From d84bb709aa4a6a155b1aaaf449cad21f02be4594 Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:43 -0700 Subject: signals, sparc: Add signal codes for ADI violations SPARC M7 processor introduces a new feature - Application Data Integrity (ADI). ADI allows MMU to catch rogue accesses to memory. When a rogue access occurs, MMU blocks the access and raises an exception. In response to the exception, kernel sends the offending task a SIGSEGV with si_code that indicates the nature of exception. This patch adds three new signal codes specific to ADI feature: 1. ADI is not enabled for the address and task attempted to access memory using ADI 2. Task attempted to access memory using wrong ADI tag and caused a deferred exception. 3. Task attempted to access memory using wrong ADI tag and caused a precise exception. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Reviewed-by: Anthony Yznaga Acked-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- include/uapi/asm-generic/siginfo.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h index 99c902e460c2..a01fd0a92b1b 100644 --- a/include/uapi/asm-generic/siginfo.h +++ b/include/uapi/asm-generic/siginfo.h @@ -246,7 +246,10 @@ typedef struct siginfo { #else # define SEGV_PKUERR 4 /* failed protection key checks */ #endif -#define NSIGSEGV 4 +#define SEGV_ACCADI 5 /* ADI not enabled for mapped object */ +#define SEGV_ADIDERR 6 /* Disrupting MCD error */ +#define SEGV_ADIPERR 7 /* Precise MCD exception */ +#define NSIGSEGV 7 /* * SIGBUS si_codes -- cgit v1.2.3 From ca827d55ebaa24de9fca36ee24e42d6fc5119ee3 Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:44 -0700 Subject: mm, swap: Add infrastructure for saving page metadata on swap If a processor supports special metadata for a page, for example ADI version tags on SPARC M7, this metadata must be saved when the page is swapped out. The same metadata must be restored when the page is swapped back in. This patch adds two new architecture specific functions - arch_do_swap_page() to be called when a page is swapped in, and arch_unmap_one() to be called when a page is being unmapped for swap out. These architecture hooks allow page metadata to be saved if the architecture supports it. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Acked-by: Jerome Marchand Reviewed-by: Anthony Yznaga Acked-by: Andrew Morton Signed-off-by: David S. Miller --- include/asm-generic/pgtable.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'include') diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 2cfa3075d148..6fbbc0b6c05e 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -400,6 +400,42 @@ static inline int pud_same(pud_t pud_a, pud_t pud_b) #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif +#ifndef __HAVE_ARCH_DO_SWAP_PAGE +/* + * Some architectures support metadata associated with a page. When a + * page is being swapped out, this metadata must be saved so it can be + * restored when the page is swapped back in. SPARC M7 and newer + * processors support an ADI (Application Data Integrity) tag for the + * page as metadata for the page. arch_do_swap_page() can restore this + * metadata when a page is swapped back in. + */ +static inline void arch_do_swap_page(struct mm_struct *mm, + struct vm_area_struct *vma, + unsigned long addr, + pte_t pte, pte_t oldpte) +{ + +} +#endif + +#ifndef __HAVE_ARCH_UNMAP_ONE +/* + * Some architectures support metadata associated with a page. When a + * page is being swapped out, this metadata must be saved so it can be + * restored when the page is swapped back in. SPARC M7 and newer + * processors support an ADI (Application Data Integrity) tag for the + * page as metadata for the page. arch_unmap_one() can save this + * metadata on a swap-out of a page. + */ +static inline int arch_unmap_one(struct mm_struct *mm, + struct vm_area_struct *vma, + unsigned long addr, + pte_t orig_pte) +{ + return 0; +} +#endif + #ifndef __HAVE_ARCH_PGD_OFFSET_GATE #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) #endif -- cgit v1.2.3 From 9035cf9a97e429e6b5291841da81c433879f5658 Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:49 -0700 Subject: mm: Add address parameter to arch_validate_prot() A protection flag may not be valid across entire address space and hence arch_validate_prot() might need the address a protection bit is being set on to ensure it is a valid protection flag. For example, sparc processors support memory corruption detection (as part of ADI feature) flag on memory addresses mapped on to physical RAM but not on PFN mapped pages or addresses mapped on to devices. This patch adds address to the parameters being passed to arch_validate_prot() so protection bits can be validated in the relevant context. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Reviewed-by: Anthony Yznaga Acked-by: Michael Ellerman (powerpc) Acked-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/mman.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mman.h b/include/linux/mman.h index 6a4d1caaff5c..4b08e9c9c538 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -92,7 +92,7 @@ static inline void vm_unacct_memory(long pages) * * Returns true if the prot flags are valid */ -static inline bool arch_validate_prot(unsigned long prot) +static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) { return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0; } -- cgit v1.2.3 From 2c2d57b5e769956fb36581e0d3cccdb5ea68038f Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:50 -0700 Subject: mm: Clear arch specific VM flags on protection change When protection bits are changed on a VMA, some of the architecture specific flags should be cleared as well. An examples of this are the PKEY flags on x86. This patch expands the current code that clears PKEY flags for x86, to support similar functionality for other architectures as well. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Reviewed-by: Anthony Yznaga Acked-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/mm.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/mm.h b/include/linux/mm.h index ad06d42adb1a..ae806dbc63ee 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -287,6 +287,12 @@ extern unsigned int kobjsize(const void *objp); /* This mask is used to clear all the VMA flags used by mlock */ #define VM_LOCKED_CLEAR_MASK (~(VM_LOCKED | VM_LOCKONFAULT)) +/* Arch-specific flags to clear when updating VM flags on protection change */ +#ifndef VM_ARCH_CLEAR +# define VM_ARCH_CLEAR VM_NONE +#endif +#define VM_FLAGS_CLEAR (ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR) + /* * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. -- cgit v1.2.3 From a4602b62d9fdea41412ba765bbf32ecfc2b6a94c Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:51 -0700 Subject: mm: Allow arch code to override copy_highpage() Some architectures can support metadata for memory pages and when a page is copied, its metadata must also be copied. Sparc processors from M7 onwards support metadata for memory pages. This metadata provides tag based protection for access to memory pages. To maintain this protection, the tag data must be copied to the new page when a page is migrated across NUMA nodes. This patch allows arch specific code to override default copy_highpage() and copy metadata along with page data upon migration. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Reviewed-by: Anthony Yznaga Acked-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/highmem.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 776f90f3a1cd..0690679832d4 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -237,6 +237,8 @@ static inline void copy_user_highpage(struct page *to, struct page *from, #endif +#ifndef __HAVE_ARCH_COPY_HIGHPAGE + static inline void copy_highpage(struct page *to, struct page *from) { char *vfrom, *vto; @@ -248,4 +250,6 @@ static inline void copy_highpage(struct page *to, struct page *from) kunmap_atomic(vfrom); } +#endif + #endif /* _LINUX_HIGHMEM_H */ -- cgit v1.2.3 From 74a04967482faa7144b93dae3b2e913870dd421c Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Fri, 23 Feb 2018 15:46:41 -0700 Subject: sparc64: Add support for ADI (Application Data Integrity) ADI is a new feature supported on SPARC M7 and newer processors to allow hardware to catch rogue accesses to memory. ADI is supported for data fetches only and not instruction fetches. An app can enable ADI on its data pages, set version tags on them and use versioned addresses to access the data pages. Upper bits of the address contain the version tag. On M7 processors, upper four bits (bits 63-60) contain the version tag. If a rogue app attempts to access ADI enabled data pages, its access is blocked and processor generates an exception. Please see Documentation/sparc/adi.txt for further details. This patch extends mprotect to enable ADI (TSTATE.mcde), enable/disable MCD (Memory Corruption Detection) on selected memory ranges, enable TTE.mcd in PTEs, return ADI parameters to userspace and save/restore ADI version tags on page swap out/in or migration. ADI is not enabled by default for any task. A task must explicitly enable ADI on a memory range and set version tag for ADI to be effective for the task. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Reviewed-by: Anthony Yznaga Signed-off-by: David S. Miller --- include/linux/mm.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/mm.h b/include/linux/mm.h index ae806dbc63ee..32fe6919a11b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -245,6 +245,9 @@ extern unsigned int kobjsize(const void *objp); # define VM_GROWSUP VM_ARCH_1 #elif defined(CONFIG_IA64) # define VM_GROWSUP VM_ARCH_1 +#elif defined(CONFIG_SPARC64) +# define VM_SPARC_ADI VM_ARCH_1 /* Uses ADI tag for access control */ +# define VM_ARCH_CLEAR VM_SPARC_ADI #elif !defined(CONFIG_MMU) # define VM_MAPPED_COPY VM_ARCH_1 /* T if mapped copy of data (nommu mmap) */ #endif -- cgit v1.2.3