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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2013 Joyent, Inc. All rights reserved.
*/
/*
* Don't Panic! If you find the blocks of assembly that follow confusing and
* you're questioning why they exist, please go read section 8 of the umem.c big
* theory statement. Next familiarize yourself with the malloc and free
* implementations in libumem's malloc.c.
*
* What follows is the amd64 implementation of the thread caching automatic
* assembly generation. The amd64 calling conventions are documented in the
* 64-bit System V ABI. For our purposes what matters is that our first argument
* will come in rdi. Our functions have to preserve rbp, rbx, and r12->r15. We
* are free to do whatever we want with rax, rcx, rdx, rsi, rdi, and r8->r11.
*
* For both our implementation of malloc and free we only use the registers we
* don't have to preserve.
*
* Malloc register usage:
* o. rdi: Original size to malloc. This never changes and is preserved.
* o. rsi: Adjusted malloc size for malloc_data_tag(s).
* o. rcx: Pointer to the tmem_t in the ulwp_t.
* o. rdx: Pointer to the tmem_t array of roots
* o. r8: Size of the cache
* o. r9: Scratch register
*
* Free register usage:
* o. rdi: Original buffer to free. This never changes and is preserved.
* o. rax: The actual buffer, adjusted for the hidden malloc_data_t(s).
* o. rcx: Pointer to the tmem_t in the ulwp_t.
* o. rdx: Pointer to the tmem_t array of roots
* o. r8: Size of the cache
* o. r9: Scratch register
*
* Once we determine what cache we are using, we increment %rdx to the
* appropriate offset and set %r8 with the size of the cache. This means that
* when we break out to the normal buffer allocation point %rdx contains the
* head of the linked list and %r8 is the amount that we have to adjust the
* thread's cached amount by.
*
* Each block of assembly has psuedocode that describes its purpose.
*/
#include <atomic.h>
#include <inttypes.h>
#include <sys/types.h>
#include <strings.h>
#include <umem_impl.h>
#include "umem_base.h"
const int umem_genasm_supported = 1;
static uintptr_t umem_genasm_mptr = (uintptr_t)&_malloc;
static size_t umem_genasm_msize = 576;
static uintptr_t umem_genasm_fptr = (uintptr_t)&_free;
static size_t umem_genasm_fsize = 576;
static uintptr_t umem_genasm_omptr = (uintptr_t)umem_malloc;
static uintptr_t umem_genasm_ofptr = (uintptr_t)umem_malloc_free;
#define UMEM_GENASM_MAX64 (UINT32_MAX / sizeof (uintptr_t))
#define PTC_JMPADDR(dest, src) (dest - (src + 4))
#define PTC_ROOT_SIZE sizeof (uintptr_t)
#define MULTINOP 0x0000441f0f
/*
* void *ptcmalloc(size_t orig_size);
*
* size_t size = orig_size + 8;
* if (size > UMEM_SECOND_ALIGN)
* size += 8;
*
* if (size < orig_size)
* goto tomalloc; ! This is overflow
*
* if (size > cache_max)
* goto tomalloc
*
* tmem_t *t = (uintptr_t)curthread() + umem_thr_offset;
* void **roots = t->tm_roots;
*/
#define PTC_MALINIT_JOUT 0x13
#define PTC_MALINIT_MCS 0x1a
#define PTC_MALINIT_JOV 0x20
#define PTC_MALINIT_SOFF 0x30
static const uint8_t malinit[] = {
0x48, 0x8d, 0x77, 0x08, /* leaq 0x8(%rdi),%rsi */
0x48, 0x83, 0xfe, 0x10, /* cmpq $0x10, %rsi */
0x76, 0x04, /* jbe +0x4 */
0x48, 0x8d, 0x77, 0x10, /* leaq 0x10(%rdi),%rsi */
0x48, 0x39, 0xfe, /* cmpq %rdi,%rsi */
0x0f, 0x82, 0x00, 0x00, 0x00, 0x00, /* jb +errout */
0x48, 0x81, 0xfe,
0x00, 0x00, 0x00, 0x00, /* cmpq sizeof ($CACHE), %rsi */
0x0f, 0x87, 0x00, 0x00, 0x00, 0x00, /* ja +errout */
0x64, 0x48, 0x8b, 0x0c, 0x25,
0x00, 0x00, 0x00, 0x00, /* movq %fs:0x0,%rcx */
0x48, 0x81, 0xc1,
0x00, 0x00, 0x00, 0x00, /* addq $SOFF, %rcx */
0x48, 0x8d, 0x51, 0x08, /* leaq 0x8(%rcx),%rdx */
};
/*
* void ptcfree(void *buf);
*
* if (buf == NULL)
* return;
*
* malloc_data_t *tag = buf;
* tag--;
* int size = tag->malloc_size;
* int tagval = UMEM_MALLOC_DECODE(tag->malloc_tag, size);
* if (tagval == MALLOC_SECOND_MAGIC) {
* tag--;
* } else if (tagval != MALLOC_MAGIC) {
* goto tofree;
* }
*
* if (size > cache_max)
* goto tofree;
*
* tmem_t *t = (uintptr_t)curthread() + umem_thr_offset;
* void **roots = t->tm_roots;
*/
#define PTC_FRINI_JDONE 0x05
#define PTC_FRINI_JFREE 0x25
#define PTC_FRINI_MCS 0x30
#define PTC_FRINI_JOV 0x36
#define PTC_FRINI_SOFF 0x46
static const uint8_t freeinit[] = {
0x48, 0x85, 0xff, /* testq %rdi,%rdi */
0x0f, 0x84, 0x00, 0x00, 0x00, 0x00, /* jmp $JDONE (done) */
0x8b, 0x77, 0xf8, /* movl -0x8(%rdi),%esi */
0x8b, 0x47, 0xfc, /* movl -0x4(%rdi),%eax */
0x01, 0xf0, /* addl %esi,%eax */
0x3d, 0x00, 0x70, 0xba, 0x16, /* cmpl $MALLOC_2_MAGIC, %eax */
0x75, 0x06, /* jne +0x6 (checkover) */
0x48, 0x8d, 0x47, 0xf0, /* leaq -0x10(%rdi),%eax */
0xeb, 0x0f, /* jmp +0xf (freebuf) */
0x3d, 0x00, 0xc0, 0x10, 0x3a, /* cmpl $MALLOC_MAGIC, %eax */
0x0f, 0x85, 0x00, 0x00, 0x00, 0x00, /* jmp +JFREE (goto torfree) */
0x48, 0x8d, 0x47, 0xf8, /* leaq -0x8(%rdi),%rax */
0x48, 0x81, 0xfe,
0x00, 0x00, 0x00, 0x00, /* cmpq sizeof ($CACHE), %rsi */
0x0f, 0x87, 0x00, 0x00, 0x00, 0x00, /* ja +errout */
0x64, 0x48, 0x8b, 0x0c, 0x25,
0x00, 0x00, 0x00, 0x00, /* movq %fs:0x0,%rcx */
0x48, 0x81, 0xc1,
0x00, 0x00, 0x00, 0x00, /* addq $SOFF, %rcx */
0x48, 0x8d, 0x51, 0x08, /* leaq 0x8(%rcx),%rdx */
};
/*
* if (size <= $CACHE_SIZE) {
* csize = $CACHE_SIZE;
* } else ... ! goto next cache
*/
#define PTC_INICACHE_CMP 0x03
#define PTC_INICACHE_SIZE 0x0c
#define PTC_INICACHE_JMP 0x11
static const uint8_t inicache[] = {
0x48, 0x81, 0xfe,
0x00, 0x00, 0x00, 0x00, /* cmpq sizeof ($CACHE), %rsi */
0x77, 0x0c, /* ja +0xc (next cache) */
0x49, 0xc7, 0xc0,
0x00, 0x00, 0x00, 0x00, /* movq sizeof ($CACHE), %r8 */
0xe9, 0x00, 0x00, 0x00, 0x00, /* jmp $JMP (allocbuf) */
};
/*
* if (size <= $CACHE_SIZE) {
* csize = $CACHE_SIZE;
* roots += $CACHE_NUM;
* } else ... ! goto next cache
*/
#define PTC_GENCACHE_CMP 0x03
#define PTC_GENCACHE_SIZE 0x0c
#define PTC_GENCACHE_NUM 0x13
#define PTC_GENCACHE_JMP 0x18
static const uint8_t gencache[] = {
0x48, 0x81, 0xfe,
0x00, 0x00, 0x00, 0x00, /* cmpq sizeof ($CACHE), %rsi */
0x77, 0x14, /* ja +0xc (next cache) */
0x49, 0xc7, 0xc0,
0x00, 0x00, 0x00, 0x00, /* movq sizeof ($CACHE), %r8 */
0x48, 0x81, 0xc2,
0x00, 0x00, 0x00, 0x00, /* addq $8*ii, %rdx */
0xe9, 0x00, 0x00, 0x00, 0x00 /* jmp +$JMP (allocbuf ) */
};
/*
* else if (size <= $CACHE_SIZE) {
* csize = $CACHE_SIZE;
* roots += $CACHE_NUM;
* } else {
* goto tofunc; ! goto tomalloc if ptcmalloc.
* } ! goto tofree if ptcfree.
*/
#define PTC_FINCACHE_CMP 0x03
#define PTC_FINCACHE_JMP 0x08
#define PTC_FINCACHE_SIZE 0x0c
#define PTC_FINCACHE_NUM 0x13
static const uint8_t fincache[] = {
0x48, 0x81, 0xfe,
0x00, 0x00, 0x00, 0x00, /* cmpq sizeof ($CACHE), %rsi */
0x77, 0x00, /* ja +JMP (to real malloc) */
0x49, 0xc7, 0xc0,
0x00, 0x00, 0x00, 0x00, /* movq sizeof ($CACHE), %r8 */
0x48, 0x81, 0xc2,
0x00, 0x00, 0x00, 0x00, /* addq $8*ii, %rdx */
};
/*
* if (*root == NULL)
* goto tomalloc;
*
* malloc_data_t *ret = *root;
* *root = *(void **)ret;
* t->tm_size += csize;
* ret->malloc_size = size;
*
* if (size > UMEM_SECOND_ALIGN) {
* ret->malloc_data = UMEM_MALLOC_ENCODE(MALLOC_SECOND_MAGIC, size);
* ret += 2;
* } else {
* ret->malloc_data = UMEM_MALLOC_ENCODE(MALLOC_SECOND_MAGIC, size);
* ret += 1;
* }
*
* return ((void *)ret);
* tomalloc:
* return (malloc(orig_size));
*/
#define PTC_MALFINI_ALLABEL 0x00
#define PTC_MALFINI_JMLABEL 0x40
#define PTC_MALFINI_JMADDR 0x41
static const uint8_t malfini[] = {
0x48, 0x8b, 0x02, /* movl (%rdx),%rax */
0x48, 0x85, 0xc0, /* testq %rax,%rax */
0x74, 0x38, /* je +0x38 (errout) */
0x4c, 0x8b, 0x08, /* movq (%rax),%r9 */
0x4c, 0x89, 0x0a, /* movq %r9,(%rdx) */
0x4c, 0x29, 0x01, /* subq %rsi,(%rcx) */
0x48, 0x83, 0xfe, 0x10, /* cmpq $0x10,%rsi */
0x76, 0x15, /* jbe +0x15 */
0x41, 0xb9, 0x00, 0x70, 0xba, 0x16, /* movl $MALLOC_MAGIC_2, %r9d */
0x89, 0x70, 0x08, /* movl %r9d,0x8(%rax) */
0x41, 0x29, 0xf1, /* subl %esi, %r9d */
0x44, 0x89, 0x48, 0x0c, /* movl %r9d, 0xc(%rax) */
0x48, 0x83, 0xc0, 0x10, /* addq $0x10, %rax */
0xc3, /* ret */
0x41, 0xb9, 0x00, 0xc0, 0x10, 0x3a, /* movl %MALLOC_MAGIC, %r9d */
0x89, 0x30, /* movl %esi,(%rax) */
0x41, 0x29, 0xf1, /* subl %esi,%r9d */
0x44, 0x89, 0x48, 0x04, /* movl %r9d,0x4(%rax) */
0x48, 0x83, 0xc0, 0x08, /* addq $0x8,%rax */
0xc3, /* ret */
0xe9, 0x00, 0x00, 0x00, 0x00 /* jmp $MALLOC */
};
/*
* if (t->tm_size + csize > umem_ptc_size)
* goto tofree;
*
* t->tm_size += csize
* *(void **)tag = *root;
* *root = tag;
* return;
* tofree:
* free(buf);
* return;
*/
#define PTC_FRFINI_RBUFLABEL 0x00
#define PTC_FRFINI_CACHEMAX 0x09
#define PTC_FRFINI_DONELABEL 0x1b
#define PTC_FRFINI_JFLABEL 0x1c
#define PTC_FRFINI_JFADDR 0x1d
static const uint8_t freefini[] = {
0x4c, 0x8b, 0x09, /* movq (%rcx),%r9 */
0x4d, 0x01, 0xc1, /* addq %r8, %r9 */
0x49, 0x81, 0xf9,
0x00, 0x00, 0x00, 0x00, /* cmpl $THR_CACHE_MAX, %r9 */
0x77, 0x0d, /* jae +0xd (torfree) */
0x4c, 0x01, 0x01, /* addq %r8,(%rcx) */
0x4c, 0x8b, 0x0a, /* movq (%rdx),%r9 */
0x4c, 0x89, 0x08, /* movq %r9,(%rax) */
0x48, 0x89, 0x02, /* movq %rax,(%rdx) */
0xc3, /* ret */
0xe9, 0x00, 0x00, 0x00, 0x00 /* jmp free */
};
/*
* Construct the initial part of malloc. off contains the offset from curthread
* to the root of the tmem structure. ep is the address of the label to error
* and jump to free. csize is the size of the largest umem_cache in ptcumem.
*/
static int
genasm_malinit(uint8_t *bp, uint32_t off, uint32_t ep, uint32_t csize)
{
uint32_t addr;
bcopy(malinit, bp, sizeof (malinit));
addr = PTC_JMPADDR(ep, PTC_MALINIT_JOUT);
bcopy(&addr, bp + PTC_MALINIT_JOUT, sizeof (addr));
bcopy(&csize, bp + PTC_MALINIT_MCS, sizeof (csize));
addr = PTC_JMPADDR(ep, PTC_MALINIT_JOV);
bcopy(&addr, bp + PTC_MALINIT_JOV, sizeof (addr));
bcopy(&off, bp + PTC_MALINIT_SOFF, sizeof (off));
return (sizeof (malinit));
}
static int
genasm_frinit(uint8_t *bp, uint32_t off, uint32_t dp, uint32_t ep, uint32_t mcs)
{
uint32_t addr;
bcopy(freeinit, bp, sizeof (freeinit));
addr = PTC_JMPADDR(dp, PTC_FRINI_JDONE);
bcopy(&addr, bp + PTC_FRINI_JDONE, sizeof (addr));
addr = PTC_JMPADDR(ep, PTC_FRINI_JFREE);
bcopy(&addr, bp + PTC_FRINI_JFREE, sizeof (addr));
bcopy(&mcs, bp + PTC_FRINI_MCS, sizeof (mcs));
addr = PTC_JMPADDR(ep, PTC_FRINI_JOV);
bcopy(&addr, bp + PTC_FRINI_JOV, sizeof (addr));
bcopy(&off, bp + PTC_FRINI_SOFF, sizeof (off));
return (sizeof (freeinit));
}
/*
* Create the initial cache entry of the specified size. The value of ap tells
* us what the address of the label to try and allocate a buffer. This value is
* an offset from the current base to that value.
*/
static int
genasm_firstcache(uint8_t *bp, uint32_t csize, uint32_t ap)
{
uint32_t addr;
bcopy(inicache, bp, sizeof (inicache));
bcopy(&csize, bp + PTC_INICACHE_CMP, sizeof (csize));
bcopy(&csize, bp + PTC_INICACHE_SIZE, sizeof (csize));
addr = PTC_JMPADDR(ap, PTC_INICACHE_JMP);
ASSERT(addr != 0);
bcopy(&addr, bp + PTC_INICACHE_JMP, sizeof (addr));
return (sizeof (inicache));
}
static int
genasm_gencache(uint8_t *bp, int num, uint32_t csize, uint32_t ap)
{
uint32_t addr;
uint32_t coff;
ASSERT(UINT32_MAX / PTC_ROOT_SIZE > num);
ASSERT(num != 0);
bcopy(gencache, bp, sizeof (gencache));
bcopy(&csize, bp + PTC_GENCACHE_CMP, sizeof (csize));
bcopy(&csize, bp + PTC_GENCACHE_SIZE, sizeof (csize));
coff = num * PTC_ROOT_SIZE;
bcopy(&coff, bp + PTC_GENCACHE_NUM, sizeof (coff));
addr = PTC_JMPADDR(ap, PTC_GENCACHE_JMP);
bcopy(&addr, bp + PTC_GENCACHE_JMP, sizeof (addr));
return (sizeof (gencache));
}
static int
genasm_lastcache(uint8_t *bp, int num, uint32_t csize, uint32_t ep)
{
uint8_t eap;
uint32_t coff;
ASSERT(ep <= 0xff && ep > 7);
ASSERT(UINT32_MAX / PTC_ROOT_SIZE > num);
bcopy(fincache, bp, sizeof (fincache));
bcopy(&csize, bp + PTC_FINCACHE_CMP, sizeof (csize));
bcopy(&csize, bp + PTC_FINCACHE_SIZE, sizeof (csize));
coff = num * PTC_ROOT_SIZE;
bcopy(&coff, bp + PTC_FINCACHE_NUM, sizeof (coff));
eap = ep - PTC_FINCACHE_JMP - 1;
bcopy(&eap, bp + PTC_FINCACHE_JMP, sizeof (eap));
return (sizeof (fincache));
}
static int
genasm_malfini(uint8_t *bp, uintptr_t mptr)
{
uint32_t addr;
bcopy(malfini, bp, sizeof (malfini));
addr = PTC_JMPADDR(mptr, ((uintptr_t)bp + PTC_MALFINI_JMADDR));
bcopy(&addr, bp + PTC_MALFINI_JMADDR, sizeof (addr));
return (sizeof (malfini));
}
static int
genasm_frfini(uint8_t *bp, uint32_t maxthr, uintptr_t fptr)
{
uint32_t addr;
bcopy(freefini, bp, sizeof (freefini));
bcopy(&maxthr, bp + PTC_FRFINI_CACHEMAX, sizeof (maxthr));
addr = PTC_JMPADDR(fptr, ((uintptr_t)bp + PTC_FRFINI_JFADDR));
bcopy(&addr, bp + PTC_FRFINI_JFADDR, sizeof (addr));
return (sizeof (freefini));
}
/*
* The malloc inline assembly is constructed as follows:
*
* o Malloc prologue assembly
* o Generic first-cache check
* o n Generic cache checks (where n = _tmem_get_entries() - 2)
* o Generic last-cache check
* o Malloc epilogue assembly
*
* Generally there are at least three caches. When there is only one cache we
* only use the generic last-cache. In the case where there are two caches, we
* just leave out the middle ones.
*/
static int
genasm_malloc(void *base, size_t len, int nents, int *umem_alloc_sizes)
{
int ii, off;
uint8_t *bp;
size_t total;
uint32_t allocoff, erroff;
total = sizeof (malinit) + sizeof (malfini) + sizeof (fincache);
if (nents >= 2)
total += sizeof (inicache) + sizeof (gencache) * (nents - 2);
if (total > len)
return (1);
erroff = total - sizeof (malfini) + PTC_MALFINI_JMLABEL;
allocoff = total - sizeof (malfini) + PTC_MALFINI_ALLABEL;
bp = base;
off = genasm_malinit(bp, umem_tmem_off, erroff,
umem_alloc_sizes[nents-1]);
bp += off;
allocoff -= off;
erroff -= off;
if (nents > 1) {
off = genasm_firstcache(bp, umem_alloc_sizes[0], allocoff);
bp += off;
allocoff -= off;
erroff -= off;
}
for (ii = 1; ii < nents - 1; ii++) {
off = genasm_gencache(bp, ii, umem_alloc_sizes[ii], allocoff);
bp += off;
allocoff -= off;
erroff -= off;
}
bp += genasm_lastcache(bp, nents - 1, umem_alloc_sizes[nents - 1],
erroff);
bp += genasm_malfini(bp, umem_genasm_omptr);
ASSERT(((uintptr_t)bp - total) == (uintptr_t)base);
return (0);
}
static int
genasm_free(void *base, size_t len, int nents, int *umem_alloc_sizes)
{
uint8_t *bp;
int ii, off;
size_t total;
uint32_t rbufoff, retoff, erroff;
/* Assume that nents has already been audited for us */
total = sizeof (freeinit) + sizeof (freefini) + sizeof (fincache);
if (nents >= 2)
total += sizeof (inicache) + sizeof (gencache) * (nents - 2);
if (total > len)
return (1);
erroff = total - (sizeof (freefini) - PTC_FRFINI_JFLABEL);
rbufoff = total - (sizeof (freefini) - PTC_FRFINI_RBUFLABEL);
retoff = total - (sizeof (freefini) - PTC_FRFINI_DONELABEL);
bp = base;
off = genasm_frinit(bp, umem_tmem_off, retoff, erroff,
umem_alloc_sizes[nents - 1]);
bp += off;
erroff -= off;
rbufoff -= off;
if (nents > 1) {
off = genasm_firstcache(bp, umem_alloc_sizes[0], rbufoff);
bp += off;
erroff -= off;
rbufoff -= off;
}
for (ii = 1; ii < nents - 1; ii++) {
off = genasm_gencache(bp, ii, umem_alloc_sizes[ii], rbufoff);
bp += off;
rbufoff -= off;
erroff -= off;
}
bp += genasm_lastcache(bp, nents - 1, umem_alloc_sizes[nents - 1],
erroff);
bp += genasm_frfini(bp, umem_ptc_size, umem_genasm_ofptr);
ASSERT(((uintptr_t)bp - total) == (uintptr_t)base);
return (0);
}
/*ARGSUSED*/
int
umem_genasm(int *cp, umem_cache_t **caches, int nc)
{
int nents, i;
uint8_t *mptr;
uint8_t *fptr;
uint64_t v, *vptr;
mptr = (void *)((uintptr_t)umem_genasm_mptr + 5);
fptr = (void *)((uintptr_t)umem_genasm_fptr + 5);
if (umem_genasm_mptr == 0 || umem_genasm_msize == 0 ||
umem_genasm_fptr == 0 || umem_genasm_fsize == 0)
return (1);
/*
* The total number of caches that we can service is the minimum of:
* o the amount supported by libc
* o the total number of umem caches
* o we use a single byte addl, so it's MAX_UINT32 / sizeof (uintptr_t)
* For 64-bit, this is MAX_UINT32 >> 3, a lot.
*/
nents = _tmem_get_nentries();
if (UMEM_GENASM_MAX64 < nents)
nents = UMEM_GENASM_MAX64;
if (nc < nents)
nents = nc;
/* Based on our constraints, this is not an error */
if (nents == 0 || umem_ptc_size == 0)
return (0);
/* Take into account the jump */
if (genasm_malloc(mptr, umem_genasm_msize, nents, cp) != 0)
return (1);
if (genasm_free(fptr, umem_genasm_fsize, nents, cp) != 0)
return (1);
/* nop out the jump with a multibyte jump */
vptr = (void *)umem_genasm_mptr;
v = MULTINOP;
v |= *vptr & (0xffffffULL << 40);
(void) atomic_swap_64(vptr, v);
vptr = (void *)umem_genasm_fptr;
v = MULTINOP;
v |= *vptr & (0xffffffULL << 40);
(void) atomic_swap_64(vptr, v);
for (i = 0; i < nents; i++)
caches[i]->cache_flags |= UMF_PTC;
return (0);
}