* Re: [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value
2015-04-03 9:42 [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value Borislav Petkov
@ 2015-04-03 11:20 ` Borislav Petkov
2015-04-03 11:52 ` Denys Vlasenko
2015-04-03 14:07 ` [tip:x86/asm] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value tip-bot for Borislav Petkov
2015-04-03 14:07 ` [tip:x86/asm] x86/asm/entry/64: Use a define for an invalid segment selector tip-bot for Borislav Petkov
2 siblings, 1 reply; 7+ messages in thread
From: Borislav Petkov @ 2015-04-03 11:20 UTC (permalink / raw)
To: Ingo Molnar
Cc: LKML, Denys Vlasenko, Andy Lutomirski, Alexei Starovoitov,
Frederic Weisbecker, H. Peter Anvin, Kees Cook, Linus Torvalds,
Oleg Nesterov, Steven Rostedt, Will Drewry
On Fri, Apr 03, 2015 at 11:42:10AM +0200, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> Commit
>
> d56fe4bf5f3c ("x86/asm/entry/64: Always set up SYSENTER MSRs")
>
> missed to add "ULL" to the 0 and wrmsrl_safe() complains:
>
> arch/x86/kernel/cpu/common.c: In function ‘syscall_init’:
> arch/x86/kernel/cpu/common.c:1226:2: warning: right shift count >= width of type
> wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
>
> Fix it.
>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Denys Vlasenko <dvlasenk@redhat.com>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Alexei Starovoitov <ast@plumgrid.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Will Drewry <wad@chromium.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
> arch/x86/kernel/cpu/common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index bb6633a87a19..2c249b57e4b5 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1223,7 +1223,7 @@ void syscall_init(void)
> wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
> #else
> wrmsrl(MSR_CSTAR, ignore_sysret);
> - wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
> + wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL);
Btw, we probably should define an invalid segment
#define GDT_ENTRY_INVALID_SEGMENT 0ULL
and use that value instead of the naked 0.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value
2015-04-03 11:20 ` Borislav Petkov
@ 2015-04-03 11:52 ` Denys Vlasenko
2015-04-03 12:05 ` Borislav Petkov
0 siblings, 1 reply; 7+ messages in thread
From: Denys Vlasenko @ 2015-04-03 11:52 UTC (permalink / raw)
To: Borislav Petkov, Ingo Molnar
Cc: LKML, Andy Lutomirski, Alexei Starovoitov, Frederic Weisbecker,
H. Peter Anvin, Kees Cook, Linus Torvalds, Oleg Nesterov,
Steven Rostedt, Will Drewry
On 04/03/2015 01:20 PM, Borislav Petkov wrote:
> On Fri, Apr 03, 2015 at 11:42:10AM +0200, Borislav Petkov wrote:
>> From: Borislav Petkov <bp@suse.de>
>>
>> Commit
>>
>> d56fe4bf5f3c ("x86/asm/entry/64: Always set up SYSENTER MSRs")
>>
>> missed to add "ULL" to the 0 and wrmsrl_safe() complains:
>>
>> arch/x86/kernel/cpu/common.c: In function ‘syscall_init’:
>> arch/x86/kernel/cpu/common.c:1226:2: warning: right shift count >= width of type
>> wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
>>
>> Fix it.
>>
>> Signed-off-by: Borislav Petkov <bp@suse.de>
>> Cc: Denys Vlasenko <dvlasenk@redhat.com>
>> Cc: Andy Lutomirski <luto@amacapital.net>
>> Cc: Alexei Starovoitov <ast@plumgrid.com>
>> Cc: Frederic Weisbecker <fweisbec@gmail.com>
>> Cc: H. Peter Anvin <hpa@zytor.com>
>> Cc: Kees Cook <keescook@chromium.org>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Oleg Nesterov <oleg@redhat.com>
>> Cc: Steven Rostedt <rostedt@goodmis.org>
>> Cc: Will Drewry <wad@chromium.org>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> ---
>> arch/x86/kernel/cpu/common.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
>> index bb6633a87a19..2c249b57e4b5 100644
>> --- a/arch/x86/kernel/cpu/common.c
>> +++ b/arch/x86/kernel/cpu/common.c
>> @@ -1223,7 +1223,7 @@ void syscall_init(void)
>> wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
>> #else
>> wrmsrl(MSR_CSTAR, ignore_sysret);
>> - wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
>> + wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL);
>
> Btw, we probably should define an invalid segment
>
> #define GDT_ENTRY_INVALID_SEGMENT 0ULL
>
> and use that value instead of the naked 0.
Why? Segment selectors aren't "long long", they are in fact "short"
(16-bit ints).
The "ULL" is used here in wrmsrl not because it's a segment,
but because wrmsrl expects a u64 parameter.
We can probably add a cast in its definition...
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value
2015-04-03 11:52 ` Denys Vlasenko
@ 2015-04-03 12:05 ` Borislav Petkov
2015-04-03 12:25 ` [PATCH] x86/asm/entry/64: Use a define for an invalid segment Borislav Petkov
0 siblings, 1 reply; 7+ messages in thread
From: Borislav Petkov @ 2015-04-03 12:05 UTC (permalink / raw)
To: Denys Vlasenko
Cc: Ingo Molnar, LKML, Andy Lutomirski, Alexei Starovoitov,
Frederic Weisbecker, H. Peter Anvin, Kees Cook, Linus Torvalds,
Oleg Nesterov, Steven Rostedt, Will Drewry
On Fri, Apr 03, 2015 at 01:52:00PM +0200, Denys Vlasenko wrote:
> Why? Segment selectors aren't "long long", they are in fact "short"
> (16-bit ints).
>
> The "ULL" is used here in wrmsrl not because it's a segment,
> but because wrmsrl expects a u64 parameter.
>
> We can probably add a cast in its definition...
Yeah, I meant to not use the naked 0. Cast should be fine.
Let me do a patch.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH] x86/asm/entry/64: Use a define for an invalid segment
2015-04-03 12:05 ` Borislav Petkov
@ 2015-04-03 12:25 ` Borislav Petkov
0 siblings, 0 replies; 7+ messages in thread
From: Borislav Petkov @ 2015-04-03 12:25 UTC (permalink / raw)
To: Denys Vlasenko
Cc: Ingo Molnar, LKML, Andy Lutomirski, Alexei Starovoitov,
Frederic Weisbecker, H. Peter Anvin, Kees Cook, Linus Torvalds,
Oleg Nesterov, Steven Rostedt, Will Drewry
On Fri, Apr 03, 2015 at 02:05:17PM +0200, Borislav Petkov wrote:
> Let me do a patch.
---
From: Borislav Petkov <bp@suse.de>
Date: Fri, 3 Apr 2015 14:22:00 +0200
Subject: [PATCH] x86/asm/entry/64: Use a define for an invalid segment
selector
... instead of a naked number, for better readability.
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/segment.h | 2 ++
arch/x86/kernel/cpu/common.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index d394899e055c..5a9856eb12ba 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -39,6 +39,8 @@
/* ... GDT has it cleared */
#define SEGMENT_GDT 0x0
+#define GDT_ENTRY_INVALID_SEG 0
+
#ifdef CONFIG_X86_32
/*
* The layout of the per-CPU GDT under Linux:
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2c249b57e4b5..a62cf04dac8a 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1223,7 +1223,7 @@ void syscall_init(void)
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
#else
wrmsrl(MSR_CSTAR, ignore_sysret);
- wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL);
+ wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG);
wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);
#endif
--
2.3.3
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [tip:x86/asm] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value
2015-04-03 9:42 [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value Borislav Petkov
2015-04-03 11:20 ` Borislav Petkov
@ 2015-04-03 14:07 ` tip-bot for Borislav Petkov
2015-04-03 14:07 ` [tip:x86/asm] x86/asm/entry/64: Use a define for an invalid segment selector tip-bot for Borislav Petkov
2 siblings, 0 replies; 7+ messages in thread
From: tip-bot for Borislav Petkov @ 2015-04-03 14:07 UTC (permalink / raw)
To: linux-tip-commits
Cc: torvalds, bp, rostedt, linux-kernel, luto, fweisbec, oleg,
dvlasenk, wad, ast, keescook, mingo, tglx, hpa
Commit-ID: 7c74d5b7b7b63fc279ed446ebd78de20d81f2824
Gitweb: http://git.kernel.org/tip/7c74d5b7b7b63fc279ed446ebd78de20d81f2824
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Fri, 3 Apr 2015 11:42:10 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 3 Apr 2015 15:29:12 +0200
x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value
Commit:
d56fe4bf5f3c ("x86/asm/entry/64: Always set up SYSENTER MSRs")
missed to add "ULL" to the 0 and wrmsrl_safe() complains:
arch/x86/kernel/cpu/common.c: In function ‘syscall_init’:
arch/x86/kernel/cpu/common.c:1226:2: warning: right shift count >= width of type wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
Fix it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a383d53..d56d307 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1184,7 +1184,7 @@ void syscall_init(void)
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
#else
wrmsrl(MSR_CSTAR, ignore_sysret);
- wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0);
+ wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL);
wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);
#endif
^ permalink raw reply related [flat|nested] 7+ messages in thread* [tip:x86/asm] x86/asm/entry/64: Use a define for an invalid segment selector
2015-04-03 9:42 [PATCH] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value Borislav Petkov
2015-04-03 11:20 ` Borislav Petkov
2015-04-03 14:07 ` [tip:x86/asm] x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value tip-bot for Borislav Petkov
@ 2015-04-03 14:07 ` tip-bot for Borislav Petkov
2 siblings, 0 replies; 7+ messages in thread
From: tip-bot for Borislav Petkov @ 2015-04-03 14:07 UTC (permalink / raw)
To: linux-tip-commits
Cc: oleg, tglx, bp, fweisbec, keescook, bp, mingo, hpa, torvalds,
linux-kernel, luto, rostedt, ast, dvlasenk, wad
Commit-ID: 6b51311c976593fb7311322b1647a912cd456ec4
Gitweb: http://git.kernel.org/tip/6b51311c976593fb7311322b1647a912cd456ec4
Author: Borislav Petkov <bp@alien8.de>
AuthorDate: Fri, 3 Apr 2015 14:25:28 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 3 Apr 2015 15:29:13 +0200
x86/asm/entry/64: Use a define for an invalid segment selector
... instead of a naked number, for better readability.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/segment.h | 2 ++
arch/x86/kernel/cpu/common.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index d394899..5a9856e 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -39,6 +39,8 @@
/* ... GDT has it cleared */
#define SEGMENT_GDT 0x0
+#define GDT_ENTRY_INVALID_SEG 0
+
#ifdef CONFIG_X86_32
/*
* The layout of the per-CPU GDT under Linux:
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index d56d307..3f70538 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1184,7 +1184,7 @@ void syscall_init(void)
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
#else
wrmsrl(MSR_CSTAR, ignore_sysret);
- wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL);
+ wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG);
wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);
#endif
^ permalink raw reply related [flat|nested] 7+ messages in thread