[PATCH v3 0/2] Update UMIP config parameter and docs

[PATCH v3 0/2] Update UMIP config parameter and docs

[Moger, Babu]

AMD 2nd generation EPYC processors support the UMIP feature. 
So, update the Kconfig and umip related documentation.

---
v3:
  Removed X86 depend check. Just kept CPU_SUP_* check.
  Updated the comments in umip.c to make it bit generic.

v2:
  Learned that for the hardware that support UMIP, we dont need to
  emulate. Removed the emulation related code and just submitting
  the config changes.


Babu Moger (2):
      x86/Kconfig: Rename UMIP config parameter
      x86/umip: Update the comments to cover generic x86 processors


 arch/x86/Kconfig                         |   10 +++++-----
 arch/x86/include/asm/disabled-features.h |    2 +-
 arch/x86/include/asm/umip.h              |    4 ++--
 arch/x86/kernel/Makefile                 |    2 +-
 arch/x86/kernel/umip.c                   |   12 ++++++------
 5 files changed, 15 insertions(+), 15 deletions(-)

--

[PATCH v3 1/2] x86/Kconfig: Rename UMIP config parameter

[Moger, Babu]

AMD 2nd generation EPYC processors support the UMIP (User-Mode
Instruction Prevention) feature. So, rename X86_INTEL_UMIP to
generic X86_UMIP and modify the text to cover both Intel and AMD.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 arch/x86/Kconfig                         |   10 +++++-----
 arch/x86/include/asm/disabled-features.h |    2 +-
 arch/x86/include/asm/umip.h              |    4 ++--
 arch/x86/kernel/Makefile                 |    2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d6e1faa28c58..b7fb285d7c0f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1880,13 +1880,13 @@ config X86_SMAP
 
 	  If unsure, say Y.
 
-config X86_INTEL_UMIP
+config X86_UMIP
 	def_bool y
-	depends on CPU_SUP_INTEL
-	prompt "Intel User Mode Instruction Prevention" if EXPERT
+	depends on CPU_SUP_INTEL || CPU_SUP_AMD
+	prompt "User Mode Instruction Prevention" if EXPERT
 	---help---
-	  The User Mode Instruction Prevention (UMIP) is a security
-	  feature in newer Intel processors. If enabled, a general
+	  User Mode Instruction Prevention (UMIP) is a security
+	  feature in newer x86 processors. If enabled, a general
 	  protection fault is issued if the SGDT, SLDT, SIDT, SMSW
 	  or STR instructions are executed in user mode. These instructions
 	  unnecessarily expose information about the hardware state.
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index a5ea841cc6d2..8e1d0bb46361 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -22,7 +22,7 @@
 # define DISABLE_SMAP	(1<<(X86_FEATURE_SMAP & 31))
 #endif
 
-#ifdef CONFIG_X86_INTEL_UMIP
+#ifdef CONFIG_X86_UMIP
 # define DISABLE_UMIP	0
 #else
 # define DISABLE_UMIP	(1<<(X86_FEATURE_UMIP & 31))
diff --git a/arch/x86/include/asm/umip.h b/arch/x86/include/asm/umip.h
index db43f2a0d92c..aeed98c3c9e1 100644
--- a/arch/x86/include/asm/umip.h
+++ b/arch/x86/include/asm/umip.h
@@ -4,9 +4,9 @@
 #include <linux/types.h>
 #include <asm/ptrace.h>
 
-#ifdef CONFIG_X86_INTEL_UMIP
+#ifdef CONFIG_X86_UMIP
 bool fixup_umip_exception(struct pt_regs *regs);
 #else
 static inline bool fixup_umip_exception(struct pt_regs *regs) { return false; }
-#endif  /* CONFIG_X86_INTEL_UMIP */
+#endif  /* CONFIG_X86_UMIP */
 #endif  /* _ASM_X86_UMIP_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 3578ad248bc9..52ce1e239525 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -134,7 +134,7 @@ obj-$(CONFIG_EFI)			+= sysfb_efi.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o
 obj-$(CONFIG_TRACING)			+= tracepoint.o
 obj-$(CONFIG_SCHED_MC_PRIO)		+= itmt.o
-obj-$(CONFIG_X86_INTEL_UMIP)		+= umip.o
+obj-$(CONFIG_X86_UMIP)			+= umip.o
 
 obj-$(CONFIG_UNWINDER_ORC)		+= unwind_orc.o
 obj-$(CONFIG_UNWINDER_FRAME_POINTER)	+= unwind_frame.o

[PATCH v3 2/2] x86/umip: Update the comments to cover generic x86 processors

[Moger, Babu]

AMD 2nd generation EPYC processors also support UMIP feature.
Update the comments to cover generic x86 processors.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 arch/x86/kernel/umip.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c
index 548fefed71ee..8ccef6c495dc 100644
--- a/arch/x86/kernel/umip.c
+++ b/arch/x86/kernel/umip.c
@@ -1,6 +1,6 @@
 /*
- * umip.c Emulation for instruction protected by the Intel User-Mode
- * Instruction Prevention feature
+ * umip.c Emulation for instruction protected by the User-Mode Instruction
+ * Prevention feature
  *
  * Copyright (c) 2017, Intel Corporation.
  * Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
@@ -18,10 +18,10 @@
 
 /** DOC: Emulation for User-Mode Instruction Prevention (UMIP)
  *
- * The feature User-Mode Instruction Prevention present in recent Intel
- * processor prevents a group of instructions (SGDT, SIDT, SLDT, SMSW and STR)
- * from being executed with CPL > 0. Otherwise, a general protection fault is
- * issued.
+ * User-Mode Instruction Prevention is a security feature present in recent
+ * x86 processors that, when enabled, prevents a group of instructions (SGDT,
+ * SIDT, SLDT, SMSW and STR) from being run in user mode by issuing a general
+ * protection fault if the instruction is executed with CPL > 0.
  *
  * Rather than relaying to the user space the general protection fault caused by
  * the UMIP-protected instructions (in the form of a SIGSEGV signal), it can be

Re: [PATCH v3 1/2] x86/Kconfig: Rename UMIP config parameter

[Ricardo Neri]

On Tue, Nov 05, 2019 at 09:25:32PM +0000, Moger, Babu wrote:
> AMD 2nd generation EPYC processors support the UMIP (User-Mode
> Instruction Prevention) feature. So, rename X86_INTEL_UMIP to
> generic X86_UMIP and modify the text to cover both Intel and AMD.
> 
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  arch/x86/Kconfig                         |   10 +++++-----
>  arch/x86/include/asm/disabled-features.h |    2 +-
>  arch/x86/include/asm/umip.h              |    4 ++--
>  arch/x86/kernel/Makefile                 |    2 +-
>  4 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index d6e1faa28c58..b7fb285d7c0f 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1880,13 +1880,13 @@ config X86_SMAP
>  
>  	  If unsure, say Y.
>  
> -config X86_INTEL_UMIP
> +config X86_UMIP
>  	def_bool y
> -	depends on CPU_SUP_INTEL
> -	prompt "Intel User Mode Instruction Prevention" if EXPERT
> +	depends on CPU_SUP_INTEL || CPU_SUP_AMD
> +	prompt "User Mode Instruction Prevention" if EXPERT
>  	---help---
> -	  The User Mode Instruction Prevention (UMIP) is a security
> -	  feature in newer Intel processors. If enabled, a general
> +	  User Mode Instruction Prevention (UMIP) is a security
> +	  feature in newer x86 processors. If enabled, a general

Better to say certain x86 processors? Intel and AMD have it but what
about others?

Thanks and BR,
Ricardo

Re: [PATCH v3 1/2] x86/Kconfig: Rename UMIP config parameter

[Borislav Petkov]

On Wed, Nov 06, 2019 at 05:31:36PM -0800, Ricardo Neri wrote:
> > +	  feature in newer x86 processors. If enabled, a general
> 
> Better to say certain x86 processors? Intel and AMD have it but what
> about others?

Changed it to "some x86 processors".

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette