2 * sortextable.c: Sort the kernel's exception table
4 * Copyright 2011 - 2012 Cavium, Inc.
6 * Based on code taken from recortmcount.c which is:
8 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
9 * Licensed under the GNU General Public License, version 2 (GPLv2).
11 * Restructured to fit Linux format, as well as other updates:
12 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
16 * Strategy: alter the vmlinux file in-place.
19 #include <sys/types.h>
31 #include <tools/be_byteshift.h>
32 #include <tools/le_byteshift.h>
35 #define EM_AARCH64 183
38 static int fd_map
; /* File descriptor for file being modified. */
39 static int mmap_failed
; /* Boolean flag. */
40 static void *ehdr_curr
; /* current ElfXX_Ehdr * for resource cleanup */
41 static struct stat sb
; /* Remember .st_size, etc. */
42 static jmp_buf jmpenv
; /* setjmp/longjmp per-file error escape */
44 /* setjmp() return values */
46 SJ_SETJMP
= 0, /* hardwired first return */
51 /* Per-file resource cleanup when multiple files. */
56 munmap(ehdr_curr
, sb
.st_size
);
60 static void __attribute__((noreturn
))
64 longjmp(jmpenv
, SJ_FAIL
);
68 * Get the whole file as a programming convenience in order to avoid
69 * malloc+lseek+read+free of many pieces. If successful, then mmap
70 * avoids copying unused pieces; else just read the whole file.
71 * Open for both read and write.
73 static void *mmap_file(char const *fname
)
77 fd_map
= open(fname
, O_RDWR
);
78 if (fd_map
< 0 || fstat(fd_map
, &sb
) < 0) {
82 if (!S_ISREG(sb
.st_mode
)) {
83 fprintf(stderr
, "not a regular file: %s\n", fname
);
86 addr
= mmap(0, sb
.st_size
, PROT_READ
|PROT_WRITE
, MAP_SHARED
,
88 if (addr
== MAP_FAILED
) {
90 fprintf(stderr
, "Could not mmap file: %s\n", fname
);
96 static uint64_t r8be(const uint64_t *x
)
98 return get_unaligned_be64(x
);
100 static uint32_t rbe(const uint32_t *x
)
102 return get_unaligned_be32(x
);
104 static uint16_t r2be(const uint16_t *x
)
106 return get_unaligned_be16(x
);
108 static uint64_t r8le(const uint64_t *x
)
110 return get_unaligned_le64(x
);
112 static uint32_t rle(const uint32_t *x
)
114 return get_unaligned_le32(x
);
116 static uint16_t r2le(const uint16_t *x
)
118 return get_unaligned_le16(x
);
121 static void w8be(uint64_t val
, uint64_t *x
)
123 put_unaligned_be64(val
, x
);
125 static void wbe(uint32_t val
, uint32_t *x
)
127 put_unaligned_be32(val
, x
);
129 static void w2be(uint16_t val
, uint16_t *x
)
131 put_unaligned_be16(val
, x
);
133 static void w8le(uint64_t val
, uint64_t *x
)
135 put_unaligned_le64(val
, x
);
137 static void wle(uint32_t val
, uint32_t *x
)
139 put_unaligned_le32(val
, x
);
141 static void w2le(uint16_t val
, uint16_t *x
)
143 put_unaligned_le16(val
, x
);
146 static uint64_t (*r8
)(const uint64_t *);
147 static uint32_t (*r
)(const uint32_t *);
148 static uint16_t (*r2
)(const uint16_t *);
149 static void (*w8
)(uint64_t, uint64_t *);
150 static void (*w
)(uint32_t, uint32_t *);
151 static void (*w2
)(uint16_t, uint16_t *);
153 typedef void (*table_sort_t
)(char *, int);
156 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
157 * the way to -256..-1, to avoid conflicting with real section
160 #define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
162 static inline int is_shndx_special(unsigned int i
)
164 return i
!= SHN_XINDEX
&& i
>= SHN_LORESERVE
&& i
<= SHN_HIRESERVE
;
167 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
168 static inline unsigned int get_secindex(unsigned int shndx
,
169 unsigned int sym_offs
,
170 const Elf32_Word
*symtab_shndx_start
)
172 if (is_shndx_special(shndx
))
173 return SPECIAL(shndx
);
174 if (shndx
!= SHN_XINDEX
)
176 return r(&symtab_shndx_start
[sym_offs
]);
179 /* 32 bit and 64 bit are very similar */
180 #include "sortextable.h"
181 #define SORTEXTABLE_64
182 #include "sortextable.h"
184 static int compare_relative_table(const void *a
, const void *b
)
186 int32_t av
= (int32_t)r(a
);
187 int32_t bv
= (int32_t)r(b
);
196 static void sort_relative_table(char *extab_image
, int image_size
)
201 * Do the same thing the runtime sort does, first normalize to
202 * being relative to the start of the section.
205 while (i
< image_size
) {
206 uint32_t *loc
= (uint32_t *)(extab_image
+ i
);
211 qsort(extab_image
, image_size
/ 8, 8, compare_relative_table
);
213 /* Now denormalize. */
215 while (i
< image_size
) {
216 uint32_t *loc
= (uint32_t *)(extab_image
+ i
);
223 do_file(char const *const fname
)
225 table_sort_t custom_sort
;
226 Elf32_Ehdr
*ehdr
= mmap_file(fname
);
229 switch (ehdr
->e_ident
[EI_DATA
]) {
231 fprintf(stderr
, "unrecognized ELF data encoding %d: %s\n",
232 ehdr
->e_ident
[EI_DATA
], fname
);
252 if (memcmp(ELFMAG
, ehdr
->e_ident
, SELFMAG
) != 0
253 || r2(&ehdr
->e_type
) != ET_EXEC
254 || ehdr
->e_ident
[EI_VERSION
] != EV_CURRENT
) {
255 fprintf(stderr
, "unrecognized ET_EXEC file %s\n", fname
);
260 switch (r2(&ehdr
->e_machine
)) {
262 fprintf(stderr
, "unrecognized e_machine %d %s\n",
263 r2(&ehdr
->e_machine
), fname
);
269 custom_sort
= sort_relative_table
;
277 switch (ehdr
->e_ident
[EI_CLASS
]) {
279 fprintf(stderr
, "unrecognized ELF class %d %s\n",
280 ehdr
->e_ident
[EI_CLASS
], fname
);
284 if (r2(&ehdr
->e_ehsize
) != sizeof(Elf32_Ehdr
)
285 || r2(&ehdr
->e_shentsize
) != sizeof(Elf32_Shdr
)) {
287 "unrecognized ET_EXEC file: %s\n", fname
);
290 do32(ehdr
, fname
, custom_sort
);
293 Elf64_Ehdr
*const ghdr
= (Elf64_Ehdr
*)ehdr
;
294 if (r2(&ghdr
->e_ehsize
) != sizeof(Elf64_Ehdr
)
295 || r2(&ghdr
->e_shentsize
) != sizeof(Elf64_Shdr
)) {
297 "unrecognized ET_EXEC file: %s\n", fname
);
300 do64(ghdr
, fname
, custom_sort
);
309 main(int argc
, char *argv
[])
311 int n_error
= 0; /* gcc-4.3.0 false positive complaint */
315 fprintf(stderr
, "usage: sortextable vmlinux...\n");
319 /* Process each file in turn, allowing deep failure. */
320 for (i
= 1; i
< argc
; i
++) {
321 char *file
= argv
[i
];
322 int const sjval
= setjmp(jmpenv
);
326 fprintf(stderr
, "internal error: %s\n", file
);
329 case SJ_SETJMP
: /* normal sequence */
330 /* Avoid problems if early cleanup() */
336 case SJ_FAIL
: /* error in do_file or below */
339 case SJ_SUCCEED
: /* premature success */
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