* [PATCH v2 0/4] arm64: put objects into proper sections
@ 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
` (3 more replies)
0 siblings, 4 replies; 6+ 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] 6+ messages in thread* [PATCH v2 1/4] arm64: vdso: add __init section marker to alloc_vectors_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 2/4] arm64: vdso: constify vm_special_mapping used for aarch32 vectors page Jisheng Zhang ` (2 subsequent siblings) 3 siblings, 0 replies; 6+ 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] 6+ messages in thread
* [PATCH v2 2/4] arm64: vdso: constify vm_special_mapping used for aarch32 vectors page 2016-08-11 13:36 [PATCH v2 0/4] arm64: put objects into proper sections 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 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly Jisheng Zhang 2016-08-11 13:36 ` [PATCH v2 4/4] arm64: apply __ro_after_init to some objects Jisheng Zhang 3 siblings, 0 replies; 6+ 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] 6+ messages in thread
* [PATCH v2 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly 2016-08-11 13:36 [PATCH v2 0/4] arm64: put objects into proper sections 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 ` [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 4/4] arm64: apply __ro_after_init to some objects Jisheng Zhang 3 siblings, 0 replies; 6+ 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] 6+ messages in thread
* [PATCH v2 4/4] arm64: apply __ro_after_init to some objects 2016-08-11 13:36 [PATCH v2 0/4] arm64: put objects into proper sections Jisheng Zhang ` (2 preceding siblings ...) 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 15:05 ` Mark Rutland 3 siblings, 1 reply; 6+ 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] 6+ messages in thread
* [PATCH v2 4/4] arm64: apply __ro_after_init to some objects 2016-08-11 13:36 ` [PATCH v2 4/4] arm64: apply __ro_after_init to some objects Jisheng Zhang @ 2016-08-11 15:05 ` Mark Rutland 0 siblings, 0 replies; 6+ 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] 6+ messages in thread
end of thread, other threads:[~2016-08-11 15:05 UTC | newest] Thread overview: 6+ 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 ` [PATCH v2 1/4] arm64: vdso: add __init section marker to alloc_vectors_page 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 ` [PATCH v2 3/4] arm64: kaslr: Fix incorrect placement of __initdata and __read_mostly Jisheng Zhang 2016-08-11 13:36 ` [PATCH v2 4/4] arm64: apply __ro_after_init to some objects Jisheng Zhang 2016-08-11 15:05 ` Mark Rutland
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