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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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08a42e86bc
Exception fixups for sections other than .text (like one in futex_init()) break the natural ordering of fixup entries, so sorting is required. Without that the result of the exception table search depends on phase of the moon. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Richard Henderson <rth@twiddle.net Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
/*
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* linux/arch/alpha/mm/extable.c
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*/
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#include <linux/module.h>
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#include <linux/sort.h>
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#include <asm/uaccess.h>
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static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->insn + x->insn;
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}
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static void swap_ex(void *a, void *b, int size)
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{
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struct exception_table_entry *ex_a = a, *ex_b = b;
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unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
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unsigned int t = ex_a->fixup.unit;
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ex_a->fixup.unit = ex_b->fixup.unit;
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ex_b->fixup.unit = t;
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ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
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ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
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}
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/*
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* The exception table needs to be sorted so that the binary
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* search that we use to find entries in it works properly.
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* This is used both for the kernel exception table and for
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* the exception tables of modules that get loaded.
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*/
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static int cmp_ex(const void *a, const void *b)
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{
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const struct exception_table_entry *x = a, *y = b;
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/* avoid overflow */
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if (ex_to_addr(x) > ex_to_addr(y))
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return 1;
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if (ex_to_addr(x) < ex_to_addr(y))
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return -1;
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return 0;
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}
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void sort_extable(struct exception_table_entry *start,
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struct exception_table_entry *finish)
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{
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sort(start, finish - start, sizeof(struct exception_table_entry),
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cmp_ex, swap_ex);
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}
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const struct exception_table_entry *
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search_extable(const struct exception_table_entry *first,
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const struct exception_table_entry *last,
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unsigned long value)
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{
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while (first <= last) {
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const struct exception_table_entry *mid;
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unsigned long mid_value;
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mid = (last - first) / 2 + first;
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mid_value = ex_to_addr(mid);
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if (mid_value == value)
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return mid;
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else if (mid_value < value)
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first = mid+1;
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else
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last = mid-1;
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}
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return NULL;
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}
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