4.9-stable review patch. If anyone has any objections, please let me know.
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This reverts commit 3a8304b7ad2e291777e8499e39390145d932a2fd, which was upstream commit 05ab1d8a4b36ee912b7087c6da127439ed0a903e.
Ben Hutchings writes:
This backport is incorrect. The part that updated __startup_64() in arch/x86/kernel/head64.c was dropped, presumably because that function doesn't exist in 4.9. However that seems to be an essential of the fix. In 4.9 the startup_64 routine in arch/x86/kernel/head_64.S would need to be changed instead.
I also found that this introduces new boot-time warnings on some systems if CONFIG_DEBUG_WX is enabled.
So, unless someone provides fixes for those issues, I think this should be reverted for the 4.9 branch.
Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/asm/fixmap.h | 10 ---------- arch/x86/include/asm/pgtable_64.h | 3 +-- arch/x86/kernel/head_64.S | 16 ++++------------ arch/x86/mm/pgtable.c | 9 --------- arch/x86/xen/mmu.c | 8 ++------ 5 files changed, 7 insertions(+), 39 deletions(-)
--- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -14,16 +14,6 @@ #ifndef _ASM_X86_FIXMAP_H #define _ASM_X86_FIXMAP_H
-/* - * Exposed to assembly code for setting up initial page tables. Cannot be - * calculated in assembly code (fixmap entries are an enum), but is sanity - * checked in the actual fixmap C code to make sure that the fixmap is - * covered fully. - */ -#define FIXMAP_PMD_NUM 2 -/* fixmap starts downwards from the 507th entry in level2_fixmap_pgt */ -#define FIXMAP_PMD_TOP 507 - #ifndef __ASSEMBLY__ #include <linux/kernel.h> #include <asm/acpi.h> --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -13,14 +13,13 @@ #include <asm/processor.h> #include <linux/bitops.h> #include <linux/threads.h> -#include <asm/fixmap.h>
extern pud_t level3_kernel_pgt[512]; extern pud_t level3_ident_pgt[512]; extern pmd_t level2_kernel_pgt[512]; extern pmd_t level2_fixmap_pgt[512]; extern pmd_t level2_ident_pgt[512]; -extern pte_t level1_fixmap_pgt[512 * FIXMAP_PMD_NUM]; +extern pte_t level1_fixmap_pgt[512]; extern pgd_t init_level4_pgt[];
#define swapper_pg_dir init_level4_pgt --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -23,7 +23,6 @@ #include "../entry/calling.h" #include <asm/export.h> #include <asm/nospec-branch.h> -#include <asm/fixmap.h>
#ifdef CONFIG_PARAVIRT #include <asm/asm-offsets.h> @@ -494,20 +493,13 @@ NEXT_PAGE(level2_kernel_pgt) KERNEL_IMAGE_SIZE/PMD_SIZE)
NEXT_PAGE(level2_fixmap_pgt) - .fill (512 - 4 - FIXMAP_PMD_NUM),8,0 - pgtno = 0 - .rept (FIXMAP_PMD_NUM) - .quad level1_fixmap_pgt + (pgtno << PAGE_SHIFT) - __START_KERNEL_map \ - + _PAGE_TABLE; - pgtno = pgtno + 1 - .endr - /* 6 MB reserved space + a 2MB hole */ - .fill 4,8,0 + .fill 506,8,0 + .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE + /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ + .fill 5,8,0
NEXT_PAGE(level1_fixmap_pgt) - .rept (FIXMAP_PMD_NUM) .fill 512,8,0 - .endr
#undef PMDS
--- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -536,15 +536,6 @@ void __native_set_fixmap(enum fixed_addr { unsigned long address = __fix_to_virt(idx);
-#ifdef CONFIG_X86_64 - /* - * Ensure that the static initial page tables are covering the - * fixmap completely. - */ - BUILD_BUG_ON(__end_of_permanent_fixed_addresses > - (FIXMAP_PMD_NUM * PTRS_PER_PTE)); -#endif - if (idx >= __end_of_fixed_addresses) { BUG(); return; --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1936,7 +1936,7 @@ void __init xen_setup_kernel_pagetable(p * L3_k[511] -> level2_fixmap_pgt */ convert_pfn_mfn(level3_kernel_pgt);
- /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */ + /* L3_k[511][506] -> level1_fixmap_pgt */ convert_pfn_mfn(level2_fixmap_pgt); } /* We get [511][511] and have Xen's version of level2_kernel_pgt */ @@ -1970,11 +1970,7 @@ void __init xen_setup_kernel_pagetable(p set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); - - for (i = 0; i < FIXMAP_PMD_NUM; i++) { - set_page_prot(level1_fixmap_pgt + i * PTRS_PER_PTE, - PAGE_KERNEL_RO); - } + set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
/* Pin down new L4 */ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,