- Feb 13, 2019
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Borislav Petkov authored
dump_thread32() in aout_core_dump() does not clear the user32 structure allocated on the stack as the first thing on function entry. As a result, the dump.u_comm, dump.u_ar0 and dump.signal which get assigned before the clearing, get overwritten. Rename that function to fill_dump() to make it clear what it does and call it first thing. This was caught while staring at a patch by Derek Robson <robsonde@gmail.com>. Signed-off-by:
Borislav Petkov <bp@suse.de> Cc: Derek Robson <robsonde@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Matz <matz@suse.de> Cc: x86@kernel.org Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20190202005512.3144-1-robsonde@gmail.com
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- Feb 10, 2019
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Juergen Gross authored
set_pmd_at() calls native_set_pmd() unconditionally on x86. This was fine as long as only huge page entries were written via set_pmd_at(), as Xen pv guests don't support those. Commit 2c91bd4a ("mm: speed up mremap by 20x on large regions") introduced a usage of set_pmd_at() possible on pv guests, leading to failures like: BUG: unable to handle kernel paging request at ffff888023e26778 #PF error: [PROT] [WRITE] RIP: e030:move_page_tables+0x7c1/0xae0 move_vma.isra.3+0xd1/0x2d0 __se_sys_mremap+0x3c6/0x5b0 do_syscall_64+0x49/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Make set_pmd_at() paravirt aware by just letting it use set_pmd(). Fixes: 2c91bd4a ("mm: speed up mremap by 20x on large regions") Reported-by:
Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by:
Juergen Gross <jgross@suse.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Cc: sstabellini@kernel.org Cc: hpa@zytor.com Cc: bp@alien8.de Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20190210074056.11842-1-jgross@suse.com
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- Feb 08, 2019
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Peter Zijlstra authored
The recent commit fe0937b2 ("x86/mm/cpa: Fold cpa_flush_range() and cpa_flush_array() into a single cpa_flush() function") accidentally made the call to make_addr_canonical_again() go away, which breaks set_mce_nospec(). Re-instate the call to convert the address back into canonical form right before invoking either CLFLUSH or INVLPG. Rename the function while at it to be shorter (and less MAGA). Fixes: fe0937b2 ("x86/mm/cpa: Fold cpa_flush_range() and cpa_flush_array() into a single cpa_flush() function") Reported-by:
Tony Luck <tony.luck@intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
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- Feb 06, 2019
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Kirill A. Shutemov authored
RDMSR in the trampoline code overwrites EDX but that register is used to indicate whether 5-level paging has to be enabled and if clobbered, leads to failure to boot on a 5-level paging machine. Preserve EDX on the stack while we are dealing with EFER. Fixes: b677dfae ("x86/boot/compressed/64: Set EFER.LME=1 in 32-bit trampoline before returning to long mode") Reported-by:
Kyle D Pelton <kyle.d.pelton@intel.com> Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by:
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- Feb 03, 2019
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Tony Luck authored
Internal injection testing crashed with a console log that said: mce: [Hardware Error]: CPU 7: Machine Check Exception: f Bank 0: bd80000000100134 This caused a lot of head scratching because the MCACOD (bits 15:0) of that status is a signature from an L1 data cache error. But Linux says that it found it in "Bank 0", which on this model CPU only reports L1 instruction cache errors. The answer was that Linux doesn't initialize "m->bank" in the case that it finds a fatal error in the mce_no_way_out() pre-scan of banks. If this was a local machine check, then this partially initialized struct mce is being passed to mce_panic(). Fix is simple: just initialize m->bank in the case of a fatal error. Fixes: 40c36e27 ("x86/mce: Fix incorrect "Machine check from unknown source" message") Signed-off-by:
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- Feb 02, 2019
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Johannes Weiner authored
"Resource Control" is a very broad term for this CPU feature, and a term that is also associated with containers, cgroups etc. This can easily cause confusion. Make the user prompt more specific. Match the config symbol name. [ bp: In the future, the corresponding ARM arch-specific code will be under ARM_CPU_RESCTRL and the arch-agnostic bits will be carved out under the CPU_RESCTRL umbrella symbol. ] Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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- Feb 01, 2019
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Kairui Song authored
Kexec-ing a kernel with "efi=noruntime" on the first kernel's command line causes the following null pointer dereference: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] Call Trace: efi_runtime_map_copy+0x28/0x30 bzImage64_load+0x688/0x872 arch_kexec_kernel_image_load+0x6d/0x70 kimage_file_alloc_init+0x13e/0x220 __x64_sys_kexec_file_load+0x144/0x290 do_syscall_64+0x55/0x1a0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Just skip the EFI info setup if EFI runtime services are not enabled. [ bp: Massage commit message. ] Suggested-by:
Dave Young <dyoung@redhat.com> Signed-off-by:
Kairui Song <kasong@redhat.com> Signed-off-by:
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- Jan 31, 2019
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Thomas Lendacky authored
The load_microcode_amd() function searches for microcode patches and attempts to apply a microcode patch if it is of different level than the currently installed level. While the processor won't actually load a level that is less than what is already installed, the logic wrongly returns UCODE_NEW thus signaling to its caller reload_store() that a late loading should be attempted. If the file-system contains an older microcode revision than what is currently running, such a late microcode reload can result in these misleading messages: x86/CPU: CPU features have changed after loading microcode, but might not take effect. x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update. These messages were issued on a system where SME/SEV are not enabled by the BIOS (MSR C001_0010[23] = 0b) because during boot, early_detect_mem_encrypt() is called and cleared the SME and SEV features in this case. However, after the wrong late load attempt, get_cpu_cap() is called and reloads the SME and SEV feature bits, resulting in the messages. Update the microcode level check to not attempt microcode loading if the current level is greater than(!) and not only equal to the current patch level. [ bp: massage commit message. ] Fixes: 2613f36e ("x86/microcode: Attempt late loading only when new microcode is present") Signed-off-by:
Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by:
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- Jan 29, 2019
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Colin Ian King authored
show_ldttss() shifts desc.base2 by 24 bit, but base2 is 8 bits of a bitfield in a u16. Due to the really great idea of integer promotion in C99 base2 is promoted to an int, because that's the standard defined behaviour when all values which can be represented by base2 fit into an int. Now if bit 7 is set in desc.base2 the result of the shift left by 24 makes the resulting integer negative and the following conversion to unsigned long legitmately sign extends first causing the upper bits 32 bits to be set in the result. Fix this by casting desc.base2 to unsigned long before the shift. Detected by CoverityScan, CID#1475635 ("Unintended sign extension") [ tglx: Reworded the changelog a bit as I actually had to lookup the standard (again) to decode the original one. ] Fixes: a1a371c4 ("x86/fault: Decode page fault OOPSes better") Signed-off-by:Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Wei Huang authored
In some old AMD KVM implementation, guest's EFER.LME bit is cleared by KVM when the hypervsior detects that the guest sets CR0.PG to 0. This causes the guest OS to reboot when it tries to return from 32-bit trampoline code because the CPU is in incorrect state: CR4.PAE=1, CR0.PG=1, CS.L=1, but EFER.LME=0. As a precaution, set EFER.LME=1 as part of long mode activation procedure. This extra step won't cause any harm when Linux is booted on a bare-metal machine. Signed-off-by:
Wei Huang <wei@redhat.com> Signed-off-by:
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Kan Liang authored
Add the Atom Tremont model number to the Intel family list. [ Tony: Also update comment at head of file to say "_X" suffix is also used for microserver parts. ] Signed-off-by:
Kan Liang <kan.liang@linux.intel.com> Signed-off-by:
Qiuxu Zhuo <qiuxu.zhuo@intel.com> Signed-off-by:
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- Jan 22, 2019
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Sinan Kaya authored
After commit 5d32a665 ("PCI/ACPI: Allow ACPI to be built without CONFIG_PCI set") dependencies on CONFIG_PCI that previously were satisfied implicitly through dependencies on CONFIG_ACPI have to be specified directly. PCI_LOCKLESS_CONFIG depends on PCI but this dependency has not been mentioned in the Kconfig so add an explicit dependency here and fix WARNING: unmet direct dependencies detected for PCI_LOCKLESS_CONFIG Depends on [n]: PCI [=n] Selected by [y]: - X86 [=y] Fixes: 5d32a665 ("PCI/ACPI: Allow ACPI to be built without CONFIG_PCI set") Signed-off-by:
Sinan Kaya <okaya@kernel.org> Signed-off-by:
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- Jan 17, 2019
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Jan Beulich authored
While in the native case entry into the kernel happens on the trampoline stack, PV Xen kernels get entered with the current thread stack right away. Hence source and destination stacks are identical in that case, and special care is needed. Other than in sync_regs() the copying done on the INT80 path isn't NMI / #MC safe, as either of these events occurring in the middle of the stack copying would clobber data on the (source) stack. There is similar code in interrupt_entry() and nmi(), but there is no fixup required because those code paths are unreachable in XEN PV guests. [ tglx: Sanitized subject, changelog, Fixes tag and stable mail address. Sigh ] Fixes: 7f2590a1 ("x86/entry/64: Use a per-CPU trampoline stack for IDT entries") Signed-off-by:
Jan Beulich <jbeulich@suse.com> Signed-off-by:
Andy Lutomirski <luto@kernel.org> Cc: Peter Anvin <hpa@zytor.com> Cc: xen-devel@lists.xenproject.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/5C3E1128020000780020DFAD@prv1-mh.provo.novell.com
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- Jan 15, 2019
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Dave Young authored
Commit b6664ba4 ("s390, kexec_file: drop arch_kexec_mem_walk()") changed the behavior of kexec_locate_mem_hole(): it will try to allocate free memory only when kbuf.mem is initialized to zero. However, x86's kexec_file_load() implementation reuses a struct kexec_buf allocated on the stack and its kbuf.mem member gets set by each kexec_add_buffer() invocation. The second kexec_add_buffer() will reuse the same kbuf but not reinitialize kbuf.mem. Therefore, explictily reset kbuf.mem each time in order for kexec_locate_mem_hole() to locate a free memory region each time. [ bp: massage commit message. ] Fixes: b6664ba4 ("s390, kexec_file: drop arch_kexec_mem_walk()") Signed-off-by:
Baoquan He <bhe@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Philipp Rudo <prudo@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yannik Sembritzki <yannik@sembritzki.me> Cc: Yi Wang <wang.yi59@zte.com.cn> Cc: kexec@lists.infradead.org Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20181228011247.GA9999@dhcp-128-65.nay.redhat.com
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Peng Hao authored
Using sizeof(pointer) for determining the size of a memset() only works when the size of the pointer and the size of type to which it points are the same. For pte_t this is only true for 64bit and 32bit-NONPAE. On 32bit PAE systems this is wrong as the pointer size is 4 byte but the PTE entry is 8 bytes. It's actually not a real world issue as this code depends on 64bit, but it's wrong nevertheless. Use sizeof(*p) for correctness sake. Fixes: aad98391 ("x86/mm/encrypt: Simplify sme_populate_pgd() and sme_populate_pgd_large()") Signed-off-by:
Peng Hao <peng.hao2@zte.com.cn> Signed-off-by:
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Dave Hansen authored
Memory protection key behavior should be the same in a child as it was in the parent before a fork. But, there is a bug that resets the state in the child at fork instead of preserving it. The creation of new mm's is a bit convoluted. At fork(), the code does: 1. memcpy() the parent mm to initialize child 2. mm_init() to initalize some select stuff stuff 3. dup_mmap() to create true copies that memcpy() did not do right For pkeys two bits of state need to be preserved across a fork: 'execute_only_pkey' and 'pkey_allocation_map'. Those are preserved by the memcpy(), but mm_init() invokes init_new_context() which overwrites 'execute_only_pkey' and 'pkey_allocation_map' with "new" values. The author of the code erroneously believed that init_new_context is *only* called at execve()-time. But, alas, init_new_context() is used at execve() and fork(). The result is that, after a fork(), the child's pkey state ends up looking like it does after an execve(), which is totally wrong. pkeys that are already allocated can be allocated again, for instance. To fix this, add code called by dup_mmap() to copy the pkey state from parent to child explicitly. Also add a comment above init_new_context() to make it more clear to the next poor sod what this code is used for. Fixes: e8c24d3a ("x86/pkeys: Allocation/free syscalls") Signed-off-by:
Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by:
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- Jan 11, 2019
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Daniel Drake authored
The outb() function takes parameters value and port, in that order. Fix the parameters used in the kalsr i8254 fallback code. Fixes: 5bfce5ef ("x86, kaslr: Provide randomness functions") Signed-off-by:
Daniel Drake <drake@endlessm.com> Signed-off-by:
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Sinan Kaya authored
After commit 5d32a665 ("PCI/ACPI: Allow ACPI to be built without CONFIG_PCI set") dependencies on CONFIG_PCI that previously were satisfied implicitly through dependencies on CONFIG_ACPI have to be specified directly. LPSS code relies on PCI infrastructure but this dependency has not been explicitly called out so do that. Fixes: 5d32a665 ("PCI/ACPI: Allow ACPI to be built without CONFIG_PCI set") Signed-off-by:
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- Jan 09, 2019
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WANG Chao authored
Commit 4cd24de3 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") replaced the RETPOLINE define with CONFIG_RETPOLINE checks. Remove the remaining pieces. [ bp: Massage commit message. ] Fixes: 4cd24de3 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Signed-off-by:
WANG Chao <chao.wang@ucloud.cn> Signed-off-by:
Zhenzhong Duan <zhenzhong.duan@oracle.com> Reviewed-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kees Cook <keescook@chromium.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: linux-kbuild@vger.kernel.org Cc: srinivas.eeda@oracle.com Cc: stable <stable@vger.kernel.org> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20181210163725.95977-1-chao.wang@ucloud.cn
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Borislav Petkov authored
CONFIG_RESCTRL is too generic. The final goal is to have a generic option called like this which is selected by the arch-specific ones CONFIG_X86_RESCTRL and CONFIG_ARM64_RESCTRL. The generic one will cover the resctrl filesystem and other generic and shared bits of functionality. Signed-off-by:
Ingo Molnar <mingo@kernel.org> Requested-by:
Linus Torvalds <torvalds@linux-foundation.org> Cc: Babu Moger <babu.moger@amd.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: James Morse <james.morse@arm.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20190108171401.GC12235@zn.tnic
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- Jan 07, 2019
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Masahiro Yamada authored
For some reasons, I accidentally got rid of "generic-y += shmparam.h" from some architectures. Restore them to fix building c6x, h8300, hexagon, m68k, microblaze, openrisc, and unicore32. Fixes: d6e4b3e3 ("arch: remove redundant UAPI generic-y defines") Signed-off-by:
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- Jan 06, 2019
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Linus Torvalds authored
Commit 594cc251 ("make 'user_access_begin()' do 'access_ok()'") broke both alpha and SH booting in qemu, as noticed by Guenter Roeck. It turns out that the bug wasn't actually in that commit itself (which would have been surprising: it was mostly a no-op), but in how the addition of access_ok() to the strncpy_from_user() and strnlen_user() functions now triggered the case where those functions would test the access of the very last byte of the user address space. The string functions actually did that user range test before too, but they did it manually by just comparing against user_addr_max(). But with user_access_begin() doing the check (using "access_ok()"), it now exposed problems in the architecture implementations of that function. For example, on alpha, the access_ok() helper macro looked like this: #define __access_ok(addr, size) \ ((get_fs().seg & (addr | size | (addr+size))) == 0) and what it basically tests is of any of the high bits get set (the USER_DS masking value is 0xfffffc0000000000). And that's completely wrong for the "addr+size" check. Because it's off-by-one for the case where we check to the very end of the user address space, which is exactly what the strn*_user() functions do. Why? Because "addr+size" will be exactly the size of the address space, so trying to access the last byte of the user address space will fail the __access_ok() check, even though it shouldn't. As a result, the user string accessor functions failed consistently - because they literally don't know how long the string is going to be, and the max access is going to be that last byte of the user address space. Side note: that alpha macro is buggy for another reason too - it re-uses the arguments twice. And SH has another version of almost the exact same bug: #define __addr_ok(addr) \ ((unsigned long __force)(addr) < current_thread_info()->addr_limit.seg) so far so good: yes, a user address must be below the limit. But then: #define __access_ok(addr, size) \ (__addr_ok((addr) + (size))) is wrong with the exact same off-by-one case: the case when "addr+size" is exactly _equal_ to the limit is actually perfectly fine (think "one byte access at the last address of the user address space") The SH version is actually seriously buggy in another way: it doesn't actually check for overflow, even though it did copy the _comment_ that talks about overflow. So it turns out that both SH and alpha actually have completely buggy implementations of access_ok(), but they happened to work in practice (although the SH overflow one is a serious serious security bug, not that anybody likely cares about SH security). This fixes the problems by using a similar macro on both alpha and SH. It isn't trying to be clever, the end address is based on this logic: unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b; which basically says "add start and length, and then subtract one unless the length was zero". We can't subtract one for a zero length, or we'd just hit an underflow instead. For a lot of access_ok() users the length is a constant, so this isn't actually as expensive as it initially looks. Reported-and-tested-by:
Guenter Roeck <linux@roeck-us.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by:
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Masahiro Yamada authored
You do not have to use define ... endef for filechk_* rules. For simple cases, the use of assignment looks cleaner, IMHO. I updated the usage for scripts/Kbuild.include in case somebody misunderstands the 'define ... endif' is the requirement. Signed-off-by:
Heiko Carstens <heiko.carstens@de.ibm.com>
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Masahiro Yamada authored
Now that Kbuild automatically creates asm-generic wrappers for missing mandatory headers, it is redundant to list the same headers in generic-y and mandatory-y. Suggested-by:
Sam Ravnborg <sam@ravnborg.org> Signed-off-by:
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Masahiro Yamada authored
These comments are leftovers of commit fcc8487d ("uapi: export all headers under uapi directories"). Prior to that commit, exported headers must be explicitly added to header-y. Now, all headers under the uapi/ directories are exported. Signed-off-by:
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Masahiro Yamada authored
This commit removes redundant generic-y defines in arch/riscv/include/asm/Kbuild. [1] It is redundant to define the same generic-y in both arch/$(ARCH)/include/asm/Kbuild and arch/$(ARCH)/include/uapi/asm/Kbuild. Remove the following generic-y: errno.h fcntl.h ioctl.h ioctls.h ipcbuf.h mman.h msgbuf.h param.h poll.h posix_types.h resource.h sembuf.h setup.h shmbuf.h signal.h socket.h sockios.h stat.h statfs.h swab.h termbits.h termios.h types.h [2] It is redundant to define generic-y when arch-specific implementation exists in arch/$(ARCH)/include/asm/*.h Remove the following generic-y: cacheflush.h module.h Signed-off-by: -
Masahiro Yamada authored
filechk_* rules often consist of multiple 'echo' lines. They must be surrounded with { } or ( ) to work correctly. Otherwise, only the string from the last 'echo' would be written into the target. Let's take care of that in the 'filechk' in scripts/Kbuild.include to clean up filechk_* rules. Signed-off-by: -
Masahiro Yamada authored
Since commit 9c2af1c7 ("kbuild: add .DELETE_ON_ERROR special target"), the target file is automatically deleted on failure. The boilerplate code ... || { rm -f $@; false; } is unneeded. Signed-off-by:
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Masahiro Yamada authored
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label". The jump label is controlled by HAVE_JUMP_LABEL, which is defined like this: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif We can improve this by testing 'asm goto' support in Kconfig, then make JUMP_LABEL depend on CC_HAS_ASM_GOTO. Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will match to the real kernel capability. Signed-off-by:
Sedat Dilek <sedat.dilek@gmail.com>
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Masahiro Yamada authored
This commit removes redundant generic-y defines in arch/nds32/include/asm/Kbuild. [1] It is redundant to define the same generic-y in both arch/$(ARCH)/include/asm/Kbuild and arch/$(ARCH)/include/uapi/asm/Kbuild. Remove the following generic-y: bitsperlong.h bpf_perf_event.h errno.h fcntl.h ioctl.h ioctls.h mman.h shmbuf.h stat.h [2] It is redundant to define generic-y when arch-specific implementation exists in arch/$(ARCH)/include/asm/*.h Remove the following generic-y: ftrace.h Signed-off-by: -
Masahiro Yamada authored
kernel/dma/Kconfig globally defines HAS_DMA as follows: config HAS_DMA bool depends on !NO_DMA default y Signed-off-by:Christoph Hellwig <hch@lst.de>
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- Jan 05, 2019
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Christoph Hellwig authored
In many cases we don't have to create a GART mapping at all, which also means there is nothing to unmap. Fix the range check that was incorrectly modified when removing the mapping_error method. Fixes: 9e8aa6b5 ("x86/amd_gart: remove the mapping_error dma_map_ops method") Reported-by:
Michal Kubecek <mkubecek@suse.cz> Signed-off-by:
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Christoph Hellwig authored
Some non-generic ia64 configs don't build swiotlb, and thus should not pull in the generic non-coherent DMA infrastructure. Fixes: 68c60834 ("swiotlb: remove dma_mark_clean") Reported-by:
Tony Luck <tony.luck@gmail.com> Signed-off-by:
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Linus Torvalds authored
This has been broken forever, and nobody ever really noticed because it's purely a performance issue. Long long ago, in commit 6175ddf0 ("x86: Clean up mem*io functions") Brian Gerst simplified the memory copies to and from iomem, since on x86, the instructions to access iomem are exactly the same as the regular instructions. That is technically true, and things worked, and nobody said anything. Besides, back then the regular memcpy was pretty simple and worked fine. Nobody noticed except for David Laight, that is. David has a testing a TLP monitor he was writing for an FPGA, and has been occasionally complaining about how memcpy_toio() writes things one byte at a time. Which is completely unacceptable from a performance standpoint, even if it happens to technically work. The reason it's writing one byte at a time is because while it's technically true that accesses to iomem are the same as accesses to regular memory on x86, the _granularity_ (and ordering) of accesses matter to iomem in ways that they don't matter to regular cached memory. In particular, when ERMS is set, we default to using "rep movsb" for larger memory copies. That is indeed perfectly fine for real memory, since the whole point is that the CPU is going to do cacheline optimizations and executes the memory copy efficiently for cached memory. With iomem? Not so much. With iomem, "rep movsb" will indeed work, but it will copy things one byte at a time. Slowly and ponderously. Now, originally, back in 2010 when commit 6175ddf0 was done, we didn't use ERMS, and this was much less noticeable. Our normal memcpy() was simpler in other ways too. Because in fact, it's not just about using the string instructions. Our memcpy() these days does things like "read and write overlapping values" to handle the last bytes of the copy. Again, for normal memory, overlapping accesses isn't an issue. For iomem? It can be. So this re-introduces the specialized memcpy_toio(), memcpy_fromio() and memset_io() functions. It doesn't particularly optimize them, but it tries to at least not be horrid, or do overlapping accesses. In fact, this uses the existing __inline_memcpy() function that we still had lying around that uses our very traditional "rep movsl" loop followed by movsw/movsb for the final bytes. Somebody may decide to try to improve on it, but if we've gone almost a decade with only one person really ever noticing and complaining, maybe it's not worth worrying about further, once it's not _completely_ broken? Reported-by:
David Laight <David.Laight@aculab.com> Signed-off-by:
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Linus Torvalds authored
This actually enables the __put_user_goto() functionality in unsafe_put_user(). For an example of the effect of this, this is the code generated for the unsafe_put_user(signo, &infop->si_signo, Efault); in the waitid() system call: movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_2] It's just one single store instruction, along with generating an exception table entry pointing to the Efault label case in case that instruction faults. Before, we would generate this: xorl %edx, %edx movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_3] testl %edx, %edx jne .L309 with the exception table generated for that 'mov' instruction causing us to jump to a stub that set %edx to -EFAULT and then jumped back to the 'testl' instruction. So not only do we now get rid of the extra code in the normal sequence, we also avoid unnecessarily keeping that extra error register live across it all. Signed-off-by: -
Linus Torvalds authored
This is finally the actual reason for the odd error handling in the "unsafe_get/put_user()" functions, introduced over three years ago. Using a "jump to error label" interface is somewhat odd, but very convenient as a programming interface, and more importantly, it fits very well with simply making the target be the exception handler address directly from the inline asm. The reason it took over three years to actually do this? We need "asm goto" support for it, which only became the default on x86 last year. It's now been a year that we've forced asm goto support (see commit e501ce95 "x86: Force asm-goto"), and so let's just do it here too. [ Side note: this commit was originally done back in 2016. The above commentary about timing is obviously about it only now getting merged into my real upstream tree - Linus ] Sadly, gcc still only supports "asm goto" with asms that do not have any outputs, so we are limited to only the put_user case for this. Maybe in several more years we can do the get_user case too. Signed-off-by:
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- Jan 04, 2019
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Helge Deller authored
The alternative coding patch for parisc in kernel 4.20 broke booting machines with PA8500-PA8700 CPUs. The problem is, that for such machines the parisc kernel automatically utilizes huge pages to access kernel text code, but the set_kernel_text_rw() function, which is used shortly before applying any alternative patches, didn't used the correctly hugepage-aligned addresses to remap the kernel text read-writeable. Fixes: 3847dab7 ("parisc: Add alternative coding infrastructure") Cc: <stable@vger.kernel.org> [4.20] Signed-off-by:
Helge Deller <deller@gmx.de>
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Masahiro Yamada authored
Enable the UniPhier MIO DMAC driver. This is used as the DMA engine for accelerating the SD/eMMC controller drivers. Signed-off-by:
Olof Johansson <olof@lixom.net>
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Davidlohr Bueso authored
This is already done for us internally by the signal machinery. Link: http://lkml.kernel.org/r/20181116002713.8474-4-dave@stgolabs.net Signed-off-by:
Davidlohr Bueso <dave@stgolabs.net> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by:
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Joel Fernandes (Google) authored
Moving page-tables at the PMD-level on x86 is known to be safe. Enable this option so that we can do fast mremap when possible. Link: http://lkml.kernel.org/r/20181108181201.88826-4-joelaf@google.com Signed-off-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Suggested-by:
Kirill A. Shutemov <kirill@shutemov.name> Acked-by:
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