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kernel-ark/arch/mips/mm/tlb-r3k.c
Emil Goode e5cd534a31 MIPS: Remove incorrect NULL check in local_flush_tlb_page() 
We check that the struct vm_area_struct pointer vma is NULL and then
dereference it a few lines below. The intent was to make sure vma is
not NULL but this is not necessary since the bug pre-dates GIT history
and seem to never have caused a problem. The tlb-4k and tlb-8k versions
of local_flush_tlb_page() don't bother checking if vma is NULL, also
vma is dereferenced before being passed to local_flush_tlb_page(),
thus it is safe to remove this NULL check.

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Reviewed-by: Jonas Gorski <jogo@openwrt.org>
Acked-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7264/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-07-30 20:59:43 +02:00

284 lines
6.4 KiB
C
Raw Blame History

/*
* r2300.c: R2000 and R3000 specific mmu/cache code.
*
* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
*
* with a lot of changes to make this thing work for R3000s
* Tx39XX R4k style caches added. HK
* Copyright (C) 1998, 1999, 2000 Harald Koerfgen
* Copyright (C) 1998 Gleb Raiko & Vladimir Roganov
* Copyright (C) 2002 Ralf Baechle
* Copyright (C) 2002 Maciej W. Rozycki
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/tlbmisc.h>
#include <asm/isadep.h>
#include <asm/io.h>
#include <asm/bootinfo.h>
#include <asm/cpu.h>
#undef DEBUG_TLB
extern void build_tlb_refill_handler(void);
/* CP0 hazard avoidance. */
#define BARRIER \
__asm__ __volatile__( \
".set push\n\t" \
".set noreorder\n\t" \
"nop\n\t" \
".set pop\n\t")
int r3k_have_wired_reg; /* should be in cpu_data? */
/* TLB operations. */
void local_flush_tlb_all(void)
{
unsigned long flags;
unsigned long old_ctx;
int entry;
#ifdef DEBUG_TLB
printk("[tlball]");
#endif
local_irq_save(flags);
old_ctx = read_c0_entryhi() & ASID_MASK;
write_c0_entrylo0(0);
entry = r3k_have_wired_reg ? read_c0_wired() : 8;
for (; entry < current_cpu_data.tlbsize; entry++) {
write_c0_index(entry << 8);
write_c0_entryhi((entry | 0x80000) << 12);
BARRIER;
tlb_write_indexed();
}
write_c0_entryhi(old_ctx);
local_irq_restore(flags);
}
void local_flush_tlb_mm(struct mm_struct *mm)
{
int cpu = smp_processor_id();
if (cpu_context(cpu, mm) != 0) {
#ifdef DEBUG_TLB
printk("[tlbmm<%lu>]", (unsigned long)cpu_context(cpu, mm));
#endif
drop_mmu_context(mm, cpu);
}
}
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;
#ifdef DEBUG_TLB
printk("[tlbrange<%lu,0x%08lx,0x%08lx>]",
cpu_context(cpu, mm) & ASID_MASK, start, end);
#endif
local_irq_save(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size <= current_cpu_data.tlbsize) {
int oldpid = read_c0_entryhi() & ASID_MASK;
int newpid = cpu_context(cpu, mm) & ASID_MASK;
start &= PAGE_MASK;
end += PAGE_SIZE - 1;
end &= PAGE_MASK;
while (start < end) {
int idx;
write_c0_entryhi(start | newpid);
start += PAGE_SIZE; /* BARRIER */
tlb_probe();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entryhi(KSEG0);
if (idx < 0) /* BARRIER */
continue;
tlb_write_indexed();
}
write_c0_entryhi(oldpid);
} else {
drop_mmu_context(mm, cpu);
}
local_irq_restore(flags);
}
}
void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
unsigned long size, flags;
#ifdef DEBUG_TLB
printk("[tlbrange<%lu,0x%08lx,0x%08lx>]", start, end);
#endif
local_irq_save(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size <= current_cpu_data.tlbsize) {
int pid = read_c0_entryhi();
start &= PAGE_MASK;
end += PAGE_SIZE - 1;
end &= PAGE_MASK;
while (start < end) {
int idx;
write_c0_entryhi(start);
start += PAGE_SIZE; /* BARRIER */
tlb_probe();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entryhi(KSEG0);
if (idx < 0) /* BARRIER */
continue;
tlb_write_indexed();
}
write_c0_entryhi(pid);
} else {
local_flush_tlb_all();
}
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 flags;
int oldpid, newpid, idx;
#ifdef DEBUG_TLB
printk("[tlbpage<%lu,0x%08lx>]", cpu_context(cpu, vma->vm_mm), page);
#endif
newpid = cpu_context(cpu, vma->vm_mm) & ASID_MASK;
page &= PAGE_MASK;
local_irq_save(flags);
oldpid = read_c0_entryhi() & ASID_MASK;
write_c0_entryhi(page | newpid);
BARRIER;
tlb_probe();
idx = read_c0_index();
write_c0_entrylo0(0);
write_c0_entryhi(KSEG0);
if (idx < 0) /* BARRIER */
goto finish;
tlb_write_indexed();
finish:
write_c0_entryhi(oldpid);
local_irq_restore(flags);
}
}
void __update_tlb(struct vm_area_struct *vma, unsigned long address, pte_t pte)
{
unsigned long flags;
int idx, pid;
/*
* Handle debugger faulting in for debugee.
*/
if (current->active_mm != vma->vm_mm)
return;
pid = read_c0_entryhi() & ASID_MASK;
#ifdef DEBUG_TLB
if ((pid != (cpu_context(cpu, vma->vm_mm) & ASID_MASK)) || (cpu_context(cpu, vma->vm_mm) == 0)) {
printk("update_mmu_cache: Wheee, bogus tlbpid mmpid=%lu tlbpid=%d\n",
(cpu_context(cpu, vma->vm_mm)), pid);
}
#endif
local_irq_save(flags);
address &= PAGE_MASK;
write_c0_entryhi(address | pid);
BARRIER;
tlb_probe();
idx = read_c0_index();
write_c0_entrylo0(pte_val(pte));
write_c0_entryhi(address | pid);
if (idx < 0) { /* BARRIER */
tlb_write_random();
} else {
tlb_write_indexed();
}
write_c0_entryhi(pid);
local_irq_restore(flags);
}
void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
unsigned long entryhi, unsigned long pagemask)
{
unsigned long flags;
unsigned long old_ctx;
static unsigned long wired = 0;
if (r3k_have_wired_reg) { /* TX39XX */
unsigned long old_pagemask;
unsigned long w;
#ifdef DEBUG_TLB
printk("[tlbwired<entry lo0 %8x, hi %8x\n, pagemask %8x>]\n",
entrylo0, entryhi, pagemask);
#endif
local_irq_save(flags);
/* Save old context and create impossible VPN2 value */
old_ctx = read_c0_entryhi() & ASID_MASK;
old_pagemask = read_c0_pagemask();
w = read_c0_wired();
write_c0_wired(w + 1);
write_c0_index(w << 8);
write_c0_pagemask(pagemask);
write_c0_entryhi(entryhi);
write_c0_entrylo0(entrylo0);
BARRIER;
tlb_write_indexed();
write_c0_entryhi(old_ctx);
write_c0_pagemask(old_pagemask);
local_flush_tlb_all();
local_irq_restore(flags);
} else if (wired < 8) {
#ifdef DEBUG_TLB
printk("[tlbwired<entry lo0 %8x, hi %8x\n>]\n",
entrylo0, entryhi);
#endif
local_irq_save(flags);
old_ctx = read_c0_entryhi() & ASID_MASK;
write_c0_entrylo0(entrylo0);
write_c0_entryhi(entryhi);
write_c0_index(wired);
wired++; /* BARRIER */
tlb_write_indexed();
write_c0_entryhi(old_ctx);
local_flush_tlb_all();
local_irq_restore(flags);
}
}
void tlb_init(void)
{
local_flush_tlb_all();
build_tlb_refill_handler();
}
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