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s390/traps,mm: add conditional trap handlers

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Add conditional trap handlers similar to conditional system calls
(COND_SYSCALL), to reduce the number of ifdefs.

Trap handlers which may or may not exist depending on config options
are supposed to have a COND_TRAP entry, which redirects to
default_trap_handler() for non-existent trap handlers during link
time.

This allows to get rid of the secure execution trap handlers for the
!PGSTE case.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2021-04-09 10:34:43 +02:00
parent 61311e3289
commit 17a363dcd2
3 changed files with 12 additions and 18 deletions
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1
arch/s390/kernel/entry.h
View file

@ -26,7 +26,6 @@ void do_dat_exception(struct pt_regs *regs);
void do_secure_storage_access(struct pt_regs *regs);
void do_non_secure_storage_access(struct pt_regs *regs);
void do_secure_storage_violation(struct pt_regs *regs);
void default_trap_handler(struct pt_regs *regs);
void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str);
void kernel_stack_overflow(struct pt_regs * regs);
void do_signal(struct pt_regs *regs);

11
arch/s390/kernel/traps.c
View file

@ -79,7 +79,7 @@ void do_per_trap(struct pt_regs *regs)
}
NOKPROBE_SYMBOL(do_per_trap);
void default_trap_handler(struct pt_regs *regs)
static void default_trap_handler(struct pt_regs *regs)
{
if (user_mode(regs)) {
report_user_fault(regs, SIGSEGV, 0);
@ -404,3 +404,12 @@ static void (*pgm_check_table[128])(struct pt_regs *regs) = {
[0x40] = monitor_event_exception,
[0x41 ... 0x7f] = default_trap_handler,
};
#define COND_TRAP(x) asm( \
".weak " __stringify(x) "\n\t" \
".set " __stringify(x) "," \
__stringify(default_trap_handler))
COND_TRAP(do_secure_storage_access);
COND_TRAP(do_non_secure_storage_access);
COND_TRAP(do_secure_storage_violation);

18
arch/s390/mm/fault.c
View file

@ -783,6 +783,7 @@ early_initcall(pfault_irq_init);
#endif /* CONFIG_PFAULT */
#if IS_ENABLED(CONFIG_PGSTE)
void do_secure_storage_access(struct pt_regs *regs)
{
unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
@ -859,19 +860,4 @@ void do_secure_storage_violation(struct pt_regs *regs)
send_sig(SIGSEGV, current, 0);
}
#else
void do_secure_storage_access(struct pt_regs *regs)
{
default_trap_handler(regs);
}
void do_non_secure_storage_access(struct pt_regs *regs)
{
default_trap_handler(regs);
}
void do_secure_storage_violation(struct pt_regs *regs)
{
default_trap_handler(regs);
}
#endif
#endif /* CONFIG_PGSTE */