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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2007-04-27 10:01:44 -0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-04-27 10:01:43 -0400
commitbe5ec363e958982454ac9b3138b0e78c032e758d (patch)
tree044e5e1baa1e878538fcd4ec6b6e7d7c0f009203 /arch/s390/mm
parent10c1031f706bbe0690d84cdbccad15b11c6dc661 (diff)
[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: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/fault.c72
1 files changed, 21 insertions, 51 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 8bc35183db59..2b76a879a7b5 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -26,9 +26,9 @@
26#include <linux/module.h> 26#include <linux/module.h>
27#include <linux/hardirq.h> 27#include <linux/hardirq.h>
28#include <linux/kprobes.h> 28#include <linux/kprobes.h>
29#include <linux/uaccess.h>
29 30
30#include <asm/system.h> 31#include <asm/system.h>
31#include <asm/uaccess.h>
32#include <asm/pgtable.h> 32#include <asm/pgtable.h>
33#include <asm/kdebug.h> 33#include <asm/kdebug.h>
34#include <asm/s390_ext.h> 34#include <asm/s390_ext.h>
@@ -263,68 +263,38 @@ extern long sys_rt_sigreturn(struct pt_regs *regs);
263extern long sys32_sigreturn(struct pt_regs *regs); 263extern long sys32_sigreturn(struct pt_regs *regs);
264extern long sys32_rt_sigreturn(struct pt_regs *regs); 264extern long sys32_rt_sigreturn(struct pt_regs *regs);
265 265
266static inline void do_sigreturn(struct mm_struct *mm, struct pt_regs *regs, 266static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
267 int rt) 267 unsigned long address, unsigned long error_code)
268{ 268{
269 u16 instruction;
270 int rc, compat;
271
272 pagefault_disable();
273 rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
274 pagefault_enable();
275 if (rc)
276 return -EFAULT;
277
269 up_read(&mm->mmap_sem); 278 up_read(&mm->mmap_sem);
270 clear_tsk_thread_flag(current, TIF_SINGLE_STEP); 279 clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
271#ifdef CONFIG_COMPAT 280#ifdef CONFIG_COMPAT
272 if (test_tsk_thread_flag(current, TIF_31BIT)) { 281 compat = test_tsk_thread_flag(current, TIF_31BIT);
273 if (rt) 282 if (compat && instruction == 0x0a77)
274 sys32_rt_sigreturn(regs); 283 sys32_sigreturn(regs);
275 else 284 else if (compat && instruction == 0x0aad)
276 sys32_sigreturn(regs); 285 sys32_rt_sigreturn(regs);
277 return;
278 }
279#endif /* CONFIG_COMPAT */
280 if (rt)
281 sys_rt_sigreturn(regs);
282 else 286 else
287#endif
288 if (instruction == 0x0a77)
283 sys_sigreturn(regs); 289 sys_sigreturn(regs);
284 return; 290 else if (instruction == 0x0aad)
285} 291 sys_rt_sigreturn(regs);
286
287static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
288 unsigned long address, unsigned long error_code)
289{
290 pgd_t *pgd;
291 pmd_t *pmd;
292 pte_t *pte;
293 u16 *instruction;
294 unsigned long pfn, uaddr = regs->psw.addr;
295
296 spin_lock(&mm->page_table_lock);
297 pgd = pgd_offset(mm, uaddr);
298 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
299 goto out_fault;
300 pmd = pmd_offset(pgd, uaddr);
301 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
302 goto out_fault;
303 pte = pte_offset_map(pmd_offset(pgd_offset(mm, uaddr), uaddr), uaddr);
304 if (!pte || !pte_present(*pte))
305 goto out_fault;
306 pfn = pte_pfn(*pte);
307 if (!pfn_valid(pfn))
308 goto out_fault;
309 spin_unlock(&mm->page_table_lock);
310
311 instruction = (u16 *) ((pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE-1)));
312 if (*instruction == 0x0a77)
313 do_sigreturn(mm, regs, 0);
314 else if (*instruction == 0x0aad)
315 do_sigreturn(mm, regs, 1);
316 else { 292 else {
317 printk("- XXX - do_exception: task = %s, primary, NO EXEC "
318 "-> SIGSEGV\n", current->comm);
319 up_read(&mm->mmap_sem);
320 current->thread.prot_addr = address; 293 current->thread.prot_addr = address;
321 current->thread.trap_no = error_code; 294 current->thread.trap_no = error_code;
322 do_sigsegv(regs, error_code, SEGV_MAPERR, address); 295 do_sigsegv(regs, error_code, SEGV_MAPERR, address);
323 } 296 }
324 return 0; 297 return 0;
325out_fault:
326 spin_unlock(&mm->page_table_lock);
327 return -EFAULT;
328} 298}
329#endif /* CONFIG_S390_EXEC_PROTECT */ 299#endif /* CONFIG_S390_EXEC_PROTECT */
330 300