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Hexagon: Add page-fault support.

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Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Richard Kuo 2011-10-31 18:54:08 -05:00 committed by Linus Torvalds
parent a7e7984099
commit 499236d9db
4 changed files with 601 additions and 0 deletions
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112
arch/hexagon/include/asm/mem-layout.h Normal file
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/*
* Memory layout definitions for the Hexagon architecture
*
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program 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
* 02110-1301, USA.
*/
#ifndef _ASM_HEXAGON_MEM_LAYOUT_H
#define _ASM_HEXAGON_MEM_LAYOUT_H
#include <linux/const.h>
/*
* Have to do this for ginormous numbers, else they get printed as
* negative numbers, which the linker no likey when you try to
* assign it to the location counter.
*/
#define PAGE_OFFSET _AC(0xc0000000, UL)
/*
* LOAD_ADDRESS is the physical/linear address of where in memory
* the kernel gets loaded. The 12 least significant bits must be zero (0)
* due to limitations on setting the EVB
*
*/
#ifndef LOAD_ADDRESS
#define LOAD_ADDRESS 0x00000000
#endif
#define TASK_SIZE (PAGE_OFFSET)
/* not sure how these are used yet */
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX TASK_SIZE
#ifndef __ASSEMBLY__
enum fixed_addresses {
FIX_KMAP_BEGIN,
FIX_KMAP_END, /* check for per-cpuism */
__end_of_fixed_addresses
};
#define MIN_KERNEL_SEG 0x300 /* From 0xc0000000 */
extern int max_kernel_seg;
/*
* Start of vmalloc virtual address space for kernel;
* supposed to be based on the amount of physical memory available
*/
#define VMALLOC_START (PAGE_OFFSET + VMALLOC_OFFSET + \
(unsigned long)high_memory)
/* Gap between physical ram and vmalloc space for guard purposes. */
#define VMALLOC_OFFSET PAGE_SIZE
/*
* Create the space between VMALLOC_START and FIXADDR_TOP backwards
* from the ... "top".
*
* Permanent IO mappings will live at 0xfexx_xxxx
* Hypervisor occupies the last 16MB page at 0xffxxxxxx
*/
#define FIXADDR_TOP 0xfe000000
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
/*
* "permanent kernel mappings", defined as long-lasting mappings of
* high-memory page frames into the kernel address space.
*/
#define LAST_PKMAP PTRS_PER_PTE
#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
/*
* To the "left" of the fixed map space is the kmap space
*
* "Permanent Kernel Mappings"; fancy (or less fancy) PTE table
* that looks like it's actually walked.
* Need to check the alignment/shift usage; some archs use
* PMD_MASK on this value
*/
#define PKMAP_BASE (FIXADDR_START-PAGE_SIZE*LAST_PKMAP)
/*
* 2 pages of guard gap between where vmalloc area ends
* and pkmap_base begins.
*/
#define VMALLOC_END (PKMAP_BASE-PAGE_SIZE*2)
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_HEXAGON_MEM_LAYOUT_H */

26
arch/hexagon/include/asm/vm_fault.h Normal file
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/*
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program 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
* 02110-1301, USA.
*/
#ifndef _ASM_HEXAGON_VM_FAULT_H
#define _ASM_HEXAGON_VM_FAULT_H
extern void execute_protection_fault(struct pt_regs *);
extern void write_protection_fault(struct pt_regs *);
extern void read_protection_fault(struct pt_regs *);
#endif

276
arch/hexagon/mm/init.c Normal file
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/*
* Memory subsystem initialization for Hexagon
*
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program 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
* 02110-1301, USA.
*/
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <asm/atomic.h>
#include <linux/highmem.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/vm_mmu.h>
/*
* Define a startpg just past the end of the kernel image and a lastpg
* that corresponds to the end of real or simulated platform memory.
*/
#define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET))
unsigned long bootmem_lastpg; /* Should be set by platform code */
/* Set as variable to limit PMD copies */
int max_kernel_seg = 0x303;
/* think this should be (page_size-1) the way it's used...*/
unsigned long zero_page_mask;
/* indicate pfn's of high memory */
unsigned long highstart_pfn, highend_pfn;
/* struct mmu_gather defined in asm-generic.h; */
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
/* Default cache attribute for newly created page tables */
unsigned long _dflt_cache_att = CACHEDEF;
/*
* The current "generation" of kernel map, which should not roll
* over until Hell freezes over. Actual bound in years needs to be
* calculated to confirm.
*/
DEFINE_SPINLOCK(kmap_gen_lock);
/* checkpatch says don't init this to 0. */
unsigned long long kmap_generation;
/*
* mem_init - initializes memory
*
* Frees up bootmem
* Fixes up more stuff for HIGHMEM
* Calculates and displays memory available/used
*/
void __init mem_init(void)
{
/* No idea where this is actually declared. Seems to evade LXR. */
totalram_pages += free_all_bootmem();
num_physpages = bootmem_lastpg; /* seriously, what? */
printk(KERN_INFO "totalram_pages = %ld\n", totalram_pages);
/*
* To-Do: someone somewhere should wipe out the bootmem map
* after we're done?
*/
/*
* This can be moved to some more virtual-memory-specific
* initialization hook at some point. Set the init_mm
* descriptors "context" value to point to the initial
* kernel segment table's physical address.
*/
init_mm.context.ptbase = __pa(init_mm.pgd);
}
/*
* free_initmem - frees memory used by stuff declared with __init
*
* Todo: free pages between __init_begin and __init_end; possibly
* some devtree related stuff as well.
*/
void __init_refok free_initmem(void)
{
}
/*
* free_initrd_mem - frees... initrd memory.
* @start - start of init memory
* @end - end of init memory
*
* Apparently has to be passed the address of the initrd memory.
*
* Wrapped by #ifdef CONFIG_BLKDEV_INITRD
*/
void free_initrd_mem(unsigned long start, unsigned long end)
{
}
void sync_icache_dcache(pte_t pte)
{
unsigned long addr;
struct page *page;
page = pte_page(pte);
addr = (unsigned long) page_address(page);
__vmcache_idsync(addr, PAGE_SIZE);
}
/*
* In order to set up page allocator "nodes",
* somebody has to call free_area_init() for UMA.
*
* In this mode, we only have one pg_data_t
* structure: contig_mem_data.
*/
void __init paging_init(void)
{
unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
/*
* This is not particularly well documented anywhere, but
* give ZONE_NORMAL all the memory, including the big holes
* left by the kernel+bootmem_map which are already left as reserved
* in the bootmem_map; free_area_init should see those bits and
* adjust accordingly.
*/
zones_sizes[ZONE_NORMAL] = max_low_pfn;
free_area_init(zones_sizes); /* sets up the zonelists and mem_map */
/*
* Start of high memory area. Will probably need something more
* fancy if we... get more fancy.
*/
high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
}
#ifndef DMA_RESERVE
#define DMA_RESERVE (4)
#endif
#define DMA_CHUNKSIZE (1<<22)
#define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
/*
* Pick out the memory size. We look for mem=size,
* where size is "size[KkMm]"
*/
static int __init early_mem(char *p)
{
unsigned long size;
char *endp;
size = memparse(p, &endp);
bootmem_lastpg = PFN_DOWN(size);
return 0;
}
early_param("mem", early_mem);
size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
void __init setup_arch_memory(void)
{
int bootmap_size;
/* XXX Todo: this probably should be cleaned up */
u32 *segtable = (u32 *) &swapper_pg_dir[0];
u32 *segtable_end;
/*
* Set up boot memory allocator
*
* The Gorman book also talks about these functions.
* This needs to change for highmem setups.
*/
/* Memory size needs to be a multiple of 16M */
bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
~((BIG_KERNEL_PAGE_SIZE) - 1));
/*
* Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
* memory allocation
*/
bootmap_size = init_bootmem(bootmem_startpg, bootmem_lastpg -
PFN_DOWN(DMA_RESERVED_BYTES));
printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
printk(KERN_INFO "bootmap_size: %d\n", bootmap_size);
printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);
/*
* The default VM page tables (will be) populated with
* VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
* higher than what we have memory for.
*/
/* this is pointer arithmetic; each entry covers 4MB */
segtable = segtable + (PAGE_OFFSET >> 22);
/* this actually only goes to the end of the first gig */
segtable_end = segtable + (1<<(30-22));
/* Move forward to the start of empty pages */
segtable += bootmem_lastpg >> (22-PAGE_SHIFT);
{
int i;
for (i = 1 ; i <= DMA_RESERVE ; i++)
segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
| __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
| __HEXAGON_C_UNC << 6
| __HVM_PDE_S_4MB);
}
printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
segtable_end);
while (segtable < (segtable_end-8))
*(segtable++) = __HVM_PDE_S_INVALID;
/* stop the pointer at the device I/O 4MB page */
printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
segtable);
#if 0
/* Other half of the early device table from vm_init_segtable. */
printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
(unsigned long) _K_init_devicetable-PAGE_OFFSET);
*segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
__HVM_PDE_S_4KB;
printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
#endif
/*
* Free all the memory that wasn't taken up by the bootmap, the DMA
* reserve, or kernel itself.
*/
free_bootmem(PFN_PHYS(bootmem_startpg)+bootmap_size,
PFN_PHYS(bootmem_lastpg - bootmem_startpg) - bootmap_size -
DMA_RESERVED_BYTES);
/*
* The bootmem allocator seemingly just lives to feed memory
* to the paging system
*/
printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
paging_init(); /* See Gorman Book, 2.3 */
/*
* At this point, the page allocator is kind of initialized, but
* apparently no pages are available (just like with the bootmem
* allocator), and need to be freed themselves via mem_init(),
* which is called by start_kernel() later on in the process
*/
}

187
arch/hexagon/mm/vm_fault.c Normal file
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/*
* Memory fault handling for Hexagon
*
* Copyright (c) 2010-2011 Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program 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
* 02110-1301, USA.
*/
/*
* Page fault handling for the Hexagon Virtual Machine.
* Can also be called by a native port emulating the HVM
* execptions.
*/
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/signal.h>
#include <linux/module.h>
#include <linux/hardirq.h>
/*
* Decode of hardware exception sends us to one of several
* entry points. At each, we generate canonical arguments
* for handling by the abstract memory management code.
*/
#define FLT_IFETCH -1
#define FLT_LOAD 0
#define FLT_STORE 1
/*
* Canonical page fault handler
*/
void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
siginfo_t info;
int si_code = SEGV_MAPERR;
int fault;
const struct exception_table_entry *fixup;
/*
* If we're in an interrupt or have no user context,
* then must not take the fault.
*/
if (unlikely(in_interrupt() || !mm))
goto no_context;
local_irq_enable();
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
good_area:
/* Address space is OK. Now check access rights. */
si_code = SEGV_ACCERR;
switch (cause) {
case FLT_IFETCH:
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
break;
case FLT_LOAD:
if (!(vma->vm_flags & VM_READ))
goto bad_area;
break;
case FLT_STORE:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
break;
}
fault = handle_mm_fault(mm, vma, address, (cause > 0));
/* The most common case -- we are done. */
if (likely(!(fault & VM_FAULT_ERROR))) {
if (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
up_read(&mm->mmap_sem);
return;
}
up_read(&mm->mmap_sem);
/* Handle copyin/out exception cases */
if (!user_mode(regs))
goto no_context;
if (fault & VM_FAULT_OOM) {
pagefault_out_of_memory();
return;
}
/* User-mode address is in the memory map, but we are
* unable to fix up the page fault.
*/
if (fault & VM_FAULT_SIGBUS) {
info.si_signo = SIGBUS;
info.si_code = BUS_ADRERR;
}
/* Address is not in the memory map */
else {
info.si_signo = SIGSEGV;
info.si_code = SEGV_ACCERR;
}
info.si_errno = 0;
info.si_addr = (void __user *)address;
force_sig_info(info.si_code, &info, current);
return;
bad_area:
up_read(&mm->mmap_sem);
if (user_mode(regs)) {
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void *)address;
force_sig_info(SIGSEGV, &info, current);
return;
}
/* Kernel-mode fault falls through */
no_context:
fixup = search_exception_tables(pt_elr(regs));
if (fixup) {
pt_set_elr(regs, fixup->fixup);
return;
}
/* Things are looking very, very bad now */
bust_spinlocks(1);
printk(KERN_EMERG "Unable to handle kernel paging request at "
"virtual address 0x%08lx, regs %p\n", address, regs);
die("Bad Kernel VA", regs, SIGKILL);
}
void read_protection_fault(struct pt_regs *regs)
{
unsigned long badvadr = pt_badva(regs);
do_page_fault(badvadr, FLT_LOAD, regs);
}
void write_protection_fault(struct pt_regs *regs)
{
unsigned long badvadr = pt_badva(regs);
do_page_fault(badvadr, FLT_STORE, regs);
}
void execute_protection_fault(struct pt_regs *regs)
{
unsigned long badvadr = pt_badva(regs);
do_page_fault(badvadr, FLT_IFETCH, regs);
}