arch/powerpc/kernel/paca.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * c 2001 PPC 64 Team, IBM Corp
  */

 #include <linux/smp.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
 #include <linux/sched/task.h>
 #include <linux/numa.h>
 #include <linux/pgtable.h>

 #include <asm/lppaca.h>
 #include <asm/paca.h>
 #include <asm/sections.h>
 #include <asm/kexec.h>
 #include <asm/svm.h>
 #include <asm/ultravisor.h>
 #include <asm/rtas.h>

 #include "setup.h"

 #ifndef CONFIG_SMP
 #define boot_cpuid 0
 #endif

 static void *__init alloc_paca_data(unsigned long size, unsigned long align,
 				unsigned long limit, int cpu)
 {
 	void *ptr;
 	int nid;

 	/*
 	 * boot_cpuid paca is allocated very early before cpu_to_node is up.
 	 * Set bottom-up mode, because the boot CPU should be on node-0,
 	 * which will put its paca in the right place.
 	 */
 	if (cpu == boot_cpuid) {
 		nid = NUMA_NO_NODE;
 		memblock_set_bottom_up(true);
 	} else {
 		nid = early_cpu_to_node(cpu);
 	}

 	ptr = memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
 				     limit, nid);
 	if (!ptr)
 		panic("cannot allocate paca data");

 	if (cpu == boot_cpuid)
 		memblock_set_bottom_up(false);

 	return ptr;
 }

 #ifdef CONFIG_PPC_PSERIES

 #define LPPACA_SIZE 0x400

 static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
 					unsigned long limit, int cpu)
 {
 	size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
 	static unsigned long shared_lppaca_size;
 	static void *shared_lppaca;
 	void *ptr;

 	if (!shared_lppaca) {
 		memblock_set_bottom_up(true);

 		shared_lppaca =
 			memblock_alloc_try_nid(shared_lppaca_total_size,
 					       PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
 					       limit, NUMA_NO_NODE);
 		if (!shared_lppaca)
 			panic("cannot allocate shared data");

 		memblock_set_bottom_up(false);
 		uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
 			      shared_lppaca_total_size >> PAGE_SHIFT);
 	}

 	ptr = shared_lppaca + shared_lppaca_size;
 	shared_lppaca_size += size;

 	/*
 	 * This is very early in boot, so no harm done if the kernel crashes at
 	 * this point.
 	 */
 	BUG_ON(shared_lppaca_size > shared_lppaca_total_size);

 	return ptr;
 }

 /*
  * See asm/lppaca.h for more detail.
  *
  * lppaca structures must must be 1kB in size, L1 cache line aligned,
  * and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
  * these requirements.
  */
 static inline void init_lppaca(struct lppaca *lppaca)
 {
 	BUILD_BUG_ON(sizeof(struct lppaca) != 640);

 	*lppaca = (struct lppaca) {
 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
 		.size = cpu_to_be16(LPPACA_SIZE),
 		.fpregs_in_use = 1,
 		.slb_count = cpu_to_be16(64),
 		.vmxregs_in_use = 0,
 		.page_ins = 0, };
 };

 static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
 {
 	struct lppaca *lp;

 	BUILD_BUG_ON(sizeof(struct lppaca) > LPPACA_SIZE);

 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
 		return NULL;

 	if (is_secure_guest())
 		lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
 	else
 		lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);

 	init_lppaca(lp);

 	return lp;
 }
 #endif /* CONFIG_PPC_PSERIES */

 #ifdef CONFIG_PPC_BOOK3S_64

 /*
  * 3 persistent SLBs are allocated here.  The buffer will be zero
  * initially, hence will all be invaild until we actually write them.
  *
  * If you make the number of persistent SLB entries dynamic, please also
  * update PR KVM to flush and restore them accordingly.
  */
 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
 {
 	struct slb_shadow *s;

 	if (cpu != boot_cpuid) {
 		/*
 		 * Boot CPU comes here before early_radix_enabled
 		 * is parsed (e.g., for disable_radix). So allocate
 		 * always and this will be fixed up in free_unused_pacas.
 		 */
 		if (early_radix_enabled())
 			return NULL;
 	}

 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);

 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
 	s->buffer_length = cpu_to_be32(sizeof(*s));

 	return s;
 }

 #endif /* CONFIG_PPC_BOOK3S_64 */

 #ifdef CONFIG_PPC_PSERIES
 /**
  * new_rtas_args() - Allocates rtas args
  * @cpu:	CPU number
  * @limit:	Memory limit for this allocation
  *
  * Allocates a struct rtas_args and return it's pointer,
  * if not in Hypervisor mode
  *
  * Return:	Pointer to allocated rtas_args
  *		NULL if CPU in Hypervisor Mode
  */
 static struct rtas_args * __init new_rtas_args(int cpu, unsigned long limit)
 {
 	limit = min_t(unsigned long, limit, RTAS_INSTANTIATE_MAX);

 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
 		return NULL;

 	return alloc_paca_data(sizeof(struct rtas_args), L1_CACHE_BYTES,
 			       limit, cpu);
 }
 #endif /* CONFIG_PPC_PSERIES */

 /* The Paca is an array with one entry per processor.  Each contains an
  * lppaca, which contains the information shared between the
  * hypervisor and Linux.
  * On systems with hardware multi-threading, there are two threads
  * per processor.  The Paca array must contain an entry for each thread.
  * The VPD Areas will give a max logical processors = 2 * max physical
  * processors.  The processor VPD array needs one entry per physical
  * processor (not thread).
  */
 struct paca_struct **paca_ptrs __read_mostly;
 EXPORT_SYMBOL(paca_ptrs);

 void __init __nostackprotector initialise_paca(struct paca_struct *new_paca, int cpu)
 {
 #ifdef CONFIG_PPC_PSERIES
 	new_paca->lppaca_ptr = NULL;
 #endif
 #ifdef CONFIG_PPC_BOOK3E
 	new_paca->kernel_pgd = swapper_pg_dir;
 #endif
 	new_paca->lock_token = 0x8000;
 	new_paca->paca_index = cpu;
 	new_paca->kernel_toc = kernel_toc_addr();
 	new_paca->kernelbase = (unsigned long) _stext;
 	/* Only set MSR:IR/DR when MMU is initialized */
 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
 	new_paca->hw_cpu_id = 0xffff;
 	new_paca->kexec_state = KEXEC_STATE_NONE;
 	new_paca->__current = &init_task;
 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 #ifdef CONFIG_PPC_BOOK3S_64
 	new_paca->slb_shadow_ptr = NULL;
 #endif

 #ifdef CONFIG_PPC_BOOK3E
 	/* For now -- if we have threads this will be adjusted later */
 	new_paca->tcd_ptr = &new_paca->tcd;
 #endif

 #ifdef CONFIG_PPC_PSERIES
 	new_paca->rtas_args_reentrant = NULL;
 #endif
 }

 /* Put the paca pointer into r13 and SPRG_PACA */
 void __nostackprotector setup_paca(struct paca_struct *new_paca)
 {
 	/* Setup r13 */
 	local_paca = new_paca;

 #ifdef CONFIG_PPC_BOOK3E
 	/* On Book3E, initialize the TLB miss exception frames */
 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 #else
 	/*
 	 * In HV mode, we setup both HPACA and PACA to avoid problems
 	 * if we do a GET_PACA() before the feature fixups have been
 	 * applied.
 	 *
 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
 	 * are not yet set up when we first reach here.
 	 */
 	if (mfmsr() & MSR_HV)
 		mtspr(SPRN_SPRG_HPACA, local_paca);
 #endif
 	mtspr(SPRN_SPRG_PACA, local_paca);

 }

 static int __initdata paca_nr_cpu_ids;
 static int __initdata paca_ptrs_size;
 static int __initdata paca_struct_size;

 void __init allocate_paca_ptrs(void)
 {
 	paca_nr_cpu_ids = nr_cpu_ids;

 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
 	if (!paca_ptrs)
 		panic("Failed to allocate %d bytes for paca pointers\n",
 		      paca_ptrs_size);

 	memset(paca_ptrs, 0x88, paca_ptrs_size);
 }

 void __init allocate_paca(int cpu)
 {
 	u64 limit;
 	struct paca_struct *paca;

 	BUG_ON(cpu >= paca_nr_cpu_ids);

 #ifdef CONFIG_PPC_BOOK3S_64
 	/*
 	 * We access pacas in real mode, and cannot take SLB faults
 	 * on them when in virtual mode, so allocate them accordingly.
 	 */
 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
 #else
 	limit = ppc64_rma_size;
 #endif

 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
 				limit, cpu);
 	paca_ptrs[cpu] = paca;

 	initialise_paca(paca, cpu);
 #ifdef CONFIG_PPC_PSERIES
 	paca->lppaca_ptr = new_lppaca(cpu, limit);
 #endif
 #ifdef CONFIG_PPC_BOOK3S_64
 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
 #endif
 #ifdef CONFIG_PPC_PSERIES
 	paca->rtas_args_reentrant = new_rtas_args(cpu, limit);
 #endif
 	paca_struct_size += sizeof(struct paca_struct);
 }

 void __init free_unused_pacas(void)
 {
 	int new_ptrs_size;

 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
 	if (new_ptrs_size < paca_ptrs_size)
 		memblock_free(__pa(paca_ptrs) + new_ptrs_size,
 					paca_ptrs_size - new_ptrs_size);

 	paca_nr_cpu_ids = nr_cpu_ids;
 	paca_ptrs_size = new_ptrs_size;

 #ifdef CONFIG_PPC_BOOK3S_64
 	if (early_radix_enabled()) {
 		/* Ugly fixup, see new_slb_shadow() */
 		memblock_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
 				sizeof(struct slb_shadow));
 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
 	}
 #endif

 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
 }

 void copy_mm_to_paca(struct mm_struct *mm)
 {
 #ifdef CONFIG_PPC_BOOK3S
 	mm_context_t *context = &mm->context;

 	get_paca()->mm_ctx_id = context->id;
 #ifdef CONFIG_PPC_MM_SLICES
 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
 	get_paca()->mm_ctx_slb_addr_limit = mm_ctx_slb_addr_limit(context);
 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
 	       LOW_SLICE_ARRAY_SZ);
 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
 	       TASK_SLICE_ARRAY_SZ(context));
 #else /* CONFIG_PPC_MM_SLICES */
 	get_paca()->mm_ctx_user_psize = context->user_psize;
 	get_paca()->mm_ctx_sllp = context->sllp;
 #endif
 #else /* !CONFIG_PPC_BOOK3S */
 	return;
 #endif
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* c 2001 PPC 64 Team, IBM Corp
	*/

	#include <linux/smp.h>
	#include <linux/export.h>
	#include <linux/memblock.h>
	#include <linux/sched/task.h>
	#include <linux/numa.h>
	#include <linux/pgtable.h>

	#include <asm/lppaca.h>
	#include <asm/paca.h>
	#include <asm/sections.h>
	#include <asm/kexec.h>
	#include <asm/svm.h>
	#include <asm/ultravisor.h>
	#include <asm/rtas.h>

	#include "setup.h"

	#ifndef CONFIG_SMP
	#define boot_cpuid 0
	#endif

	static void *__init alloc_paca_data(unsigned long size, unsigned long align,
	unsigned long limit, int cpu)
	{
	void *ptr;
	int nid;

	/*
	* boot_cpuid paca is allocated very early before cpu_to_node is up.
	* Set bottom-up mode, because the boot CPU should be on node-0,
	* which will put its paca in the right place.
	*/
	if (cpu == boot_cpuid) {
	nid = NUMA_NO_NODE;
	memblock_set_bottom_up(true);
	} else {
	nid = early_cpu_to_node(cpu);
	}

	ptr = memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
	limit, nid);
	if (!ptr)
	panic("cannot allocate paca data");

	if (cpu == boot_cpuid)
	memblock_set_bottom_up(false);

	return ptr;
	}

	#ifdef CONFIG_PPC_PSERIES

	#define LPPACA_SIZE 0x400

	static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
	unsigned long limit, int cpu)
	{
	size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
	static unsigned long shared_lppaca_size;
	static void *shared_lppaca;
	void *ptr;

	if (!shared_lppaca) {
	memblock_set_bottom_up(true);

	shared_lppaca =
	memblock_alloc_try_nid(shared_lppaca_total_size,
	PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
	limit, NUMA_NO_NODE);
	if (!shared_lppaca)
	panic("cannot allocate shared data");

	memblock_set_bottom_up(false);
	uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
	shared_lppaca_total_size >> PAGE_SHIFT);
	}

	ptr = shared_lppaca + shared_lppaca_size;
	shared_lppaca_size += size;

	/*
	* This is very early in boot, so no harm done if the kernel crashes at
	* this point.
	*/
	BUG_ON(shared_lppaca_size > shared_lppaca_total_size);

	return ptr;
	}

	/*
	* See asm/lppaca.h for more detail.
	*
	* lppaca structures must must be 1kB in size, L1 cache line aligned,
	* and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
	* these requirements.
	*/
	static inline void init_lppaca(struct lppaca *lppaca)
	{
	BUILD_BUG_ON(sizeof(struct lppaca) != 640);

	*lppaca = (struct lppaca) {
	.desc = cpu_to_be32(0xd397d781), /* "LpPa" */
	.size = cpu_to_be16(LPPACA_SIZE),
	.fpregs_in_use = 1,
	.slb_count = cpu_to_be16(64),
	.vmxregs_in_use = 0,
	.page_ins = 0, };
	};

	static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
	{
	struct lppaca *lp;

	BUILD_BUG_ON(sizeof(struct lppaca) > LPPACA_SIZE);

	if (early_cpu_has_feature(CPU_FTR_HVMODE))
	return NULL;

	if (is_secure_guest())
	lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
	else
	lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);

	init_lppaca(lp);

	return lp;
	}
	#endif /* CONFIG_PPC_PSERIES */

	#ifdef CONFIG_PPC_BOOK3S_64

	/*
	* 3 persistent SLBs are allocated here. The buffer will be zero
	* initially, hence will all be invaild until we actually write them.
	*
	* If you make the number of persistent SLB entries dynamic, please also
	* update PR KVM to flush and restore them accordingly.
	*/
	static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
	{
	struct slb_shadow *s;

	if (cpu != boot_cpuid) {
	/*
	* Boot CPU comes here before early_radix_enabled
	* is parsed (e.g., for disable_radix). So allocate
	* always and this will be fixed up in free_unused_pacas.
	*/
	if (early_radix_enabled())
	return NULL;
	}

	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);

	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
	s->buffer_length = cpu_to_be32(sizeof(*s));

	return s;
	}

	#endif /* CONFIG_PPC_BOOK3S_64 */

	#ifdef CONFIG_PPC_PSERIES
	/**
	* new_rtas_args() - Allocates rtas args
	* @cpu: CPU number
	* @limit: Memory limit for this allocation
	*
	* Allocates a struct rtas_args and return it's pointer,
	* if not in Hypervisor mode
	*
	* Return: Pointer to allocated rtas_args
	* NULL if CPU in Hypervisor Mode
	*/
	static struct rtas_args * __init new_rtas_args(int cpu, unsigned long limit)
	{
	limit = min_t(unsigned long, limit, RTAS_INSTANTIATE_MAX);

	if (early_cpu_has_feature(CPU_FTR_HVMODE))
	return NULL;

	return alloc_paca_data(sizeof(struct rtas_args), L1_CACHE_BYTES,
	limit, cpu);
	}
	#endif /* CONFIG_PPC_PSERIES */

	/* The Paca is an array with one entry per processor. Each contains an
	* lppaca, which contains the information shared between the
	* hypervisor and Linux.
	* On systems with hardware multi-threading, there are two threads
	* per processor. The Paca array must contain an entry for each thread.
	* The VPD Areas will give a max logical processors = 2 * max physical
	* processors. The processor VPD array needs one entry per physical
	* processor (not thread).
	*/
	struct paca_struct **paca_ptrs __read_mostly;
	EXPORT_SYMBOL(paca_ptrs);

	void __init __nostackprotector initialise_paca(struct paca_struct *new_paca, int cpu)
	{
	#ifdef CONFIG_PPC_PSERIES
	new_paca->lppaca_ptr = NULL;
	#endif
	#ifdef CONFIG_PPC_BOOK3E
	new_paca->kernel_pgd = swapper_pg_dir;
	#endif
	new_paca->lock_token = 0x8000;
	new_paca->paca_index = cpu;
	new_paca->kernel_toc = kernel_toc_addr();
	new_paca->kernelbase = (unsigned long) _stext;
	/* Only set MSR:IR/DR when MMU is initialized */
	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR \| MSR_DR);
	new_paca->hw_cpu_id = 0xffff;
	new_paca->kexec_state = KEXEC_STATE_NONE;
	new_paca->__current = &init_task;
	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
	#ifdef CONFIG_PPC_BOOK3S_64
	new_paca->slb_shadow_ptr = NULL;
	#endif

	#ifdef CONFIG_PPC_BOOK3E
	/* For now -- if we have threads this will be adjusted later */
	new_paca->tcd_ptr = &new_paca->tcd;
	#endif

	#ifdef CONFIG_PPC_PSERIES
	new_paca->rtas_args_reentrant = NULL;
	#endif
	}

	/* Put the paca pointer into r13 and SPRG_PACA */
	void __nostackprotector setup_paca(struct paca_struct *new_paca)
	{
	/* Setup r13 */
	local_paca = new_paca;

	#ifdef CONFIG_PPC_BOOK3E
	/* On Book3E, initialize the TLB miss exception frames */
	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
	#else
	/*
	* In HV mode, we setup both HPACA and PACA to avoid problems
	* if we do a GET_PACA() before the feature fixups have been
	* applied.
	*
	* Normally you should test against CPU_FTR_HVMODE, but CPU features
	* are not yet set up when we first reach here.
	*/
	if (mfmsr() & MSR_HV)
	mtspr(SPRN_SPRG_HPACA, local_paca);
	#endif
	mtspr(SPRN_SPRG_PACA, local_paca);

	}

	static int __initdata paca_nr_cpu_ids;
	static int __initdata paca_ptrs_size;
	static int __initdata paca_struct_size;

	void __init allocate_paca_ptrs(void)
	{
	paca_nr_cpu_ids = nr_cpu_ids;

	paca_ptrs_size = sizeof(struct paca_struct ) nr_cpu_ids;
	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
	if (!paca_ptrs)
	panic("Failed to allocate %d bytes for paca pointers\n",
	paca_ptrs_size);

	memset(paca_ptrs, 0x88, paca_ptrs_size);
	}

	void __init allocate_paca(int cpu)
	{
	u64 limit;
	struct paca_struct *paca;

	BUG_ON(cpu >= paca_nr_cpu_ids);

	#ifdef CONFIG_PPC_BOOK3S_64
	/*
	* We access pacas in real mode, and cannot take SLB faults
	* on them when in virtual mode, so allocate them accordingly.
	*/
	limit = min(ppc64_bolted_size(), ppc64_rma_size);
	#else
	limit = ppc64_rma_size;
	#endif

	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
	limit, cpu);
	paca_ptrs[cpu] = paca;

	initialise_paca(paca, cpu);
	#ifdef CONFIG_PPC_PSERIES
	paca->lppaca_ptr = new_lppaca(cpu, limit);
	#endif
	#ifdef CONFIG_PPC_BOOK3S_64
	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
	#endif
	#ifdef CONFIG_PPC_PSERIES
	paca->rtas_args_reentrant = new_rtas_args(cpu, limit);
	#endif
	paca_struct_size += sizeof(struct paca_struct);
	}

	void __init free_unused_pacas(void)
	{
	int new_ptrs_size;

	new_ptrs_size = sizeof(struct paca_struct ) nr_cpu_ids;
	if (new_ptrs_size < paca_ptrs_size)
	memblock_free(__pa(paca_ptrs) + new_ptrs_size,
	paca_ptrs_size - new_ptrs_size);

	paca_nr_cpu_ids = nr_cpu_ids;
	paca_ptrs_size = new_ptrs_size;

	#ifdef CONFIG_PPC_BOOK3S_64
	if (early_radix_enabled()) {
	/* Ugly fixup, see new_slb_shadow() */
	memblock_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
	sizeof(struct slb_shadow));
	paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
	}
	#endif

	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
	paca_ptrs_size + paca_struct_size, nr_cpu_ids);
	}

	void copy_mm_to_paca(struct mm_struct *mm)
	{
	#ifdef CONFIG_PPC_BOOK3S
	mm_context_t *context = &mm->context;

	get_paca()->mm_ctx_id = context->id;
	#ifdef CONFIG_PPC_MM_SLICES
	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
	get_paca()->mm_ctx_slb_addr_limit = mm_ctx_slb_addr_limit(context);
	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
	LOW_SLICE_ARRAY_SZ);
	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
	TASK_SLICE_ARRAY_SZ(context));
	#else /* CONFIG_PPC_MM_SLICES */
	get_paca()->mm_ctx_user_psize = context->user_psize;
	get_paca()->mm_ctx_sllp = context->sllp;
	#endif
	#else /* !CONFIG_PPC_BOOK3S */
	return;
	#endif
	}