM_ALLOC_ZERO);
m->valid = VM_PAGE_BITS_ALL;
VM_OBJECT_UNLOCK(shared_page_obj);
}
SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
NULL);
void
exec_sysvec_init(void *param)
{
struct sysentvec *sv;
sv = (struct sysentvec *)param;
if ((sv->sv_flags & SV_SHP) == 0)
return;
sv->sv_shared_page_obj = shared_page_obj;
sv->sv_sigcode_base = sv->sv_shared_page_base +
shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
}

3
sys/sys/imgact.h
View File

@ -34,6 +34,8 @@
#include <sys/uio.h>
#include <vm/vm.h>
#define MAXSHELLCMDLEN PAGE_SIZE
struct image_args {
@ -75,6 +77,7 @@ struct image_params {
int canarylen;
unsigned long pagesizes;
int pagesizeslen;
vm_prot_t stack_prot;
};
#ifdef _KERNEL

12
sys/sys/sysent.h
View File

@ -116,12 +116,17 @@ struct sysentvec {
int (*sv_fetch_syscall_args)(struct thread *, struct
syscall_args *);
const char **sv_syscallnames;
vm_offset_t sv_shared_page_base;
vm_offset_t sv_shared_page_len;
vm_offset_t sv_sigcode_base;
void *sv_shared_page_obj;
};
#define SV_ILP32 0x000100
#define SV_LP64 0x000200
#define SV_IA32 0x004000
#define SV_AOUT 0x008000
#define SV_SHP 0x010000
#define SV_ABI_MASK 0xff
#define SV_CURPROC_FLAG(x) (curproc->p_sysent->sv_flags & (x))
@ -222,6 +227,13 @@ int lkmressys(struct thread *, struct nosys_args *);
int syscall_thread_enter(struct thread *td, struct sysent *se);
void syscall_thread_exit(struct thread *td, struct sysent *se);
int shared_page_fill(int size, int align, const char *data);
void exec_sysvec_init(void *param);
#define INIT_SYSENTVEC(name, sv) \
SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY, \
(sysinit_cfunc_t)exec_sysvec_init, sv);
#endif /* _KERNEL */
#endif /* !_SYS_SYSENT_H_ */