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authorLinus Torvalds <torvalds@linux-foundation.org>2021-06-20 09:09:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-20 09:09:58 -0700
commit8363e795eb79a74c857ba89e3b04668a33fe3344 (patch)
treeedfdbfa3be22e945ce84260d2a48b7fb6cdac210 /arch/x86/include/asm
parentb84a7c286cecf0604a5f8bd5dfcd5e1ca7233e15 (diff)
parent28e5e44aa3f4e0e0370864ed008fb5e2d85f4dc8 (diff)
Merge tag 'x86_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov: "A first set of urgent fixes to the FPU/XSTATE handling mess^W code. (There's a lot more in the pipe): - Prevent corruption of the XSTATE buffer in signal handling by validating what is being copied from userspace first. - Invalidate other task's preserved FPU registers on XRSTOR failure (#PF) because latter can still modify some of them. - Restore the proper PKRU value in case userspace modified it - Reset FPU state when signal restoring fails Other: - Map EFI boot services data memory as encrypted in a SEV guest so that the guest can access it and actually boot properly - Two SGX correctness fixes: proper resources freeing and a NUMA fix" * tag 'x86_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Avoid truncating memblocks for SGX memory x86/sgx: Add missing xa_destroy() when virtual EPC is destroyed x86/fpu: Reset state for all signal restore failures x86/pkru: Write hardware init value to PKRU when xstate is init x86/process: Check PF_KTHREAD and not current->mm for kernel threads x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer x86/fpu: Prevent state corruption in __fpu__restore_sig() x86/ioremap: Map EFI-reserved memory as encrypted for SEV
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/fpu/internal.h13
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index ceeba9f63172..fdee23ea4e17 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -578,10 +578,17 @@ static inline void switch_fpu_finish(struct fpu *new_fpu)
* PKRU state is switched eagerly because it needs to be valid before we
* return to userland e.g. for a copy_to_user() operation.
*/
- if (current->mm) {
+ if (!(current->flags & PF_KTHREAD)) {
+ /*
+ * If the PKRU bit in xsave.header.xfeatures is not set,
+ * then the PKRU component was in init state, which means
+ * XRSTOR will set PKRU to 0. If the bit is not set then
+ * get_xsave_addr() will return NULL because the PKRU value
+ * in memory is not valid. This means pkru_val has to be
+ * set to 0 and not to init_pkru_value.
+ */
pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
- if (pk)
- pkru_val = pk->pkru;
+ pkru_val = pk ? pk->pkru : 0;
}
__write_pkru(pkru_val);
}