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[S390] addressing mode limits and psw address wrapping

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An instruction with an address right below the adress limit for the
current addressing mode will wrap. The instruction restart logic in
the protection fault handler and the signal code need to follow the
wrapping rules to find the correct instruction address.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2011-10-30 15:16:48 +01:00
parent 20b40a794b
commit ccf45cafb0
4 changed files with 29 additions and 4 deletions
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22
arch/s390/include/asm/processor.h
View File

@ -187,7 +187,6 @@ static inline void __load_psw(psw_t psw)
* Set PSW mask to specified value, while leaving the
* PSW addr pointing to the next instruction.
*/
static inline void __load_psw_mask (unsigned long mask)
{
unsigned long addr;
@ -212,6 +211,27 @@ static inline void __load_psw_mask (unsigned long mask)
: "=&d" (addr), "=Q" (psw) : "Q" (psw) : "memory", "cc");
#endif /* __s390x__ */
}
/*
* Rewind PSW instruction address by specified number of bytes.
*/
static inline unsigned long __rewind_psw(psw_t psw, unsigned long ilc)
{
#ifndef __s390x__
if (psw.addr & PSW_ADDR_AMODE)
/* 31 bit mode */
return (psw.addr - ilc) | PSW_ADDR_AMODE;
/* 24 bit mode */
return (psw.addr - ilc) & ((1UL << 24) - 1);
#else
unsigned long mask;
mask = (psw.mask & PSW_MASK_EA) ? -1UL :
(psw.mask & PSW_MASK_BA) ? (1UL << 31) - 1 :
(1UL << 24) - 1;
return (psw.addr - ilc) & mask;
#endif
}
/*
* Function to stop a processor until an interruption occurred

4
arch/s390/include/asm/ptrace.h
View File

@ -236,6 +236,8 @@ typedef struct
#define PSW_MASK_ASC 0x0000C000UL
#define PSW_MASK_CC 0x00003000UL
#define PSW_MASK_PM 0x00000F00UL
#define PSW_MASK_EA 0x00000000UL
#define PSW_MASK_BA 0x00000000UL
#define PSW_ADDR_AMODE 0x80000000UL
#define PSW_ADDR_INSN 0x7FFFFFFFUL
@ -261,6 +263,8 @@ typedef struct
#define PSW_MASK_ASC 0x0000C00000000000UL
#define PSW_MASK_CC 0x0000300000000000UL
#define PSW_MASK_PM 0x00000F0000000000UL
#define PSW_MASK_EA 0x0000000100000000UL
#define PSW_MASK_BA 0x0000000080000000UL
#define PSW_ADDR_AMODE 0x0000000000000000UL
#define PSW_ADDR_INSN 0xFFFFFFFFFFFFFFFFUL

5
arch/s390/kernel/signal.c
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@ -447,8 +447,9 @@ void do_signal(struct pt_regs *regs)
/* fallthrough */
case -ERESTARTNOINTR:
regs->gprs[2] = regs->orig_gpr2;
regs->psw.addr = regs->psw.addr -
(regs->svc_code >> 16);
regs->psw.addr =
__rewind_psw(regs->psw,
regs->svc_code >> 16);
break;
}
/* No longer in a system call */

2
arch/s390/mm/fault.c
View File

@ -393,7 +393,7 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long pgm_int_code,
int fault;
/* Protection exception is suppressing, decrement psw address. */
regs->psw.addr -= (pgm_int_code >> 16);
regs->psw.addr = __rewind_psw(regs->psw, pgm_int_code >> 16);
/*
* Check for low-address protection. This needs to be treated
* as a special case because the translation exception code