forked from Minki/linux
96d4f267e4
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>
92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/*
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* SH specific backtracing code for oprofile
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*
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* Copyright 2007 STMicroelectronics Ltd.
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*
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* Author: Dave Peverley <dpeverley@mpc-data.co.uk>
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*
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* Based on ARM oprofile backtrace code by Richard Purdie and in turn, i386
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* oprofile backtrace code by John Levon, David Smith
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <linux/kallsyms.h>
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#include <linux/mm.h>
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#include <asm/unwinder.h>
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#include <asm/ptrace.h>
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#include <linux/uaccess.h>
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#include <asm/sections.h>
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#include <asm/stacktrace.h>
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static int backtrace_stack(void *data, char *name)
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{
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/* Yes, we want all stacks */
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return 0;
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}
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static void backtrace_address(void *data, unsigned long addr, int reliable)
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{
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unsigned int *depth = data;
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if ((*depth)--)
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oprofile_add_trace(addr);
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}
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static struct stacktrace_ops backtrace_ops = {
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.stack = backtrace_stack,
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.address = backtrace_address,
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};
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/* Limit to stop backtracing too far. */
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static int backtrace_limit = 20;
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static unsigned long *
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user_backtrace(unsigned long *stackaddr, struct pt_regs *regs)
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{
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unsigned long buf_stack;
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/* Also check accessibility of address */
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if (!access_ok(stackaddr, sizeof(unsigned long)))
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return NULL;
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if (__copy_from_user_inatomic(&buf_stack, stackaddr, sizeof(unsigned long)))
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return NULL;
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/* Quick paranoia check */
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if (buf_stack & 3)
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return NULL;
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oprofile_add_trace(buf_stack);
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stackaddr++;
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return stackaddr;
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}
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void sh_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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unsigned long *stackaddr;
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/*
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* Paranoia - clip max depth as we could get lost in the weeds.
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*/
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if (depth > backtrace_limit)
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depth = backtrace_limit;
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stackaddr = (unsigned long *)kernel_stack_pointer(regs);
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if (!user_mode(regs)) {
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if (depth)
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unwind_stack(NULL, regs, stackaddr,
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&backtrace_ops, &depth);
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return;
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}
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while (depth-- && (stackaddr != NULL))
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stackaddr = user_backtrace(stackaddr, regs);
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}
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