linux/arch/m68k/sun3/mmu_emu.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

430 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
** Tablewalk MMU emulator
**
** by Toshiyasu Morita
**
** Started 1/16/98 @ 2:22 am
*/
#include <linux/init.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/delay.h>
#include <linux/bootmem.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/sched/mm.h>
#include <asm/setup.h>
#include <asm/traps.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/sun3mmu.h>
#include <asm/segment.h>
#include <asm/oplib.h>
#include <asm/mmu_context.h>
#include <asm/dvma.h>
#undef DEBUG_MMU_EMU
#define DEBUG_PROM_MAPS
/*
** Defines
*/
#define CONTEXTS_NUM 8
#define SEGMAPS_PER_CONTEXT_NUM 2048
#define PAGES_PER_SEGMENT 16
#define PMEGS_NUM 256
#define PMEG_MASK 0xFF
/*
** Globals
*/
unsigned long m68k_vmalloc_end;
EXPORT_SYMBOL(m68k_vmalloc_end);
unsigned long pmeg_vaddr[PMEGS_NUM];
unsigned char pmeg_alloc[PMEGS_NUM];
unsigned char pmeg_ctx[PMEGS_NUM];
/* pointers to the mm structs for each task in each
context. 0xffffffff is a marker for kernel context */
static struct mm_struct *ctx_alloc[CONTEXTS_NUM] = {
[0] = (struct mm_struct *)0xffffffff
};
/* has this context been mmdrop'd? */
static unsigned char ctx_avail = CONTEXTS_NUM-1;
/* array of pages to be marked off for the rom when we do mem_init later */
/* 256 pages lets the rom take up to 2mb of physical ram.. I really
hope it never wants mote than that. */
unsigned long rom_pages[256];
/* Print a PTE value in symbolic form. For debugging. */
void print_pte (pte_t pte)
{
#if 0
/* Verbose version. */
unsigned long val = pte_val (pte);
pr_cont(" pte=%lx [addr=%lx",
val, (val & SUN3_PAGE_PGNUM_MASK) << PAGE_SHIFT);
if (val & SUN3_PAGE_VALID) pr_cont(" valid");
if (val & SUN3_PAGE_WRITEABLE) pr_cont(" write");
if (val & SUN3_PAGE_SYSTEM) pr_cont(" sys");
if (val & SUN3_PAGE_NOCACHE) pr_cont(" nocache");
if (val & SUN3_PAGE_ACCESSED) pr_cont(" accessed");
if (val & SUN3_PAGE_MODIFIED) pr_cont(" modified");
switch (val & SUN3_PAGE_TYPE_MASK) {
case SUN3_PAGE_TYPE_MEMORY: pr_cont(" memory"); break;
case SUN3_PAGE_TYPE_IO: pr_cont(" io"); break;
case SUN3_PAGE_TYPE_VME16: pr_cont(" vme16"); break;
case SUN3_PAGE_TYPE_VME32: pr_cont(" vme32"); break;
}
pr_cont("]\n");
#else
/* Terse version. More likely to fit on a line. */
unsigned long val = pte_val (pte);
char flags[7], *type;
flags[0] = (val & SUN3_PAGE_VALID) ? 'v' : '-';
flags[1] = (val & SUN3_PAGE_WRITEABLE) ? 'w' : '-';
flags[2] = (val & SUN3_PAGE_SYSTEM) ? 's' : '-';
flags[3] = (val & SUN3_PAGE_NOCACHE) ? 'x' : '-';
flags[4] = (val & SUN3_PAGE_ACCESSED) ? 'a' : '-';
flags[5] = (val & SUN3_PAGE_MODIFIED) ? 'm' : '-';
flags[6] = '\0';
switch (val & SUN3_PAGE_TYPE_MASK) {
case SUN3_PAGE_TYPE_MEMORY: type = "memory"; break;
case SUN3_PAGE_TYPE_IO: type = "io" ; break;
case SUN3_PAGE_TYPE_VME16: type = "vme16" ; break;
case SUN3_PAGE_TYPE_VME32: type = "vme32" ; break;
default: type = "unknown?"; break;
}
pr_cont(" pte=%08lx [%07lx %s %s]\n",
val, (val & SUN3_PAGE_PGNUM_MASK) << PAGE_SHIFT, flags, type);
#endif
}
/* Print the PTE value for a given virtual address. For debugging. */
void print_pte_vaddr (unsigned long vaddr)
{
pr_cont(" vaddr=%lx [%02lx]", vaddr, sun3_get_segmap (vaddr));
print_pte (__pte (sun3_get_pte (vaddr)));
}
/*
* Initialise the MMU emulator.
*/
void __init mmu_emu_init(unsigned long bootmem_end)
{
unsigned long seg, num;
int i,j;
memset(rom_pages, 0, sizeof(rom_pages));
memset(pmeg_vaddr, 0, sizeof(pmeg_vaddr));
memset(pmeg_alloc, 0, sizeof(pmeg_alloc));
memset(pmeg_ctx, 0, sizeof(pmeg_ctx));
/* pmeg align the end of bootmem, adding another pmeg,
* later bootmem allocations will likely need it */
bootmem_end = (bootmem_end + (2 * SUN3_PMEG_SIZE)) & ~SUN3_PMEG_MASK;
/* mark all of the pmegs used thus far as reserved */
for (i=0; i < __pa(bootmem_end) / SUN3_PMEG_SIZE ; ++i)
pmeg_alloc[i] = 2;
/* I'm thinking that most of the top pmeg's are going to be
used for something, and we probably shouldn't risk it */
for(num = 0xf0; num <= 0xff; num++)
pmeg_alloc[num] = 2;
/* liberate all existing mappings in the rest of kernel space */
for(seg = bootmem_end; seg < 0x0f800000; seg += SUN3_PMEG_SIZE) {
i = sun3_get_segmap(seg);
if(!pmeg_alloc[i]) {
#ifdef DEBUG_MMU_EMU
pr_info("freed:");
print_pte_vaddr (seg);
#endif
sun3_put_segmap(seg, SUN3_INVALID_PMEG);
}
}
j = 0;
for (num=0, seg=0x0F800000; seg<0x10000000; seg+=16*PAGE_SIZE) {
if (sun3_get_segmap (seg) != SUN3_INVALID_PMEG) {
#ifdef DEBUG_PROM_MAPS
for(i = 0; i < 16; i++) {
pr_info("mapped:");
print_pte_vaddr (seg + (i*PAGE_SIZE));
break;
}
#endif
// the lowest mapping here is the end of our
// vmalloc region
if (!m68k_vmalloc_end)
m68k_vmalloc_end = seg;
// mark the segmap alloc'd, and reserve any
// of the first 0xbff pages the hardware is
// already using... does any sun3 support > 24mb?
pmeg_alloc[sun3_get_segmap(seg)] = 2;
}
}
dvma_init();
/* blank everything below the kernel, and we've got the base
mapping to start all the contexts off with... */
for(seg = 0; seg < PAGE_OFFSET; seg += SUN3_PMEG_SIZE)
sun3_put_segmap(seg, SUN3_INVALID_PMEG);
set_fs(MAKE_MM_SEG(3));
for(seg = 0; seg < 0x10000000; seg += SUN3_PMEG_SIZE) {
i = sun3_get_segmap(seg);
for(j = 1; j < CONTEXTS_NUM; j++)
(*(romvec->pv_setctxt))(j, (void *)seg, i);
}
set_fs(KERNEL_DS);
}
/* erase the mappings for a dead context. Uses the pg_dir for hints
as the pmeg tables proved somewhat unreliable, and unmapping all of
TASK_SIZE was much slower and no more stable. */
/* todo: find a better way to keep track of the pmegs used by a
context for when they're cleared */
void clear_context(unsigned long context)
{
unsigned char oldctx;
unsigned long i;
if(context) {
if(!ctx_alloc[context])
panic("clear_context: context not allocated\n");
ctx_alloc[context]->context = SUN3_INVALID_CONTEXT;
ctx_alloc[context] = (struct mm_struct *)0;
ctx_avail++;
}
oldctx = sun3_get_context();
sun3_put_context(context);
for(i = 0; i < SUN3_INVALID_PMEG; i++) {
if((pmeg_ctx[i] == context) && (pmeg_alloc[i] == 1)) {
sun3_put_segmap(pmeg_vaddr[i], SUN3_INVALID_PMEG);
pmeg_ctx[i] = 0;
pmeg_alloc[i] = 0;
pmeg_vaddr[i] = 0;
}
}
sun3_put_context(oldctx);
}
/* gets an empty context. if full, kills the next context listed to
die first */
/* This context invalidation scheme is, well, totally arbitrary, I'm
sure it could be much more intelligent... but it gets the job done
for now without much overhead in making it's decision. */
/* todo: come up with optimized scheme for flushing contexts */
unsigned long get_free_context(struct mm_struct *mm)
{
unsigned long new = 1;
static unsigned char next_to_die = 1;
if(!ctx_avail) {
/* kill someone to get our context */
new = next_to_die;
clear_context(new);
next_to_die = (next_to_die + 1) & 0x7;
if(!next_to_die)
next_to_die++;
} else {
while(new < CONTEXTS_NUM) {
if(ctx_alloc[new])
new++;
else
break;
}
// check to make sure one was really free...
if(new == CONTEXTS_NUM)
panic("get_free_context: failed to find free context");
}
ctx_alloc[new] = mm;
ctx_avail--;
return new;
}
/*
* Dynamically select a `spare' PMEG and use it to map virtual `vaddr' in
* `context'. Maintain internal PMEG management structures. This doesn't
* actually map the physical address, but does clear the old mappings.
*/
//todo: better allocation scheme? but is extra complexity worthwhile?
//todo: only clear old entries if necessary? how to tell?
inline void mmu_emu_map_pmeg (int context, int vaddr)
{
static unsigned char curr_pmeg = 128;
int i;
/* Round address to PMEG boundary. */
vaddr &= ~SUN3_PMEG_MASK;
/* Find a spare one. */
while (pmeg_alloc[curr_pmeg] == 2)
++curr_pmeg;
#ifdef DEBUG_MMU_EMU
pr_info("mmu_emu_map_pmeg: pmeg %x to context %d vaddr %x\n",
curr_pmeg, context, vaddr);
#endif
/* Invalidate old mapping for the pmeg, if any */
if (pmeg_alloc[curr_pmeg] == 1) {
sun3_put_context(pmeg_ctx[curr_pmeg]);
sun3_put_segmap (pmeg_vaddr[curr_pmeg], SUN3_INVALID_PMEG);
sun3_put_context(context);
}
/* Update PMEG management structures. */
// don't take pmeg's away from the kernel...
if(vaddr >= PAGE_OFFSET) {
/* map kernel pmegs into all contexts */
unsigned char i;
for(i = 0; i < CONTEXTS_NUM; i++) {
sun3_put_context(i);
sun3_put_segmap (vaddr, curr_pmeg);
}
sun3_put_context(context);
pmeg_alloc[curr_pmeg] = 2;
pmeg_ctx[curr_pmeg] = 0;
}
else {
pmeg_alloc[curr_pmeg] = 1;
pmeg_ctx[curr_pmeg] = context;
sun3_put_segmap (vaddr, curr_pmeg);
}
pmeg_vaddr[curr_pmeg] = vaddr;
/* Set hardware mapping and clear the old PTE entries. */
for (i=0; i<SUN3_PMEG_SIZE; i+=SUN3_PTE_SIZE)
sun3_put_pte (vaddr + i, SUN3_PAGE_SYSTEM);
/* Consider a different one next time. */
++curr_pmeg;
}
/*
* Handle a pagefault at virtual address `vaddr'; check if there should be a
* page there (specifically, whether the software pagetables indicate that
* there is). This is necessary due to the limited size of the second-level
* Sun3 hardware pagetables (256 groups of 16 pages). If there should be a
* mapping present, we select a `spare' PMEG and use it to create a mapping.
* `read_flag' is nonzero for a read fault; zero for a write. Returns nonzero
* if we successfully handled the fault.
*/
//todo: should we bump minor pagefault counter? if so, here or in caller?
//todo: possibly inline this into bus_error030 in <asm/buserror.h> ?
// kernel_fault is set when a kernel page couldn't be demand mapped,
// and forces another try using the kernel page table. basically a
// hack so that vmalloc would work correctly.
int mmu_emu_handle_fault (unsigned long vaddr, int read_flag, int kernel_fault)
{
unsigned long segment, offset;
unsigned char context;
pte_t *pte;
pgd_t * crp;
if(current->mm == NULL) {
crp = swapper_pg_dir;
context = 0;
} else {
context = current->mm->context;
if(kernel_fault)
crp = swapper_pg_dir;
else
crp = current->mm->pgd;
}
#ifdef DEBUG_MMU_EMU
pr_info("mmu_emu_handle_fault: vaddr=%lx type=%s crp=%p\n",
vaddr, read_flag ? "read" : "write", crp);
#endif
segment = (vaddr >> SUN3_PMEG_SIZE_BITS) & 0x7FF;
offset = (vaddr >> SUN3_PTE_SIZE_BITS) & 0xF;
#ifdef DEBUG_MMU_EMU
pr_info("mmu_emu_handle_fault: segment=%lx offset=%lx\n", segment,
offset);
#endif
pte = (pte_t *) pgd_val (*(crp + segment));
//todo: next line should check for valid pmd properly.
if (!pte) {
// pr_info("mmu_emu_handle_fault: invalid pmd\n");
return 0;
}
pte = (pte_t *) __va ((unsigned long)(pte + offset));
/* Make sure this is a valid page */
if (!(pte_val (*pte) & SUN3_PAGE_VALID))
return 0;
/* Make sure there's a pmeg allocated for the page */
if (sun3_get_segmap (vaddr&~SUN3_PMEG_MASK) == SUN3_INVALID_PMEG)
mmu_emu_map_pmeg (context, vaddr);
/* Write the pte value to hardware MMU */
sun3_put_pte (vaddr&PAGE_MASK, pte_val (*pte));
/* Update software copy of the pte value */
// I'm not sure this is necessary. If this is required, we ought to simply
// copy this out when we reuse the PMEG or at some other convenient time.
// Doing it here is fairly meaningless, anyway, as we only know about the
// first access to a given page. --m
if (!read_flag) {
if (pte_val (*pte) & SUN3_PAGE_WRITEABLE)
pte_val (*pte) |= (SUN3_PAGE_ACCESSED
| SUN3_PAGE_MODIFIED);
else
return 0; /* Write-protect error. */
} else
pte_val (*pte) |= SUN3_PAGE_ACCESSED;
#ifdef DEBUG_MMU_EMU
pr_info("seg:%ld crp:%p ->", get_fs().seg, crp);
print_pte_vaddr (vaddr);
pr_cont("\n");
#endif
return 1;
}