linux/arch/powerpc/mm/slb.c
Brian King 46db2f86a3 powerpc/pseries: Fix to handle slb resize across migration
The SLB can change sizes across a live migration, which was not
being handled, resulting in possible machine crashes during
migration if migrating to a machine which has a smaller max SLB
size than the source machine. Fix this by first reducing the
SLB size to the minimum possible value, which is 32, prior to
migration. Then during the device tree update which occurs after
migration, we make the call to ensure the SLB gets updated. Also
add the slb_size to the lparcfg output so that the migration
tools can check to make sure the kernel has this capability
before allowing migration in scenarios where the SLB size will change.

BenH: Fixed #include <asm/mmu-hash64.h> -> <asm/mmu.h> to avoid
      breaking ppc32 build

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-02 16:19:01 +10:00

339 lines
10 KiB
C

/*
* PowerPC64 SLB support.
*
* Copyright (C) 2004 David Gibson <dwg@au.ibm.com>, IBM
* Based on earlier code written by:
* Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
* Copyright (c) 2001 Dave Engebretsen
* Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
*
*
* This program 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.
*/
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/paca.h>
#include <asm/cputable.h>
#include <asm/cacheflush.h>
#include <asm/smp.h>
#include <asm/firmware.h>
#include <linux/compiler.h>
#include <asm/udbg.h>
extern void slb_allocate_realmode(unsigned long ea);
extern void slb_allocate_user(unsigned long ea);
static void slb_allocate(unsigned long ea)
{
/* Currently, we do real mode for all SLBs including user, but
* that will change if we bring back dynamic VSIDs
*/
slb_allocate_realmode(ea);
}
#define slb_esid_mask(ssize) \
(((ssize) == MMU_SEGSIZE_256M)? ESID_MASK: ESID_MASK_1T)
static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
unsigned long slot)
{
return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | slot;
}
#define slb_vsid_shift(ssize) \
((ssize) == MMU_SEGSIZE_256M? SLB_VSID_SHIFT: SLB_VSID_SHIFT_1T)
static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
unsigned long flags)
{
return (get_kernel_vsid(ea, ssize) << slb_vsid_shift(ssize)) | flags |
((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
}
static inline void slb_shadow_update(unsigned long ea, int ssize,
unsigned long flags,
unsigned long entry)
{
/*
* Clear the ESID first so the entry is not valid while we are
* updating it. No write barriers are needed here, provided
* we only update the current CPU's SLB shadow buffer.
*/
get_slb_shadow()->save_area[entry].esid = 0;
get_slb_shadow()->save_area[entry].vsid = mk_vsid_data(ea, ssize, flags);
get_slb_shadow()->save_area[entry].esid = mk_esid_data(ea, ssize, entry);
}
static inline void slb_shadow_clear(unsigned long entry)
{
get_slb_shadow()->save_area[entry].esid = 0;
}
static inline void create_shadowed_slbe(unsigned long ea, int ssize,
unsigned long flags,
unsigned long entry)
{
/*
* Updating the shadow buffer before writing the SLB ensures
* we don't get a stale entry here if we get preempted by PHYP
* between these two statements.
*/
slb_shadow_update(ea, ssize, flags, entry);
asm volatile("slbmte %0,%1" :
: "r" (mk_vsid_data(ea, ssize, flags)),
"r" (mk_esid_data(ea, ssize, entry))
: "memory" );
}
static void __slb_flush_and_rebolt(void)
{
/* If you change this make sure you change SLB_NUM_BOLTED
* appropriately too. */
unsigned long linear_llp, vmalloc_llp, lflags, vflags;
unsigned long ksp_esid_data, ksp_vsid_data;
linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
lflags = SLB_VSID_KERNEL | linear_llp;
vflags = SLB_VSID_KERNEL | vmalloc_llp;
ksp_esid_data = mk_esid_data(get_paca()->kstack, mmu_kernel_ssize, 2);
if ((ksp_esid_data & ~0xfffffffUL) <= PAGE_OFFSET) {
ksp_esid_data &= ~SLB_ESID_V;
ksp_vsid_data = 0;
slb_shadow_clear(2);
} else {
/* Update stack entry; others don't change */
slb_shadow_update(get_paca()->kstack, mmu_kernel_ssize, lflags, 2);
ksp_vsid_data = get_slb_shadow()->save_area[2].vsid;
}
/* We need to do this all in asm, so we're sure we don't touch
* the stack between the slbia and rebolting it. */
asm volatile("isync\n"
"slbia\n"
/* Slot 1 - first VMALLOC segment */
"slbmte %0,%1\n"
/* Slot 2 - kernel stack */
"slbmte %2,%3\n"
"isync"
:: "r"(mk_vsid_data(VMALLOC_START, mmu_kernel_ssize, vflags)),
"r"(mk_esid_data(VMALLOC_START, mmu_kernel_ssize, 1)),
"r"(ksp_vsid_data),
"r"(ksp_esid_data)
: "memory");
}
void slb_flush_and_rebolt(void)
{
WARN_ON(!irqs_disabled());
/*
* We can't take a PMU exception in the following code, so hard
* disable interrupts.
*/
hard_irq_disable();
__slb_flush_and_rebolt();
get_paca()->slb_cache_ptr = 0;
}
void slb_vmalloc_update(void)
{
unsigned long vflags;
vflags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmalloc_psize].sllp;
slb_shadow_update(VMALLOC_START, mmu_kernel_ssize, vflags, 1);
slb_flush_and_rebolt();
}
/* Helper function to compare esids. There are four cases to handle.
* 1. The system is not 1T segment size capable. Use the GET_ESID compare.
* 2. The system is 1T capable, both addresses are < 1T, use the GET_ESID compare.
* 3. The system is 1T capable, only one of the two addresses is > 1T. This is not a match.
* 4. The system is 1T capable, both addresses are > 1T, use the GET_ESID_1T macro to compare.
*/
static inline int esids_match(unsigned long addr1, unsigned long addr2)
{
int esid_1t_count;
/* System is not 1T segment size capable. */
if (!cpu_has_feature(CPU_FTR_1T_SEGMENT))
return (GET_ESID(addr1) == GET_ESID(addr2));
esid_1t_count = (((addr1 >> SID_SHIFT_1T) != 0) +
((addr2 >> SID_SHIFT_1T) != 0));
/* both addresses are < 1T */
if (esid_1t_count == 0)
return (GET_ESID(addr1) == GET_ESID(addr2));
/* One address < 1T, the other > 1T. Not a match */
if (esid_1t_count == 1)
return 0;
/* Both addresses are > 1T. */
return (GET_ESID_1T(addr1) == GET_ESID_1T(addr2));
}
/* Flush all user entries from the segment table of the current processor. */
void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
{
unsigned long offset;
unsigned long slbie_data = 0;
unsigned long pc = KSTK_EIP(tsk);
unsigned long stack = KSTK_ESP(tsk);
unsigned long exec_base;
/*
* We need interrupts hard-disabled here, not just soft-disabled,
* so that a PMU interrupt can't occur, which might try to access
* user memory (to get a stack trace) and possible cause an SLB miss
* which would update the slb_cache/slb_cache_ptr fields in the PACA.
*/
hard_irq_disable();
offset = get_paca()->slb_cache_ptr;
if (!cpu_has_feature(CPU_FTR_NO_SLBIE_B) &&
offset <= SLB_CACHE_ENTRIES) {
int i;
asm volatile("isync" : : : "memory");
for (i = 0; i < offset; i++) {
slbie_data = (unsigned long)get_paca()->slb_cache[i]
<< SID_SHIFT; /* EA */
slbie_data |= user_segment_size(slbie_data)
<< SLBIE_SSIZE_SHIFT;
slbie_data |= SLBIE_C; /* C set for user addresses */
asm volatile("slbie %0" : : "r" (slbie_data));
}
asm volatile("isync" : : : "memory");
} else {
__slb_flush_and_rebolt();
}
/* Workaround POWER5 < DD2.1 issue */
if (offset == 1 || offset > SLB_CACHE_ENTRIES)
asm volatile("slbie %0" : : "r" (slbie_data));
get_paca()->slb_cache_ptr = 0;
get_paca()->context = mm->context;
/*
* preload some userspace segments into the SLB.
* Almost all 32 and 64bit PowerPC executables are linked at
* 0x10000000 so it makes sense to preload this segment.
*/
exec_base = 0x10000000;
if (is_kernel_addr(pc) || is_kernel_addr(stack) ||
is_kernel_addr(exec_base))
return;
slb_allocate(pc);
if (!esids_match(pc, stack))
slb_allocate(stack);
if (!esids_match(pc, exec_base) &&
!esids_match(stack, exec_base))
slb_allocate(exec_base);
}
static inline void patch_slb_encoding(unsigned int *insn_addr,
unsigned int immed)
{
*insn_addr = (*insn_addr & 0xffff0000) | immed;
flush_icache_range((unsigned long)insn_addr, 4+
(unsigned long)insn_addr);
}
void slb_set_size(u16 size)
{
extern unsigned int *slb_compare_rr_to_size;
if (mmu_slb_size == size)
return;
mmu_slb_size = size;
patch_slb_encoding(slb_compare_rr_to_size, mmu_slb_size);
}
void slb_initialize(void)
{
unsigned long linear_llp, vmalloc_llp, io_llp;
unsigned long lflags, vflags;
static int slb_encoding_inited;
extern unsigned int *slb_miss_kernel_load_linear;
extern unsigned int *slb_miss_kernel_load_io;
extern unsigned int *slb_compare_rr_to_size;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
extern unsigned int *slb_miss_kernel_load_vmemmap;
unsigned long vmemmap_llp;
#endif
/* Prepare our SLB miss handler based on our page size */
linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
io_llp = mmu_psize_defs[mmu_io_psize].sllp;
vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
get_paca()->vmalloc_sllp = SLB_VSID_KERNEL | vmalloc_llp;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
vmemmap_llp = mmu_psize_defs[mmu_vmemmap_psize].sllp;
#endif
if (!slb_encoding_inited) {
slb_encoding_inited = 1;
patch_slb_encoding(slb_miss_kernel_load_linear,
SLB_VSID_KERNEL | linear_llp);
patch_slb_encoding(slb_miss_kernel_load_io,
SLB_VSID_KERNEL | io_llp);
patch_slb_encoding(slb_compare_rr_to_size,
mmu_slb_size);
pr_devel("SLB: linear LLP = %04lx\n", linear_llp);
pr_devel("SLB: io LLP = %04lx\n", io_llp);
#ifdef CONFIG_SPARSEMEM_VMEMMAP
patch_slb_encoding(slb_miss_kernel_load_vmemmap,
SLB_VSID_KERNEL | vmemmap_llp);
pr_devel("SLB: vmemmap LLP = %04lx\n", vmemmap_llp);
#endif
}
get_paca()->stab_rr = SLB_NUM_BOLTED;
/* On iSeries the bolted entries have already been set up by
* the hypervisor from the lparMap data in head.S */
if (firmware_has_feature(FW_FEATURE_ISERIES))
return;
lflags = SLB_VSID_KERNEL | linear_llp;
vflags = SLB_VSID_KERNEL | vmalloc_llp;
/* Invalidate the entire SLB (even slot 0) & all the ERATS */
asm volatile("isync":::"memory");
asm volatile("slbmte %0,%0"::"r" (0) : "memory");
asm volatile("isync; slbia; isync":::"memory");
create_shadowed_slbe(PAGE_OFFSET, mmu_kernel_ssize, lflags, 0);
create_shadowed_slbe(VMALLOC_START, mmu_kernel_ssize, vflags, 1);
/* For the boot cpu, we're running on the stack in init_thread_union,
* which is in the first segment of the linear mapping, and also
* get_paca()->kstack hasn't been initialized yet.
* For secondary cpus, we need to bolt the kernel stack entry now.
*/
slb_shadow_clear(2);
if (raw_smp_processor_id() != boot_cpuid &&
(get_paca()->kstack & slb_esid_mask(mmu_kernel_ssize)) > PAGE_OFFSET)
create_shadowed_slbe(get_paca()->kstack,
mmu_kernel_ssize, lflags, 2);
asm volatile("isync":::"memory");
}