Commit be5ec363 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

[S390] No execute support cleanup.



Simplify the signal_return function that checks for the two special
system calls sigreturn and rt_sigreturn. No need to do a page table
walk, a call to copy_from_user while disabled page faults will work
as well.
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent 10c1031f
......@@ -26,9 +26,9 @@
#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
#include <asm/s390_ext.h>
......@@ -263,68 +263,38 @@ extern long sys_rt_sigreturn(struct pt_regs *regs);
extern long sys32_sigreturn(struct pt_regs *regs);
extern long sys32_rt_sigreturn(struct pt_regs *regs);
static inline void do_sigreturn(struct mm_struct *mm, struct pt_regs *regs,
int rt)
static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
unsigned long address, unsigned long error_code)
{
u16 instruction;
int rc, compat;
pagefault_disable();
rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
pagefault_enable();
if (rc)
return -EFAULT;
up_read(&mm->mmap_sem);
clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(current, TIF_31BIT)) {
if (rt)
sys32_rt_sigreturn(regs);
else
sys32_sigreturn(regs);
return;
}
#endif /* CONFIG_COMPAT */
if (rt)
sys_rt_sigreturn(regs);
compat = test_tsk_thread_flag(current, TIF_31BIT);
if (compat && instruction == 0x0a77)
sys32_sigreturn(regs);
else if (compat && instruction == 0x0aad)
sys32_rt_sigreturn(regs);
else
#endif
if (instruction == 0x0a77)
sys_sigreturn(regs);
return;
}
static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
unsigned long address, unsigned long error_code)
{
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
u16 *instruction;
unsigned long pfn, uaddr = regs->psw.addr;
spin_lock(&mm->page_table_lock);
pgd = pgd_offset(mm, uaddr);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
goto out_fault;
pmd = pmd_offset(pgd, uaddr);
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
goto out_fault;
pte = pte_offset_map(pmd_offset(pgd_offset(mm, uaddr), uaddr), uaddr);
if (!pte || !pte_present(*pte))
goto out_fault;
pfn = pte_pfn(*pte);
if (!pfn_valid(pfn))
goto out_fault;
spin_unlock(&mm->page_table_lock);
instruction = (u16 *) ((pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE-1)));
if (*instruction == 0x0a77)
do_sigreturn(mm, regs, 0);
else if (*instruction == 0x0aad)
do_sigreturn(mm, regs, 1);
else if (instruction == 0x0aad)
sys_rt_sigreturn(regs);
else {
printk("- XXX - do_exception: task = %s, primary, NO EXEC "
"-> SIGSEGV\n", current->comm);
up_read(&mm->mmap_sem);
current->thread.prot_addr = address;
current->thread.trap_no = error_code;
do_sigsegv(regs, error_code, SEGV_MAPERR, address);
}
return 0;
out_fault:
spin_unlock(&mm->page_table_lock);
return -EFAULT;
}
#endif /* CONFIG_S390_EXEC_PROTECT */
......
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