cregit-Linux how code gets into the kernel

Release 4.16 arch/sh/mm/extable_64.c

Directory: arch/sh/mm
/*
 * arch/sh/mm/extable_64.c
 *
 * Copyright (C) 2003 Richard Curnow
 * Copyright (C) 2003, 2004  Paul Mundt
 *
 * Cloned from the 2.5 SH version..
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/bsearch.h>
#include <linux/rwsem.h>
#include <linux/extable.h>
#include <linux/uaccess.h>

extern unsigned long copy_user_memcpy, copy_user_memcpy_end;
extern void __copy_user_fixup(void);


static const struct exception_table_entry __copy_user_fixup_ex = {
	.fixup = (unsigned long)&__copy_user_fixup,
};

/*
 * Some functions that may trap due to a bad user-mode address have too
 * many loads and stores in them to make it at all practical to label
 * each one and put them all in the main exception table.
 *
 * In particular, the fast memcpy routine is like this.  It's fix-up is
 * just to fall back to a slow byte-at-a-time copy, which is handled the
 * conventional way.  So it's functionally OK to just handle any trap
 * occurring in the fast memcpy with that fixup.
 */

static const struct exception_table_entry *check_exception_ranges(unsigned long addr) { if ((addr >= (unsigned long)&copy_user_memcpy) && (addr <= (unsigned long)&copy_user_memcpy_end)) return &__copy_user_fixup_ex; return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Paul Mundt44100.00%1100.00%
Total44100.00%1100.00%


static int cmp_ex_search(const void *key, const void *elt) { const struct exception_table_entry *_elt = elt; unsigned long _key = *(unsigned long *)key; /* avoid overflow */ if (_key > _elt->insn) return 1; if (_key < _elt->insn) return -1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Meyer63100.00%1100.00%
Total63100.00%1100.00%

/* Simple binary search */
const struct exception_table_entry * search_extable(const struct exception_table_entry *base, const size_t num, unsigned long value) { const struct exception_table_entry *mid; mid = check_exception_ranges(value); if (mid) return mid; return bsearch(&value, base, num, sizeof(struct exception_table_entry), cmp_ex_search); }

Contributors

PersonTokensPropCommitsCommitProp
Paul Mundt4167.21%150.00%
Thomas Meyer2032.79%150.00%
Total61100.00%2100.00%


int fixup_exception(struct pt_regs *regs) { const struct exception_table_entry *fixup; fixup = search_exception_tables(regs->pc); if (fixup) { regs->pc = fixup->fixup; return 1; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Paul Mundt45100.00%1100.00%
Total45100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Paul Mundt17266.15%350.00%
Thomas Meyer8633.08%116.67%
Linus Torvalds10.38%116.67%
Paul Gortmaker10.38%116.67%
Total260100.00%6100.00%
Directory: arch/sh/mm
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