[PATCH 1/5] UML - Runtime host VMSPLIT detection
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is needed on i386 if UML is to run on hosts with varying VMSPLITs without recompilation. TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of an include of pgtable.h from processor.h, which can cause include loops. On i386, task_size is calculated early in boot by probing the address space in a binary search to figure out where the boundary between usable and non-usable memory is. This tries to make sure that a page that is considered to be in userspace is, or can be made, read-write. I'm concerned about a system-global VDSO page in kernel memory being hit and considered to be a userspace page. On x86_64, task_size is just the old value of CONFIG_TOP_ADDR. A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in arch/um/Makefile are also gone. I noticed and fixed a missing extern in os.h when adding os_get_task_size. Note: This has been revised to fix the 32-bit UML on 64-bit host bug that Miklos ran into. Signed-off-by: Jeff Dike <[EMAIL PROTECTED]> --- arch/um/Kconfig | 11 -- arch/um/Kconfig.i386| 37 - arch/um/Kconfig.x86_64 |4 - arch/um/Makefile| 11 -- arch/um/defconfig |3 arch/um/include/as-layout.h |2 arch/um/include/os.h|5 + arch/um/kernel/exec.c |2 arch/um/kernel/um_arch.c| 16 +++- arch/um/os-Linux/sys-i386/Makefile |2 arch/um/os-Linux/sys-i386/task_size.c | 120 arch/um/os-Linux/sys-x86_64/Makefile|2 arch/um/os-Linux/sys-x86_64/task_size.c |5 + include/asm-um/fixmap.h |3 include/asm-um/processor-generic.h |5 - 15 files changed, 153 insertions(+), 75 deletions(-) Index: linux-2.6-git/arch/um/kernel/um_arch.c === --- linux-2.6-git.orig/arch/um/kernel/um_arch.c 2008-02-06 11:19:07.0 -0500 +++ linux-2.6-git/arch/um/kernel/um_arch.c 2008-02-06 11:31:53.0 -0500 @@ -241,6 +241,11 @@ static struct notifier_block panic_exit_ }; /* Set during early boot */ +unsigned long task_size; +EXPORT_SYMBOL(task_size); + +unsigned long host_task_size; + unsigned long brk_start; unsigned long end_iomem; EXPORT_SYMBOL(end_iomem); @@ -267,6 +272,13 @@ int __init linux_main(int argc, char **a if (have_root == 0) add_arg(DEFAULT_COMMAND_LINE); + host_task_size = os_get_task_size(); + /* +* TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps +* out +*/ + task_size = host_task_size & PGDIR_MASK; + /* OS sanity checks that need to happen before the kernel runs */ os_early_checks(); @@ -303,7 +315,7 @@ int __init linux_main(int argc, char **a highmem = 0; iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; - max_physmem = CONFIG_TOP_ADDR - uml_physmem - iomem_size - MIN_VMALLOC; + max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; /* * Zones have to begin on a 1 << MAX_ORDER page boundary, @@ -335,7 +347,7 @@ int __init linux_main(int argc, char **a } virtmem_size = physmem_size; - avail = CONFIG_TOP_ADDR - start_vm; + avail = TASK_SIZE - start_vm; if (physmem_size > avail) virtmem_size = avail; end_vm = start_vm + virtmem_size; Index: linux-2.6-git/include/asm-um/processor-generic.h === --- linux-2.6-git.orig/include/asm-um/processor-generic.h 2008-02-06 11:19:09.0 -0500 +++ linux-2.6-git/include/asm-um/processor-generic.h2008-02-06 11:31:53.0 -0500 @@ -11,7 +11,6 @@ struct pt_regs; struct task_struct; #include "asm/ptrace.h" -#include "asm/pgtable.h" #include "registers.h" #include "sysdep/archsetjmp.h" @@ -92,7 +91,9 @@ static inline void mm_copy_segments(stru /* * User space process size: 3GB (default). */ -#define TASK_SIZE (CONFIG_TOP_ADDR & PGDIR_MASK) +extern unsigned long task_size; + +#define TASK_SIZE (task_size) /* This decides where the kernel will search for a free chunk of vm * space during mmap's. Index: linux-2.6-git/arch/um/include/os.h === --- linux-2.6-git.orig/arch/um/include/os.h 2008-02-06 11:19:07.0 -0500 +++ linux-2.6-git/arch/um/include/os.h 2008-02-06 11:31:53.0 -0500 @@ -295,6 +295,9 @@ extern void maybe_sigio_broken(int fd, i extern int os_arch_prctl(int pid, int code, unsigned long *addr); /* tty.c
[PATCH 1/5] UML - Runtime host VMSPLIT detection
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is needed on i386 if UML is to run on hosts with varying VMSPLITs without recompilation. TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of an include of pgtable.h from processor.h, which can cause include loops. On i386, task_size is calculated early in boot by probing the address space in a binary search to figure out where the boundary between usable and non-usable memory is. This tries to make sure that a page that is considered to be in userspace is, or can be made, read-write. I'm concerned about a system-global VDSO page in kernel memory being hit and considered to be a userspace page. On x86_64, task_size is just the old value of CONFIG_TOP_ADDR. A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in arch/um/Makefile are also gone. I noticed and fixed a missing extern in os.h when adding os_get_task_size. Note: This has been revised to fix the 32-bit UML on 64-bit host bug that Miklos ran into. Signed-off-by: Jeff Dike [EMAIL PROTECTED] --- arch/um/Kconfig | 11 -- arch/um/Kconfig.i386| 37 - arch/um/Kconfig.x86_64 |4 - arch/um/Makefile| 11 -- arch/um/defconfig |3 arch/um/include/as-layout.h |2 arch/um/include/os.h|5 + arch/um/kernel/exec.c |2 arch/um/kernel/um_arch.c| 16 +++- arch/um/os-Linux/sys-i386/Makefile |2 arch/um/os-Linux/sys-i386/task_size.c | 120 arch/um/os-Linux/sys-x86_64/Makefile|2 arch/um/os-Linux/sys-x86_64/task_size.c |5 + include/asm-um/fixmap.h |3 include/asm-um/processor-generic.h |5 - 15 files changed, 153 insertions(+), 75 deletions(-) Index: linux-2.6-git/arch/um/kernel/um_arch.c === --- linux-2.6-git.orig/arch/um/kernel/um_arch.c 2008-02-06 11:19:07.0 -0500 +++ linux-2.6-git/arch/um/kernel/um_arch.c 2008-02-06 11:31:53.0 -0500 @@ -241,6 +241,11 @@ static struct notifier_block panic_exit_ }; /* Set during early boot */ +unsigned long task_size; +EXPORT_SYMBOL(task_size); + +unsigned long host_task_size; + unsigned long brk_start; unsigned long end_iomem; EXPORT_SYMBOL(end_iomem); @@ -267,6 +272,13 @@ int __init linux_main(int argc, char **a if (have_root == 0) add_arg(DEFAULT_COMMAND_LINE); + host_task_size = os_get_task_size(); + /* +* TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps +* out +*/ + task_size = host_task_size PGDIR_MASK; + /* OS sanity checks that need to happen before the kernel runs */ os_early_checks(); @@ -303,7 +315,7 @@ int __init linux_main(int argc, char **a highmem = 0; iomem_size = (iomem_size + PAGE_SIZE - 1) PAGE_MASK; - max_physmem = CONFIG_TOP_ADDR - uml_physmem - iomem_size - MIN_VMALLOC; + max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; /* * Zones have to begin on a 1 MAX_ORDER page boundary, @@ -335,7 +347,7 @@ int __init linux_main(int argc, char **a } virtmem_size = physmem_size; - avail = CONFIG_TOP_ADDR - start_vm; + avail = TASK_SIZE - start_vm; if (physmem_size avail) virtmem_size = avail; end_vm = start_vm + virtmem_size; Index: linux-2.6-git/include/asm-um/processor-generic.h === --- linux-2.6-git.orig/include/asm-um/processor-generic.h 2008-02-06 11:19:09.0 -0500 +++ linux-2.6-git/include/asm-um/processor-generic.h2008-02-06 11:31:53.0 -0500 @@ -11,7 +11,6 @@ struct pt_regs; struct task_struct; #include asm/ptrace.h -#include asm/pgtable.h #include registers.h #include sysdep/archsetjmp.h @@ -92,7 +91,9 @@ static inline void mm_copy_segments(stru /* * User space process size: 3GB (default). */ -#define TASK_SIZE (CONFIG_TOP_ADDR PGDIR_MASK) +extern unsigned long task_size; + +#define TASK_SIZE (task_size) /* This decides where the kernel will search for a free chunk of vm * space during mmap's. Index: linux-2.6-git/arch/um/include/os.h === --- linux-2.6-git.orig/arch/um/include/os.h 2008-02-06 11:19:07.0 -0500 +++ linux-2.6-git/arch/um/include/os.h 2008-02-06 11:31:53.0 -0500 @@ -295,6 +295,9 @@ extern void maybe_sigio_broken(int fd, i extern int os_arch_prctl(int pid, int code, unsigned long *addr); /* tty.c */ -int
