WSL2-Linux-Kernel/include/linux/uaccess.h

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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>
2017-11-01 17:07:57 +03:00
/* SPDX-License-Identifier: GPL-2.0 */
[PATCH] x86: cache pollution aware __copy_from_user_ll() Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:04:16 +04:00
#ifndef __LINUX_UACCESS_H__
#define __LINUX_UACCESS_H__
#include <linux/instrumented.h>
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
#include <linux/sched.h>
#include <linux/thread_info.h>
#define uaccess_kernel() segment_eq(get_fs(), KERNEL_DS)
[PATCH] x86: cache pollution aware __copy_from_user_ll() Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:04:16 +04:00
#include <asm/uaccess.h>
/*
* Architectures should provide two primitives (raw_copy_{to,from}_user())
* and get rid of their private instances of copy_{to,from}_user() and
* __copy_{to,from}_user{,_inatomic}().
*
* raw_copy_{to,from}_user(to, from, size) should copy up to size bytes and
* return the amount left to copy. They should assume that access_ok() has
* already been checked (and succeeded); they should *not* zero-pad anything.
* No KASAN or object size checks either - those belong here.
*
* Both of these functions should attempt to copy size bytes starting at from
* into the area starting at to. They must not fetch or store anything
* outside of those areas. Return value must be between 0 (everything
* copied successfully) and size (nothing copied).
*
* If raw_copy_{to,from}_user(to, from, size) returns N, size - N bytes starting
* at to must become equal to the bytes fetched from the corresponding area
* starting at from. All data past to + size - N must be left unmodified.
*
* If copying succeeds, the return value must be 0. If some data cannot be
* fetched, it is permitted to copy less than had been fetched; the only
* hard requirement is that not storing anything at all (i.e. returning size)
* should happen only when nothing could be copied. In other words, you don't
* have to squeeze as much as possible - it is allowed, but not necessary.
*
* For raw_copy_from_user() to always points to kernel memory and no faults
* on store should happen. Interpretation of from is affected by set_fs().
* For raw_copy_to_user() it's the other way round.
*
* Both can be inlined - it's up to architectures whether it wants to bother
* with that. They should not be used directly; they are used to implement
* the 6 functions (copy_{to,from}_user(), __copy_{to,from}_user_inatomic())
* that are used instead. Out of those, __... ones are inlined. Plain
* copy_{to,from}_user() might or might not be inlined. If you want them
* inlined, have asm/uaccess.h define INLINE_COPY_{TO,FROM}_USER.
*
* NOTE: only copy_from_user() zero-pads the destination in case of short copy.
* Neither __copy_from_user() nor __copy_from_user_inatomic() zero anything
* at all; their callers absolutely must check the return value.
*
* Biarch ones should also provide raw_copy_in_user() - similar to the above,
* but both source and destination are __user pointers (affected by set_fs()
* as usual) and both source and destination can trigger faults.
*/
static __always_inline __must_check unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
instrument_copy_from_user(to, from, n);
check_object_size(to, n, false);
return raw_copy_from_user(to, from, n);
}
static __always_inline __must_check unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_fault();
instrument_copy_from_user(to, from, n);
check_object_size(to, n, false);
return raw_copy_from_user(to, from, n);
}
/**
* __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
* The caller should also make sure he pins the user space address
* so that we don't result in page fault and sleep.
*/
static __always_inline __must_check unsigned long
__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
{
instrument_copy_to_user(to, from, n);
check_object_size(from, n, true);
return raw_copy_to_user(to, from, n);
}
static __always_inline __must_check unsigned long
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
instrument_copy_to_user(to, from, n);
check_object_size(from, n, true);
return raw_copy_to_user(to, from, n);
}
#ifdef INLINE_COPY_FROM_USER
static inline __must_check unsigned long
_copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
might_fault();
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 05:57:57 +03:00
if (likely(access_ok(from, n))) {
instrument_copy_from_user(to, from, n);
res = raw_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
#else
extern __must_check unsigned long
_copy_from_user(void *, const void __user *, unsigned long);
#endif
#ifdef INLINE_COPY_TO_USER
static inline __must_check unsigned long
_copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 05:57:57 +03:00
if (access_ok(to, n)) {
instrument_copy_to_user(to, from, n);
n = raw_copy_to_user(to, from, n);
}
return n;
}
#else
extern __must_check unsigned long
_copy_to_user(void __user *, const void *, unsigned long);
#endif
static __always_inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (likely(check_copy_size(to, n, false)))
n = _copy_from_user(to, from, n);
return n;
}
static __always_inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (likely(check_copy_size(from, n, true)))
n = _copy_to_user(to, from, n);
return n;
}
#ifdef CONFIG_COMPAT
static __always_inline unsigned long __must_check
copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
might_fault();
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 05:57:57 +03:00
if (access_ok(to, n) && access_ok(from, n))
n = raw_copy_in_user(to, from, n);
return n;
}
#endif
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
static __always_inline void pagefault_disabled_inc(void)
{
current->pagefault_disabled++;
}
static __always_inline void pagefault_disabled_dec(void)
{
current->pagefault_disabled--;
}
/*
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
* These routines enable/disable the pagefault handler. If disabled, it will
* not take any locks and go straight to the fixup table.
*
* User access methods will not sleep when called from a pagefault_disabled()
* environment.
*/
static inline void pagefault_disable(void)
{
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
pagefault_disabled_inc();
/*
* make sure to have issued the store before a pagefault
* can hit.
*/
barrier();
}
static inline void pagefault_enable(void)
{
/*
* make sure to issue those last loads/stores before enabling
* the pagefault handler again.
*/
barrier();
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
pagefault_disabled_dec();
}
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
/*
* Is the pagefault handler disabled? If so, user access methods will not sleep.
*/
static inline bool pagefault_disabled(void)
{
return current->pagefault_disabled != 0;
}
sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:06 +03:00
mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler Introduce faulthandler_disabled() and use it to check for irq context and disabled pagefaults (via pagefault_disable()) in the pagefault handlers. Please note that we keep the in_atomic() checks in place - to detect whether in irq context (in which case preemption is always properly disabled). In contrast, preempt_disable() should never be used to disable pagefaults. With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt counter, and therefore the result of in_atomic() differs. We validate that condition by using might_fault() checks when calling might_sleep(). Therefore, add a comment to faulthandler_disabled(), describing why this is needed. faulthandler_disabled() and pagefault_disable() are defined in linux/uaccess.h, so let's properly add that include to all relevant files. This patch is based on a patch from Thomas Gleixner. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-11 18:52:11 +03:00
/*
* The pagefault handler is in general disabled by pagefault_disable() or
* when in irq context (via in_atomic()).
*
* This function should only be used by the fault handlers. Other users should
* stick to pagefault_disabled().
* Please NEVER use preempt_disable() to disable the fault handler. With
* !CONFIG_PREEMPT_COUNT, this is like a NOP. So the handler won't be disabled.
* in_atomic() will report different values based on !CONFIG_PREEMPT_COUNT.
*/
#define faulthandler_disabled() (pagefault_disabled() || in_atomic())
[PATCH] x86: cache pollution aware __copy_from_user_ll() Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:04:16 +04:00
#ifndef ARCH_HAS_NOCACHE_UACCESS
static inline __must_check unsigned long
__copy_from_user_inatomic_nocache(void *to, const void __user *from,
unsigned long n)
[PATCH] x86: cache pollution aware __copy_from_user_ll() Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:04:16 +04:00
{
return __copy_from_user_inatomic(to, from, n);
}
#endif /* ARCH_HAS_NOCACHE_UACCESS */
lib: introduce copy_struct_from_user() helper A common pattern for syscall extensions is increasing the size of a struct passed from userspace, such that the zero-value of the new fields result in the old kernel behaviour (allowing for a mix of userspace and kernel vintages to operate on one another in most cases). While this interface exists for communication in both directions, only one interface is straightforward to have reasonable semantics for (userspace passing a struct to the kernel). For kernel returns to userspace, what the correct semantics are (whether there should be an error if userspace is unaware of a new extension) is very syscall-dependent and thus probably cannot be unified between syscalls (a good example of this problem is [1]). Previously there was no common lib/ function that implemented the necessary extension-checking semantics (and different syscalls implemented them slightly differently or incompletely[2]). Future patches replace common uses of this pattern to make use of copy_struct_from_user(). Some in-kernel selftests that insure that the handling of alignment and various byte patterns are all handled identically to memchr_inv() usage. [1]: commit 1251201c0d34 ("sched/core: Fix uclamp ABI bug, clean up and robustify sched_read_attr() ABI logic and code") [2]: For instance {sched_setattr,perf_event_open,clone3}(2) all do do similar checks to copy_struct_from_user() while rt_sigprocmask(2) always rejects differently-sized struct arguments. Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20191001011055.19283-2-cyphar@cyphar.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-10-01 04:10:52 +03:00
extern __must_check int check_zeroed_user(const void __user *from, size_t size);
/**
* copy_struct_from_user: copy a struct from userspace
* @dst: Destination address, in kernel space. This buffer must be @ksize
* bytes long.
* @ksize: Size of @dst struct.
* @src: Source address, in userspace.
* @usize: (Alleged) size of @src struct.
*
* Copies a struct from userspace to kernel space, in a way that guarantees
* backwards-compatibility for struct syscall arguments (as long as future
* struct extensions are made such that all new fields are *appended* to the
* old struct, and zeroed-out new fields have the same meaning as the old
* struct).
*
* @ksize is just sizeof(*dst), and @usize should've been passed by userspace.
* The recommended usage is something like the following:
*
* SYSCALL_DEFINE2(foobar, const struct foo __user *, uarg, size_t, usize)
* {
* int err;
* struct foo karg = {};
*
* if (usize > PAGE_SIZE)
* return -E2BIG;
* if (usize < FOO_SIZE_VER0)
* return -EINVAL;
*
* err = copy_struct_from_user(&karg, sizeof(karg), uarg, usize);
* if (err)
* return err;
*
* // ...
* }
*
* There are three cases to consider:
* * If @usize == @ksize, then it's copied verbatim.
* * If @usize < @ksize, then the userspace has passed an old struct to a
* newer kernel. The rest of the trailing bytes in @dst (@ksize - @usize)
* are to be zero-filled.
* * If @usize > @ksize, then the userspace has passed a new struct to an
* older kernel. The trailing bytes unknown to the kernel (@usize - @ksize)
* are checked to ensure they are zeroed, otherwise -E2BIG is returned.
*
* Returns (in all cases, some data may have been copied):
* * -E2BIG: (@usize > @ksize) and there are non-zero trailing bytes in @src.
* * -EFAULT: access to userspace failed.
*/
static __always_inline __must_check int
copy_struct_from_user(void *dst, size_t ksize, const void __user *src,
size_t usize)
{
size_t size = min(ksize, usize);
size_t rest = max(ksize, usize) - size;
/* Deal with trailing bytes. */
if (usize < ksize) {
memset(dst + size, 0, rest);
} else if (usize > ksize) {
int ret = check_zeroed_user(src + size, rest);
if (ret <= 0)
return ret ?: -E2BIG;
}
/* Copy the interoperable parts of the struct. */
if (copy_from_user(dst, src, size))
return -EFAULT;
return 0;
}
bool probe_kernel_read_allowed(const void *unsafe_src, size_t size);
extern long probe_kernel_read(void *dst, const void *src, size_t size);
extern long probe_user_read(void *dst, const void __user *src, size_t size);
extern long notrace probe_kernel_write(void *dst, const void *src, size_t size);
extern long notrace probe_user_write(void __user *dst, const void *src, size_t size);
long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr,
long count);
long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
long count);
long strnlen_user_nofault(const void __user *unsafe_addr, long count);
/**
* probe_kernel_address(): safely attempt to read from a location
* @addr: address to read from
* @retval: read into this variable
*
* Returns 0 on success, or -EFAULT.
*/
#define probe_kernel_address(addr, retval) \
probe_kernel_read(&retval, addr, sizeof(retval))
#ifndef user_access_begin
#define user_access_begin(ptr,len) access_ok(ptr, len)
#define user_access_end() do { } while (0)
uaccess: implement a proper unsafe_copy_to_user() and switch filldir over to it In commit 9f79b78ef744 ("Convert filldir[64]() from __put_user() to unsafe_put_user()") I made filldir() use unsafe_put_user(), which improves code generation on x86 enormously. But because we didn't have a "unsafe_copy_to_user()", the dirent name copy was also done by hand with unsafe_put_user() in a loop, and it turns out that a lot of other architectures didn't like that, because unlike x86, they have various alignment issues. Most non-x86 architectures trap and fix it up, and some (like xtensa) will just fail unaligned put_user() accesses unconditionally. Which makes that "copy using put_user() in a loop" not work for them at all. I could make that code do explicit alignment etc, but the architectures that don't like unaligned accesses also don't really use the fancy "user_access_begin/end()" model, so they might just use the regular old __copy_to_user() interface. So this commit takes that looping implementation, turns it into the x86 version of "unsafe_copy_to_user()", and makes other architectures implement the unsafe copy version as __copy_to_user() (the same way they do for the other unsafe_xyz() accessor functions). Note that it only does this for the copying _to_ user space, and we still don't have a unsafe version of copy_from_user(). That's partly because we have no current users of it, but also partly because the copy_from_user() case is slightly different and cannot efficiently be implemented in terms of a unsafe_get_user() loop (because gcc can't do asm goto with outputs). It would be trivial to do this using "rep movsb", which would work really nicely on newer x86 cores, but really badly on some older ones. Al Viro is looking at cleaning up all our user copy routines to make this all a non-issue, but for now we have this simple-but-stupid version for x86 that works fine for the dirent name copy case because those names are short strings and we simply don't need anything fancier. Fixes: 9f79b78ef744 ("Convert filldir[64]() from __put_user() to unsafe_put_user()") Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-and-tested-by: Tony Luck <tony.luck@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-10-07 22:56:48 +03:00
#define unsafe_op_wrap(op, err) do { if (unlikely(op)) goto err; } while (0)
#define unsafe_get_user(x,p,e) unsafe_op_wrap(__get_user(x,p),e)
#define unsafe_put_user(x,p,e) unsafe_op_wrap(__put_user(x,p),e)
#define unsafe_copy_to_user(d,s,l,e) unsafe_op_wrap(__copy_to_user(d,s,l),e)
static inline unsigned long user_access_save(void) { return 0UL; }
static inline void user_access_restore(unsigned long flags) { }
#endif
uaccess: Add user_read_access_begin/end and user_write_access_begin/end Some architectures like powerpc64 have the capability to separate read access and write access protection. For get_user() and copy_from_user(), powerpc64 only open read access. For put_user() and copy_to_user(), powerpc64 only open write access. But when using unsafe_get_user() or unsafe_put_user(), user_access_begin open both read and write. Other architectures like powerpc book3s 32 bits only allow write access protection. And on this architecture protection is an heavy operation as it requires locking/unlocking per segment of 256Mbytes. On those architecture it is therefore desirable to do the unlocking only for write access. (Note that book3s/32 ranges from very old powermac from the 90's with powerpc 601 processor, till modern ADSL boxes with PowerQuicc II processors for instance so it is still worth considering.) In order to avoid any risk based of hacking some variable parameters passed to user_access_begin/end that would allow hacking and leaving user access open or opening too much, it is preferable to use dedicated static functions that can't be overridden. Add a user_read_access_begin and user_read_access_end to only open read access. Add a user_write_access_begin and user_write_access_end to only open write access. By default, when undefined, those new access helpers default on the existing user_access_begin and user_access_end. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/36e43241c7f043a24b5069e78c6a7edd11043be5.1585898438.git.christophe.leroy@c-s.fr
2020-04-03 10:20:50 +03:00
#ifndef user_write_access_begin
#define user_write_access_begin user_access_begin
#define user_write_access_end user_access_end
#endif
#ifndef user_read_access_begin
#define user_read_access_begin user_access_begin
#define user_read_access_end user_access_end
#endif
#ifdef CONFIG_HARDENED_USERCOPY
void usercopy_warn(const char *name, const char *detail, bool to_user,
unsigned long offset, unsigned long len);
void __noreturn usercopy_abort(const char *name, const char *detail,
bool to_user, unsigned long offset,
unsigned long len);
#endif
[PATCH] x86: cache pollution aware __copy_from_user_ll() Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:04:16 +04:00
#endif /* __LINUX_UACCESS_H__ */