Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1518968 > unrolled thread
| Started by | Borislav Petkov <bp@alien8.de> |
|---|---|
| First post | 2016-11-10 14:20 +0100 |
| Last post | 2016-11-11 02:30 +0100 |
| Articles | 2 — 2 participants |
Back to article view | Back to linux.kernel
This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by
below is the oldest one visible, not the original post.
Re: [RFC PATCH v3 02/20] x86: Set the write-protect cache mode for full PAT support Borislav Petkov <bp@alien8.de> - 2016-11-10 14:20 +0100
Re: [RFC PATCH v3 02/20] x86: Set the write-protect cache mode for full PAT support "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2016-11-11 02:30 +0100
| From | Borislav Petkov <bp@alien8.de> |
|---|---|
| Date | 2016-11-10 14:20 +0100 |
| Subject | Re: [RFC PATCH v3 02/20] x86: Set the write-protect cache mode for full PAT support |
| Message-ID | <sBXqN-6H1-5@gated-at.bofh.it> |
+ Toshi.
On Wed, Nov 09, 2016 at 06:34:48PM -0600, Tom Lendacky wrote:
> For processors that support PAT, set the write-protect cache mode
> (_PAGE_CACHE_MODE_WP) entry to the actual write-protect value (x05).
>
> Acked-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/mm/pat.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> index 170cc4f..87e8952 100644
> --- a/arch/x86/mm/pat.c
> +++ b/arch/x86/mm/pat.c
> @@ -355,7 +355,7 @@ void pat_init(void)
> * 010 2 UC-: _PAGE_CACHE_MODE_UC_MINUS
> * 011 3 UC : _PAGE_CACHE_MODE_UC
> * 100 4 WB : Reserved
> - * 101 5 WC : Reserved
> + * 101 5 WP : _PAGE_CACHE_MODE_WP
> * 110 6 UC-: Reserved
> * 111 7 WT : _PAGE_CACHE_MODE_WT
> *
> @@ -363,7 +363,7 @@ void pat_init(void)
> * corresponding types in the presence of PAT errata.
> */
> pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
> - PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, WT);
> + PAT(4, WB) | PAT(5, WP) | PAT(6, UC_MINUS) | PAT(7, WT);
> }
>
> if (!boot_cpu_done) {
>
>
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
[toc] | [next] | [standalone]
| From | "Kani, Toshimitsu" <toshi.kani@hpe.com> |
|---|---|
| Date | 2016-11-11 02:30 +0100 |
| Message-ID | <sC8Pf-5SO-1@gated-at.bofh.it> |
| In reply to | #1518968 |
On Thu, 2016-11-10 at 14:14 +0100, Borislav Petkov wrote: > + Toshi. > > On Wed, Nov 09, 2016 at 06:34:48PM -0600, Tom Lendacky wrote: > > > > For processors that support PAT, set the write-protect cache mode > > (_PAGE_CACHE_MODE_WP) entry to the actual write-protect value > > (x05). Using slot 6 may be more cautious (for the same reason slot 7 was used for WT), but I do not have a strong opinion for it. set_page_memtype() cannot track the use of WP type since there is no extra-bit available for WP, but WP is only supported by early_memremap_xx() interfaces in this series. So, I think we should just document that WP is only intended for temporary mappings at boot- time until this issue is resolved. Also, we need to make sure that this early_memremap for WP is only called after pat_init() is done. A nit - please add WP to the function header comment below. "This function initializes PAT MSR and PAT table with an OS-defined value to enable additional cache attributes, WC and WT." Thanks, -Toshi
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web