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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>
132 lines
3.0 KiB
C
132 lines
3.0 KiB
C
/**
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* Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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**/
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#include <linux/time.h>
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <asm/processor.h>
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#include <linux/uaccess.h>
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#include <asm/compat.h>
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#include <asm/oprofile_impl.h>
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#define STACK_SP(STACK) *(STACK)
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#define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
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#define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
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#ifdef CONFIG_PPC64
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#define STACK_LR(STACK) STACK_LR64(STACK)
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#else
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#define STACK_LR(STACK) STACK_LR32(STACK)
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#endif
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static unsigned int user_getsp32(unsigned int sp, int is_first)
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{
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unsigned int stack_frame[2];
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void __user *p = compat_ptr(sp);
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if (!access_ok(p, sizeof(stack_frame)))
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return 0;
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/*
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* The most likely reason for this is that we returned -EFAULT,
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* which means that we've done all that we can do from
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* interrupt context.
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*/
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if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR32(stack_frame));
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/*
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* We do not enforce increasing stack addresses here because
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* we may transition to a different stack, eg a signal handler.
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*/
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return STACK_SP(stack_frame);
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}
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#ifdef CONFIG_PPC64
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static unsigned long user_getsp64(unsigned long sp, int is_first)
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{
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unsigned long stack_frame[3];
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if (!access_ok((void __user *)sp, sizeof(stack_frame)))
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return 0;
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if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
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sizeof(stack_frame)))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR64(stack_frame));
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return STACK_SP(stack_frame);
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}
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#endif
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static unsigned long kernel_getsp(unsigned long sp, int is_first)
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{
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unsigned long *stack_frame = (unsigned long *)sp;
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if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
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return 0;
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if (!is_first)
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oprofile_add_trace(STACK_LR(stack_frame));
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/*
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* We do not enforce increasing stack addresses here because
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* we might be transitioning from an interrupt stack to a kernel
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* stack. validate_sp() is designed to understand this, so just
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* use it.
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*/
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return STACK_SP(stack_frame);
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}
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void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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unsigned long sp = regs->gpr[1];
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int first_frame = 1;
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/* We ditch the top stackframe so need to loop through an extra time */
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depth += 1;
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if (!user_mode(regs)) {
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while (depth--) {
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sp = kernel_getsp(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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} else {
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pagefault_disable();
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#ifdef CONFIG_PPC64
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if (!is_32bit_task()) {
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while (depth--) {
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sp = user_getsp64(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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pagefault_enable();
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return;
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}
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#endif
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while (depth--) {
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sp = user_getsp32(sp, first_frame);
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if (!sp)
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break;
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first_frame = 0;
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}
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pagefault_enable();
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}
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}
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