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wolfssl/linuxkm/linuxkm_memory.c

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/* linuxkm_memory.c
*
* Copyright (C) 2006-2023 wolfSSL Inc.
*
* This file is part of wolfSSL.
*
* wolfSSL is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* wolfSSL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
*/
/* included by wolfcrypt/src/memory.c */
#ifdef HAVE_KVMALLOC
/* adapted from kvrealloc() draft by Changli Gao, 2010-05-13 */
void *lkm_realloc(void *ptr, size_t newsize) {
void *nptr;
size_t oldsize;
if (unlikely(newsize == 0)) {
kvfree(ptr);
return ZERO_SIZE_PTR;
}
if (unlikely(ptr == NULL))
return kvmalloc_node(newsize, GFP_KERNEL, NUMA_NO_NODE);
if (is_vmalloc_addr(ptr)) {
/* no way to discern the size of the old allocation,
* because the kernel doesn't export find_vm_area(). if
* it did, we could then call get_vm_area_size() on the
* returned struct vm_struct.
*/
return NULL;
} else {
#ifndef __PIE__
struct page *page;
page = virt_to_head_page(ptr);
if (PageSlab(page) || PageCompound(page)) {
if (newsize < PAGE_SIZE)
#endif /* ! __PIE__ */
return krealloc(ptr, newsize, GFP_KERNEL);
#ifndef __PIE__
oldsize = ksize(ptr);
} else {
oldsize = page->private;
if (newsize <= oldsize)
return ptr;
}
#endif /* ! __PIE__ */
}
nptr = kvmalloc_node(newsize, GFP_KERNEL, NUMA_NO_NODE);
if (nptr != NULL) {
memcpy(nptr, ptr, oldsize);
kvfree(ptr);
}
return nptr;
}
#endif /* HAVE_KVMALLOC */
#if defined(WOLFSSL_LINUXKM_USE_SAVE_VECTOR_REGISTERS) && defined(CONFIG_X86)
/* kernel 4.19 -- the most recent LTS before 5.4 -- lacks the necessary safety
* checks in __kernel_fpu_begin(), and lacks TIF_NEED_FPU_LOAD.
*/
#if (LINUX_VERSION_CODE < KERNEL_VERSION(5, 4, 0))
#error WOLFSSL_LINUXKM_USE_SAVE_VECTOR_REGISTERS on x86 requires kernel 5.4.0 or higher.
#endif
static unsigned int wc_linuxkm_fpu_states_n_tracked = 0;
struct wc_thread_fpu_count_ent {
volatile pid_t pid;
unsigned int fpu_state;
};
struct wc_thread_fpu_count_ent *wc_linuxkm_fpu_states = NULL;
#ifdef WOLFSSL_COMMERCIAL_LICENSE
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
#error WOLFSSL_COMMERCIAL_LICENSE requires LINUXKM_FPU_STATES_FOLLOW_THREADS
#endif
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wnested-externs"
/* avoid dependence on "alternatives_patched" and "xfd_validate_state()". */
#undef CONFIG_X86_DEBUG_FPU
#include "../kernel/fpu/internal.h"
#include "../kernel/fpu/xstate.h"
#pragma GCC diagnostic pop
static union wc_linuxkm_fpu_savebuf {
byte buf[1024]; /* must be 64-byte-aligned */
struct fpstate fpstate;
} *wc_linuxkm_fpu_savebufs = NULL;
#endif /* WOLFSSL_COMMERCIAL_LICENSE */
#define WC_FPU_COUNT_MASK 0x7fffffffU
#define WC_FPU_SAVED_MASK 0x80000000U
WARN_UNUSED_RESULT int allocate_wolfcrypt_linuxkm_fpu_states(void)
{
if (wc_linuxkm_fpu_states != NULL) {
static int warned_for_repeat_alloc = 0;
if (! warned_for_repeat_alloc) {
pr_err("attempt at repeat allocation"
" in allocate_wolfcrypt_linuxkm_fpu_states\n");
warned_for_repeat_alloc = 1;
}
return BAD_STATE_E;
}
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
if (nr_cpu_ids >= 16)
wc_linuxkm_fpu_states_n_tracked = nr_cpu_ids * 2;
else
wc_linuxkm_fpu_states_n_tracked = 32;
#else
wc_linuxkm_fpu_states_n_tracked = nr_cpu_ids;
#endif
wc_linuxkm_fpu_states =
(struct wc_thread_fpu_count_ent *)malloc(
wc_linuxkm_fpu_states_n_tracked * sizeof(wc_linuxkm_fpu_states[0]));
if (! wc_linuxkm_fpu_states) {
pr_err("allocation of %lu bytes for "
"wc_linuxkm_fpu_states failed.\n",
nr_cpu_ids * sizeof(struct fpu_state *));
return MEMORY_E;
}
memset(wc_linuxkm_fpu_states, 0, wc_linuxkm_fpu_states_n_tracked
* sizeof(wc_linuxkm_fpu_states[0]));
#ifdef WOLFSSL_COMMERCIAL_LICENSE
wc_linuxkm_fpu_savebufs = (union wc_linuxkm_fpu_savebuf *)malloc(
wc_linuxkm_fpu_states_n_tracked * sizeof(*wc_linuxkm_fpu_savebufs));
if (! wc_linuxkm_fpu_savebufs) {
pr_err("allocation of %lu bytes for "
"wc_linuxkm_fpu_savebufs failed.\n",
WC_LINUXKM_ROUND_UP_P_OF_2(wc_linuxkm_fpu_states_n_tracked)
* sizeof(*wc_linuxkm_fpu_savebufs));
free(wc_linuxkm_fpu_states);
wc_linuxkm_fpu_states = NULL;
return MEMORY_E;
}
if ((uintptr_t)wc_linuxkm_fpu_savebufs
& (WC_LINUXKM_ROUND_UP_P_OF_2(sizeof(*wc_linuxkm_fpu_savebufs)) - 1))
{
pr_err("allocation of %lu bytes for "
"wc_linuxkm_fpu_savebufs allocated with wrong alignment 0x%lx.\n",
WC_LINUXKM_ROUND_UP_P_OF_2(wc_linuxkm_fpu_states_n_tracked)
* sizeof(*wc_linuxkm_fpu_savebufs),
(uintptr_t)wc_linuxkm_fpu_savebufs);
free(wc_linuxkm_fpu_savebufs);
wc_linuxkm_fpu_savebufs = NULL;
free(wc_linuxkm_fpu_states);
wc_linuxkm_fpu_states = NULL;
return MEMORY_E;
}
#endif
return 0;
}
void free_wolfcrypt_linuxkm_fpu_states(void) {
struct wc_thread_fpu_count_ent *i, *i_endptr;
pid_t i_pid;
if (wc_linuxkm_fpu_states == NULL) {
pr_err("free_wolfcrypt_linuxkm_fpu_states called"
" before allocate_wolfcrypt_linuxkm_fpu_states.\n");
return;
}
for (i = wc_linuxkm_fpu_states,
i_endptr = &wc_linuxkm_fpu_states[wc_linuxkm_fpu_states_n_tracked];
i < i_endptr;
++i)
{
i_pid = __atomic_load_n(&i->pid, __ATOMIC_CONSUME);
if (i_pid == 0)
continue;
if (i->fpu_state != 0) {
pr_err("free_wolfcrypt_linuxkm_fpu_states called"
" with nonzero state 0x%x for pid %d.\n", i->fpu_state, i_pid);
i->fpu_state = 0;
}
}
#ifdef WOLFSSL_COMMERCIAL_LICENSE
free(wc_linuxkm_fpu_savebufs);
wc_linuxkm_fpu_savebufs = NULL;
#endif
free(wc_linuxkm_fpu_states);
wc_linuxkm_fpu_states = NULL;
}
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
/* legacy thread-local storage facility for tracking recursive fpu
* pushing/popping
*/
static struct wc_thread_fpu_count_ent *wc_linuxkm_fpu_state_assoc(int create_p) {
struct wc_thread_fpu_count_ent *i, *i_endptr, *i_empty;
pid_t my_pid = task_pid_nr(current), i_pid;
{
static int _warned_on_null = 0;
if (wc_linuxkm_fpu_states == NULL)
{
if (_warned_on_null == 0) {
pr_err("wc_linuxkm_fpu_state_assoc called by pid %d"
" before allocate_wolfcrypt_linuxkm_fpu_states.\n", my_pid);
_warned_on_null = 1;
}
return NULL;
}
}
i_endptr = &wc_linuxkm_fpu_states[wc_linuxkm_fpu_states_n_tracked];
for (;;) {
for (i = wc_linuxkm_fpu_states,
i_empty = NULL;
i < i_endptr;
++i)
{
i_pid = __atomic_load_n(&i->pid, __ATOMIC_CONSUME);
if (i_pid == my_pid)
return i;
if ((i_empty == NULL) && (i_pid == 0))
i_empty = i;
}
if ((i_empty == NULL) || (! create_p))
return NULL;
i_pid = 0;
if (__atomic_compare_exchange_n(
&(i_empty->pid),
&i_pid,
my_pid,
0 /* weak */,
__ATOMIC_SEQ_CST /* success_memmodel */,
__ATOMIC_SEQ_CST /* failure_memmodel */))
{
return i_empty;
}
}
}
#else /* !LINUXKM_FPU_STATES_FOLLOW_THREADS */
/* lock-free O(1)-lookup CPU-local storage facility for tracking recursive fpu
* pushing/popping.
*
* caller must have already called kernel_fpu_begin() or preempt_disable()
* before entering this or the streamlined inline version of it below.
*/
static struct wc_thread_fpu_count_ent *wc_linuxkm_fpu_state_assoc_unlikely(int create_p) {
int my_cpu = raw_smp_processor_id();
pid_t my_pid = task_pid_nr(current), slot_pid;
struct wc_thread_fpu_count_ent *slot;
{
static int _warned_on_null = 0;
if (wc_linuxkm_fpu_states == NULL)
{
if (_warned_on_null == 0) {
pr_err("wc_linuxkm_fpu_state_assoc called by pid %d"
" before allocate_wolfcrypt_linuxkm_fpu_states.\n", my_pid);
_warned_on_null = 1;
}
return NULL;
}
}
slot = &wc_linuxkm_fpu_states[my_cpu];
slot_pid = __atomic_load_n(&slot->pid, __ATOMIC_CONSUME);
if (slot_pid == my_pid) {
if (create_p) {
static int _warned_on_redundant_create_p = 0;
if (_warned_on_redundant_create_p < 10) {
pr_err("wc_linuxkm_fpu_state_assoc called with create_p=1 by"
" pid %d on cpu %d with cpu slot already reserved by"
" said pid.\n", my_pid, my_cpu);
++_warned_on_redundant_create_p;
}
}
return slot;
}
if (create_p) {
if (slot_pid == 0) {
__atomic_store_n(&slot->pid, my_pid, __ATOMIC_RELEASE);
return slot;
} else {
/* if the slot is already occupied, that can be benign due to a
* migration, but it will require fixup by the thread that owns the
* slot, which will happen when it releases its lock, or sooner (see
* below).
*/
static int _warned_on_mismatched_pid = 0;
if (_warned_on_mismatched_pid < 10) {
pr_warn("wc_linuxkm_fpu_state_assoc called by pid %d on cpu %d"
" but cpu slot already reserved by pid %d.\n",
my_pid, my_cpu, slot_pid);
++_warned_on_mismatched_pid;
}
return NULL;
}
} else {
/* check for migration. this can happen despite our best efforts if any
* I/O occured while locked, e.g. kernel messages like "uninitialized
* urandom read". since we're locked now, we can safely migrate the
* entry in wc_linuxkm_fpu_states[], freeing up the slot on the previous
* cpu.
*/
unsigned int cpu_i;
for (cpu_i = 0; cpu_i < wc_linuxkm_fpu_states_n_tracked; ++cpu_i) {
if (__atomic_load_n(
&wc_linuxkm_fpu_states[cpu_i].pid,
__ATOMIC_CONSUME)
== my_pid)
{
wc_linuxkm_fpu_states[my_cpu] = wc_linuxkm_fpu_states[cpu_i];
__atomic_store_n(&wc_linuxkm_fpu_states[cpu_i].fpu_state, 0,
__ATOMIC_RELEASE);
__atomic_store_n(&wc_linuxkm_fpu_states[cpu_i].pid, 0,
__ATOMIC_RELEASE);
return &wc_linuxkm_fpu_states[my_cpu];
}
}
return NULL;
}
}
static inline struct wc_thread_fpu_count_ent *wc_linuxkm_fpu_state_assoc(
int create_p)
{
int my_cpu = raw_smp_processor_id(); /* my_cpu is only trustworthy if we're
* already nonpreemptible -- we'll
* determine that soon enough by
* checking if the pid matches or,
* failing that, if create_p.
*/
pid_t my_pid = task_pid_nr(current), slot_pid;
struct wc_thread_fpu_count_ent *slot;
if (unlikely(wc_linuxkm_fpu_states == NULL))
return wc_linuxkm_fpu_state_assoc_unlikely(create_p);
slot = &wc_linuxkm_fpu_states[my_cpu];
slot_pid = __atomic_load_n(&slot->pid, __ATOMIC_CONSUME);
if (slot_pid == my_pid) {
if (unlikely(create_p))
return wc_linuxkm_fpu_state_assoc_unlikely(create_p);
else
return slot;
}
if (likely(create_p)) {
if (likely(slot_pid == 0)) {
__atomic_store_n(&slot->pid, my_pid, __ATOMIC_RELEASE);
return slot;
} else {
return wc_linuxkm_fpu_state_assoc_unlikely(create_p);
}
} else {
return wc_linuxkm_fpu_state_assoc_unlikely(create_p);
}
}
#endif /* !LINUXKM_FPU_STATES_FOLLOW_THREADS */
#ifdef WOLFSSL_COMMERCIAL_LICENSE
static struct fpstate *wc_linuxkm_fpstate_buf_from_fpu_state(
struct wc_thread_fpu_count_ent *state)
{
size_t i = (size_t)(state - wc_linuxkm_fpu_states) / sizeof(*state);
return &wc_linuxkm_fpu_savebufs[i].fpstate;
}
#endif
static void wc_linuxkm_fpu_state_release_unlikely(
struct wc_thread_fpu_count_ent *ent)
{
if (ent->fpu_state != 0) {
static int warned_nonzero_fpu_state = 0;
if (! warned_nonzero_fpu_state) {
pr_err("wc_linuxkm_fpu_state_free for pid %d"
" with nonzero fpu_state 0x%x.\n", ent->pid, ent->fpu_state);
warned_nonzero_fpu_state = 1;
}
ent->fpu_state = 0;
}
__atomic_store_n(&ent->pid, 0, __ATOMIC_RELEASE);
}
static inline void wc_linuxkm_fpu_state_release(
struct wc_thread_fpu_count_ent *ent)
{
if (unlikely(ent->fpu_state != 0))
return wc_linuxkm_fpu_state_release_unlikely(ent);
__atomic_store_n(&ent->pid, 0, __ATOMIC_RELEASE);
}
WARN_UNUSED_RESULT int save_vector_registers_x86(void)
{
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
struct wc_thread_fpu_count_ent *pstate = wc_linuxkm_fpu_state_assoc(1);
#else
struct wc_thread_fpu_count_ent *pstate = wc_linuxkm_fpu_state_assoc(0);
#endif
/* allow for nested calls */
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
if (pstate == NULL)
return MEMORY_E;
#endif
if (
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
(pstate != NULL) &&
#endif
(pstate->fpu_state != 0U))
{
if (unlikely((pstate->fpu_state & WC_FPU_COUNT_MASK)
== WC_FPU_COUNT_MASK))
{
pr_err("save_vector_registers_x86 recursion register overflow for "
"pid %d.\n", pstate->pid);
return BAD_STATE_E;
} else {
++pstate->fpu_state;
return 0;
}
}
if (irq_fpu_usable()
#if (LINUX_VERSION_CODE < KERNEL_VERSION(5, 17, 0))
/* work around a kernel bug -- see linux commit 59f5ede3bc0f0.
* what we really want here is this_cpu_read(in_kernel_fpu), but
* in_kernel_fpu is an unexported static array.
*/
&& !test_thread_flag(TIF_NEED_FPU_LOAD)
#endif
)
{
#ifdef WOLFSSL_COMMERCIAL_LICENSE
struct fpstate *fpstate = wc_linuxkm_fpstate_buf_from_fpu_state(pstate);
fpregs_lock();
fpstate->xfeatures = ~0UL;
os_xsave(fpstate);
#else /* !WOLFSSL_COMMERCIAL_LICENSE */
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_COUNT) && \
(LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0))
/* inhibit migration, which gums up the algorithm in
* kernel_fpu_{begin,end}().
*/
migrate_disable();
#endif
kernel_fpu_begin();
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
pstate = wc_linuxkm_fpu_state_assoc(1);
if (pstate == NULL) {
kernel_fpu_end();
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_COUNT) && \
(LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0)) && \
!defined(WOLFSSL_COMMERCIAL_LICENSE)
migrate_enable();
#endif
return BAD_STATE_E;
}
#endif
#endif /* !WOLFSSL_COMMERCIAL_LICENSE */
/* set msb to 0 to trigger kernel_fpu_end() at cleanup. */
pstate->fpu_state = 1U;
} else if (in_nmi() || (hardirq_count() > 0) || (softirq_count() > 0)) {
static int warned_fpu_forbidden = 0;
if (! warned_fpu_forbidden)
pr_err("save_vector_registers_x86 called from IRQ handler.\n");
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
wc_linuxkm_fpu_state_release(pstate);
#endif
return BAD_STATE_E;
} else if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
static int warned_fpu_forbidden = 0;
if (! warned_fpu_forbidden)
pr_err("save_vector_registers_x86 called with !irq_fpu_usable from"
" thread without previous FPU save.\n");
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
wc_linuxkm_fpu_state_release(pstate);
#endif
return BAD_STATE_E;
} else {
/* assume already safely in_kernel_fpu from caller, but recursively
* preempt_disable() to be extra-safe.
*/
preempt_disable();
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_COUNT) && \
(LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0)) && \
!defined(WOLFSSL_COMMERCIAL_LICENSE)
migrate_disable();
#endif
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
pstate = wc_linuxkm_fpu_state_assoc(1);
if (pstate == NULL) {
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_COUNT) && \
(LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0)) && \
!defined(WOLFSSL_COMMERCIAL_LICENSE)
migrate_enable();
#endif
preempt_enable();
return BAD_STATE_E;
}
#endif
/* set msb to 1 to inhibit kernel_fpu_end() at cleanup. */
pstate->fpu_state =
WC_FPU_SAVED_MASK + 1U;
}
return 0;
}
void restore_vector_registers_x86(void)
{
struct wc_thread_fpu_count_ent *pstate = wc_linuxkm_fpu_state_assoc(0);
if (unlikely(pstate == NULL)) {
pr_err("restore_vector_registers_x86 called by pid %d on CPU %d "
"with no saved state.\n", task_pid_nr(current),
raw_smp_processor_id());
return;
}
if ((--pstate->fpu_state & WC_FPU_COUNT_MASK) > 0U) {
return;
}
if (pstate->fpu_state == 0U) {
#ifdef WOLFSSL_COMMERCIAL_LICENSE
struct fpstate *fpstate = wc_linuxkm_fpstate_buf_from_fpu_state(pstate);
os_xrstor(fpstate, fpstate->xfeatures);
fpregs_unlock();
#else
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
wc_linuxkm_fpu_state_release(pstate);
#endif
kernel_fpu_end();
#endif
} else {
pstate->fpu_state = 0U;
#ifndef LINUXKM_FPU_STATES_FOLLOW_THREADS
wc_linuxkm_fpu_state_release(pstate);
#endif
preempt_enable();
}
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_COUNT) && \
(LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0)) && \
!defined(WOLFSSL_COMMERCIAL_LICENSE)
migrate_enable();
#endif
#ifdef LINUXKM_FPU_STATES_FOLLOW_THREADS
wc_linuxkm_fpu_state_release(pstate);
#endif
return;
}
#endif /* WOLFSSL_LINUXKM_USE_SAVE_VECTOR_REGISTERS && CONFIG_X86 */
#if defined(__PIE__) && (LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0))
/* needed in 6.1+ because show_free_areas() static definition in mm.h calls
* __show_free_areas(), which isn't exported (neither was show_free_areas()).
*/
void my__show_free_areas(
unsigned int flags,
nodemask_t *nodemask,
int max_zone_idx)
{
(void)flags;
(void)nodemask;
(void)max_zone_idx;
return;
}
#endif
#if defined(__PIE__) && defined(CONFIG_FORTIFY_SOURCE)
/* needed because FORTIFY_SOURCE inline implementations call fortify_panic(). */
void __my_fortify_panic(const char *name) {
pr_emerg("__my_fortify_panic in %s\n", name);
BUG();
}
#endif
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