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// SPDX-License-Identifier: GPL-2.0
/*
* Standard user space access functions based on mvcp/mvcs and doing
* interesting things in the secondary space mode.
*
* Copyright IBM Corp. 2006,2014
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <asm/asm-extable.h>
#include <asm/ctlreg.h>
#include <asm/skey.h>
#ifdef CONFIG_DEBUG_ENTRY
void debug_user_asce(int exit)
{
struct lowcore *lc = get_lowcore();
struct ctlreg cr1, cr7;
local_ctl_store(1, &cr1);
local_ctl_store(7, &cr7);
if (cr1.val == lc->user_asce.val && cr7.val == lc->user_asce.val)
return;
panic("incorrect ASCE on kernel %s\n"
"cr1: %016lx cr7: %016lx\n"
"kernel: %016lx user: %016lx\n",
exit ? "exit" : "entry", cr1.val, cr7.val,
lc->kernel_asce.val, lc->user_asce.val);
}
#endif /*CONFIG_DEBUG_ENTRY */
#define CMPXCHG_USER_KEY_MAX_LOOPS 128
static nokprobe_inline int __cmpxchg_key_small(void *address, unsigned int *uval,
unsigned int old, unsigned int new,
unsigned int mask, unsigned long key)
{
unsigned long count;
unsigned int prev;
int rc = 0;
skey_regions_initialize();
asm_inline volatile(
"20: spka 0(%[key])\n"
" llill %[count],%[max_loops]\n"
"0: l %[prev],%[address]\n"
"1: nr %[prev],%[mask]\n"
" xilf %[mask],0xffffffff\n"
" or %[new],%[prev]\n"
" or %[prev],%[tmp]\n"
"2: lr %[tmp],%[prev]\n"
"3: cs %[prev],%[new],%[address]\n"
"4: jnl 5f\n"
" xr %[tmp],%[prev]\n"
" xr %[new],%[tmp]\n"
" nr %[tmp],%[mask]\n"
" jnz 5f\n"
" brct %[count],2b\n"
"5: spka %[default_key]\n"
"21:\n"
EX_TABLE_UA_LOAD_REG(0b, 5b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REG(1b, 5b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REG(3b, 5b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REG(4b, 5b, %[rc], %[prev])
SKEY_REGION(20b, 21b)
: [rc] "+&d" (rc),
[prev] "=&d" (prev),
[address] "+Q" (*(int *)address),
[tmp] "+&d" (old),
[new] "+&d" (new),
[mask] "+&d" (mask),
[count] "=a" (count)
: [key] "%[count]" (key << 4),
[default_key] "J" (PAGE_DEFAULT_KEY),
[max_loops] "J" (CMPXCHG_USER_KEY_MAX_LOOPS)
: "memory", "cc");
*uval = prev;
if (!count)
rc = -EAGAIN;
return rc;
}
int __kprobes __cmpxchg_key1(void *addr, unsigned char *uval, unsigned char old,
unsigned char new, unsigned long key)
{
unsigned long address = (unsigned long)addr;
unsigned int prev, shift, mask, _old, _new;
int rc;
shift = (3 ^ (address & 3)) << 3;
address ^= address & 3;
_old = (unsigned int)old << shift;
_new = (unsigned int)new << shift;
mask = ~(0xff << shift);
rc = __cmpxchg_key_small((void *)address, &prev, _old, _new, mask, key);
*uval = prev >> shift;
return rc;
}
EXPORT_SYMBOL(__cmpxchg_key1);
int __kprobes __cmpxchg_key2(void *addr, unsigned short *uval, unsigned short old,
unsigned short new, unsigned long key)
{
unsigned long address = (unsigned long)addr;
unsigned int prev, shift, mask, _old, _new;
int rc;
shift = (2 ^ (address & 2)) << 3;
address ^= address & 2;
_old = (unsigned int)old << shift;
_new = (unsigned int)new << shift;
mask = ~(0xffff << shift);
rc = __cmpxchg_key_small((void *)address, &prev, _old, _new, mask, key);
*uval = prev >> shift;
return rc;
}
EXPORT_SYMBOL(__cmpxchg_key2);
int __kprobes __cmpxchg_key4(void *address, unsigned int *uval, unsigned int old,
unsigned int new, unsigned long key)
{
unsigned int prev = old;
int rc = 0;
skey_regions_initialize();
asm_inline volatile(
"20: spka 0(%[key])\n"
"0: cs %[prev],%[new],%[address]\n"
"1: spka %[default_key]\n"
"21:\n"
EX_TABLE_UA_LOAD_REG(0b, 1b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REG(1b, 1b, %[rc], %[prev])
SKEY_REGION(20b, 21b)
: [rc] "+&d" (rc),
[prev] "+&d" (prev),
[address] "+Q" (*(int *)address)
: [new] "d" (new),
[key] "a" (key << 4),
[default_key] "J" (PAGE_DEFAULT_KEY)
: "memory", "cc");
*uval = prev;
return rc;
}
EXPORT_SYMBOL(__cmpxchg_key4);
int __kprobes __cmpxchg_key8(void *address, unsigned long *uval, unsigned long old,
unsigned long new, unsigned long key)
{
unsigned long prev = old;
int rc = 0;
skey_regions_initialize();
asm_inline volatile(
"20: spka 0(%[key])\n"
"0: csg %[prev],%[new],%[address]\n"
"1: spka %[default_key]\n"
"21:\n"
EX_TABLE_UA_LOAD_REG(0b, 1b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REG(1b, 1b, %[rc], %[prev])
SKEY_REGION(20b, 21b)
: [rc] "+&d" (rc),
[prev] "+&d" (prev),
[address] "+QS" (*(long *)address)
: [new] "d" (new),
[key] "a" (key << 4),
[default_key] "J" (PAGE_DEFAULT_KEY)
: "memory", "cc");
*uval = prev;
return rc;
}
EXPORT_SYMBOL(__cmpxchg_key8);
int __kprobes __cmpxchg_key16(void *address, __uint128_t *uval, __uint128_t old,
__uint128_t new, unsigned long key)
{
__uint128_t prev = old;
int rc = 0;
skey_regions_initialize();
asm_inline volatile(
"20: spka 0(%[key])\n"
"0: cdsg %[prev],%[new],%[address]\n"
"1: spka %[default_key]\n"
"21:\n"
EX_TABLE_UA_LOAD_REGPAIR(0b, 1b, %[rc], %[prev])
EX_TABLE_UA_LOAD_REGPAIR(1b, 1b, %[rc], %[prev])
SKEY_REGION(20b, 21b)
: [rc] "+&d" (rc),
[prev] "+&d" (prev),
[address] "+QS" (*(__int128_t *)address)
: [new] "d" (new),
[key] "a" (key << 4),
[default_key] "J" (PAGE_DEFAULT_KEY)
: "memory", "cc");
*uval = prev;
return rc;
}
EXPORT_SYMBOL(__cmpxchg_key16);
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