I found that symbols defined by .comm in head.S are placed in random
order (with binutils 2.17). For example, here is a tail of
System.map:
801ce000 B fw_arg3
801ce004 B fw_arg1
801cf000 B swapper_pg_dir
801d0000 B invalid_pte_table
801d1000 B fw_arg2
801d1008 B kernelsp
801d1010 B fw_arg0
801d1018 B pgd_current
801d1020 A __bss_stop
801d1020 A _end
It looks less efficient while fw_arg[0-3] are all 4 byte.
Is there any point on declaring those symbols in asm file? If
nothing, how about moving them to C file? And I can not see why
kernel_sp and pgd_current have 8-byte size even on 32-bit kernel.
Here is a proposal patch. Comments?
Signed-off-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
---
arch/mips/kernel/asm-offsets.c | 4 ----
arch/mips/kernel/head.S | 25 -------------------------
arch/mips/kernel/setup.c | 17 +++++++++++++++++
3 files changed, 17 insertions(+), 29 deletions(-)
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index ff88b06..ea7df4b 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -234,10 +234,6 @@ void output_mm_defines(void)
constant("#define _PMD_SHIFT ", PMD_SHIFT);
constant("#define _PGDIR_SHIFT ", PGDIR_SHIFT);
linefeed;
- constant("#define _PGD_ORDER ", PGD_ORDER);
- constant("#define _PMD_ORDER ", PMD_ORDER);
- constant("#define _PTE_ORDER ", PTE_ORDER);
- linefeed;
constant("#define _PTRS_PER_PGD ", PTRS_PER_PGD);
constant("#define _PTRS_PER_PMD ", PTRS_PER_PMD);
constant("#define _PTRS_PER_PTE ", PTRS_PER_PTE);
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index 9a7811d..6f57ca4 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -231,28 +231,3 @@ NESTED(smp_bootstrap, 16, sp)
#endif /* CONFIG_SMP */
__FINIT
-
- .comm kernelsp, NR_CPUS * 8, 8
- .comm pgd_current, NR_CPUS * 8, 8
-
- .comm fw_arg0, SZREG, SZREG # firmware arguments
- .comm fw_arg1, SZREG, SZREG
- .comm fw_arg2, SZREG, SZREG
- .comm fw_arg3, SZREG, SZREG
-
- .macro page name, order
- .comm \name, (_PAGE_SIZE << \order), (_PAGE_SIZE << \order)
- .endm
-
- /*
- * On 64-bit we've got three-level pagetables with a slightly
- * different layout ...
- */
- page swapper_pg_dir, _PGD_ORDER
-#ifdef CONFIG_64BIT
-#if defined(CONFIG_MODULES) && !defined(CONFIG_BUILD_ELF64)
- page module_pg_dir, _PGD_ORDER
-#endif
- page invalid_pmd_table, _PMD_ORDER
-#endif
- page invalid_pte_table, _PTE_ORDER
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 89440a0..dc307e4 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -541,3 +541,20 @@ int __init dsp_disable(char *s)
}
__setup("nodsp", dsp_disable);
+
+unsigned long kernelsp[NR_CPUS];
+unsigned long pgd_current[NR_CPUS];
+unsigned long fw_arg0, fw_arg1, fw_arg2, fw_arg3;
+/*
+ * On 64-bit we've got three-level pagetables with a slightly
+ * different layout ...
+ */
+#define __page_aligned(order) __attribute__((__aligned__(PAGE_SIZE<<order)))
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned(PGD_ORDER);
+#ifdef CONFIG_64BIT
+#if defined(CONFIG_MODULES) && !defined(CONFIG_BUILD_ELF64)
+pgd_t module_pg_dir[PTRS_PER_PGD] __page_aligned(PGD_ORDER);
+#endif
+pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned(PMD_ORDER);
+#endif
+pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned(PTE_ORDER);
