ca520cab25
Pull locking and atomic updates from Ingo Molnar:
"Main changes in this cycle are:
- Extend atomic primitives with coherent logic op primitives
(atomic_{or,and,xor}()) and deprecate the old partial APIs
(atomic_{set,clear}_mask())
The old ops were incoherent with incompatible signatures across
architectures and with incomplete support. Now every architecture
supports the primitives consistently (by Peter Zijlstra)
- Generic support for 'relaxed atomics':
- _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return()
- atomic_read_acquire()
- atomic_set_release()
This came out of porting qwrlock code to arm64 (by Will Deacon)
- Clean up the fragile static_key APIs that were causing repeat bugs,
by introducing a new one:
DEFINE_STATIC_KEY_TRUE(name);
DEFINE_STATIC_KEY_FALSE(name);
which define a key of different types with an initial true/false
value.
Then allow:
static_branch_likely()
static_branch_unlikely()
to take a key of either type and emit the right instruction for the
case. To be able to know the 'type' of the static key we encode it
in the jump entry (by Peter Zijlstra)
- Static key self-tests (by Jason Baron)
- qrwlock optimizations (by Waiman Long)
- small futex enhancements (by Davidlohr Bueso)
- ... and misc other changes"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits)
jump_label/x86: Work around asm build bug on older/backported GCCs
locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations
locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h
locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics
locking/qrwlock: Implement queue_write_unlock() using smp_store_release()
locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition
locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t'
locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication
locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations
locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
locking/static_keys: Make verify_keys() static
jump label, locking/static_keys: Update docs
locking/static_keys: Provide a selftest
jump_label: Provide a self-test
s390/uaccess, locking/static_keys: employ static_branch_likely()
x86, tsc, locking/static_keys: Employ static_branch_likely()
locking/static_keys: Add selftest
locking/static_keys: Add a new static_key interface
locking/static_keys: Rework update logic
locking/static_keys: Add static_key_{en,dis}able() helpers
...
380 lines
9.8 KiB
C
380 lines
9.8 KiB
C
/*
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* Standard user space access functions based on mvcp/mvcs and doing
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* interesting things in the secondary space mode.
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*
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* Copyright IBM Corp. 2006,2014
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Gerald Schaefer (gerald.schaefer@de.ibm.com)
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*/
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#include <linux/jump_label.h>
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#include <linux/uaccess.h>
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#include <linux/export.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <asm/mmu_context.h>
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#include <asm/facility.h>
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static DEFINE_STATIC_KEY_FALSE(have_mvcos);
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static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
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unsigned long size)
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{
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register unsigned long reg0 asm("0") = 0x81UL;
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unsigned long tmp1, tmp2;
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tmp1 = -4096UL;
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asm volatile(
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"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
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"9: jz 7f\n"
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"1: algr %0,%3\n"
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" slgr %1,%3\n"
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" slgr %2,%3\n"
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" j 0b\n"
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"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
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" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
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" slgr %4,%1\n"
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" clgr %0,%4\n" /* copy crosses next page boundary? */
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" jnh 4f\n"
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"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
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"10:slgr %0,%4\n"
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" algr %2,%4\n"
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"4: lghi %4,-1\n"
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" algr %4,%0\n" /* copy remaining size, subtract 1 */
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" bras %3,6f\n" /* memset loop */
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" xc 0(1,%2),0(%2)\n"
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"5: xc 0(256,%2),0(%2)\n"
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" la %2,256(%2)\n"
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"6: aghi %4,-256\n"
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" jnm 5b\n"
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" ex %4,0(%3)\n"
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" j 8f\n"
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"7:slgr %0,%0\n"
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"8:\n"
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EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
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: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
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: "d" (reg0) : "cc", "memory");
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return size;
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}
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static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
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unsigned long size)
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{
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unsigned long tmp1, tmp2;
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load_kernel_asce();
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tmp1 = -256UL;
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asm volatile(
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" sacf 0\n"
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"0: mvcp 0(%0,%2),0(%1),%3\n"
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"10:jz 8f\n"
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"1: algr %0,%3\n"
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" la %1,256(%1)\n"
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" la %2,256(%2)\n"
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"2: mvcp 0(%0,%2),0(%1),%3\n"
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"11:jnz 1b\n"
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" j 8f\n"
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"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
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" lghi %3,-4096\n"
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" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
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" slgr %4,%1\n"
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" clgr %0,%4\n" /* copy crosses next page boundary? */
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" jnh 5f\n"
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"4: mvcp 0(%4,%2),0(%1),%3\n"
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"12:slgr %0,%4\n"
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" algr %2,%4\n"
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"5: lghi %4,-1\n"
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" algr %4,%0\n" /* copy remaining size, subtract 1 */
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" bras %3,7f\n" /* memset loop */
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" xc 0(1,%2),0(%2)\n"
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"6: xc 0(256,%2),0(%2)\n"
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" la %2,256(%2)\n"
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"7: aghi %4,-256\n"
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" jnm 6b\n"
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" ex %4,0(%3)\n"
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" j 9f\n"
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"8:slgr %0,%0\n"
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"9: sacf 768\n"
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EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
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EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
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: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
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: : "cc", "memory");
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return size;
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}
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unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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if (static_branch_likely(&have_mvcos))
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return copy_from_user_mvcos(to, from, n);
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return copy_from_user_mvcp(to, from, n);
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}
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EXPORT_SYMBOL(__copy_from_user);
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static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
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unsigned long size)
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{
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register unsigned long reg0 asm("0") = 0x810000UL;
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unsigned long tmp1, tmp2;
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tmp1 = -4096UL;
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asm volatile(
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"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
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"6: jz 4f\n"
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"1: algr %0,%3\n"
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" slgr %1,%3\n"
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" slgr %2,%3\n"
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" j 0b\n"
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"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
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" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
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" slgr %4,%1\n"
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" clgr %0,%4\n" /* copy crosses next page boundary? */
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" jnh 5f\n"
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"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
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"7: slgr %0,%4\n"
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" j 5f\n"
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"4: slgr %0,%0\n"
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"5:\n"
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EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
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: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
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: "d" (reg0) : "cc", "memory");
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return size;
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}
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static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
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unsigned long size)
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{
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unsigned long tmp1, tmp2;
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load_kernel_asce();
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tmp1 = -256UL;
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asm volatile(
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" sacf 0\n"
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"0: mvcs 0(%0,%1),0(%2),%3\n"
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"7: jz 5f\n"
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"1: algr %0,%3\n"
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" la %1,256(%1)\n"
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" la %2,256(%2)\n"
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"2: mvcs 0(%0,%1),0(%2),%3\n"
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"8: jnz 1b\n"
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" j 5f\n"
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"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
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" lghi %3,-4096\n"
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" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
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" slgr %4,%1\n"
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" clgr %0,%4\n" /* copy crosses next page boundary? */
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" jnh 6f\n"
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"4: mvcs 0(%4,%1),0(%2),%3\n"
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"9: slgr %0,%4\n"
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" j 6f\n"
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"5: slgr %0,%0\n"
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"6: sacf 768\n"
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EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
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EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
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: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
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: : "cc", "memory");
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return size;
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}
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unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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if (static_branch_likely(&have_mvcos))
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return copy_to_user_mvcos(to, from, n);
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return copy_to_user_mvcs(to, from, n);
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}
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EXPORT_SYMBOL(__copy_to_user);
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static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
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unsigned long size)
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{
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register unsigned long reg0 asm("0") = 0x810081UL;
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unsigned long tmp1, tmp2;
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tmp1 = -4096UL;
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/* FIXME: copy with reduced length. */
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asm volatile(
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"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
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" jz 2f\n"
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"1: algr %0,%3\n"
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" slgr %1,%3\n"
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" slgr %2,%3\n"
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" j 0b\n"
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"2:slgr %0,%0\n"
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"3: \n"
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EX_TABLE(0b,3b)
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: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
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: "d" (reg0) : "cc", "memory");
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return size;
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}
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static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
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unsigned long size)
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{
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unsigned long tmp1;
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load_kernel_asce();
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asm volatile(
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" sacf 256\n"
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" aghi %0,-1\n"
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" jo 5f\n"
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" bras %3,3f\n"
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"0: aghi %0,257\n"
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"1: mvc 0(1,%1),0(%2)\n"
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" la %1,1(%1)\n"
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" la %2,1(%2)\n"
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" aghi %0,-1\n"
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" jnz 1b\n"
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" j 5f\n"
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"2: mvc 0(256,%1),0(%2)\n"
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" la %1,256(%1)\n"
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" la %2,256(%2)\n"
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"3: aghi %0,-256\n"
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" jnm 2b\n"
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"4: ex %0,1b-0b(%3)\n"
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"5: slgr %0,%0\n"
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"6: sacf 768\n"
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EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
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: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
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: : "cc", "memory");
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return size;
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}
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unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
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{
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if (static_branch_likely(&have_mvcos))
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return copy_in_user_mvcos(to, from, n);
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return copy_in_user_mvc(to, from, n);
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}
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EXPORT_SYMBOL(__copy_in_user);
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static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
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{
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register unsigned long reg0 asm("0") = 0x810000UL;
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unsigned long tmp1, tmp2;
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tmp1 = -4096UL;
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asm volatile(
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"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
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" jz 4f\n"
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"1: algr %0,%2\n"
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" slgr %1,%2\n"
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" j 0b\n"
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"2: la %3,4095(%1)\n"/* %4 = to + 4095 */
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" nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
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" slgr %3,%1\n"
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" clgr %0,%3\n" /* copy crosses next page boundary? */
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" jnh 5f\n"
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"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
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" slgr %0,%3\n"
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" j 5f\n"
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"4:slgr %0,%0\n"
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"5:\n"
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EX_TABLE(0b,2b) EX_TABLE(3b,5b)
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: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
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: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
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return size;
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}
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static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
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{
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unsigned long tmp1, tmp2;
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load_kernel_asce();
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asm volatile(
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" sacf 256\n"
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" aghi %0,-1\n"
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" jo 5f\n"
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" bras %3,3f\n"
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" xc 0(1,%1),0(%1)\n"
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"0: aghi %0,257\n"
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" la %2,255(%1)\n" /* %2 = ptr + 255 */
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" srl %2,12\n"
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" sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
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" slgr %2,%1\n"
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" clgr %0,%2\n" /* clear crosses next page boundary? */
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" jnh 5f\n"
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" aghi %2,-1\n"
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"1: ex %2,0(%3)\n"
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" aghi %2,1\n"
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" slgr %0,%2\n"
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" j 5f\n"
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"2: xc 0(256,%1),0(%1)\n"
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" la %1,256(%1)\n"
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"3: aghi %0,-256\n"
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" jnm 2b\n"
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"4: ex %0,0(%3)\n"
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"5: slgr %0,%0\n"
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"6: sacf 768\n"
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EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
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: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
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: : "cc", "memory");
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return size;
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}
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unsigned long __clear_user(void __user *to, unsigned long size)
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{
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if (static_branch_likely(&have_mvcos))
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return clear_user_mvcos(to, size);
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return clear_user_xc(to, size);
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}
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EXPORT_SYMBOL(__clear_user);
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static inline unsigned long strnlen_user_srst(const char __user *src,
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unsigned long size)
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{
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register unsigned long reg0 asm("0") = 0;
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unsigned long tmp1, tmp2;
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asm volatile(
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" la %2,0(%1)\n"
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" la %3,0(%0,%1)\n"
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" slgr %0,%0\n"
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" sacf 256\n"
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"0: srst %3,%2\n"
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" jo 0b\n"
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" la %0,1(%3)\n" /* strnlen_user results includes \0 */
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" slgr %0,%1\n"
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"1: sacf 768\n"
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EX_TABLE(0b,1b)
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: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
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: "d" (reg0) : "cc", "memory");
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return size;
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}
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unsigned long __strnlen_user(const char __user *src, unsigned long size)
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{
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if (unlikely(!size))
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return 0;
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load_kernel_asce();
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return strnlen_user_srst(src, size);
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}
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EXPORT_SYMBOL(__strnlen_user);
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long __strncpy_from_user(char *dst, const char __user *src, long size)
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{
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size_t done, len, offset, len_str;
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if (unlikely(size <= 0))
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return 0;
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done = 0;
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do {
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offset = (size_t)src & ~PAGE_MASK;
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len = min(size - done, PAGE_SIZE - offset);
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if (copy_from_user(dst, src, len))
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return -EFAULT;
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len_str = strnlen(dst, len);
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done += len_str;
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src += len_str;
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dst += len_str;
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} while ((len_str == len) && (done < size));
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return done;
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}
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EXPORT_SYMBOL(__strncpy_from_user);
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static int __init uaccess_init(void)
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{
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if (test_facility(27))
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static_branch_enable(&have_mvcos);
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return 0;
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}
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early_initcall(uaccess_init);
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