From 29934b0fb8ff5afa61832ea56aec65befab30511 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 22 Mar 2016 14:28:17 -0700 Subject: [PATCH] x86/extable: use generic search and sort routines Replace the arch specific versions of search_extable() and sort_extable() with calls to the generic ones, which now support relative exception tables as well. Signed-off-by: Ard Biesheuvel Acked-by: H. Peter Anvin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/include/asm/uaccess.h | 5 +- arch/x86/mm/extable.c | 108 --------------------------------- 2 files changed, 2 insertions(+), 111 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 88bff6dd23ad..a969ae607be8 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -105,9 +105,8 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un struct exception_table_entry { int insn, fixup, handler; }; -/* This is not the generic standard exception_table_entry format */ -#define ARCH_HAS_SORT_EXTABLE -#define ARCH_HAS_SEARCH_EXTABLE + +#define ARCH_HAS_RELATIVE_EXTABLE extern int fixup_exception(struct pt_regs *regs, int trapnr); extern bool ex_has_fault_handler(unsigned long ip); diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 9dd7e4b7fcde..82447b3fba38 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -1,16 +1,9 @@ #include -#include -#include #include typedef bool (*ex_handler_t)(const struct exception_table_entry *, struct pt_regs *, int); -static inline unsigned long -ex_insn_addr(const struct exception_table_entry *x) -{ - return (unsigned long)&x->insn + x->insn; -} static inline unsigned long ex_fixup_addr(const struct exception_table_entry *x) { @@ -110,104 +103,3 @@ int __init early_fixup_exception(unsigned long *ip) *ip = new_ip; return 1; } - -/* - * Search one exception table for an entry corresponding to the - * given instruction address, and return the address of the entry, - * or NULL if none is found. - * We use a binary search, and thus we assume that the table is - * already sorted. - */ -const struct exception_table_entry * -search_extable(const struct exception_table_entry *first, - const struct exception_table_entry *last, - unsigned long value) -{ - while (first <= last) { - const struct exception_table_entry *mid; - unsigned long addr; - - mid = ((last - first) >> 1) + first; - addr = ex_insn_addr(mid); - if (addr < value) - first = mid + 1; - else if (addr > value) - last = mid - 1; - else - return mid; - } - return NULL; -} - -/* - * The exception table needs to be sorted so that the binary - * search that we use to find entries in it works properly. - * This is used both for the kernel exception table and for - * the exception tables of modules that get loaded. - * - */ -static int cmp_ex(const void *a, const void *b) -{ - const struct exception_table_entry *x = a, *y = b; - - /* - * This value will always end up fittin in an int, because on - * both i386 and x86-64 the kernel symbol-reachable address - * space is < 2 GiB. - * - * This compare is only valid after normalization. - */ - return x->insn - y->insn; -} - -void sort_extable(struct exception_table_entry *start, - struct exception_table_entry *finish) -{ - struct exception_table_entry *p; - int i; - - /* Convert all entries to being relative to the start of the section */ - i = 0; - for (p = start; p < finish; p++) { - p->insn += i; - i += 4; - p->fixup += i; - i += 4; - p->handler += i; - i += 4; - } - - sort(start, finish - start, sizeof(struct exception_table_entry), - cmp_ex, NULL); - - /* Denormalize all entries */ - i = 0; - for (p = start; p < finish; p++) { - p->insn -= i; - i += 4; - p->fixup -= i; - i += 4; - p->handler -= i; - i += 4; - } -} - -#ifdef CONFIG_MODULES -/* - * If the exception table is sorted, any referring to the module init - * will be at the beginning or the end. - */ -void trim_init_extable(struct module *m) -{ - /*trim the beginning*/ - while (m->num_exentries && - within_module_init(ex_insn_addr(&m->extable[0]), m)) { - m->extable++; - m->num_exentries--; - } - /*trim the end*/ - while (m->num_exentries && - within_module_init(ex_insn_addr(&m->extable[m->num_exentries-1]), m)) - m->num_exentries--; -} -#endif /* CONFIG_MODULES */