kernel.git/arch/sparc, branch linux-4.11.y

sparc64: Fix gup_huge_pmd

2017-07-21T05:00:09Z

[ Upstream commit dbd2667a4fb9ce4f547982b07cd69dda127c47ea ] The function assumes that each PMD points to head of a huge page. This is not correct as a PMD can point to start of any 8M region with a, say 256M, hugepage. The fix ensures that it points to the correct head of any PMD huge page. Cc: Julian Calaby Signed-off-by: Nitin Gupta Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Adding the type of exported symbols

2017-07-21T05:00:09Z

[ Upstream commit f5a651f1d5e524cab345250a783702fb6a3f14d6 ] Missing symbol type for few functions prevents genksyms from generating symbol versions for those functions. This patch fixes them. Signed-off-by: Nagarathnam Muthusamy Reviewed-by: Babu Moger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sed regex in Makefile.build requires line break between exported symbols

2017-07-21T05:00:09Z

[ Upstream commit d16c0649feb4fe4e814f44803df5a617769c3233 ] The following regex in Makefile.build matches only one ___EXPORT_SYMBOL per line. sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ATOMIC_OPS macro in atomic_64.S expands multiple symbols in same line hence version generation is done only for the last matched symbol. This patch adds new line between the symbol expansions. Signed-off-by: Nagarathnam Muthusamy Reviewed-by: Babu Moger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Adding asm-prototypes.h for genksyms to generate crc

2017-07-21T05:00:08Z

[ Upstream commit bdca8cc096203b17ad0ac4e19f50578207e054d2 ] This patch adds the prototypes of assembly defined functions to asm-prototypes.h. Some prototypes are directly added as they are not present in any existing header files. Signed-off-by: Nagarathnam Muthusamy Reviewed-by: Babu Moger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

mm: larger stack guard gap, between vmas

2017-06-24T05:06:22Z

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds [wt: backport to 4.11: adjust context] Signed-off-by: Willy Tarreau Signed-off-by: Greg Kroah-Hartman

arch/sparc: support NR_CPUS = 4096

2017-06-14T13:07:36Z

[ Upstream commit c79a13734d104b5b147d7cb0870276ccdd660dae ] Linux SPARC64 limits NR_CPUS to 4064 because init_cpu_send_mondo_info() only allocates a single page for NR_CPUS mondo entries. Thus we cannot use all 4096 CPUs on some SPARC platforms. To fix, allocate (2^order) pages where order is set according to the size of cpu_list for possible cpus. Since cpu_list_pa and cpu_mondo_block_pa are not used in asm code, there are no imm13 offsets from the base PA that will break because they can only reach one page. Orabug: 25505750 Signed-off-by: Jane Chu Reviewed-by: Bob Picco Reviewed-by: Atish Patra Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sparc64: delete old wrap code

2017-06-14T13:07:36Z

[ Upstream commit 0197e41ce70511dc3b71f7fefa1a676e2b5cd60b ] The old method that is using xcall and softint to get new context id is deleted, as it is replaced by a method of using per_cpu_secondary_mm without xcall to perform the context wrap. Signed-off-by: Pavel Tatashin Reviewed-by: Bob Picco Reviewed-by: Steven Sistare Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sparc64: new context wrap

2017-06-14T13:07:36Z

[ Upstream commit a0582f26ec9dfd5360ea2f35dd9a1b026f8adda0 ] The current wrap implementation has a race issue: it is called outside of the ctx_alloc_lock, and also does not wait for all CPUs to complete the wrap. This means that a thread can get a new context with a new version and another thread might still be running with the same context. The problem is especially severe on CPUs with shared TLBs, like sun4v. I used the following test to very quickly reproduce the problem: - start over 8K processes (must be more than context IDs) - write and read values at a memory location in every process. Very quickly memory corruptions start happening, and what we read back does not equal what we wrote. Several approaches were explored before settling on this one: Approach 1: Move smp_new_mmu_context_version() inside ctx_alloc_lock, and wait for every process to complete the wrap. (Note: every CPU must WAIT before leaving smp_new_mmu_context_version_client() until every one arrives). This approach ends up with deadlocks, as some threads own locks which other threads are waiting for, and they never receive softint until these threads exit smp_new_mmu_context_version_client(). Since we do not allow the exit, deadlock happens. Approach 2: Handle wrap right during mondo interrupt. Use etrap/rtrap to enter into into C code, and issue new versions to every CPU. This approach adds some overhead to runtime: in switch_mm() we must add some checks to make sure that versions have not changed due to wrap while we were loading the new secondary context. (could be protected by PSTATE_IE but that degrades performance as on M7 and older CPUs as it takes 50 cycles for each access). Also, we still need a global per-cpu array of MMs to know where we need to load new contexts, otherwise we can change context to a thread that is going way (if we received mondo between switch_mm() and switch_to() time). Finally, there are some issues with window registers in rtrap() when context IDs are changed during CPU mondo time. The approach in this patch is the simplest and has almost no impact on runtime. We use the array with mm's where last secondary contexts were loaded onto CPUs and bump their versions to the new generation without changing context IDs. If a new process comes in to get a context ID, it will go through get_new_mmu_context() because of version mismatch. But the running processes do not need to be interrupted. And wrap is quicker as we do not need to xcall and wait for everyone to receive and complete wrap. Signed-off-by: Pavel Tatashin Reviewed-by: Bob Picco Reviewed-by: Steven Sistare Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sparc64: add per-cpu mm of secondary contexts

2017-06-14T13:07:36Z

[ Upstream commit 7a5b4bbf49fe86ce77488a70c5dccfe2d50d7a2d ] The new wrap is going to use information from this array to figure out mm's that currently have valid secondary contexts setup. Signed-off-by: Pavel Tatashin Reviewed-by: Bob Picco Reviewed-by: Steven Sistare Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sparc64: redefine first version

2017-06-14T13:07:36Z

[ Upstream commit c4415235b2be0cc791572e8e7f7466ab8f73a2bf ] CTX_FIRST_VERSION defines the first context version, but also it defines first context. This patch redefines it to only include the first context version. Signed-off-by: Pavel Tatashin Reviewed-by: Bob Picco Reviewed-by: Steven Sistare Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman