search for: fixmap

Looks to me like the first series of patches should be OK to post now. I propose that: 001-apply-to-page-range.patch 001a-reboot-use-struct.patch 002-sync-bitops.patch 003-remove-ring0-assumptions.patch 004-abstract-asm.patch 005-cpuid-cleanup.patch unfix-fixmap.patch fixmap-bootparam.patch remove-read-hazard-from-cow.patch pte-clear-not-present.patch pgd-free-mm.patch notes-segment.patch are all good candidates for posting. I just went through all these and cleaned them up a bit, mostly by adding Subject: lines and diffstats, but I...

This most curious patch allows the fixmap on i386 to be unfixed. The = result is that we can create a dynamically sizable hole at the top of = kernel linear address space. I know at least some virtualization = developers are interested in being able to achieve this to achieve = run-time sizing of a hole in which a hypervisor can live...

This most curious patch allows the fixmap on i386 to be unfixed. The = result is that we can create a dynamically sizable hole at the top of = kernel linear address space. I know at least some virtualization = developers are interested in being able to achieve this to achieve = run-time sizing of a hole in which a hypervisor can live...

...except on Intel family 5 processors. Signed-off-by: Kees Cook <keescook at chromium.org> Cc: Eric Northup <digitaleric at google.com> --- v3: - clarify commit, thanks to HPA - add missing header file, thanks to buildbot. :) v2: - clarify commit and comments --- arch/x86/include/asm/fixmap.h | 4 +--- arch/x86/kernel/cpu/intel.c | 18 +----------------- arch/x86/kernel/traps.c | 9 +++++++++ arch/x86/xen/mmu.c | 4 +--- 4 files changed, 12 insertions(+), 23 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index a09...

...except on Intel family 5 processors. Signed-off-by: Kees Cook <keescook at chromium.org> Cc: Eric Northup <digitaleric at google.com> --- v3: - clarify commit, thanks to HPA - add missing header file, thanks to buildbot. :) v2: - clarify commit and comments --- arch/x86/include/asm/fixmap.h | 4 +--- arch/x86/kernel/cpu/intel.c | 18 +----------------- arch/x86/kernel/traps.c | 9 +++++++++ arch/x86/xen/mmu.c | 4 +--- 4 files changed, 12 insertions(+), 23 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index a09...

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> When NR_CPUS increases the fixmap might need more than the page allocated by head_32.S. This patch introduces the logic to calculate the additional memory that is going to be required by early_ioremap_page_table_range_init: - enough memory to allocate the pte pages needed to cover the fixmap virtual memory range, minus the single...

..., Jun 07, 2023 at 08:49:15PM +0800, Dave Hansen wrote: >> What problems does this patch set solve? How might that solution be >> visible to end users? Why is this problem important to you? > > We want to build the kernel as PIE and allow the kernel image area, > including the fixmap area, to be placed at any virtual address. You are still failing to tell us why you want that and which problem this solves. Just that fact that you want to something is not an argument. > We have also implemented a PV Linux guest based on PIE, which can be > used in software virtualization...

...s gets quite complex, since we need to force the guest to map a given area, after the fact, hoping that it didn't map it someplace else before we get to the code to map it. This can be done, but doing it this way is (for now) much easier. What I've done here, is to make a large area in the FIXMAP region. The guest will not use this area for anything, since it is reserved for only running a HV. So by making a FIXMAP area, we force this area reserved for HV use. Now the host can load the hypervisor text section into this area and force it mapped to the guest without worrying that the guest w...

...s gets quite complex, since we need to force the guest to map a given area, after the fact, hoping that it didn't map it someplace else before we get to the code to map it. This can be done, but doing it this way is (for now) much easier. What I've done here, is to make a large area in the FIXMAP region. The guest will not use this area for anything, since it is reserved for only running a HV. So by making a FIXMAP area, we force this area reserved for HV use. Now the host can load the hypervisor text section into this area and force it mapped to the guest without worrying that the guest w...

...hole at top of memory (0-512 MB)" + range 0 512 + default "0" + help + Useful for creating a hole in the top of memory when running + inside of a virtual machine monitor. + source "mm/Kconfig" config HAVE_ARCH_EARLY_PFN_TO_NID Index: linux-2.6.13/include/asm-i386/fixmap.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/fixmap.h 2005-08-24 09:30:43.000000000 -0700 +++ linux-2.6.13/include/asm-i386/fixmap.h 2005-08-24 10:04:42.000000000 -0700 @@ -20,7 +20,7 @@ * Leave one empty page between vmalloc'ed...

...hole at top of memory (0-512 MB)" + range 0 512 + default "0" + help + Useful for creating a hole in the top of memory when running + inside of a virtual machine monitor. + source "mm/Kconfig" config HAVE_ARCH_EARLY_PFN_TO_NID Index: linux-2.6.13/include/asm-i386/fixmap.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/fixmap.h 2005-08-24 09:30:43.000000000 -0700 +++ linux-2.6.13/include/asm-i386/fixmap.h 2005-08-24 10:04:42.000000000 -0700 @@ -20,7 +20,7 @@ * Leave one empty page between vmalloc'ed...

...from exec-shield? I'm not against it, but it needs tons of testing in -mm first. Since the vsyscall page has been at a fixed address, there might be real programs that hardcoded it etc. I'd also want sign-off from Gerd and Ingo, obviously. Linus ==== Name: Move vsyscall page out of fixmap into normal vma as per mmap Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Rather than move the stack down, use get_unmapped_area for the vsyscall page, as the exec-shield patch does. This means we need a pointer in the thread_info, too. This steals half of the code from Gerd Hoffman...

...from exec-shield? I'm not against it, but it needs tons of testing in -mm first. Since the vsyscall page has been at a fixed address, there might be real programs that hardcoded it etc. I'd also want sign-off from Gerd and Ingo, obviously. Linus ==== Name: Move vsyscall page out of fixmap into normal vma as per mmap Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Rather than move the stack down, use get_unmapped_area for the vsyscall page, as the exec-shield patch does. This means we need a pointer in the thread_info, too. This steals half of the code from Gerd Hoffman...

...ong end) @@ -648,9 +670,9 @@ void __init extend_init_mapping(unsigned } } -static void __init find_early_table_space(unsigned long end) +static unsigned long __init find_early_table_space(unsigned long end) { - unsigned long puds, pmds, ptes, tables; + unsigned long puds, pmds, ptes, tables, fixmap_tables; puds = (end + PUD_SIZE - 1) >> PUD_SHIFT; pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT; @@ -660,7 +682,16 @@ static void __init find_early_table_spac round_up(pmds * 8, PAGE_SIZE) + round_up(ptes * 8, PAGE_SIZE); - extend_init_mapping(tables); + /* Also reserve pages...

...h --- arch/alpha/include/asm/kmap_types.h | 15 --------------- arch/ia64/include/asm/kmap_types.h | 13 ------------- arch/openrisc/mm/init.c | 1 - arch/openrisc/mm/ioremap.c | 1 - arch/parisc/include/asm/kmap_types.h | 13 ------------- arch/um/include/asm/fixmap.h | 1 - arch/um/include/asm/kmap_types.h | 13 ------------- include/asm-generic/Kbuild | 1 - include/asm-generic/kmap_types.h | 11 ----------- include/linux/highmem.h | 2 -- 10 files changed, 71 deletions(-) --- a/arch/alpha/include/asm/kmap...

...-off-by: Thomas Gleixner <tglx at linutronix.de> Cc: Nick Hu <nickhu at andestech.com> Cc: Greentime Hu <green.hu at gmail.com> Cc: Vincent Chen <deanbo422 at gmail.com> --- V3: Remove the kmap types cruft --- arch/nds32/Kconfig.cpu | 1 arch/nds32/include/asm/fixmap.h | 4 +-- arch/nds32/include/asm/highmem.h | 22 +++++++++++++---- arch/nds32/mm/Makefile | 1 arch/nds32/mm/highmem.c | 48 --------------------------------------- 5 files changed, 19 insertions(+), 57 deletions(-) --- a/arch/nds32/Kconfig.cpu +++ b/arch/nds32/Kcon...

...y (0-256 MB)" + range 0 256 + default "64" if X86_VMI + default "0" if !X86_VMI + help + Useful for creating a hole in the top of memory when running + inside of a virtual machine monitor. + config ACPI_SRAT bool default y Index: linux-2.6.16-rc3/include/asm-i386/fixmap.h =================================================================== --- linux-2.6.16-rc3.orig/include/asm-i386/fixmap.h 2006-02-22 15:48:23.000000000 -0800 +++ linux-2.6.16-rc3/include/asm-i386/fixmap.h 2006-02-22 16:33:27.000000000 -0800 @@ -20,7 +20,7 @@ * Leave one empty page between vmalloc...

...y (0-256 MB)" + range 0 256 + default "64" if X86_VMI + default "0" if !X86_VMI + help + Useful for creating a hole in the top of memory when running + inside of a virtual machine monitor. + config ACPI_SRAT bool default y Index: linux-2.6.16-rc3/include/asm-i386/fixmap.h =================================================================== --- linux-2.6.16-rc3.orig/include/asm-i386/fixmap.h 2006-02-22 15:48:23.000000000 -0800 +++ linux-2.6.16-rc3/include/asm-i386/fixmap.h 2006-02-22 16:33:27.000000000 -0800 @@ -20,7 +20,7 @@ * Leave one empty page between vmalloc...

Paravirt-ops guests which move the fixmap also end up moving the syscall = VDSO. This fails if it is prelinked at a fixed address, which is why = COMPAT_VDSO is broken under CONFIG_VMI (and also under CONFIG_XEN). = Several options are available to try to address this. Jan had cooked up = a patch for Xen that used build magic to fin...

Paravirt-ops guests which move the fixmap also end up moving the syscall = VDSO. This fails if it is prelinked at a fixed address, which is why = COMPAT_VDSO is broken under CONFIG_VMI (and also under CONFIG_XEN). = Several options are available to try to address this. Jan had cooked up = a patch for Xen that used build magic to fin...