linux/arch/s390/include/asm/ctl_reg.h

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/*
* Copyright IBM Corp. 1999, 2009
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#ifndef __ASM_CTL_REG_H
#define __ASM_CTL_REG_H
#include <linux/bug.h>
#define __ctl_load(array, low, high) { \
typedef struct { char _[sizeof(array)]; } addrtype; \
\
BUILD_BUG_ON(sizeof(addrtype) != (high - low + 1) * sizeof(long));\
asm volatile( \
" lctlg %1,%2,%0\n" \
: : "Q" (*(addrtype *)(&array)), "i" (low), "i" (high));\
}
#define __ctl_store(array, low, high) { \
typedef struct { char _[sizeof(array)]; } addrtype; \
\
BUILD_BUG_ON(sizeof(addrtype) != (high - low + 1) * sizeof(long));\
asm volatile( \
" stctg %1,%2,%0\n" \
: "=Q" (*(addrtype *)(&array)) \
: "i" (low), "i" (high)); \
}
static inline void __ctl_set_bit(unsigned int cr, unsigned int bit)
{
unsigned long reg;
__ctl_store(reg, cr, cr);
reg |= 1UL << bit;
__ctl_load(reg, cr, cr);
}
static inline void __ctl_clear_bit(unsigned int cr, unsigned int bit)
{
unsigned long reg;
__ctl_store(reg, cr, cr);
reg &= ~(1UL << bit);
__ctl_load(reg, cr, cr);
}
void smp_ctl_set_bit(int cr, int bit);
void smp_ctl_clear_bit(int cr, int bit);
union ctlreg0 {
unsigned long val;
struct {
unsigned long : 32;
unsigned long : 3;
unsigned long lap : 1; /* Low-address-protection control */
unsigned long : 4;
unsigned long edat : 1; /* Enhanced-DAT-enablement control */
s390/nmi: fix vector register corruption If a machine check happens, the machine has the vector facility installed and the extended save area exists, the cpu will save vector register contents into the extended save area. This is regardless of control register 0 contents, which enables and disables the vector facility during runtime. On each machine check we should validate the vector registers. The current code however tries to validate the registers only if the running task is using vector registers in user space. However even the current code is broken and causes vector register corruption on machine checks, if user space uses them: the prefix area contains a pointer (absolute address) to the machine check extended save area. In order to save some space the save area was put into an unused area of the second prefix page. When validating vector register contents the code uses the absolute address of the extended save area, which is wrong. Due to prefixing the vector instructions will then access contents using absolute addresses instead of real addresses, where the machine stored the contents. If the above would work there is still the problem that register validition would only happen if user space uses vector registers. If kernel space uses them also, this may also lead to vector register content corruption: if the kernel makes use of vector instructions, but the current running user space context does not, the machine check handler will validate floating point registers instead of vector registers. Given the fact that writing to a floating point register may change the upper halve of the corresponding vector register, we also experience vector register corruption in this case. Fix all of these issues, and always validate vector registers on each machine check, if the machine has the vector facility installed and the extended save area is defined. Cc: <stable@vger.kernel.org> # 4.1+ Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-07 14:40:49 +08:00
unsigned long : 4;
unsigned long afp : 1; /* AFP-register control */
unsigned long vx : 1; /* Vector enablement control */
unsigned long : 17;
};
};
#ifdef CONFIG_SMP
# define ctl_set_bit(cr, bit) smp_ctl_set_bit(cr, bit)
# define ctl_clear_bit(cr, bit) smp_ctl_clear_bit(cr, bit)
#else
# define ctl_set_bit(cr, bit) __ctl_set_bit(cr, bit)
# define ctl_clear_bit(cr, bit) __ctl_clear_bit(cr, bit)
#endif
#endif /* __ASM_CTL_REG_H */