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Message-ID: <20061113163141.GE17429@in.ibm.com> Date: Mon, 13 Nov 2006 11:31:41 -0500 From: Vivek Goyal <vgoyal@...ibm.com> To: linux kernel mailing list <linux-kernel@...r.kernel.org> Cc: Reloc Kernel List <fastboot@...ts.osdl.org>, ebiederm@...ssion.com, akpm@...l.org, ak@...e.de, hpa@...or.com, magnus.damm@...il.com, lwang@...hat.com, dzickus@...hat.com Subject: [RFC] [PATCH 4/16] x86_64: Clean up the early boot page table - Merge physmem_pgt and ident_pgt, removing physmem_pgt. The merge is broken as soon as mm/init.c:init_memory_mapping is run. - As physmem_pgt is gone don't export it in pgtable.h. - Use defines from pgtable.h for page permissions. - Fix the physical memory identity mapping so it is at the correct address. - Remove the physical memory mapping from wakeup_level4_pgt it is at the wrong address so we can't possibly be usinging it. - Simply NEXT_PAGE the work to calculate the phys_ alias of the labels was very cool. Unfortuantely it was a brittle special purpose hack that makes maitenance more difficult. Instead just use label - __START_KERNEL_map like we do everywhere else in assembly. Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com> Signed-off-by: Vivek Goyal <vgoyal@...ibm.com> --- arch/x86_64/kernel/head.S | 61 +++++++++++++++++++------------------------ include/asm-x86_64/pgtable.h | 1 2 files changed, 28 insertions(+), 34 deletions(-) diff -puN arch/x86_64/kernel/head.S~x86_64-Cleanup-the-early-boot-page-table arch/x86_64/kernel/head.S --- linux-2.6.19-rc5-reloc/arch/x86_64/kernel/head.S~x86_64-Cleanup-the-early-boot-page-table 2006-11-09 22:55:39.000000000 -0500 +++ linux-2.6.19-rc5-reloc-root/arch/x86_64/kernel/head.S 2006-11-09 22:55:39.000000000 -0500 @@ -13,6 +13,7 @@ #include <linux/init.h> #include <asm/desc.h> #include <asm/segment.h> +#include <asm/pgtable.h> #include <asm/page.h> #include <asm/msr.h> #include <asm/cache.h> @@ -252,52 +253,48 @@ ljumpvector: ENTRY(stext) ENTRY(_stext) - $page = 0 #define NEXT_PAGE(name) \ - $page = $page + 1; \ - .org $page * 0x1000; \ - phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \ + .balign PAGE_SIZE; \ ENTRY(name) +/* Automate the creation of 1 to 1 mapping pmd entries */ +#define PMDS(START, PERM, COUNT) \ + i = 0 ; \ + .rept (COUNT) ; \ + .quad (START) + (i << 21) + (PERM) ; \ + i = i + 1 ; \ + .endr + NEXT_PAGE(init_level4_pgt) /* This gets initialized in x86_64_start_kernel */ .fill 512,8,0 NEXT_PAGE(level3_ident_pgt) - .quad phys_level2_ident_pgt | 0x007 + .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .fill 511,8,0 NEXT_PAGE(level3_kernel_pgt) .fill 510,8,0 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ - .quad phys_level2_kernel_pgt | 0x007 + .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE .fill 1,8,0 NEXT_PAGE(level2_ident_pgt) - /* 40MB for bootup. */ - i = 0 - .rept 20 - .quad i << 21 | 0x083 - i = i + 1 - .endr - .fill 492,8,0 + /* Since I easily can, map the first 1G. + * Don't set NX because code runs from these pages. + */ + PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD) NEXT_PAGE(level2_kernel_pgt) /* 40MB kernel mapping. The kernel code cannot be bigger than that. When you change this change KERNEL_TEXT_SIZE in page.h too. */ /* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */ - i = 0 - .rept 20 - .quad i << 21 | 0x183 - i = i + 1 - .endr + PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL, + KERNEL_TEXT_SIZE/PMD_SIZE) /* Module mapping starts here */ - .fill 492,8,0 - -NEXT_PAGE(level3_physmem_pgt) - .quad phys_level2_kernel_pgt | 0x007 /* so that __va works even before pagetable_init */ - .fill 511,8,0 + .fill (PTRS_PER_PMD - (KERNEL_TEXT_SIZE/PMD_SIZE)),8,0 +#undef PMDS #undef NEXT_PAGE .data @@ -305,12 +302,10 @@ NEXT_PAGE(level3_physmem_pgt) #ifdef CONFIG_ACPI_SLEEP .align PAGE_SIZE ENTRY(wakeup_level4_pgt) - .quad phys_level3_ident_pgt | 0x007 - .fill 255,8,0 - .quad phys_level3_physmem_pgt | 0x007 - .fill 254,8,0 + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE + .fill 510,8,0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad phys_level3_kernel_pgt | 0x007 + .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE #endif #ifndef CONFIG_HOTPLUG_CPU @@ -324,12 +319,12 @@ ENTRY(wakeup_level4_pgt) */ .align PAGE_SIZE ENTRY(boot_level4_pgt) - .quad phys_level3_ident_pgt | 0x007 - .fill 255,8,0 - .quad phys_level3_physmem_pgt | 0x007 - .fill 254,8,0 + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE + .fill 257,8,0 + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE + .fill 252,8,0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad phys_level3_kernel_pgt | 0x007 + .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE .data diff -puN include/asm-x86_64/pgtable.h~x86_64-Cleanup-the-early-boot-page-table include/asm-x86_64/pgtable.h --- linux-2.6.19-rc5-reloc/include/asm-x86_64/pgtable.h~x86_64-Cleanup-the-early-boot-page-table 2006-11-09 22:55:39.000000000 -0500 +++ linux-2.6.19-rc5-reloc-root/include/asm-x86_64/pgtable.h 2006-11-09 22:55:39.000000000 -0500 @@ -15,7 +15,6 @@ #include <asm/pda.h> extern pud_t level3_kernel_pgt[512]; -extern pud_t level3_physmem_pgt[512]; extern pud_t level3_ident_pgt[512]; extern pmd_t level2_kernel_pgt[512]; extern pgd_t init_level4_pgt[]; _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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