The patch titled
Allow for per-cpu data being in .tdata and .tbss sections
has been removed from the -mm tree. Its filename is
allow-for-per-cpu-data-being-in-tdata-and-tbss-sections.patch
This patch was dropped because Paul said it offered no discernable benefit
------------------------------------------------------
Subject: Allow for per-cpu data being in .tdata and .tbss sections
From: Paul Mackerras <paulus@xxxxxxxxx>
This lays the groundwork for using __thread for per-cpu variables. The
toolchain will put initialized __thread variables into a .tdata section,
and uninitialized __thread variables into a .tbss section. Thus the module
loader needs to cope with two per-cpu sections, of which one is initialized
and the other must be zeroed.
With this patch, the module loader looks for .tdata and .tbss, and if it
finds neither, falls back to the .data.percpu section that we currently
use. This patch extends the various percpu_modcopy implementations to take
two size parameters: the first is the amount to initialize and the second
is the amount to zero following that. At the moment all percpu_modcopy
implementations simply check that the amount to zero is zero.
I have a following patch that makes 64-bit powerpc use __thread for per-cpu
variables.
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/ia64/kernel/module.c | 4 +
include/asm-generic/percpu.h | 3 -
include/asm-ia64/percpu.h | 3 -
include/asm-powerpc/percpu.h | 3 -
include/asm-s390/percpu.h | 3 -
include/asm-sparc64/percpu.h | 3 -
include/asm-x86_64/percpu.h | 3 -
kernel/module.c | 87 ++++++++++++++++++++++++---------
8 files changed, 79 insertions(+), 30 deletions(-)
diff -puN arch/ia64/kernel/module.c~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections arch/ia64/kernel/module.c
--- devel/arch/ia64/kernel/module.c~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/arch/ia64/kernel/module.c 2006-06-09 03:14:53.000000000 -0700
@@ -944,9 +944,11 @@ module_arch_cleanup (struct module *mod)
#ifdef CONFIG_SMP
void
-percpu_modcopy (void *pcpudst, const void *src, unsigned long size)
+percpu_modcopy(void *pcpudst, const void *src, unsigned long size,
+ unsigned long zero_size)
{
unsigned int i;
+ BUG_ON(zero_size != 0);
for_each_possible_cpu(i) {
memcpy(pcpudst + __per_cpu_offset[i], src, size);
}
diff -puN include/asm-ia64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-ia64/percpu.h
--- devel/include/asm-ia64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/include/asm-ia64/percpu.h 2006-06-09 03:14:53.000000000 -0700
@@ -44,7 +44,8 @@ DECLARE_PER_CPU(unsigned long, local_per
#define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __ia64_per_cpu_var(local_per_cpu_offset)))
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __ia64_per_cpu_var(local_per_cpu_offset)))
-extern void percpu_modcopy(void *pcpudst, const void *src, unsigned long size);
+extern void percpu_modcopy(void *pcpudst, const void *src,
+ unsigned long size, unsigned long zero_size);
extern void setup_per_cpu_areas (void);
extern void *per_cpu_init(void);
diff -puN include/asm-powerpc/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-powerpc/percpu.h
--- devel/include/asm-powerpc/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/include/asm-powerpc/percpu.h 2006-06-09 03:14:35.000000000 -0700
@@ -25,9 +25,10 @@
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size) \
+#define percpu_modcopy(pcpudst, src, size, zero_size) \
do { \
unsigned int __i; \
+ BUG_ON(zero_size != 0); \
for_each_possible_cpu(__i) \
memcpy((pcpudst)+__per_cpu_offset(__i), \
(src), (size)); \
diff -puN include/asm-s390/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-s390/percpu.h
--- devel/include/asm-s390/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/include/asm-s390/percpu.h 2006-06-09 03:14:35.000000000 -0700
@@ -44,9 +44,10 @@ extern unsigned long __per_cpu_offset[NR
#define per_cpu(var,cpu) __reloc_hide(var,__per_cpu_offset[cpu])
/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size) \
+#define percpu_modcopy(pcpudst, src, size, zero_size) \
do { \
unsigned int __i; \
+ BUG_ON(zero_size != 0); \
for_each_possible_cpu(__i) \
memcpy((pcpudst)+__per_cpu_offset[__i], \
(src), (size)); \
diff -puN include/asm-sparc64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-sparc64/percpu.h
--- devel/include/asm-sparc64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/include/asm-sparc64/percpu.h 2006-06-09 03:14:35.000000000 -0700
@@ -24,9 +24,10 @@ register unsigned long __local_per_cpu_o
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __local_per_cpu_offset))
/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size) \
+#define percpu_modcopy(pcpudst, src, size, zero_size) \
do { \
unsigned int __i; \
+ BUG_ON(zero_size != 0); \
for_each_possible_cpu(__i) \
memcpy((pcpudst)+__per_cpu_offset(__i), \
(src), (size)); \
diff -puN include/asm-x86_64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-x86_64/percpu.h
--- devel/include/asm-x86_64/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/include/asm-x86_64/percpu.h 2006-06-09 03:14:35.000000000 -0700
@@ -24,9 +24,10 @@
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size) \
+#define percpu_modcopy(pcpudst, src, size, zero_size) \
do { \
unsigned int __i; \
+ BUG_ON(zero_size != 0); \
for_each_possible_cpu(__i) \
memcpy((pcpudst)+__per_cpu_offset(__i), \
(src), (size)); \
diff -puN kernel/module.c~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections kernel/module.c
--- devel/kernel/module.c~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:35.000000000 -0700
+++ devel-akpm/kernel/module.c 2006-06-09 03:14:53.000000000 -0700
@@ -356,11 +356,28 @@ static void percpu_modfree(void *freeme)
}
}
-static unsigned int find_pcpusec(Elf_Ehdr *hdr,
- Elf_Shdr *sechdrs,
- const char *secstrings)
+static void find_pcpusecs(Elf_Ehdr *hdr,
+ Elf_Shdr *sechdrs,
+ const char *secstrings,
+ unsigned int pcpuindex[2])
{
- return find_sec(hdr, sechdrs, secstrings, ".data.percpu");
+ /*
+ * Some architectures use __thread for per-cpu variables,
+ * and that generates .tdata and .tbss sections.
+ */
+ pcpuindex[0] = find_sec(hdr, sechdrs, secstrings, ".tdata");
+ pcpuindex[1] = find_sec(hdr, sechdrs, secstrings, ".tbss");
+ if (pcpuindex[0])
+ return;
+ if (pcpuindex[1] && !pcpuindex[0]) {
+ /* move .tbss to pcpuindex[0], it makes things easier later */
+ pcpuindex[0] = pcpuindex[1];
+ pcpuindex[1] = 0;
+ return;
+ }
+
+ /* look for the generic .data.percpu if no .tdata */
+ pcpuindex[0] = find_sec(hdr, sechdrs, secstrings, ".data.percpu");
}
static int percpu_modinit(void)
@@ -391,17 +408,20 @@ static inline void percpu_modfree(void *
{
BUG();
}
-static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
- Elf_Shdr *sechdrs,
- const char *secstrings)
+static inline void find_pcpusecs(Elf_Ehdr *hdr,
+ Elf_Shdr *sechdrs,
+ const char *secstrings,
+ unsigned int pcpuindex[2])
{
- return 0;
+ pcpuindex[0] = 0;
+ pcpuindex[1] = 0;
}
static inline void percpu_modcopy(void *pcpudst, const void *src,
- unsigned long size)
+ unsigned long size, unsigned long zero_size)
{
- /* pcpusec should be 0, and size of that section should be 0. */
+ /* there should be no per-cpu data to copy or clear */
BUG_ON(size != 0);
+ BUG_ON(zero_size != 0);
}
#endif /* CONFIG_SMP */
@@ -1125,7 +1145,7 @@ static int simplify_symbols(Elf_Shdr *se
unsigned int symindex,
const char *strtab,
unsigned int versindex,
- unsigned int pcpuindex,
+ unsigned int pcpuindex[2],
struct module *mod)
{
Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
@@ -1169,9 +1189,13 @@ static int simplify_symbols(Elf_Shdr *se
default:
/* Divert to percpu allocation if a percpu var. */
- if (sym[i].st_shndx == pcpuindex)
+ if (sym[i].st_shndx == pcpuindex[0])
secbase = (unsigned long)mod->percpu;
- else
+ else if (sym[i].st_shndx == pcpuindex[1]) {
+ /* .tbss follows .tdata */
+ secbase = (unsigned long)mod->percpu
+ + sechdrs[pcpuindex[0]].sh_size;
+ } else
secbase = sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
@@ -1405,8 +1429,9 @@ static struct module *load_module(void _
char *secstrings, *args, *modmagic, *strtab = NULL;
unsigned int i, symindex = 0, strindex = 0, setupindex, exindex,
exportindex, modindex, obsparmindex, infoindex, gplindex,
- crcindex, gplcrcindex, versindex, pcpuindex, gplfutureindex,
+ crcindex, gplcrcindex, versindex, pcpuindex[2], gplfutureindex,
gplfuturecrcindex, unwindex = 0;
+ unsigned int pcpusize = 0, pcpuinitsize = 0;
struct module *mod;
long err = 0;
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -1495,7 +1520,7 @@ static struct module *load_module(void _
obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
- pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
+ find_pcpusecs(hdr, sechdrs, secstrings, pcpuindex);
#ifdef ARCH_UNWIND_SECTION_NAME
unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME);
#endif
@@ -1548,16 +1573,32 @@ static struct module *load_module(void _
if (err < 0)
goto free_mod;
- if (pcpuindex) {
- /* We have a special allocation for this section. */
- percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size,
- sechdrs[pcpuindex].sh_addralign,
- mod->name);
+ if (pcpuindex[0]) {
+ /* We have a special allocation for these sections. */
+ unsigned int align = 0;
+ int i, j;
+
+ i = pcpuindex[0];
+ pcpusize = sechdrs[i].sh_size;
+ align = sechdrs[i].sh_addralign;
+ sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ if (sechdrs[i].sh_type != SHT_NOBITS)
+ pcpuinitsize = pcpusize;
+ if (pcpuindex[1]) {
+ /* have both .tdata and .tbss */
+ j = pcpuindex[1];
+ pcpusize = ALIGN(pcpusize, sechdrs[j].sh_addralign);
+ sechdrs[i].sh_size = pcpusize;
+ if (sechdrs[j].sh_addralign > align)
+ align = sechdrs[j].sh_addralign;
+ pcpusize += sechdrs[j].sh_size;
+ sechdrs[j].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ }
+ percpu = percpu_modalloc(pcpusize, align, mod->name);
if (!percpu) {
err = -ENOMEM;
goto free_mod;
}
- sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
mod->percpu = percpu;
}
@@ -1686,8 +1727,8 @@ static struct module *load_module(void _
sort_extable(extable, extable + mod->num_exentries);
/* Finally, copy percpu area over. */
- percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
- sechdrs[pcpuindex].sh_size);
+ percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex[0]].sh_addr,
+ pcpuinitsize, pcpusize - pcpuinitsize);
add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
diff -puN include/asm-generic/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections include/asm-generic/percpu.h
--- devel/include/asm-generic/percpu.h~allow-for-per-cpu-data-being-in-tdata-and-tbss-sections 2006-06-09 03:14:48.000000000 -0700
+++ devel-akpm/include/asm-generic/percpu.h 2006-06-09 03:14:48.000000000 -0700
@@ -17,9 +17,10 @@ extern unsigned long __per_cpu_offset[NR
#define __raw_get_cpu_var(var) per_cpu(var, raw_smp_processor_id())
/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size) \
+#define percpu_modcopy(pcpudst, src, size, zero_size) \
do { \
unsigned int __i; \
+ BUG_ON(zero_size != 0); \
for_each_possible_cpu(__i) \
memcpy((pcpudst)+__per_cpu_offset[__i], \
(src), (size)); \
_
Patches currently in -mm which might be from paulus@xxxxxxxxx are
macintosh-mangle-caps-lock-events-on-adb-keyboards.patch
ppp_async-hang-fix.patch
git-powerpc.patch
powerpc-kbuild-warning-fix.patch
powerpc-vdso-updates.patch
work-around-ppc64-bootup-bug-by-making-mutex-debugging-save-restore-irqs.patch
powerpc-implement-support-for-setting.patch
powerpc-implement-pr_et_unalign-prctls-for-powerpc.patch
add-poisonh-and-patch-primary-users.patch
x86-powerpc-make-hardirq_ctx-and-softirq_ctx-__read_mostly.patch
define-__raw_get_cpu_var-and-use-it.patch
allow-for-per-cpu-data-being-in-tdata-and-tbss-sections.patch
apple-motion-sensor-driver.patch
fix-broken-dubious-driver-suspend-methods.patch
drivers-use-list_move.patch
lock-validator-add-per_cpu_offset-fix.patch
-
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