mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-01-08 14:23:19 +00:00
87d5986345
Remove set_fs support from s390. With doing this rework address space handling and simplify it. As a result address spaces are now setup like this: CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE ----------------------------|-----------|-----------|----------- user space | user | user | kernel kernel, normal execution | kernel | user | kernel kernel, kvm guest execution | gmap | user | kernel To achieve this the getcpu vdso syscall is removed in order to avoid secondary address mode and a separate vdso address space in for user space. The getcpu vdso syscall will be implemented differently with a subsequent patch. The kernel accesses user space always via secondary address space. This happens in different ways: - with mvcos in home space mode and directly read/write to secondary address space - with mvcs/mvcp in primary space mode and copy from primary space to secondary space or vice versa - with e.g. cs in secondary space mode and access secondary space Switching translation modes happens with sacf before and after instructions which access user space, like before. Lazy handling of control register reloading is removed in the hope to make everything simpler, but at the cost of making kernel entry and exit a bit slower. That is: on kernel entry the primary asce is always changed to contain the kernel asce, and on kernel exit the primary asce is changed again so it contains the user asce. In kernel mode there is only one exception to the primary asce: when kvm guests are executed the primary asce contains the gmap asce (which describes the guest address space). The primary asce is reset to kernel asce whenever kvm guest execution is interrupted, so that this doesn't has to be taken into account for any user space accesses. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
370 lines
9.4 KiB
C
370 lines
9.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
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static DEFINE_STATIC_KEY_FALSE(have_mvcos);
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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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static inline int copy_with_mvcos(void)
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{
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if (static_branch_likely(&have_mvcos))
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return 1;
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return 0;
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}
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#else
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static inline int copy_with_mvcos(void)
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{
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return 1;
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}
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#endif
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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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"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,%2),0(%1),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_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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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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"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: mvcp 0(%0,%2),0(%1),%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: mvcp 0(%4,%2),0(%1),%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 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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if (copy_with_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(raw_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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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 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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if (copy_with_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(raw_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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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 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
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{
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if (copy_with_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(raw_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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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 (copy_with_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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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 & (L1_CACHE_BYTES - 1);
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len = min(size - done, L1_CACHE_BYTES - 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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