* [PATCH v2 0/4] arm64: put objects into proper sections
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
This series tries to put objects into proper sections.
patch1 puts alloc_vectors_page() into .init section. This is a clean up
patch.
patch2 constify vm_special_mapping used for aarch32 vectors page.
patch3 fix the incorrect placement of __initdata and __read_mostly
patch4 apply __ro_after_init to some objects
Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly for performance reason. Then inspired by
Kees's patch[1], I think __ro_after_init is better.
[1] http://www.spinics.net/lists/arm-kernel/msg523188.html
Changes since v1:
- use __ro_after_init instead of __read_mostly
- find more objects to be suitable for __ro_after_init
- add one more patch to fix the incorrect placement of __initdata and
__read_mostly
Jisheng Zhang (4):
arm64: vdso: add __init section marker to alloc_vectors_page
arm64: vdso: constify vm_special_mapping used for aarch32 vectors page
arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly
arm64: apply __ro_after_init to some objects
arch/arm64/kernel/cpu_ops.c | 2 +-
arch/arm64/kernel/kaslr.c | 4 ++--
arch/arm64/kernel/vdso.c | 31 +++++++++++++++----------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/arm64/mm/init.c | 4 ++--
arch/arm64/mm/mmu.c | 2 +-
6 files changed, 22 insertions(+), 23 deletions(-)
--
2.8.1
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2 0/4] arm64: put objects into proper sections
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: linux-arm-kernel
This series tries to put objects into proper sections.
patch1 puts alloc_vectors_page() into .init section. This is a clean up
patch.
patch2 constify vm_special_mapping used for aarch32 vectors page.
patch3 fix the incorrect placement of __initdata and __read_mostly
patch4 apply __ro_after_init to some objects
Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly for performance reason. Then inspired by
Kees's patch[1], I think __ro_after_init is better.
[1] http://www.spinics.net/lists/arm-kernel/msg523188.html
Changes since v1:
- use __ro_after_init instead of __read_mostly
- find more objects to be suitable for __ro_after_init
- add one more patch to fix the incorrect placement of __initdata and
__read_mostly
Jisheng Zhang (4):
arm64: vdso: add __init section marker to alloc_vectors_page
arm64: vdso: constify vm_special_mapping used for aarch32 vectors page
arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly
arm64: apply __ro_after_init to some objects
arch/arm64/kernel/cpu_ops.c | 2 +-
arch/arm64/kernel/kaslr.c | 4 ++--
arch/arm64/kernel/vdso.c | 31 +++++++++++++++----------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/arm64/mm/init.c | 4 ++--
arch/arm64/mm/mmu.c | 2 +-
6 files changed, 22 insertions(+), 23 deletions(-)
--
2.8.1
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2 1/4] arm64: vdso: add __init section marker to alloc_vectors_page
2016-08-11 13:36 ` Jisheng Zhang
@ 2016-08-11 13:36 ` Jisheng Zhang
-1 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
It is not needed after booting, this patch moves the alloc_vectors_page
function to the __init section.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 076312b..e320e8f 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -55,7 +55,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
*/
static struct page *vectors_page[1];
-static int alloc_vectors_page(void)
+static int __init alloc_vectors_page(void)
{
extern char __kuser_helper_start[], __kuser_helper_end[];
extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 1/4] arm64: vdso: add __init section marker to alloc_vectors_page
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: linux-arm-kernel
It is not needed after booting, this patch moves the alloc_vectors_page
function to the __init section.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 076312b..e320e8f 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -55,7 +55,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
*/
static struct page *vectors_page[1];
-static int alloc_vectors_page(void)
+static int __init alloc_vectors_page(void)
{
extern char __kuser_helper_start[], __kuser_helper_end[];
extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 2/4] arm64: vdso: constify vm_special_mapping used for aarch32 vectors page
2016-08-11 13:36 ` Jisheng Zhang
@ 2016-08-11 13:36 ` Jisheng Zhang
-1 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
The vm_special_mapping spec which is used for aarch32 vectors page is
never modified, so mark it as const.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index e320e8f..10ad8ab 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -88,7 +88,7 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
unsigned long addr = AARCH32_VECTORS_BASE;
- static struct vm_special_mapping spec = {
+ static const struct vm_special_mapping spec = {
.name = "[vectors]",
.pages = vectors_page,
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 2/4] arm64: vdso: constify vm_special_mapping used for aarch32 vectors page
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: linux-arm-kernel
The vm_special_mapping spec which is used for aarch32 vectors page is
never modified, so mark it as const.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index e320e8f..10ad8ab 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -88,7 +88,7 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
unsigned long addr = AARCH32_VECTORS_BASE;
- static struct vm_special_mapping spec = {
+ static const struct vm_special_mapping spec = {
.name = "[vectors]",
.pages = vectors_page,
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly
2016-08-11 13:36 ` Jisheng Zhang
@ 2016-08-11 13:36 ` Jisheng Zhang
-1 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
__initdata and __read_mostly should be placed after the variable name
for the variable to be placed in the intended section.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/kaslr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index b054691..8ebabc4 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -20,8 +20,8 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
-u64 __read_mostly module_alloc_base;
-u16 __initdata memstart_offset_seed;
+u64 module_alloc_base __read_mostly;
+u16 memstart_offset_seed __initdata;
static __init u64 get_kaslr_seed(void *fdt)
{
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: linux-arm-kernel
__initdata and __read_mostly should be placed after the variable name
for the variable to be placed in the intended section.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/kaslr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index b054691..8ebabc4 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -20,8 +20,8 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
-u64 __read_mostly module_alloc_base;
-u16 __initdata memstart_offset_seed;
+u64 module_alloc_base __read_mostly;
+u16 memstart_offset_seed __initdata;
static __init u64 get_kaslr_seed(void *fdt)
{
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 4/4] arm64: apply __ro_after_init to some objects
2016-08-11 13:36 ` Jisheng Zhang
@ 2016-08-11 13:36 ` Jisheng Zhang
-1 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
These objects are set during initialization, thereafter are read only.
Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly from performance point of view. Then inspired
by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
better to mark them as __ro_after_init. What's more, I find some more
objects are also read only after init. So apply __ro_after_init to all
of them.
This patch also removes global vdso_pagelist and tries to clean up
vdso_spec[] assignment code.
[1] http://www.spinics.net/lists/arm-kernel/msg523188.html
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/cpu_ops.c | 2 +-
arch/arm64/kernel/kaslr.c | 2 +-
arch/arm64/kernel/vdso.c | 27 +++++++++++++--------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/arm64/mm/init.c | 4 ++--
arch/arm64/mm/mmu.c | 2 +-
6 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index c7cfb8f..6d32d1a 100644
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -28,7 +28,7 @@ extern const struct cpu_operations smp_spin_table_ops;
extern const struct cpu_operations acpi_parking_protocol_ops;
extern const struct cpu_operations cpu_psci_ops;
-const struct cpu_operations *cpu_ops[NR_CPUS];
+const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
static const struct cpu_operations *dt_supported_cpu_ops[] __initconst = {
&smp_spin_table_ops,
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index 8ebabc4..93c47e1 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -20,7 +20,7 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
-u64 module_alloc_base __read_mostly;
+u64 module_alloc_base __ro_after_init;
u16 memstart_offset_seed __initdata;
static __init u64 get_kaslr_seed(void *fdt)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 10ad8ab..0af41de 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -37,8 +37,7 @@
#include <asm/vdso_datapage.h>
extern char vdso_start, vdso_end;
-static unsigned long vdso_pages;
-static struct page **vdso_pagelist;
+static unsigned long vdso_pages __ro_after_init;
/*
* The vDSO data page.
@@ -53,7 +52,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
/*
* Create and map the vectors page for AArch32 tasks.
*/
-static struct page *vectors_page[1];
+static struct page *vectors_page[1] __ro_after_init;
static int __init alloc_vectors_page(void)
{
@@ -110,11 +109,19 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
}
#endif /* CONFIG_COMPAT */
-static struct vm_special_mapping vdso_spec[2];
+static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
+ {
+ .name = "[vvar]",
+ },
+ {
+ .name = "[vdso]",
+ },
+};
static int __init vdso_init(void)
{
int i;
+ struct page **vdso_pagelist;
if (memcmp(&vdso_start, "\177ELF", 4)) {
pr_err("vDSO is not a valid ELF object!\n");
@@ -138,16 +145,8 @@ static int __init vdso_init(void)
for (i = 0; i < vdso_pages; i++)
vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i);
- /* Populate the special mapping structures */
- vdso_spec[0] = (struct vm_special_mapping) {
- .name = "[vvar]",
- .pages = vdso_pagelist,
- };
-
- vdso_spec[1] = (struct vm_special_mapping) {
- .name = "[vdso]",
- .pages = &vdso_pagelist[1],
- };
+ vdso_spec[0].pages = vdso_pagelist;
+ vdso_spec[1].pages = &vdso_pagelist[1];
return 0;
}
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index c4284c4..59d44e7 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -30,7 +30,7 @@
#include <asm/cacheflush.h>
-static int swiotlb __read_mostly;
+static int swiotlb __ro_after_init;
static pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot,
bool coherent)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index bbb7ee7..e8b81ea 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -55,8 +55,8 @@
* executes, which assigns it its actual value. So use a default value
* that cannot be mistaken for a real physical address.
*/
-s64 memstart_addr __read_mostly = -1;
-phys_addr_t arm64_dma_phys_limit __read_mostly;
+s64 memstart_addr __ro_after_init = -1;
+phys_addr_t arm64_dma_phys_limit __ro_after_init;
#ifdef CONFIG_BLK_DEV_INITRD
static int __init early_initrd(char *p)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 4989948..6029bed 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -46,7 +46,7 @@
u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
-u64 kimage_voffset __read_mostly;
+u64 kimage_voffset __ro_after_init;
EXPORT_SYMBOL(kimage_voffset);
/*
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v2 4/4] arm64: apply __ro_after_init to some objects
@ 2016-08-11 13:36 ` Jisheng Zhang
0 siblings, 0 replies; 12+ messages in thread
From: Jisheng Zhang @ 2016-08-11 13:36 UTC (permalink / raw)
To: linux-arm-kernel
These objects are set during initialization, thereafter are read only.
Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly from performance point of view. Then inspired
by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
better to mark them as __ro_after_init. What's more, I find some more
objects are also read only after init. So apply __ro_after_init to all
of them.
This patch also removes global vdso_pagelist and tries to clean up
vdso_spec[] assignment code.
[1] http://www.spinics.net/lists/arm-kernel/msg523188.html
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/cpu_ops.c | 2 +-
arch/arm64/kernel/kaslr.c | 2 +-
arch/arm64/kernel/vdso.c | 27 +++++++++++++--------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/arm64/mm/init.c | 4 ++--
arch/arm64/mm/mmu.c | 2 +-
6 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index c7cfb8f..6d32d1a 100644
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -28,7 +28,7 @@ extern const struct cpu_operations smp_spin_table_ops;
extern const struct cpu_operations acpi_parking_protocol_ops;
extern const struct cpu_operations cpu_psci_ops;
-const struct cpu_operations *cpu_ops[NR_CPUS];
+const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
static const struct cpu_operations *dt_supported_cpu_ops[] __initconst = {
&smp_spin_table_ops,
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index 8ebabc4..93c47e1 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -20,7 +20,7 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
-u64 module_alloc_base __read_mostly;
+u64 module_alloc_base __ro_after_init;
u16 memstart_offset_seed __initdata;
static __init u64 get_kaslr_seed(void *fdt)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 10ad8ab..0af41de 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -37,8 +37,7 @@
#include <asm/vdso_datapage.h>
extern char vdso_start, vdso_end;
-static unsigned long vdso_pages;
-static struct page **vdso_pagelist;
+static unsigned long vdso_pages __ro_after_init;
/*
* The vDSO data page.
@@ -53,7 +52,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
/*
* Create and map the vectors page for AArch32 tasks.
*/
-static struct page *vectors_page[1];
+static struct page *vectors_page[1] __ro_after_init;
static int __init alloc_vectors_page(void)
{
@@ -110,11 +109,19 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
}
#endif /* CONFIG_COMPAT */
-static struct vm_special_mapping vdso_spec[2];
+static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
+ {
+ .name = "[vvar]",
+ },
+ {
+ .name = "[vdso]",
+ },
+};
static int __init vdso_init(void)
{
int i;
+ struct page **vdso_pagelist;
if (memcmp(&vdso_start, "\177ELF", 4)) {
pr_err("vDSO is not a valid ELF object!\n");
@@ -138,16 +145,8 @@ static int __init vdso_init(void)
for (i = 0; i < vdso_pages; i++)
vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i);
- /* Populate the special mapping structures */
- vdso_spec[0] = (struct vm_special_mapping) {
- .name = "[vvar]",
- .pages = vdso_pagelist,
- };
-
- vdso_spec[1] = (struct vm_special_mapping) {
- .name = "[vdso]",
- .pages = &vdso_pagelist[1],
- };
+ vdso_spec[0].pages = vdso_pagelist;
+ vdso_spec[1].pages = &vdso_pagelist[1];
return 0;
}
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index c4284c4..59d44e7 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -30,7 +30,7 @@
#include <asm/cacheflush.h>
-static int swiotlb __read_mostly;
+static int swiotlb __ro_after_init;
static pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot,
bool coherent)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index bbb7ee7..e8b81ea 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -55,8 +55,8 @@
* executes, which assigns it its actual value. So use a default value
* that cannot be mistaken for a real physical address.
*/
-s64 memstart_addr __read_mostly = -1;
-phys_addr_t arm64_dma_phys_limit __read_mostly;
+s64 memstart_addr __ro_after_init = -1;
+phys_addr_t arm64_dma_phys_limit __ro_after_init;
#ifdef CONFIG_BLK_DEV_INITRD
static int __init early_initrd(char *p)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 4989948..6029bed 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -46,7 +46,7 @@
u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
-u64 kimage_voffset __read_mostly;
+u64 kimage_voffset __ro_after_init;
EXPORT_SYMBOL(kimage_voffset);
/*
--
2.8.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v2 4/4] arm64: apply __ro_after_init to some objects
2016-08-11 13:36 ` Jisheng Zhang
@ 2016-08-11 15:05 ` Mark Rutland
-1 siblings, 0 replies; 12+ messages in thread
From: Mark Rutland @ 2016-08-11 15:05 UTC (permalink / raw)
To: Jisheng Zhang
Cc: catalin.marinas, will.deacon, lorenzo.pieralisi, keescook,
linux-kernel, linux-arm-kernel
Hi,
On Thu, Aug 11, 2016 at 09:36:49PM +0800, Jisheng Zhang wrote:
> These objects are set during initialization, thereafter are read only.
>
> Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
> cpu_ops as __read_mostly from performance point of view. Then inspired
> by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
> better to mark them as __ro_after_init. What's more, I find some more
> objects are also read only after init. So apply __ro_after_init to all
> of them.
>
> This patch also removes global vdso_pagelist and tries to clean up
> vdso_spec[] assignment code.
>
> [1] http://www.spinics.net/lists/arm-kernel/msg523188.html
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
> arch/arm64/kernel/cpu_ops.c | 2 +-
> arch/arm64/kernel/kaslr.c | 2 +-
> arch/arm64/kernel/vdso.c | 27 +++++++++++++--------------
> arch/arm64/mm/dma-mapping.c | 2 +-
> arch/arm64/mm/init.c | 4 ++--
> arch/arm64/mm/mmu.c | 2 +-
> 6 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
> index c7cfb8f..6d32d1a 100644
> --- a/arch/arm64/kernel/cpu_ops.c
> +++ b/arch/arm64/kernel/cpu_ops.c
> @@ -28,7 +28,7 @@ extern const struct cpu_operations smp_spin_table_ops;
> extern const struct cpu_operations acpi_parking_protocol_ops;
> extern const struct cpu_operations cpu_psci_ops;
>
> -const struct cpu_operations *cpu_ops[NR_CPUS];
> +const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
It looks like we need to include <linux/cache.h> for __ro_after_init.
While we seem to get that via some transitive include, that's not
guaranteed to remain the case, and it's not something we should rely
upon.
Please explicitly include <linux/cache.h> when __ro_after_init is added.
> - /* Populate the special mapping structures */
> - vdso_spec[0] = (struct vm_special_mapping) {
> - .name = "[vvar]",
> - .pages = vdso_pagelist,
> - };
> -
> - vdso_spec[1] = (struct vm_special_mapping) {
> - .name = "[vdso]",
> - .pages = &vdso_pagelist[1],
> - };
> + vdso_spec[0].pages = vdso_pagelist;
> + vdso_spec[1].pages = &vdso_pagelist[1];
While the original code was also this way, could we please make these a
little more consistent? e.g.
vdso_spec[0].pages = &vdso_pagelist[0];
vdso_spec[1].pages = &vdso_pagelist[1];
That way it raises few false alarms for anyone looking at the code.
Otherwise, this patch looks largely fine.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2 4/4] arm64: apply __ro_after_init to some objects
@ 2016-08-11 15:05 ` Mark Rutland
0 siblings, 0 replies; 12+ messages in thread
From: Mark Rutland @ 2016-08-11 15:05 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On Thu, Aug 11, 2016 at 09:36:49PM +0800, Jisheng Zhang wrote:
> These objects are set during initialization, thereafter are read only.
>
> Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
> cpu_ops as __read_mostly from performance point of view. Then inspired
> by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
> better to mark them as __ro_after_init. What's more, I find some more
> objects are also read only after init. So apply __ro_after_init to all
> of them.
>
> This patch also removes global vdso_pagelist and tries to clean up
> vdso_spec[] assignment code.
>
> [1] http://www.spinics.net/lists/arm-kernel/msg523188.html
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
> arch/arm64/kernel/cpu_ops.c | 2 +-
> arch/arm64/kernel/kaslr.c | 2 +-
> arch/arm64/kernel/vdso.c | 27 +++++++++++++--------------
> arch/arm64/mm/dma-mapping.c | 2 +-
> arch/arm64/mm/init.c | 4 ++--
> arch/arm64/mm/mmu.c | 2 +-
> 6 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
> index c7cfb8f..6d32d1a 100644
> --- a/arch/arm64/kernel/cpu_ops.c
> +++ b/arch/arm64/kernel/cpu_ops.c
> @@ -28,7 +28,7 @@ extern const struct cpu_operations smp_spin_table_ops;
> extern const struct cpu_operations acpi_parking_protocol_ops;
> extern const struct cpu_operations cpu_psci_ops;
>
> -const struct cpu_operations *cpu_ops[NR_CPUS];
> +const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
It looks like we need to include <linux/cache.h> for __ro_after_init.
While we seem to get that via some transitive include, that's not
guaranteed to remain the case, and it's not something we should rely
upon.
Please explicitly include <linux/cache.h> when __ro_after_init is added.
> - /* Populate the special mapping structures */
> - vdso_spec[0] = (struct vm_special_mapping) {
> - .name = "[vvar]",
> - .pages = vdso_pagelist,
> - };
> -
> - vdso_spec[1] = (struct vm_special_mapping) {
> - .name = "[vdso]",
> - .pages = &vdso_pagelist[1],
> - };
> + vdso_spec[0].pages = vdso_pagelist;
> + vdso_spec[1].pages = &vdso_pagelist[1];
While the original code was also this way, could we please make these a
little more consistent? e.g.
vdso_spec[0].pages = &vdso_pagelist[0];
vdso_spec[1].pages = &vdso_pagelist[1];
That way it raises few false alarms for anyone looking at the code.
Otherwise, this patch looks largely fine.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2016-08-11 15:06 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-11 13:36 [PATCH v2 0/4] arm64: put objects into proper sections Jisheng Zhang
2016-08-11 13:36 ` Jisheng Zhang
2016-08-11 13:36 ` [PATCH v2 1/4] arm64: vdso: add __init section marker to alloc_vectors_page Jisheng Zhang
2016-08-11 13:36 ` Jisheng Zhang
2016-08-11 13:36 ` [PATCH v2 2/4] arm64: vdso: constify vm_special_mapping used for aarch32 vectors page Jisheng Zhang
2016-08-11 13:36 ` Jisheng Zhang
2016-08-11 13:36 ` [PATCH v2 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly Jisheng Zhang
2016-08-11 13:36 ` Jisheng Zhang
2016-08-11 13:36 ` [PATCH v2 4/4] arm64: apply __ro_after_init to some objects Jisheng Zhang
2016-08-11 13:36 ` Jisheng Zhang
2016-08-11 15:05 ` Mark Rutland
2016-08-11 15:05 ` Mark Rutland
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