linux/arch/mips/mm/tlb-r4k.c
Kees Cook 3f649ab728 treewide: Remove uninitialized_var() usage
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:15 -07:00

583 lines
14 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
* Copyright (C) 1997, 1998, 1999, 2000 Ralf Baechle ralf@gnu.org
* Carsten Langgaard, carstenl@mips.com
* Copyright (C) 2002 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/cpu_pm.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/export.h>
#include <asm/cpu.h>
#include <asm/cpu-type.h>
#include <asm/bootinfo.h>
#include <asm/hazards.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <asm/tlbmisc.h>
extern void build_tlb_refill_handler(void);
/*
* LOONGSON-2 has a 4 entry itlb which is a subset of jtlb, LOONGSON-3 has
* a 4 entry itlb and a 4 entry dtlb which are subsets of jtlb. Unfortunately,
* itlb/dtlb are not totally transparent to software.
*/
static inline void flush_micro_tlb(void)
{
switch (current_cpu_type()) {
case CPU_LOONGSON2EF:
write_c0_diag(LOONGSON_DIAG_ITLB);
break;
case CPU_LOONGSON64:
write_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
break;
default:
break;
}
}
static inline void flush_micro_tlb_vm(struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_EXEC)
flush_micro_tlb();
}
void local_flush_tlb_all(void)
{
unsigned long flags;
unsigned long old_ctx;
int entry, ftlbhighset;
local_irq_save(flags);
/* Save old context and create impossible VPN2 value */
old_ctx = read_c0_entryhi();
htw_stop();
write_c0_entrylo0(0);
write_c0_entrylo1(0);
entry = num_wired_entries();
/*
* Blast 'em all away.
* If there are any wired entries, fall back to iterating
*/
if (cpu_has_tlbinv && !entry) {
if (current_cpu_data.tlbsizevtlb) {
write_c0_index(0);
mtc0_tlbw_hazard();
tlbinvf(); /* invalidate VTLB */
}
ftlbhighset = current_cpu_data.tlbsizevtlb +
current_cpu_data.tlbsizeftlbsets;
for (entry = current_cpu_data.tlbsizevtlb;
entry < ftlbhighset;
entry++) {
write_c0_index(entry);
mtc0_tlbw_hazard();
tlbinvf(); /* invalidate one FTLB set */
}
} else {
while (entry < current_cpu_data.tlbsize) {
/* Make sure all entries differ. */
write_c0_entryhi(UNIQUE_ENTRYHI(entry));
write_c0_index(entry);
mtc0_tlbw_hazard();
tlb_write_indexed();
entry++;
}
}
tlbw_use_hazard();
write_c0_entryhi(old_ctx);
htw_start();
flush_micro_tlb();
local_irq_restore(flags);
}
EXPORT_SYMBOL(local_flush_tlb_all);
void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
int cpu = smp_processor_id();
if (cpu_context(cpu, mm) != 0) {
unsigned long size, flags;
local_irq_save(flags);
start = round_down(start, PAGE_SIZE << 1);
end = round_up(end, PAGE_SIZE << 1);
size = (end - start) >> (PAGE_SHIFT + 1);
if (size <= (current_cpu_data.tlbsizeftlbsets ?
current_cpu_data.tlbsize / 8 :
current_cpu_data.tlbsize / 2)) {
unsigned long old_entryhi, old_mmid;
int newpid = cpu_asid(cpu, mm);
old_entryhi = read_c0_entryhi();
if (cpu_has_mmid) {
old_mmid = read_c0_memorymapid();
write_c0_memorymapid(newpid);
}
htw_stop();
while (start < end) {
int idx;
if (cpu_has_mmid)
write_c0_entryhi(start);
else
write_c0_entryhi(start | newpid);
start += (PAGE_SIZE << 1);
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entrylo1(0);
if (idx < 0)
continue;
/* Make sure all entries differ. */
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
mtc0_tlbw_hazard();
tlb_write_indexed();
}
tlbw_use_hazard();
write_c0_entryhi(old_entryhi);
if (cpu_has_mmid)
write_c0_memorymapid(old_mmid);
htw_start();
} else {
drop_mmu_context(mm);
}
flush_micro_tlb();
local_irq_restore(flags);
}
}
void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
unsigned long size, flags;
local_irq_save(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
size = (size + 1) >> 1;
if (size <= (current_cpu_data.tlbsizeftlbsets ?
current_cpu_data.tlbsize / 8 :
current_cpu_data.tlbsize / 2)) {
int pid = read_c0_entryhi();
start &= (PAGE_MASK << 1);
end += ((PAGE_SIZE << 1) - 1);
end &= (PAGE_MASK << 1);
htw_stop();
while (start < end) {
int idx;
write_c0_entryhi(start);
start += (PAGE_SIZE << 1);
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entrylo1(0);
if (idx < 0)
continue;
/* Make sure all entries differ. */
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
mtc0_tlbw_hazard();
tlb_write_indexed();
}
tlbw_use_hazard();
write_c0_entryhi(pid);
htw_start();
} else {
local_flush_tlb_all();
}
flush_micro_tlb();
local_irq_restore(flags);
}
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
int cpu = smp_processor_id();
if (cpu_context(cpu, vma->vm_mm) != 0) {
unsigned long old_mmid;
unsigned long flags, old_entryhi;
int idx;
page &= (PAGE_MASK << 1);
local_irq_save(flags);
old_entryhi = read_c0_entryhi();
htw_stop();
if (cpu_has_mmid) {
old_mmid = read_c0_memorymapid();
write_c0_entryhi(page);
write_c0_memorymapid(cpu_asid(cpu, vma->vm_mm));
} else {
write_c0_entryhi(page | cpu_asid(cpu, vma->vm_mm));
}
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entrylo1(0);
if (idx < 0)
goto finish;
/* Make sure all entries differ. */
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
finish:
write_c0_entryhi(old_entryhi);
if (cpu_has_mmid)
write_c0_memorymapid(old_mmid);
htw_start();
flush_micro_tlb_vm(vma);
local_irq_restore(flags);
}
}
/*
* This one is only used for pages with the global bit set so we don't care
* much about the ASID.
*/
void local_flush_tlb_one(unsigned long page)
{
unsigned long flags;
int oldpid, idx;
local_irq_save(flags);
oldpid = read_c0_entryhi();
htw_stop();
page &= (PAGE_MASK << 1);
write_c0_entryhi(page);
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entrylo1(0);
if (idx >= 0) {
/* Make sure all entries differ. */
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
}
write_c0_entryhi(oldpid);
htw_start();
flush_micro_tlb();
local_irq_restore(flags);
}
/*
* We will need multiple versions of update_mmu_cache(), one that just
* updates the TLB with the new pte(s), and another which also checks
* for the R4k "end of page" hardware bug and does the needy.
*/
void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte)
{
unsigned long flags;
pgd_t *pgdp;
p4d_t *p4dp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
int idx, pid;
/*
* Handle debugger faulting in for debugee.
*/
if (current->active_mm != vma->vm_mm)
return;
local_irq_save(flags);
htw_stop();
address &= (PAGE_MASK << 1);
if (cpu_has_mmid) {
write_c0_entryhi(address);
} else {
pid = read_c0_entryhi() & cpu_asid_mask(&current_cpu_data);
write_c0_entryhi(address | pid);
}
pgdp = pgd_offset(vma->vm_mm, address);
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
p4dp = p4d_offset(pgdp, address);
pudp = pud_offset(p4dp, address);
pmdp = pmd_offset(pudp, address);
idx = read_c0_index();
#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
/* this could be a huge page */
if (pmd_huge(*pmdp)) {
unsigned long lo;
write_c0_pagemask(PM_HUGE_MASK);
ptep = (pte_t *)pmdp;
lo = pte_to_entrylo(pte_val(*ptep));
write_c0_entrylo0(lo);
write_c0_entrylo1(lo + (HPAGE_SIZE >> 7));
mtc0_tlbw_hazard();
if (idx < 0)
tlb_write_random();
else
tlb_write_indexed();
tlbw_use_hazard();
write_c0_pagemask(PM_DEFAULT_MASK);
} else
#endif
{
ptep = pte_offset_map(pmdp, address);
#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
#ifdef CONFIG_XPA
write_c0_entrylo0(pte_to_entrylo(ptep->pte_high));
if (cpu_has_xpa)
writex_c0_entrylo0(ptep->pte_low & _PFNX_MASK);
ptep++;
write_c0_entrylo1(pte_to_entrylo(ptep->pte_high));
if (cpu_has_xpa)
writex_c0_entrylo1(ptep->pte_low & _PFNX_MASK);
#else
write_c0_entrylo0(ptep->pte_high);
ptep++;
write_c0_entrylo1(ptep->pte_high);
#endif
#else
write_c0_entrylo0(pte_to_entrylo(pte_val(*ptep++)));
write_c0_entrylo1(pte_to_entrylo(pte_val(*ptep)));
#endif
mtc0_tlbw_hazard();
if (idx < 0)
tlb_write_random();
else
tlb_write_indexed();
}
tlbw_use_hazard();
htw_start();
flush_micro_tlb_vm(vma);
local_irq_restore(flags);
}
void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
unsigned long entryhi, unsigned long pagemask)
{
#ifdef CONFIG_XPA
panic("Broken for XPA kernels");
#else
unsigned int old_mmid;
unsigned long flags;
unsigned long wired;
unsigned long old_pagemask;
unsigned long old_ctx;
local_irq_save(flags);
if (cpu_has_mmid) {
old_mmid = read_c0_memorymapid();
write_c0_memorymapid(MMID_KERNEL_WIRED);
}
/* Save old context and create impossible VPN2 value */
old_ctx = read_c0_entryhi();
htw_stop();
old_pagemask = read_c0_pagemask();
wired = num_wired_entries();
write_c0_wired(wired + 1);
write_c0_index(wired);
tlbw_use_hazard(); /* What is the hazard here? */
write_c0_pagemask(pagemask);
write_c0_entryhi(entryhi);
write_c0_entrylo0(entrylo0);
write_c0_entrylo1(entrylo1);
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
write_c0_entryhi(old_ctx);
if (cpu_has_mmid)
write_c0_memorymapid(old_mmid);
tlbw_use_hazard(); /* What is the hazard here? */
htw_start();
write_c0_pagemask(old_pagemask);
local_flush_tlb_all();
local_irq_restore(flags);
#endif
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
int has_transparent_hugepage(void)
{
static unsigned int mask = -1;
if (mask == -1) { /* first call comes during __init */
unsigned long flags;
local_irq_save(flags);
write_c0_pagemask(PM_HUGE_MASK);
back_to_back_c0_hazard();
mask = read_c0_pagemask();
write_c0_pagemask(PM_DEFAULT_MASK);
local_irq_restore(flags);
}
return mask == PM_HUGE_MASK;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/*
* Used for loading TLB entries before trap_init() has started, when we
* don't actually want to add a wired entry which remains throughout the
* lifetime of the system
*/
int temp_tlb_entry;
__init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
unsigned long entryhi, unsigned long pagemask)
{
int ret = 0;
unsigned long flags;
unsigned long wired;
unsigned long old_pagemask;
unsigned long old_ctx;
local_irq_save(flags);
/* Save old context and create impossible VPN2 value */
htw_stop();
old_ctx = read_c0_entryhi();
old_pagemask = read_c0_pagemask();
wired = num_wired_entries();
if (--temp_tlb_entry < wired) {
printk(KERN_WARNING
"No TLB space left for add_temporary_entry\n");
ret = -ENOSPC;
goto out;
}
write_c0_index(temp_tlb_entry);
write_c0_pagemask(pagemask);
write_c0_entryhi(entryhi);
write_c0_entrylo0(entrylo0);
write_c0_entrylo1(entrylo1);
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
write_c0_entryhi(old_ctx);
write_c0_pagemask(old_pagemask);
htw_start();
out:
local_irq_restore(flags);
return ret;
}
static int ntlb;
static int __init set_ntlb(char *str)
{
get_option(&str, &ntlb);
return 1;
}
__setup("ntlb=", set_ntlb);
/*
* Configure TLB (for init or after a CPU has been powered off).
*/
static void r4k_tlb_configure(void)
{
/*
* You should never change this register:
* - On R4600 1.7 the tlbp never hits for pages smaller than
* the value in the c0_pagemask register.
* - The entire mm handling assumes the c0_pagemask register to
* be set to fixed-size pages.
*/
write_c0_pagemask(PM_DEFAULT_MASK);
back_to_back_c0_hazard();
if (read_c0_pagemask() != PM_DEFAULT_MASK)
panic("MMU doesn't support PAGE_SIZE=0x%lx", PAGE_SIZE);
write_c0_wired(0);
if (current_cpu_type() == CPU_R10000 ||
current_cpu_type() == CPU_R12000 ||
current_cpu_type() == CPU_R14000 ||
current_cpu_type() == CPU_R16000)
write_c0_framemask(0);
if (cpu_has_rixi) {
/*
* Enable the no read, no exec bits, and enable large physical
* address.
*/
#ifdef CONFIG_64BIT
set_c0_pagegrain(PG_RIE | PG_XIE | PG_ELPA);
#else
set_c0_pagegrain(PG_RIE | PG_XIE);
#endif
}
temp_tlb_entry = current_cpu_data.tlbsize - 1;
/* From this point on the ARC firmware is dead. */
local_flush_tlb_all();
/* Did I tell you that ARC SUCKS? */
}
void tlb_init(void)
{
r4k_tlb_configure();
if (ntlb) {
if (ntlb > 1 && ntlb <= current_cpu_data.tlbsize) {
int wired = current_cpu_data.tlbsize - ntlb;
write_c0_wired(wired);
write_c0_index(wired-1);
printk("Restricting TLB to %d entries\n", ntlb);
} else
printk("Ignoring invalid argument ntlb=%d\n", ntlb);
}
build_tlb_refill_handler();
}
static int r4k_tlb_pm_notifier(struct notifier_block *self, unsigned long cmd,
void *v)
{
switch (cmd) {
case CPU_PM_ENTER_FAILED:
case CPU_PM_EXIT:
r4k_tlb_configure();
break;
}
return NOTIFY_OK;
}
static struct notifier_block r4k_tlb_pm_notifier_block = {
.notifier_call = r4k_tlb_pm_notifier,
};
static int __init r4k_tlb_init_pm(void)
{
return cpu_pm_register_notifier(&r4k_tlb_pm_notifier_block);
}
arch_initcall(r4k_tlb_init_pm);