Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
[S390] user-copy optimization fallout.
Fix new restore_sigregs function. It copies the user space copy of the
old psw without correcting the psw.mask and the psw.addr high order bit.
While we are at it, simplify save_sigregs a bit.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
+7
-10
+7
-10
arch/s390/kernel/signal.c
+7
-10
arch/s390/kernel/signal.c
···
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/* Returns non-zero on fault. */
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static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
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{
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-
unsigned long old_mask = regs->psw.mask;
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_sigregs user_sregs;
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save_access_regs(current->thread.acrs);
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/* Copy a 'clean' PSW mask to the user to avoid leaking
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information about whether PER is currently on. */
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regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
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memcpy(&user_sregs.regs.psw, ®s->psw, sizeof(sregs->regs.psw) +
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-
sizeof(sregs->regs.gprs));
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regs->psw.mask = old_mask;
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+
user_sregs.regs.psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
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user_sregs.regs.psw.addr = regs->psw.addr;
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memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
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memcpy(&user_sregs.regs.acrs, current->thread.acrs,
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sizeof(sregs->regs.acrs));
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/*
···
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/* Returns positive number on error */
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static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
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{
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unsigned long old_mask = regs->psw.mask;
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int err;
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_sigregs user_sregs;
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···
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
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regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
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regs->psw.addr |= PSW_ADDR_AMODE;
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if (err)
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return err;
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memcpy(®s->psw, &user_sregs.regs.psw, sizeof(sregs->regs.psw) +
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sizeof(sregs->regs.gprs));
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regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
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user_sregs.regs.psw.mask);
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regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
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memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
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memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
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sizeof(sregs->regs.acrs));
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restore_access_regs(current->thread.acrs);