| Message ID | 1455726594-16104-2-git-send-email-jeremy.linton@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 17 February 2016 at 17:29, Jeremy Linton <jeremy.linton@arm.com> wrote: > This change allows ALIGN_RODATA for 16k and 64k kernels. > In the case of 64k kernels it actually aligns to the CONT_SIZE ... and 16k kernels ... > rather than the SECTION_SIZE (which is 512M). This makes it generally > more useful, especially for CONT enabled kernels. > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> It probably makes sense to mention here that the alignment is 2 MB for all page sizes. Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm64/Kconfig.debug | 12 ++++++------ > arch/arm64/kernel/vmlinux.lds.S | 11 ++++++----- > 2 files changed, 12 insertions(+), 11 deletions(-) > > diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug > index e13c4bf..65705ee 100644 > --- a/arch/arm64/Kconfig.debug > +++ b/arch/arm64/Kconfig.debug > @@ -59,15 +59,15 @@ config DEBUG_RODATA > If in doubt, say Y > > config DEBUG_ALIGN_RODATA > - depends on DEBUG_RODATA && ARM64_4K_PAGES > + depends on DEBUG_RODATA > bool "Align linker sections up to SECTION_SIZE" > help > If this option is enabled, sections that may potentially be marked as > - read only or non-executable will be aligned up to the section size of > - the kernel. This prevents sections from being split into pages and > - avoids a potential TLB penalty. The downside is an increase in > - alignment and potentially wasted space. Turn on this option if > - performance is more important than memory pressure. > + read only or non-executable will be aligned up to the section size > + or contiguous hint size of the kernel. This prevents sections from > + being split into pages and avoids a potential TLB penalty. The downside > + is an increase in alignment and potentially wasted space. Turn on > + this option if performance is more important than memory pressure. > > If in doubt, say N > > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index b78a3c7..8f4fc2c 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -63,13 +63,14 @@ PECOFF_FILE_ALIGNMENT = 0x200; > #endif > > #if defined(CONFIG_DEBUG_ALIGN_RODATA) > -#define ALIGN_DEBUG_RO . = ALIGN(1<<SECTION_SHIFT); > -#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO > +#if defined(CONFIG_ARM64_4K_PAGES) > +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(SECTION_SIZE); > +#else > +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(CONT_SIZE); > +#endif > #elif defined(CONFIG_DEBUG_RODATA) > -#define ALIGN_DEBUG_RO . = ALIGN(1<<PAGE_SHIFT); > -#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO > +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(PAGE_SIZE); > #else > -#define ALIGN_DEBUG_RO > #define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(min); > #endif > > -- > 2.4.3 >
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index e13c4bf..65705ee 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -59,15 +59,15 @@ config DEBUG_RODATA If in doubt, say Y config DEBUG_ALIGN_RODATA - depends on DEBUG_RODATA && ARM64_4K_PAGES + depends on DEBUG_RODATA bool "Align linker sections up to SECTION_SIZE" help If this option is enabled, sections that may potentially be marked as - read only or non-executable will be aligned up to the section size of - the kernel. This prevents sections from being split into pages and - avoids a potential TLB penalty. The downside is an increase in - alignment and potentially wasted space. Turn on this option if - performance is more important than memory pressure. + read only or non-executable will be aligned up to the section size + or contiguous hint size of the kernel. This prevents sections from + being split into pages and avoids a potential TLB penalty. The downside + is an increase in alignment and potentially wasted space. Turn on + this option if performance is more important than memory pressure. If in doubt, say N diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index b78a3c7..8f4fc2c 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -63,13 +63,14 @@ PECOFF_FILE_ALIGNMENT = 0x200; #endif #if defined(CONFIG_DEBUG_ALIGN_RODATA) -#define ALIGN_DEBUG_RO . = ALIGN(1<<SECTION_SHIFT); -#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO +#if defined(CONFIG_ARM64_4K_PAGES) +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(SECTION_SIZE); +#else +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(CONT_SIZE); +#endif #elif defined(CONFIG_DEBUG_RODATA) -#define ALIGN_DEBUG_RO . = ALIGN(1<<PAGE_SHIFT); -#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(PAGE_SIZE); #else -#define ALIGN_DEBUG_RO #define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(min); #endif
This change allows ALIGN_RODATA for 16k and 64k kernels. In the case of 64k kernels it actually aligns to the CONT_SIZE rather than the SECTION_SIZE (which is 512M). This makes it generally more useful, especially for CONT enabled kernels. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- arch/arm64/Kconfig.debug | 12 ++++++------ arch/arm64/kernel/vmlinux.lds.S | 11 ++++++----- 2 files changed, 12 insertions(+), 11 deletions(-)