From 2b67fc46061b2171fb8fbb55d1ac717abd533569 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 5 Feb 2007 21:16:47 +0100 Subject: [S390] Get rid of a lot of sparse warnings. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/s390/mm/init.c') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 4bb21be..6315f75 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -107,8 +108,6 @@ static void __init setup_ro_region(void) } } -extern void vmem_map_init(void); - /* * paging_init() sets up the page tables */ -- cgit v1.1 From 60383201c2c155fae2aaffd483d09eb4198b6356 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 5 Feb 2007 21:16:52 +0100 Subject: [S390] Remove pointless/unreliable kernel messages. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/s390/mm/init.c') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 6315f75..0e7e9ac 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -175,8 +175,6 @@ void __init mem_init(void) printk("Write protected kernel read-only data: %#lx - %#lx\n", (unsigned long)&__start_rodata, PFN_ALIGN((unsigned long)&__end_rodata) - 1); - printk("Virtual memmap size: %ldk\n", - (max_pfn * sizeof(struct page)) >> 10); } void free_initmem(void) -- cgit v1.1 From c1821c2e9711adc3cd298a16b7237c92a2cee78d Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Mon, 5 Feb 2007 21:18:17 +0100 Subject: [S390] noexec protection This provides a noexec protection on s390 hardware. Our hardware does not have any bits left in the pte for a hw noexec bit, so this is a different approach using shadow page tables and a special addressing mode that allows separate address spaces for code and data. As a special feature of our "secondary-space" addressing mode, separate page tables can be specified for the translation of data addresses (storage operands) and instruction addresses. The shadow page table is used for the instruction addresses and the standard page table for the data addresses. The shadow page table is linked to the standard page table by a pointer in page->lru.next of the struct page corresponding to the page that contains the standard page table (since page->private is not really private with the pte_lock and the page table pages are not in the LRU list). Depending on the software bits of a pte, it is either inserted into both page tables or just into the standard (data) page table. Pages of a vma that does not have the VM_EXEC bit set get mapped only in the data address space. Any try to execute code on such a page will cause a page translation exception. The standard reaction to this is a SIGSEGV with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the kernel to the signal stack frame. Unfortunately, the signal return mechanism cannot be modified to use an SA_RESTORER because the exception unwinding code depends on the system call opcode stored behind the signal stack frame. This feature requires that user space is executed in secondary-space mode and the kernel in home-space mode, which means that the addressing modes need to be switched and that the noexec protection only works for user space. After switching the addressing modes, we cannot use the mvcp/mvcs instructions anymore to copy between kernel and user space. A new mvcos instruction has been added to the z9 EC/BC hardware which allows to copy between arbitrary address spaces, but on older hardware the page tables need to be walked manually. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/s390/mm/init.c') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 0e7e9ac..162a338 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -104,7 +104,7 @@ static void __init setup_ro_region(void) pmd = pmd_offset(pgd, address); pte = pte_offset_kernel(pmd, address); new_pte = mk_pte_phys(address, __pgprot(_PAGE_RO)); - set_pte(pte, new_pte); + *pte = new_pte; } } @@ -124,11 +124,11 @@ void __init paging_init(void) #ifdef CONFIG_64BIT pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERN_REGION_TABLE; for (i = 0; i < PTRS_PER_PGD; i++) - pgd_clear(pg_dir + i); + pgd_clear_kernel(pg_dir + i); #else pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERNSEG_TABLE; for (i = 0; i < PTRS_PER_PGD; i++) - pmd_clear((pmd_t *)(pg_dir + i)); + pmd_clear_kernel((pmd_t *)(pg_dir + i)); #endif vmem_map_init(); setup_ro_region(); -- cgit v1.1 From 162e006ef59266b9ebf34e3d15ca1f3d9ee956d7 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 5 Feb 2007 21:18:41 +0100 Subject: [S390] Mark kernel text section read-only. Set read-only flag in the page table entries for the kernel image text section. This will catch all instruction caused corruptions withing the text section. Instruction replacement via kprobes still works, since it bypasses now dynamic address translation. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'arch/s390/mm/init.c') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 162a338..b3e7c45 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -26,7 +26,6 @@ #include #include #include - #include #include #include @@ -96,8 +95,8 @@ static void __init setup_ro_region(void) pte_t new_pte; unsigned long address, end; - address = ((unsigned long)&__start_rodata) & PAGE_MASK; - end = PFN_ALIGN((unsigned long)&__end_rodata); + address = ((unsigned long)&_stext) & PAGE_MASK; + end = PFN_ALIGN((unsigned long)&_eshared); for (; address < end; address += PAGE_SIZE) { pgd = pgd_offset_k(address); @@ -173,8 +172,8 @@ void __init mem_init(void) datasize >>10, initsize >> 10); printk("Write protected kernel read-only data: %#lx - %#lx\n", - (unsigned long)&__start_rodata, - PFN_ALIGN((unsigned long)&__end_rodata) - 1); + (unsigned long)&_stext, + PFN_ALIGN((unsigned long)&_eshared) - 1); } void free_initmem(void) -- cgit v1.1