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x86-64: Handle PC-relative relocations on per-CPU data

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This is in preparation of using RIP-relative addressing in many of the
per-CPU accesses.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5458A15A0200007800044A9A@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jan Beulich 2014-11-04 08:50:18 +00:00 committed by Thomas Gleixner
parent 2c773dd31f
commit 6d24c5f72d
2 changed files with 40 additions and 10 deletions
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14
arch/x86/boot/compressed/misc.c
View file

@ -260,7 +260,7 @@ static void handle_relocations(void *output, unsigned long output_len)
/*
* Process relocations: 32 bit relocations first then 64 bit after.
* Two sets of binary relocations are added to the end of the kernel
* Three sets of binary relocations are added to the end of the kernel
* before compression. Each relocation table entry is the kernel
* address of the location which needs to be updated stored as a
* 32-bit value which is sign extended to 64 bits.
@ -270,6 +270,8 @@ static void handle_relocations(void *output, unsigned long output_len)
* kernel bits...
* 0 - zero terminator for 64 bit relocations
* 64 bit relocation repeated
* 0 - zero terminator for inverse 32 bit relocations
* 32 bit inverse relocation repeated
* 0 - zero terminator for 32 bit relocations
* 32 bit relocation repeated
*
@ -286,6 +288,16 @@ static void handle_relocations(void *output, unsigned long output_len)
*(uint32_t *)ptr += delta;
}
#ifdef CONFIG_X86_64
while (*--reloc) {
long extended = *reloc;
extended += map;
ptr = (unsigned long)extended;
if (ptr < min_addr || ptr > max_addr)
error("inverse 32-bit relocation outside of kernel!\n");
*(int32_t *)ptr -= delta;
}
for (reloc--; *reloc; reloc--) {
long extended = *reloc;
extended += map;

36
arch/x86/tools/relocs.c
View file

@ -20,7 +20,10 @@ struct relocs {
static struct relocs relocs16;
static struct relocs relocs32;
#if ELF_BITS == 64
static struct relocs relocs32neg;
static struct relocs relocs64;
#endif
struct section {
Elf_Shdr shdr;
@ -762,11 +765,16 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
switch (r_type) {
case R_X86_64_NONE:
/* NONE can be ignored. */
break;
case R_X86_64_PC32:
/*
* NONE can be ignored and PC relative relocations don't
* need to be adjusted.
* PC relative relocations don't need to be adjusted unless
* referencing a percpu symbol.
*/
if (is_percpu_sym(sym, symname))
add_reloc(&relocs32neg, offset);
break;
case R_X86_64_32:
@ -986,7 +994,10 @@ static void emit_relocs(int as_text, int use_real_mode)
/* Order the relocations for more efficient processing */
sort_relocs(&relocs16);
sort_relocs(&relocs32);
#if ELF_BITS == 64
sort_relocs(&relocs32neg);
sort_relocs(&relocs64);
#endif
/* Print the relocations */
if (as_text) {
@ -1007,14 +1018,21 @@ static void emit_relocs(int as_text, int use_real_mode)
for (i = 0; i < relocs32.count; i++)
write_reloc(relocs32.offset[i], stdout);
} else {
if (ELF_BITS == 64) {
/* Print a stop */
write_reloc(0, stdout);
#if ELF_BITS == 64
/* Print a stop */
write_reloc(0, stdout);
/* Now print each relocation */
for (i = 0; i < relocs64.count; i++)
write_reloc(relocs64.offset[i], stdout);
}
/* Now print each relocation */
for (i = 0; i < relocs64.count; i++)
write_reloc(relocs64.offset[i], stdout);
/* Print a stop */
write_reloc(0, stdout);
/* Now print each inverse 32-bit relocation */
for (i = 0; i < relocs32neg.count; i++)
write_reloc(relocs32neg.offset[i], stdout);
#endif
/* Print a stop */
write_reloc(0, stdout);