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Message-Id: <20170810172615.51965-22-thgarnie@google.com>
Date: Thu, 10 Aug 2017 10:26:13 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: Herbert Xu <herbert@...dor.apana.org.au>,
"David S . Miller" <davem@...emloft.net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>,
Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
Thomas Garnier <thgarnie@...gle.com>,
Matthias Kaehlcke <mka@...omium.org>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
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Cc: x86@...nel.org,
linux-crypto@...r.kernel.org,
linux-kernel@...r.kernel.org,
xen-devel@...ts.xenproject.org,
kvm@...r.kernel.org,
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kernel-hardening@...ts.openwall.com
Subject: [RFC v2 21/23] x86/relocs: Add option to generate 64-bit relocations
The x86 relocation tool generates a list of 32-bit signed integers. There
was no need to use 64-bit integers because all addresses where above the 2G
top of the memory.
This change add a large-reloc option to generate 64-bit unsigned integers.
It can be used when the kernel plan to go below the top 2G and 32-bit
integers are not enough.
Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
---
arch/x86/tools/relocs.c | 60 +++++++++++++++++++++++++++++++++---------
arch/x86/tools/relocs.h | 4 +--
arch/x86/tools/relocs_common.c | 15 +++++++----
3 files changed, 60 insertions(+), 19 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 70f523dd68ff..19b3e6c594b1 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -12,8 +12,14 @@
static Elf_Ehdr ehdr;
+#if ELF_BITS == 64
+typedef uint64_t rel_off_t;
+#else
+typedef uint32_t rel_off_t;
+#endif
+
struct relocs {
- uint32_t *offset;
+ rel_off_t *offset;
unsigned long count;
unsigned long size;
};
@@ -627,7 +633,7 @@ static void print_absolute_relocs(void)
printf("\n");
}
-static void add_reloc(struct relocs *r, uint32_t offset)
+static void add_reloc(struct relocs *r, rel_off_t offset)
{
if (r->count == r->size) {
unsigned long newsize = r->size + 50000;
@@ -983,26 +989,48 @@ static void sort_relocs(struct relocs *r)
qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
}
-static int write32(uint32_t v, FILE *f)
+static int write32(rel_off_t rel, FILE *f)
{
- unsigned char buf[4];
+ unsigned char buf[sizeof(uint32_t)];
+ uint32_t v = (uint32_t)rel;
put_unaligned_le32(v, buf);
- return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
+ return fwrite(buf, 1, sizeof(buf), f) == sizeof(buf) ? 0 : -1;
}
-static int write32_as_text(uint32_t v, FILE *f)
+static int write32_as_text(rel_off_t rel, FILE *f)
{
+ uint32_t v = (uint32_t)rel;
return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
}
-static void emit_relocs(int as_text, int use_real_mode)
+static int write64(rel_off_t rel, FILE *f)
+{
+ unsigned char buf[sizeof(uint64_t)];
+ uint64_t v = (uint64_t)rel;
+
+ put_unaligned_le64(v, buf);
+ return fwrite(buf, 1, sizeof(buf), f) == sizeof(buf) ? 0 : -1;
+}
+
+static int write64_as_text(rel_off_t rel, FILE *f)
+{
+ uint64_t v = (uint64_t)rel;
+ return fprintf(f, "\t.quad 0x%016"PRIx64"\n", v) > 0 ? 0 : -1;
+}
+
+static void emit_relocs(int as_text, int use_real_mode, int use_large_reloc)
{
int i;
- int (*write_reloc)(uint32_t, FILE *) = write32;
+ int (*write_reloc)(rel_off_t, FILE *);
int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
const char *symname);
+ if (use_large_reloc)
+ write_reloc = write64;
+ else
+ write_reloc = write32;
+
#if ELF_BITS == 64
if (!use_real_mode)
do_reloc = do_reloc64;
@@ -1013,6 +1041,9 @@ static void emit_relocs(int as_text, int use_real_mode)
do_reloc = do_reloc32;
else
do_reloc = do_reloc_real;
+
+ /* Large relocations only for 64-bit */
+ use_large_reloc = 0;
#endif
/* Collect up the relocations */
@@ -1036,8 +1067,13 @@ static void emit_relocs(int as_text, int use_real_mode)
* gas will like.
*/
printf(".section \".data.reloc\",\"a\"\n");
- printf(".balign 4\n");
- write_reloc = write32_as_text;
+ if (use_large_reloc) {
+ printf(".balign 8\n");
+ write_reloc = write64_as_text;
+ } else {
+ printf(".balign 4\n");
+ write_reloc = write32_as_text;
+ }
}
if (use_real_mode) {
@@ -1131,7 +1167,7 @@ static void print_reloc_info(void)
void process(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info)
+ int show_reloc_info, int use_large_reloc)
{
regex_init(use_real_mode);
read_ehdr(fp);
@@ -1153,5 +1189,5 @@ void process(FILE *fp, int use_real_mode, int as_text,
print_reloc_info();
return;
}
- emit_relocs(as_text, use_real_mode);
+ emit_relocs(as_text, use_real_mode, use_large_reloc);
}
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
index 1d23bf953a4a..cb771cc4412d 100644
--- a/arch/x86/tools/relocs.h
+++ b/arch/x86/tools/relocs.h
@@ -30,8 +30,8 @@ enum symtype {
void process_32(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info);
+ int show_reloc_info, int use_large_reloc);
void process_64(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info);
+ int show_reloc_info, int use_large_reloc);
#endif /* RELOCS_H */
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
index acab636bcb34..9cf1391af50a 100644
--- a/arch/x86/tools/relocs_common.c
+++ b/arch/x86/tools/relocs_common.c
@@ -11,14 +11,14 @@ void die(char *fmt, ...)
static void usage(void)
{
- die("relocs [--abs-syms|--abs-relocs|--reloc-info|--text|--realmode]" \
- " vmlinux\n");
+ die("relocs [--abs-syms|--abs-relocs|--reloc-info|--text|--realmode|" \
+ "--large-reloc] vmlinux\n");
}
int main(int argc, char **argv)
{
int show_absolute_syms, show_absolute_relocs, show_reloc_info;
- int as_text, use_real_mode;
+ int as_text, use_real_mode, use_large_reloc;
const char *fname;
FILE *fp;
int i;
@@ -29,6 +29,7 @@ int main(int argc, char **argv)
show_reloc_info = 0;
as_text = 0;
use_real_mode = 0;
+ use_large_reloc = 0;
fname = NULL;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
@@ -53,6 +54,10 @@ int main(int argc, char **argv)
use_real_mode = 1;
continue;
}
+ if (strcmp(arg, "--large-reloc") == 0) {
+ use_large_reloc = 1;
+ continue;
+ }
}
else if (!fname) {
fname = arg;
@@ -74,11 +79,11 @@ int main(int argc, char **argv)
if (e_ident[EI_CLASS] == ELFCLASS64)
process_64(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs,
- show_reloc_info);
+ show_reloc_info, use_large_reloc);
else
process_32(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs,
- show_reloc_info);
+ show_reloc_info, use_large_reloc);
fclose(fp);
return 0;
}
--
2.14.0.434.g98096fd7a8-goog
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