[tip:x86/fpu] x86/fpu: Remove irq_ts_save() and irq_ts_restore()

2016-11-01 Thread tip-bot for Andy Lutomirski 
Commit-ID:  5a83d60c074ddf4f6364be25654a643d0e941824
Gitweb: http://git.kernel.org/tip/5a83d60c074ddf4f6364be25654a643d0e941824
Author: Andy Lutomirski 
AuthorDate: Mon, 31 Oct 2016 15:18:44 -0700
Committer:  Ingo Molnar 
CommitDate: Tue, 1 Nov 2016 07:47:54 +0100

x86/fpu: Remove irq_ts_save() and irq_ts_restore()

Now that lazy FPU is gone, we don't use CR0.TS (except possibly in
KVM guest mode).  Remove irq_ts_save(), irq_ts_restore(), and all of
their callers.

Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: Fenghua Yu 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Quentin Casasnovas 
Cc: Rik van Riel 
Cc: Rusty Russell 
Cc: Thomas Gleixner 
Cc: kvm list 
Link: 
http://lkml.kernel.org/r/70b9b9e7ba70659bedcb08aba63d0f9214f338f2.1477951965.git.l...@kernel.org
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/fpu/api.h   | 10 --
 arch/x86/kernel/fpu/core.c   | 29 -
 drivers/char/hw_random/via-rng.c |  8 ++--
 drivers/crypto/padlock-aes.c | 23 ++-
 drivers/crypto/padlock-sha.c | 18 --
 5 files changed, 4 insertions(+), 84 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 1429a7c..0877ae0 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -27,16 +27,6 @@ extern void kernel_fpu_end(void);
 extern bool irq_fpu_usable(void);
 
 /*
- * Some instructions like VIA's padlock instructions generate a spurious
- * DNA fault but don't modify SSE registers. And these instructions
- * get used from interrupt context as well. To prevent these kernel 
instructions
- * in interrupt context interacting wrongly with other user/kernel fpu usage, 
we
- * should use them only in the context of irq_ts_save/restore()
- */
-extern int  irq_ts_save(void);
-extern void irq_ts_restore(int TS_state);
-
-/*
  * Query the presence of one or more xfeatures. Works on any legacy CPU as 
well.
  *
  * If 'feature_name' is set then put a human-readable description of
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 52f56844..7d8e262 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -138,35 +138,6 @@ void kernel_fpu_end(void)
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
 
 /*
- * CR0::TS save/restore functions:
- */
-int irq_ts_save(void)
-{
-   /*
-* If in process context and not atomic, we can take a spurious DNA 
fault.
-* Otherwise, doing clts() in process context requires disabling 
preemption
-* or some heavy lifting like kernel_fpu_begin()
-*/
-   if (!in_atomic())
-   return 0;
-
-   if (read_cr0() & X86_CR0_TS) {
-   clts();
-   return 1;
-   }
-
-   return 0;
-}
-EXPORT_SYMBOL_GPL(irq_ts_save);
-
-void irq_ts_restore(int TS_state)
-{
-   if (TS_state)
-   stts();
-}
-EXPORT_SYMBOL_GPL(irq_ts_restore);
-
-/*
  * Save the FPU state (mark it for reload if necessary):
  *
  * This only ever gets called for the current task.
diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index 44ce806..d1f5bb5 100644
--- a/drivers/char/hw_random/via-rng.c
+++ b/drivers/char/hw_random/via-rng.c
@@ -70,21 +70,17 @@ enum {
  * until we have 4 bytes, thus returning a u32 at a time,
  * instead of the current u8-at-a-time.
  *
- * Padlock instructions can generate a spurious DNA fault, so
- * we have to call them in the context of irq_ts_save/restore()
+ * Padlock instructions can generate a spurious DNA fault, but the
+ * kernel doesn't use CR0.TS, so this doesn't matter.
  */
 
 static inline u32 xstore(u32 *addr, u32 edx_in)
 {
u32 eax_out;
-   int ts_state;
-
-   ts_state = irq_ts_save();
 
asm(".byte 0x0F,0xA7,0xC0 /* xstore %%edi (addr=%0) */"
: "=m" (*addr), "=a" (eax_out), "+d" (edx_in), "+D" (addr));
 
-   irq_ts_restore(ts_state);
return eax_out;
 }
 
diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c
index 441e86b..b386974 100644
--- a/drivers/crypto/padlock-aes.c
+++ b/drivers/crypto/padlock-aes.c
@@ -183,8 +183,8 @@ static inline void padlock_store_cword(struct cword *cword)
 
 /*
  * While the padlock instructions don't use FP/SSE registers, they
- * generate a spurious DNA fault when cr0.ts is '1'. These instructions
- * should be used only inside the

[tip:x86/fpu] x86/fpu: Remove irq_ts_save() and irq_ts_restore()

2016-11-01 Thread tip-bot for Andy Lutomirski 
Commit-ID:  5a83d60c074ddf4f6364be25654a643d0e941824
Gitweb: http://git.kernel.org/tip/5a83d60c074ddf4f6364be25654a643d0e941824
Author: Andy Lutomirski 
AuthorDate: Mon, 31 Oct 2016 15:18:44 -0700
Committer:  Ingo Molnar 
CommitDate: Tue, 1 Nov 2016 07:47:54 +0100

x86/fpu: Remove irq_ts_save() and irq_ts_restore()

Now that lazy FPU is gone, we don't use CR0.TS (except possibly in
KVM guest mode).  Remove irq_ts_save(), irq_ts_restore(), and all of
their callers.

Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: Fenghua Yu 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Quentin Casasnovas 
Cc: Rik van Riel 
Cc: Rusty Russell 
Cc: Thomas Gleixner 
Cc: kvm list 
Link: 
http://lkml.kernel.org/r/70b9b9e7ba70659bedcb08aba63d0f9214f338f2.1477951965.git.l...@kernel.org
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/fpu/api.h   | 10 --
 arch/x86/kernel/fpu/core.c   | 29 -
 drivers/char/hw_random/via-rng.c |  8 ++--
 drivers/crypto/padlock-aes.c | 23 ++-
 drivers/crypto/padlock-sha.c | 18 --
 5 files changed, 4 insertions(+), 84 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 1429a7c..0877ae0 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -27,16 +27,6 @@ extern void kernel_fpu_end(void);
 extern bool irq_fpu_usable(void);
 
 /*
- * Some instructions like VIA's padlock instructions generate a spurious
- * DNA fault but don't modify SSE registers. And these instructions
- * get used from interrupt context as well. To prevent these kernel 
instructions
- * in interrupt context interacting wrongly with other user/kernel fpu usage, 
we
- * should use them only in the context of irq_ts_save/restore()
- */
-extern int  irq_ts_save(void);
-extern void irq_ts_restore(int TS_state);
-
-/*
  * Query the presence of one or more xfeatures. Works on any legacy CPU as 
well.
  *
  * If 'feature_name' is set then put a human-readable description of
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 52f56844..7d8e262 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -138,35 +138,6 @@ void kernel_fpu_end(void)
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
 
 /*
- * CR0::TS save/restore functions:
- */
-int irq_ts_save(void)
-{
-   /*
-* If in process context and not atomic, we can take a spurious DNA 
fault.
-* Otherwise, doing clts() in process context requires disabling 
preemption
-* or some heavy lifting like kernel_fpu_begin()
-*/
-   if (!in_atomic())
-   return 0;
-
-   if (read_cr0() & X86_CR0_TS) {
-   clts();
-   return 1;
-   }
-
-   return 0;
-}
-EXPORT_SYMBOL_GPL(irq_ts_save);
-
-void irq_ts_restore(int TS_state)
-{
-   if (TS_state)
-   stts();
-}
-EXPORT_SYMBOL_GPL(irq_ts_restore);
-
-/*
  * Save the FPU state (mark it for reload if necessary):
  *
  * This only ever gets called for the current task.
diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index 44ce806..d1f5bb5 100644
--- a/drivers/char/hw_random/via-rng.c
+++ b/drivers/char/hw_random/via-rng.c
@@ -70,21 +70,17 @@ enum {
  * until we have 4 bytes, thus returning a u32 at a time,
  * instead of the current u8-at-a-time.
  *
- * Padlock instructions can generate a spurious DNA fault, so
- * we have to call them in the context of irq_ts_save/restore()
+ * Padlock instructions can generate a spurious DNA fault, but the
+ * kernel doesn't use CR0.TS, so this doesn't matter.
  */
 
 static inline u32 xstore(u32 *addr, u32 edx_in)
 {
u32 eax_out;
-   int ts_state;
-
-   ts_state = irq_ts_save();
 
asm(".byte 0x0F,0xA7,0xC0 /* xstore %%edi (addr=%0) */"
: "=m" (*addr), "=a" (eax_out), "+d" (edx_in), "+D" (addr));
 
-   irq_ts_restore(ts_state);
return eax_out;
 }
 
diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c
index 441e86b..b386974 100644
--- a/drivers/crypto/padlock-aes.c
+++ b/drivers/crypto/padlock-aes.c
@@ -183,8 +183,8 @@ static inline void padlock_store_cword(struct cword *cword)
 
 /*
  * While the padlock instructions don't use FP/SSE registers, they
- * generate a spurious DNA fault when cr0.ts is '1'. These instructions
- * should be used only inside the irq_ts_save/restore() context
+ * generate a spurious DNA fault when CR0.TS is '1'.  Fortunately,
+ * the kernel doesn't use CR0.TS.
  */
 
 static inline void rep_xcrypt_ecb(const u8 *input, u8 *output, void *key,
@@ -298,24 +298,18 @@ static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 
*output, void *key,
 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 {
struct aes_ctx *ctx = aes_ctx(tfm);
-