Commit 4f63b320 authored Mar 05, 2020 by Alexey Dobriyan Committed by Borislav Petkov Feb 05, 2021

x86/asm: Fixup TASK_SIZE_MAX comment



Comment says "by preventing anything executable" which is not true. Even
PROT_NONE mapping can't be installed at (1<<47 - 4096).

  mmap(0x7ffffffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM

 [ bp: Fixup to the moved location in page_64_types.h. ]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200305181719.GA5490@avx2

parent f22fecaf

arch/x86/include/asm/page_64_types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -66,7 +66,7 @@
		* On Intel CPUs, if a SYSCALL instruction is at the highest canonical
		* address, then that syscall will enter the kernel with a
		* non-canonical return address, and SYSRET will explode dangerously.
		* We avoid this particular problem by preventing anything executable
		* We avoid this particular problem by preventing anything
		* from being mapped at the maximum canonical address.
		*
		* On AMD CPUs in the Ryzen family, there's a nasty bug in which the