diff options
| author | David Daney <david.daney@cavium.com> | 2012-08-14 20:08:01 +0200 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2012-10-11 11:02:40 +0200 |
| commit | 485172b3dff29f888a88d3dba8caec5d589a4049 (patch) | |
| tree | f496bccfd49a973be2f4789baa45574dbcb96af0 /arch/mips/kernel/vmlinux.lds.S | |
| parent | vmlinux.lds.h: Allow architectures to add sections to the front of .bss (diff) | |
| download | linux-485172b3dff29f888a88d3dba8caec5d589a4049.tar.xz linux-485172b3dff29f888a88d3dba8caec5d589a4049.zip | |
MIPS: Align swapper_pg_dir to 64K for better TLB Refill code.
We can save an instruction in the TLB Refill path for kernel mappings
by aligning swapper_pg_dir on a 64K boundary. The address of
swapper_pg_dir can be generated with a single LUI instead of
LUI/{D}ADDUI.
The alignment of __init_end is bumped up to 64K so there are no holes
between it and swapper_pg_dir, which is placed at the very beginning
of .bss.
The alignment of invalid_pmd_table and invalid_pte_table can be
relaxed to PAGE_SIZE. We do this by using __page_aligned_bss, which
has the added benefit of eliminating alignment holes in .bss.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org,
Cc: linux-kernel@vger.kernel.org
Acked-by: Arnd Bergmann <arnd@arndb.de>
Patchwork: https://patchwork.linux-mips.org/patch/4220/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/mips/kernel/vmlinux.lds.S | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index df243a64f430..007ccbe1e264 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -1,6 +1,13 @@ #include <asm/asm-offsets.h> #include <asm/page.h> #include <asm/thread_info.h> + +/* + * Put .bss..swapper_pg_dir as the first thing in .bss. This will + * ensure that it has .bss alignment (64K). + */ +#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir) + #include <asm-generic/vmlinux.lds.h> #undef mips @@ -119,11 +126,21 @@ SECTIONS } PERCPU_SECTION(1 << CONFIG_MIPS_L1_CACHE_SHIFT) - . = ALIGN(PAGE_SIZE); + /* + * Align to 64K in attempt to eliminate holes before the + * .bss..swapper_pg_dir section at the start of .bss. This + * also satisfies PAGE_SIZE alignment as the largest page size + * allowed is 64K. + */ + . = ALIGN(0x10000); __init_end = .; /* freed after init ends here */ - BSS_SECTION(0, 0, 0) + /* + * Force .bss to 64K alignment so that .bss..swapper_pg_dir + * gets that alignment. .sbss should be empty, so there will be + * no holes after __init_end. */ + BSS_SECTION(0, 0x10000, 0) _end = . ; |