Revision df43d903828c59afb9e93b59835127a02e1f8144 authored by Linus Torvalds on 02 September 2021, 01:41:13 UTC, committed by Linus Torvalds on 02 September 2021, 01:41:13 UTC
Pull printk updates from Petr Mladek: - Optionally, provide an index of possible printk messages via <debugfs>/printk/index/. It can be used when monitoring important kernel messages on a farm of various hosts. The monitor has to be updated when some messages has changed or are not longer available by a newly deployed kernel. - Add printk.console_no_auto_verbose boot parameter. It allows to generate crash dump even with slow consoles in a reasonable time frame. - Remove printk_safe buffers. The messages are always stored directly to the main logbuffer, even in NMI or recursive context. Also it allows to serialize syslog operations by a mutex instead of a spin lock. - Misc clean up and build fixes. * tag 'printk-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk/index: Fix -Wunused-function warning lib/nmi_backtrace: Serialize even messages about idle CPUs printk: Add printk.console_no_auto_verbose boot parameter printk: Remove console_silent() lib/test_scanf: Handle n_bits == 0 in random tests printk: syslog: close window between wait and read printk: convert @syslog_lock to mutex printk: remove NMI tracking printk: remove safe buffers printk: track/limit recursion lib/nmi_backtrace: explicitly serialize banner and regs printk: Move the printk() kerneldoc comment to its new home printk/index: Fix warning about missing prototypes MIPS/asm/printk: Fix build failure caused by printk printk: index: Add indexing support to dev_printk printk: Userspace format indexing support printk: Rework parse_prefix into printk_parse_prefix printk: Straighten out log_flags into printk_info_flags string_helpers: Escape double quotes in escape_special printk/console: Check consistent sequence number when handling race in console_unlock()
regset.c
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/regset.h>
static int __regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
void *p = *data, *to_free = NULL;
int res;
if (!regset->regset_get)
return -EOPNOTSUPP;
if (size > regset->n * regset->size)
size = regset->n * regset->size;
if (!p) {
to_free = p = kzalloc(size, GFP_KERNEL);
if (!p)
return -ENOMEM;
}
res = regset->regset_get(target, regset,
(struct membuf){.p = p, .left = size});
if (res < 0) {
kfree(to_free);
return res;
}
*data = p;
return size - res;
}
int regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void *data)
{
return __regset_get(target, regset, size, &data);
}
EXPORT_SYMBOL(regset_get);
int regset_get_alloc(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
*data = NULL;
return __regset_get(target, regset, size, data);
}
EXPORT_SYMBOL(regset_get_alloc);
/**
* copy_regset_to_user - fetch a thread's user_regset data into user memory
* @target: thread to be examined
* @view: &struct user_regset_view describing user thread machine state
* @setno: index in @view->regsets
* @offset: offset into the regset data, in bytes
* @size: amount of data to copy, in bytes
* @data: user-mode pointer to copy into
*/
int copy_regset_to_user(struct task_struct *target,
const struct user_regset_view *view,
unsigned int setno,
unsigned int offset, unsigned int size,
void __user *data)
{
const struct user_regset *regset = &view->regsets[setno];
void *buf;
int ret;
ret = regset_get_alloc(target, regset, size, &buf);
if (ret > 0)
ret = copy_to_user(data, buf, ret) ? -EFAULT : 0;
kfree(buf);
return ret;
}
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