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Code Activity

s390/signal: remove sigreturn on stack

Browse source 
{rt_}sigreturn is now called from the vdso, so we no longer
need the svc on the stack, and therefore no hack to support that
mechanism on machines with non-executable stack.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2021-06-25 15:06:06 +02:00 • committed by Vasily Gorbik
parent df29a7440c
commit fbf50f47ea
4 changed files with 2 additions and 36 deletions
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1
arch/s390/include/asm/entry-common.h
View file

@ -14,7 +14,6 @@
#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_GUARDED_STORAGE | _TIF_PER_TRAP)
void do_per_trap(struct pt_regs *regs);
void do_syscall(struct pt_regs *regs);
#ifdef CONFIG_DEBUG_ENTRY
static __always_inline void arch_check_user_regs(struct pt_regs *regs)

2
arch/s390/kernel/syscall.c
View file

@ -108,7 +108,7 @@ SYSCALL_DEFINE0(ni_syscall)
return -ENOSYS;
}
void do_syscall(struct pt_regs *regs)
static void do_syscall(struct pt_regs *regs)
{
unsigned long nr;

12
arch/s390/kernel/traps.c
View file

@ -301,10 +301,9 @@ static void (*pgm_check_table[128])(struct pt_regs *regs);
void noinstr __do_pgm_check(struct pt_regs *regs)
{
unsigned long last_break = S390_lowcore.breaking_event_addr;
unsigned int trapnr, syscall_redirect = 0;
unsigned int trapnr;
irqentry_state_t state;
add_random_kstack_offset();
regs->int_code = *(u32 *)&S390_lowcore.pgm_ilc;
regs->int_parm_long = S390_lowcore.trans_exc_code;
@ -346,18 +345,9 @@ void noinstr __do_pgm_check(struct pt_regs *regs)
trapnr = regs->int_code & PGM_INT_CODE_MASK;
if (trapnr)
pgm_check_table[trapnr](regs);
syscall_redirect = user_mode(regs) && test_pt_regs_flag(regs, PIF_SYSCALL);
out:
local_irq_disable();
irqentry_exit(regs, state);
if (syscall_redirect) {
enter_from_user_mode(regs);
local_irq_enable();
regs->orig_gpr2 = regs->gprs[2];
do_syscall(regs);
exit_to_user_mode();
}
}
/*

23
arch/s390/mm/fault.c
View file

@ -285,26 +285,6 @@ static noinline void do_sigbus(struct pt_regs *regs)
(void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK));
}
static noinline int signal_return(struct pt_regs *regs)
{
u16 instruction;
int rc;
rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
if (rc)
return rc;
if (instruction == 0x0a77) {
set_pt_regs_flag(regs, PIF_SYSCALL);
regs->int_code = 0x00040077;
return 0;
} else if (instruction == 0x0aad) {
set_pt_regs_flag(regs, PIF_SYSCALL);
regs->int_code = 0x000400ad;
return 0;
}
return -EACCES;
}
static noinline void do_fault_error(struct pt_regs *regs, int access,
vm_fault_t fault)
{
@ -312,9 +292,6 @@ static noinline void do_fault_error(struct pt_regs *regs, int access,
switch (fault) {
case VM_FAULT_BADACCESS:
if (access == VM_EXEC && signal_return(regs) == 0)
break;
fallthrough;
case VM_FAULT_BADMAP:
/* Bad memory access. Check if it is kernel or user space. */
if (user_mode(regs)) {