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linux/arch/sparc/kernel/wuf.S
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

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* wuf.S: Window underflow trap handler for the Sparc.
*
* Copyright (C) 1995 David S. Miller
*/
#include <asm/contregs.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/psr.h>
#include <asm/smp.h>
#include <asm/asi.h>
#include <asm/winmacro.h>
#include <asm/asmmacro.h>
#include <asm/thread_info.h>
/* Just like the overflow handler we define macros for registers
* with fixed meanings in this routine.
*/
#define t_psr l0
#define t_pc l1
#define t_npc l2
#define t_wim l3
/* Don't touch the above registers or else you die horribly... */
/* Now macros for the available scratch registers in this routine. */
#define twin_tmp1 l4
#define twin_tmp2 l5
#define curptr g6
.text
.align 4
/* The trap entry point has executed the following:
*
* rd %psr, %l0
* rd %wim, %l3
* b fill_window_entry
* andcc %l0, PSR_PS, %g0
*/
/* Datum current_thread_info->uwinmask contains at all times a bitmask
* where if any user windows are active, at least one bit will
* be set in to mask. If no user windows are active, the bitmask
* will be all zeroes.
*/
/* To get an idea of what has just happened to cause this
* trap take a look at this diagram:
*
* 1 2 3 4 <-- Window number
* ----------
* T O W I <-- Symbolic name
*
* O == the window that execution was in when
* the restore was attempted
*
* T == the trap itself has save'd us into this
* window
*
* W == this window is the one which is now invalid
* and must be made valid plus loaded from the
* stack
*
* I == this window will be the invalid one when we
* are done and return from trap if successful
*/
/* BEGINNING OF PATCH INSTRUCTIONS */
/* On 7-window Sparc the boot code patches fnwin_patch1
* with the following instruction.
*/
.globl fnwin_patch1_7win, fnwin_patch2_7win
fnwin_patch1_7win: srl %t_wim, 6, %twin_tmp2
fnwin_patch2_7win: and %twin_tmp1, 0x7f, %twin_tmp1
/* END OF PATCH INSTRUCTIONS */
.globl fill_window_entry, fnwin_patch1, fnwin_patch2
fill_window_entry:
/* LOCATION: Window 'T' */
/* Compute what the new %wim is going to be if we retrieve
* the proper window off of the stack.
*/
sll %t_wim, 1, %twin_tmp1
fnwin_patch1: srl %t_wim, 7, %twin_tmp2
or %twin_tmp1, %twin_tmp2, %twin_tmp1
fnwin_patch2: and %twin_tmp1, 0xff, %twin_tmp1
wr %twin_tmp1, 0x0, %wim /* Make window 'I' invalid */
andcc %t_psr, PSR_PS, %g0
be fwin_from_user
restore %g0, %g0, %g0 /* Restore to window 'O' */
/* Trapped from kernel, we trust that the kernel does not
* 'over restore' sorta speak and just grab the window
* from the stack and return. Easy enough.
*/
fwin_from_kernel:
/* LOCATION: Window 'O' */
restore %g0, %g0, %g0
/* LOCATION: Window 'W' */
LOAD_WINDOW(sp) /* Load it up */
/* Spin the wheel... */
save %g0, %g0, %g0
save %g0, %g0, %g0
/* I'd like to buy a vowel please... */
/* LOCATION: Window 'T' */
/* Now preserve the condition codes in %psr, pause, and
* return from trap. This is the simplest case of all.
*/
wr %t_psr, 0x0, %psr
WRITE_PAUSE
jmp %t_pc
rett %t_npc
fwin_from_user:
/* LOCATION: Window 'O' */
restore %g0, %g0, %g0 /* Restore to window 'W' */
/* LOCATION: Window 'W' */
/* Branch to the stack validation routine */
b srmmu_fwin_stackchk
andcc %sp, 0x7, %g0
#define STACK_OFFSET (THREAD_SIZE - TRACEREG_SZ - STACKFRAME_SZ)
fwin_user_stack_is_bolixed:
/* LOCATION: Window 'W' */
/* Place a pt_regs frame on the kernel stack, save back
* to the trap window and call c-code to deal with this.
*/
LOAD_CURRENT(l4, l5)
sethi %hi(STACK_OFFSET), %l5
or %l5, %lo(STACK_OFFSET), %l5
add %l4, %l5, %l5
/* Store globals into pt_regs frame. */
STORE_PT_GLOBALS(l5)
STORE_PT_YREG(l5, g3)
/* Save current in a global while we change windows. */
mov %l4, %curptr
save %g0, %g0, %g0
/* LOCATION: Window 'O' */
rd %psr, %g3 /* Read %psr in live user window */
mov %fp, %g4 /* Save bogus frame pointer. */
save %g0, %g0, %g0
/* LOCATION: Window 'T' */
sethi %hi(STACK_OFFSET), %l5
or %l5, %lo(STACK_OFFSET), %l5
add %curptr, %l5, %sp
/* Build rest of pt_regs. */
STORE_PT_INS(sp)
STORE_PT_PRIV(sp, t_psr, t_pc, t_npc)
/* re-set trap time %wim value */
wr %t_wim, 0x0, %wim
/* Fix users window mask and buffer save count. */
mov 0x1, %g5
sll %g5, %g3, %g5
st %g5, [%curptr + TI_UWINMASK] ! one live user window still
st %g0, [%curptr + TI_W_SAVED] ! no windows in the buffer
wr %t_psr, PSR_ET, %psr ! enable traps
nop
call window_underflow_fault
mov %g4, %o0
b ret_trap_entry
clr %l6
fwin_user_stack_is_ok:
/* LOCATION: Window 'W' */
/* The users stack area is kosher and mapped, load the
* window and fall through to the finish up routine.
*/
LOAD_WINDOW(sp)
/* Round and round she goes... */
save %g0, %g0, %g0 /* Save to window 'O' */
save %g0, %g0, %g0 /* Save to window 'T' */
/* Where she'll trap nobody knows... */
/* LOCATION: Window 'T' */
fwin_user_finish_up:
/* LOCATION: Window 'T' */
wr %t_psr, 0x0, %psr
WRITE_PAUSE
jmp %t_pc
rett %t_npc
/* Here come the architecture specific checks for stack.
* mappings. Note that unlike the window overflow handler
* we only need to check whether the user can read from
* the appropriate addresses. Also note that we are in
* an invalid window which will be loaded, and this means
* that until we actually load the window up we are free
* to use any of the local registers contained within.
*
* On success these routine branch to fwin_user_stack_is_ok
* if the area at %sp is user readable and the window still
* needs to be loaded, else fwin_user_finish_up if the
* routine has done the loading itself. On failure (bogus
* user stack) the routine shall branch to the label called
* fwin_user_stack_is_bolixed.
*
* Contrary to the arch-specific window overflow stack
* check routines in wof.S, these routines are free to use
* any of the local registers they want to as this window
* does not belong to anyone at this point, however the
* outs and ins are still verboten as they are part of
* 'someone elses' window possibly.
*/
.globl srmmu_fwin_stackchk
srmmu_fwin_stackchk:
/* LOCATION: Window 'W' */
/* Caller did 'andcc %sp, 0x7, %g0' */
bne fwin_user_stack_is_bolixed
sethi %hi(PAGE_OFFSET), %l5
/* Check if the users stack is in kernel vma, then our
* trial and error technique below would succeed for
* the 'wrong' reason.
*/
mov AC_M_SFSR, %l4
cmp %l5, %sp
bleu fwin_user_stack_is_bolixed
LEON_PI( lda [%l4] ASI_LEON_MMUREGS, %g0) ! clear fault status
SUN_PI_( lda [%l4] ASI_M_MMUREGS, %g0) ! clear fault status
/* The technique is, turn off faults on this processor,
* just let the load rip, then check the sfsr to see if
* a fault did occur. Then we turn on fault traps again
* and branch conditionally based upon what happened.
*/
LEON_PI(lda [%g0] ASI_LEON_MMUREGS, %l5) ! read mmu-ctrl reg
SUN_PI_(lda [%g0] ASI_M_MMUREGS, %l5) ! read mmu-ctrl reg
or %l5, 0x2, %l5 ! turn on no-fault bit
LEON_PI(sta %l5, [%g0] ASI_LEON_MMUREGS) ! store it
SUN_PI_(sta %l5, [%g0] ASI_M_MMUREGS) ! store it
/* Cross fingers and go for it. */
LOAD_WINDOW(sp)
/* A penny 'saved'... */
save %g0, %g0, %g0
save %g0, %g0, %g0
/* Is a BADTRAP earned... */
/* LOCATION: Window 'T' */
LEON_PI(lda [%g0] ASI_LEON_MMUREGS, %twin_tmp1) ! load mmu-ctrl again
SUN_PI_(lda [%g0] ASI_M_MMUREGS, %twin_tmp1) ! load mmu-ctrl again
andn %twin_tmp1, 0x2, %twin_tmp1 ! clear no-fault bit
LEON_PI(sta %twin_tmp1, [%g0] ASI_LEON_MMUREGS) ! store it
SUN_PI_(sta %twin_tmp1, [%g0] ASI_M_MMUREGS) ! store it
mov AC_M_SFAR, %twin_tmp2
LEON_PI(lda [%twin_tmp2] ASI_LEON_MMUREGS, %g0) ! read fault address
SUN_PI_(lda [%twin_tmp2] ASI_M_MMUREGS, %g0) ! read fault address
mov AC_M_SFSR, %twin_tmp2
LEON_PI(lda [%twin_tmp2] ASI_LEON_MMUREGS, %twin_tmp2) ! read fault status
SUN_PI_(lda [%twin_tmp2] ASI_M_MMUREGS, %twin_tmp2) ! read fault status
andcc %twin_tmp2, 0x2, %g0 ! did fault occur?
bne 1f ! yep, cleanup
nop
wr %t_psr, 0x0, %psr
nop
b fwin_user_finish_up + 0x4
nop
/* Did I ever tell you about my window lobotomy?
* anyways... fwin_user_stack_is_bolixed expects
* to be in window 'W' so make it happy or else
* we watchdog badly.
*/
1:
restore %g0, %g0, %g0
b fwin_user_stack_is_bolixed ! oh well
restore %g0, %g0, %g0
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