From: Anton Blanchard <anton@samba.org>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
mikey@neuling.org, cyrilbur@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 14/19] powerpc: Add ppc_strict_facility_enable boot option
Date: Wed, 28 Oct 2015 11:51:02 +1100 [thread overview]
Message-ID: <1445993467-667-14-git-send-email-anton@samba.org> (raw)
In-Reply-To: <1445993467-667-1-git-send-email-anton@samba.org>
Add a boot option that strictly manages the MSR unavailable bits.
This catches kernel uses of FP/Altivec/SPE that would otherwise
corrupt user state.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Documentation/kernel-parameters.txt | 6 ++++++
arch/powerpc/include/asm/reg.h | 9 +++++++++
arch/powerpc/include/asm/switch_to.h | 24 +++++++++++++++++++-----
arch/powerpc/kernel/process.c | 17 +++++++++++++++--
4 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 22a4b68..f535a02 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2939,6 +2939,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
may be specified.
Format: <port>,<port>....
+ ppc_strict_facility_enable
+ [PPC] This option catches any kernel floating point,
+ Altivec, VSX and SPE outside of regions specifically
+ allowed (eg kernel_enable_fpu()/kernel_disable_fpu()).
+ There is some performance impact when enabling this.
+
print-fatal-signals=
[KNL] debug: print fatal signals
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 987dac0..eb2986e 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1214,6 +1214,15 @@ static inline void mtmsr_isync(unsigned long val)
: "r" ((unsigned long)(v)) \
: "memory")
+extern void msr_check_and_set(unsigned long bits);
+extern bool strict_msr_control;
+extern void __msr_check_and_clear(unsigned long bits);
+static inline void msr_check_and_clear(unsigned long bits)
+{
+ if (strict_msr_control)
+ __msr_check_and_clear(bits);
+}
+
static inline unsigned long mfvtb (void)
{
#ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index dbc4caa..b6a4951 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -4,6 +4,8 @@
#ifndef _ASM_POWERPC_SWITCH_TO_H
#define _ASM_POWERPC_SWITCH_TO_H
+#include <asm/reg.h>
+
struct thread_struct;
struct task_struct;
struct pt_regs;
@@ -27,15 +29,15 @@ extern void giveup_spe(struct task_struct *);
extern void load_up_spe(struct task_struct *);
extern void switch_booke_debug_regs(struct debug_reg *new_debug);
-static inline void disable_kernel_fp(void) { }
-static inline void disable_kernel_altivec(void) { }
-static inline void disable_kernel_spe(void) { }
-static inline void disable_kernel_vsx(void) { }
-
#ifdef CONFIG_PPC_FPU
extern void flush_fp_to_thread(struct task_struct *);
extern void giveup_fpu(struct task_struct *);
extern void __giveup_fpu(struct task_struct *);
+static inline void disable_kernel_fp(void)
+{
+ msr_check_and_clear(MSR_FP);
+}
+
#else
static inline void flush_fp_to_thread(struct task_struct *t) { }
static inline void giveup_fpu(struct task_struct *t) { }
@@ -46,6 +48,10 @@ static inline void __giveup_fpu(struct task_struct *t) { }
extern void flush_altivec_to_thread(struct task_struct *);
extern void giveup_altivec(struct task_struct *);
extern void __giveup_altivec(struct task_struct *);
+static inline void disable_kernel_altivec(void)
+{
+ msr_check_and_clear(MSR_VEC);
+}
#else
static inline void flush_altivec_to_thread(struct task_struct *t) { }
static inline void giveup_altivec(struct task_struct *t) { }
@@ -54,6 +60,10 @@ static inline void __giveup_altivec(struct task_struct *t) { }
#ifdef CONFIG_VSX
extern void flush_vsx_to_thread(struct task_struct *);
+static inline void disable_kernel_vsx(void)
+{
+ msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);
+}
#else
static inline void flush_vsx_to_thread(struct task_struct *t)
{
@@ -62,6 +72,10 @@ static inline void flush_vsx_to_thread(struct task_struct *t)
#ifdef CONFIG_SPE
extern void flush_spe_to_thread(struct task_struct *);
+static inline void disable_kernel_spe(void)
+{
+ msr_check_and_clear(MSR_SPE);
+}
#else
static inline void flush_spe_to_thread(struct task_struct *t)
{
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 5f244d0..878ea17 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -87,7 +87,19 @@ static void check_if_tm_restore_required(struct task_struct *tsk)
static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
-static void msr_check_and_set(unsigned long bits)
+bool strict_msr_control;
+EXPORT_SYMBOL(strict_msr_control);
+
+static int __init enable_strict_msr_control(char *str)
+{
+ strict_msr_control = true;
+ pr_info("Enabling strict facility control\n");
+
+ return 0;
+}
+early_param("ppc_strict_facility_enable", enable_strict_msr_control);
+
+void msr_check_and_set(unsigned long bits)
{
unsigned long oldmsr = mfmsr();
unsigned long newmsr;
@@ -103,7 +115,7 @@ static void msr_check_and_set(unsigned long bits)
mtmsr_isync(newmsr);
}
-static void msr_check_and_clear(unsigned long bits)
+void __msr_check_and_clear(unsigned long bits)
{
unsigned long oldmsr = mfmsr();
unsigned long newmsr;
@@ -118,6 +130,7 @@ static void msr_check_and_clear(unsigned long bits)
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
}
+EXPORT_SYMBOL(__msr_check_and_clear);
#ifdef CONFIG_PPC_FPU
void giveup_fpu(struct task_struct *tsk)
--
2.5.0
next prev parent reply other threads:[~2015-10-28 0:51 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 0:50 [PATCH 01/19] powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch Anton Blanchard
2015-10-28 0:50 ` [PATCH 02/19] powerpc: Don't disable MSR bits in do_load_up_transact_*() functions Anton Blanchard
2015-10-28 0:50 ` [PATCH 03/19] powerpc: Create context switch helpers save_sprs() and restore_sprs() Anton Blanchard
2015-10-28 0:50 ` [PATCH 04/19] powerpc: Remove redundant mflr in _switch Anton Blanchard
2015-10-28 0:50 ` [PATCH 05/19] powerpc: Remove UP only lazy floating point and vector optimisations Anton Blanchard
2015-10-28 0:50 ` [PATCH 06/19] powerpc: Simplify TM restore checks Anton Blanchard
2015-10-28 0:50 ` [PATCH 07/19] powerpc: Create mtmsrd_isync() Anton Blanchard
2015-10-28 0:50 ` [PATCH 08/19] powerpc: Remove NULL task struct pointer checks in FP and vector code Anton Blanchard
2015-10-28 0:50 ` [PATCH 09/19] powerpc: Move part of giveup_fpu,altivec,spe into c Anton Blanchard
2015-10-28 3:17 ` [PATCH 09/19] powerpc: Move part of giveup_fpu, altivec, spe " kbuild test robot
2015-10-28 0:50 ` [PATCH 10/19] powerpc: Move part of giveup_vsx " Anton Blanchard
2015-10-28 0:50 ` [PATCH 11/19] crypto: vmx: Only call enable_kernel_vsx() Anton Blanchard
2015-10-28 0:51 ` [PATCH 12/19] powerpc: Create msr_check_and_{set,clear}() Anton Blanchard
2015-10-28 0:51 ` [PATCH 13/19] powerpc: Create disable_kernel_{fp,altivec,vsx,spe}() Anton Blanchard
2015-10-28 0:51 ` Anton Blanchard [this message]
2015-10-28 0:51 ` [PATCH 15/19] powerpc: Remove fp_enable() and vec_enable(), use msr_check_and_{set, clear}() Anton Blanchard
2015-10-28 0:51 ` [PATCH 16/19] powerpc: create giveup_all() Anton Blanchard
2015-10-28 0:51 ` [PATCH 17/19] powerpc: create flush_all_to_thread() Anton Blanchard
2015-10-28 0:51 ` [PATCH 18/19] powerpc: Rearrange __switch_to() Anton Blanchard
2015-10-28 0:51 ` [PATCH 19/19] powerpc: clean up asm/switch_to.h Anton Blanchard
2015-10-28 3:19 ` kbuild test robot
2015-10-28 4:24 ` kbuild test robot
-- strict thread matches above, loose matches on Subject: below --
2015-10-29 0:43 [PATCH 00/19] Context switch improvements Anton Blanchard
2015-10-29 0:44 ` [PATCH 14/19] powerpc: Add ppc_strict_facility_enable boot option Anton Blanchard
2017-09-02 3:48 ` Benjamin Herrenschmidt
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