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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2006-10-19 21:47:18 -0400
committerPaul Mackerras <paulus@samba.org>2006-10-24 21:54:07 -0400
commit0909c8c2d547e45ca50e2492b08ec93a37b35237 (patch)
tree23e66e1dc9a5bd674ba1375b5fccd2cb0d5787a8 /arch/powerpc/kernel
parent7aeb732428fc8e2ecae6d432873770c12f04a979 (diff)
[POWERPC] Support feature fixups in vdso's
This patch reworks the feature fixup mecanism so vdso's can be fixed up. The main issue was that the construct: .long label (or .llong on 64 bits) will not work in the case of a shared library like the vdso. It will generate an empty placeholder in the fixup table along with a reloc, which is not something we can deal with in the vdso. The idea here (thanks Alan Modra !) is to instead use something like: 1: .long label - 1b That is, the feature fixup tables no longer contain addresses of bits of code to patch, but offsets of such code from the fixup table entry itself. That is properly resolved by ld when building the .so's. I've modified the fixup mecanism generically to use that method for the rest of the kernel as well. Another trick is that the 32 bits vDSO included in the 64 bits kernel need to have a table in the 64 bits format. However, gas does not support 32 bits code with a statement of the form: .llong label - 1b (Or even just .llong label) That is, it cannot emit the right fixup/relocation for the linker to use to assign a 32 bits address to an .llong field. Thus, in the specific case of the 32 bits vdso built as part of the 64 bits kernel, we are using a modified macro that generates: .long 0xffffffff .llong label - 1b Note that is assumes that the value is negative which is enforced by the .lds (those offsets are always negative as the .text is always before the fixup table and gas doesn't support emiting the reloc the other way around). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/cputable.c11
-rw-r--r--arch/powerpc/kernel/setup_32.c2
-rw-r--r--arch/powerpc/kernel/setup_64.c4
-rw-r--r--arch/powerpc/kernel/vdso.c43
-rw-r--r--arch/powerpc/kernel/vdso32/vdso32.lds.S12
-rw-r--r--arch/powerpc/kernel/vdso64/vdso64.lds.S10
6 files changed, 73 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 6fdfaa4a82b8..bfd499ee3753 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1202,14 +1202,13 @@ struct cpu_spec *identify_cpu(unsigned long offset)
1202 return NULL; 1202 return NULL;
1203} 1203}
1204 1204
1205void do_feature_fixups(unsigned long offset, unsigned long value, 1205void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
1206 void *fixup_start, void *fixup_end)
1207{ 1206{
1208 struct fixup_entry { 1207 struct fixup_entry {
1209 unsigned long mask; 1208 unsigned long mask;
1210 unsigned long value; 1209 unsigned long value;
1211 unsigned int *start; 1210 long start_off;
1212 unsigned int *end; 1211 long end_off;
1213 } *fcur, *fend; 1212 } *fcur, *fend;
1214 1213
1215 fcur = fixup_start; 1214 fcur = fixup_start;
@@ -1224,8 +1223,8 @@ void do_feature_fixups(unsigned long offset, unsigned long value,
1224 /* These PTRRELOCs will disappear once the new scheme for 1223 /* These PTRRELOCs will disappear once the new scheme for
1225 * modules and vdso is implemented 1224 * modules and vdso is implemented
1226 */ 1225 */
1227 pstart = PTRRELOC(fcur->start); 1226 pstart = ((unsigned int *)fcur) + (fcur->start_off / 4);
1228 pend = PTRRELOC(fcur->end); 1227 pend = ((unsigned int *)fcur) + (fcur->end_off / 4);
1229 1228
1230 for (p = pstart; p < pend; p++) { 1229 for (p = pstart; p < pend; p++) {
1231 *p = 0x60000000u; 1230 *p = 0x60000000u;
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 769e511783b0..a4c2964a3ca6 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -103,7 +103,7 @@ unsigned long __init early_init(unsigned long dt_ptr)
103 */ 103 */
104 spec = identify_cpu(offset); 104 spec = identify_cpu(offset);
105 105
106 do_feature_fixups(offset, spec->cpu_features, 106 do_feature_fixups(spec->cpu_features,
107 PTRRELOC(&__start___ftr_fixup), 107 PTRRELOC(&__start___ftr_fixup),
108 PTRRELOC(&__stop___ftr_fixup)); 108 PTRRELOC(&__stop___ftr_fixup));
109 109
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 1969b5686eee..16278968dab6 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -354,9 +354,9 @@ void __init setup_system(void)
354 /* Apply the CPUs-specific and firmware specific fixups to kernel 354 /* Apply the CPUs-specific and firmware specific fixups to kernel
355 * text (nop out sections not relevant to this CPU or this firmware) 355 * text (nop out sections not relevant to this CPU or this firmware)
356 */ 356 */
357 do_feature_fixups(0, cur_cpu_spec->cpu_features, 357 do_feature_fixups(cur_cpu_spec->cpu_features,
358 &__start___ftr_fixup, &__stop___ftr_fixup); 358 &__start___ftr_fixup, &__stop___ftr_fixup);
359 do_feature_fixups(0, powerpc_firmware_features, 359 do_feature_fixups(powerpc_firmware_features,
360 &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup); 360 &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
361 361
362 /* 362 /*
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 1a7e19cdab39..c913ad5cad29 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -36,6 +36,8 @@
36#include <asm/vdso.h> 36#include <asm/vdso.h>
37#include <asm/vdso_datapage.h> 37#include <asm/vdso_datapage.h>
38 38
39#include "setup.h"
40
39#undef DEBUG 41#undef DEBUG
40 42
41#ifdef DEBUG 43#ifdef DEBUG
@@ -586,6 +588,43 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
586 return 0; 588 return 0;
587} 589}
588 590
591
592static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
593 struct lib64_elfinfo *v64)
594{
595 void *start32;
596 unsigned long size32;
597
598#ifdef CONFIG_PPC64
599 void *start64;
600 unsigned long size64;
601
602 start64 = find_section64(v64->hdr, "__ftr_fixup", &size64);
603 if (start64)
604 do_feature_fixups(cur_cpu_spec->cpu_features,
605 start64, start64 + size64);
606
607 start64 = find_section64(v64->hdr, "__fw_ftr_fixup", &size64);
608 if (start64)
609 do_feature_fixups(powerpc_firmware_features,
610 start64, start64 + size64);
611#endif /* CONFIG_PPC64 */
612
613 start32 = find_section32(v32->hdr, "__ftr_fixup", &size32);
614 if (start32)
615 do_feature_fixups(cur_cpu_spec->cpu_features,
616 start32, start32 + size32);
617
618#ifdef CONFIG_PPC64
619 start32 = find_section32(v32->hdr, "__fw_ftr_fixup", &size32);
620 if (start32)
621 do_feature_fixups(powerpc_firmware_features,
622 start32, start32 + size32);
623#endif /* CONFIG_PPC64 */
624
625 return 0;
626}
627
589static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32, 628static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
590 struct lib64_elfinfo *v64) 629 struct lib64_elfinfo *v64)
591{ 630{
@@ -634,6 +673,9 @@ static __init int vdso_setup(void)
634 if (vdso_fixup_datapage(&v32, &v64)) 673 if (vdso_fixup_datapage(&v32, &v64))
635 return -1; 674 return -1;
636 675
676 if (vdso_fixup_features(&v32, &v64))
677 return -1;
678
637 if (vdso_fixup_alt_funcs(&v32, &v64)) 679 if (vdso_fixup_alt_funcs(&v32, &v64))
638 return -1; 680 return -1;
639 681
@@ -714,6 +756,7 @@ void __init vdso_init(void)
714 * Setup the syscall map in the vDOS 756 * Setup the syscall map in the vDOS
715 */ 757 */
716 vdso_setup_syscall_map(); 758 vdso_setup_syscall_map();
759
717 /* 760 /*
718 * Initialize the vDSO images in memory, that is do necessary 761 * Initialize the vDSO images in memory, that is do necessary
719 * fixups of vDSO symbols, locate trampolines, etc... 762 * fixups of vDSO symbols, locate trampolines, etc...
diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S
index 6187af2d54c3..26e138c4ce17 100644
--- a/arch/powerpc/kernel/vdso32/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S
@@ -32,6 +32,18 @@ SECTIONS
32 PROVIDE (_etext = .); 32 PROVIDE (_etext = .);
33 PROVIDE (etext = .); 33 PROVIDE (etext = .);
34 34
35 . = ALIGN(8);
36 __ftr_fixup : {
37 *(__ftr_fixup)
38 }
39
40#ifdef CONFIG_PPC64
41 . = ALIGN(8);
42 __fw_ftr_fixup : {
43 *(__fw_ftr_fixup)
44 }
45#endif
46
35 /* Other stuff is appended to the text segment: */ 47 /* Other stuff is appended to the text segment: */
36 .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) } 48 .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
37 .rodata1 : { *(.rodata1) } 49 .rodata1 : { *(.rodata1) }
diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S
index 4a2b6dc0960c..2d70f35d50b5 100644
--- a/arch/powerpc/kernel/vdso64/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S
@@ -31,6 +31,16 @@ SECTIONS
31 PROVIDE (_etext = .); 31 PROVIDE (_etext = .);
32 PROVIDE (etext = .); 32 PROVIDE (etext = .);
33 33
34 . = ALIGN(8);
35 __ftr_fixup : {
36 *(__ftr_fixup)
37 }
38
39 . = ALIGN(8);
40 __fw_ftr_fixup : {
41 *(__fw_ftr_fixup)
42 }
43
34 /* Other stuff is appended to the text segment: */ 44 /* Other stuff is appended to the text segment: */
35 .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) } 45 .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
36 .rodata1 : { *(.rodata1) } 46 .rodata1 : { *(.rodata1) }