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| author | kib <kib@FreeBSD.org> | 2018-01-14 09:29:06 +0000 |
|---|---|---|
| committer | Luiz Souza <luiz@netgate.com> | 2018-02-21 15:09:16 -0300 |
| commit | 001f0026e57a3eb35ce93f3eb9ee0fa92f4f9501 (patch) | |
| tree | 359e78ca0a3540200b0484b9b43e7fd49546f6e8 /sys/amd64/amd64/support.S | |
| parent | 6624855e9ca0cad07bc4fc708a1a580e14e219e4 (diff) | |
| download | FreeBSD-src-001f0026e57a3eb35ce93f3eb9ee0fa92f4f9501.zip FreeBSD-src-001f0026e57a3eb35ce93f3eb9ee0fa92f4f9501.tar.gz | |
MFC r327816, r327834:
Update comment explaining the check, to reality.
(cherry picked from commit e02369b09e64d8f72734fb231ef6480c8959c36f)
Diffstat (limited to 'sys/amd64/amd64/support.S')
| -rw-r--r-- | sys/amd64/amd64/support.S | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S index 041f5f1..efa023e 100644 --- a/sys/amd64/amd64/support.S +++ b/sys/amd64/amd64/support.S @@ -226,12 +226,11 @@ ENTRY(copyout) jz done_copyout /* - * Check explicitly for non-user addresses. If 486 write protection - * is being used, this check is essential because we are in kernel - * mode so the h/w does not provide any protection against writing - * kernel addresses. + * Check explicitly for non-user addresses. This check is essential + * because it prevents usermode from writing into the kernel. We do + * not verify anywhere else that the user did not specify a rogue + * address. */ - /* * First, prevent address wrapping. */ |
