[PATCH 1/3] powerpc/mm/64s: Consolidate SLB assertions

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE2832d

5 messages, 3 authors, 2018-11-07 · open the first message on its own page

[PATCH 1/3] powerpc/mm/64s: Consolidate SLB assertions

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-11-06 12:41:39

The code for assert_slb_exists() and assert_slb_notexists() is almost
identical, except for the polarity of the WARN_ON(). In a future patch
we'll need to modify this code, so consolidate it now into a single
function.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/mm/slb.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index c3fdf2969d9f..f3e002ee457b 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c

@@ -58,7 +58,7 @@ static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
 	return __mk_vsid_data(get_kernel_vsid(ea, ssize), ssize, flags);
 }
 
-static void assert_slb_exists(unsigned long ea)
+static void assert_slb_presence(bool present, unsigned long ea)
 {
 #ifdef CONFIG_DEBUG_VM
 	unsigned long tmp;

@@ -66,19 +66,8 @@ static void assert_slb_exists(unsigned long ea)
 	WARN_ON_ONCE(mfmsr() & MSR_EE);
 
 	asm volatile("slbfee. %0, %1" : "=r"(tmp) : "r"(ea) : "cr0");
-	WARN_ON(tmp == 0);
-#endif
-}
 
-static void assert_slb_notexists(unsigned long ea)
-{
-#ifdef CONFIG_DEBUG_VM
-	unsigned long tmp;
-
-	WARN_ON_ONCE(mfmsr() & MSR_EE);
-
-	asm volatile("slbfee. %0, %1" : "=r"(tmp) : "r"(ea) : "cr0");
-	WARN_ON(tmp != 0);
+	WARN_ON(present == (tmp == 0));
 #endif
 }

@@ -114,7 +103,7 @@ static inline void create_shadowed_slbe(unsigned long ea, int ssize,
 	 */
 	slb_shadow_update(ea, ssize, flags, index);
 
-	assert_slb_notexists(ea);
+	assert_slb_presence(false, ea);
 	asm volatile("slbmte  %0,%1" :
 		     : "r" (mk_vsid_data(ea, ssize, flags)),
 		       "r" (mk_esid_data(ea, ssize, index))

@@ -137,7 +126,7 @@ void __slb_restore_bolted_realmode(void)
 		       "r" (be64_to_cpu(p->save_area[index].esid)));
 	}
 
-	assert_slb_exists(local_paca->kstack);
+	assert_slb_presence(true, local_paca->kstack);
 }
 
 /*

@@ -185,7 +174,7 @@ void slb_flush_and_restore_bolted(void)
 		     :: "r" (be64_to_cpu(p->save_area[KSTACK_INDEX].vsid)),
 			"r" (be64_to_cpu(p->save_area[KSTACK_INDEX].esid))
 		     : "memory");
-	assert_slb_exists(get_paca()->kstack);
+	assert_slb_presence(true, get_paca()->kstack);
 
 	get_paca()->slb_cache_ptr = 0;

@@ -443,9 +432,9 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
 				ea = (unsigned long)
 					get_paca()->slb_cache[i] << SID_SHIFT;
 				/*
-				 * Could assert_slb_exists here, but hypervisor
-				 * or machine check could have come in and
-				 * removed the entry at this point.
+				 * Could assert_slb_presence(true) here, but
+				 * hypervisor or machine check could have come
+				 * in and removed the entry at this point.
 				 */
 
 				slbie_data = ea;

@@ -676,7 +665,7 @@ static long slb_insert_entry(unsigned long ea, unsigned long context,
 	 * User preloads should add isync afterwards in case the kernel
 	 * accesses user memory before it returns to userspace with rfid.
 	 */
-	assert_slb_notexists(ea);
+	assert_slb_presence(false, ea);
 	asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data));
 
 	barrier();

-- 
2.17.2

[PATCH 2/3] powerpc/mm/64s: Use PPC_SLBFEE macro

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-11-06 12:44:37

Old toolchains don't know about slbfee and break the build, eg:
  {standard input}:37: Error: Unrecognized opcode: `slbfee.'

Fix it by using the macro version. We need to add an underscore
version that takes raw register numbers from the inline asm, rather
than our Rx macros.

Fixes: e15a4fea4dee ("powerpc/64s/hash: Add some SLB debugging tests")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/include/asm/ppc-opcode.h | 2 ++
 arch/powerpc/mm/slb.c                 | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 6093bc8f74e5..a6e9e314c707 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h

@@ -493,6 +493,8 @@
 					__PPC_RS(t) | __PPC_RA0(a) | __PPC_RB(b))
 #define PPC_SLBFEE_DOT(t, b)	stringify_in_c(.long PPC_INST_SLBFEE | \
 					__PPC_RT(t) | __PPC_RB(b))
+#define __PPC_SLBFEE_DOT(t, b)	stringify_in_c(.long PPC_INST_SLBFEE |	\
+					       ___PPC_RT(t) | ___PPC_RB(b))
 #define PPC_ICBT(c,a,b)		stringify_in_c(.long PPC_INST_ICBT | \
 				       __PPC_CT(c) | __PPC_RA0(a) | __PPC_RB(b))
 /* PASemi instructions */

diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index f3e002ee457b..457fd29448b1 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c

@@ -19,6 +19,7 @@
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/paca.h>
+#include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 #include <asm/cacheflush.h>
 #include <asm/smp.h>

@@ -65,7 +66,7 @@ static void assert_slb_presence(bool present, unsigned long ea)
 
 	WARN_ON_ONCE(mfmsr() & MSR_EE);
 
-	asm volatile("slbfee. %0, %1" : "=r"(tmp) : "r"(ea) : "cr0");
+	asm volatile(__PPC_SLBFEE_DOT(%0, %1) : "=r"(tmp) : "r"(ea) : "cr0");
 
 	WARN_ON(present == (tmp == 0));
 #endif

-- 
2.17.2

[PATCH 3/3] powerpc/mm/64s: Only use slbfee on CPUs that support it

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-11-06 12:47:35

The slbfee instruction was only added in ISA 2.05 (Power6), it's not
supported on older CPUs. We don't have a CPU feature for that ISA
version though, so just use the ISA 2.06 feature flag.

Fixes: e15a4fea4dee ("powerpc/64s/hash: Add some SLB debugging tests")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/mm/slb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index 457fd29448b1..b663a36f9ada 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c

@@ -66,6 +66,9 @@ static void assert_slb_presence(bool present, unsigned long ea)
 
 	WARN_ON_ONCE(mfmsr() & MSR_EE);
 
+	if (!cpu_has_feature(CPU_FTR_ARCH_206))
+		return;
+
 	asm volatile(__PPC_SLBFEE_DOT(%0, %1) : "=r"(tmp) : "r"(ea) : "cr0");
 
 	WARN_ON(present == (tmp == 0));

-- 
2.17.2

Re: [PATCH 3/3] powerpc/mm/64s: Only use slbfee on CPUs that support it

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2018-11-07 00:23:20

On Tue,  6 Nov 2018 23:37:09 +1100
Michael Ellerman [off-list ref] wrote:

The slbfee instruction was only added in ISA 2.05 (Power6), it's not
supported on older CPUs. We don't have a CPU feature for that ISA
version though, so just use the ISA 2.06 feature flag.

Fixes: e15a4fea4dee ("powerpc/64s/hash: Add some SLB debugging tests")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Ugh, thank for fixing all that up. Looks good.

Thanks,
Nick

quoted hunk

---
 arch/powerpc/mm/slb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index 457fd29448b1..b663a36f9ada 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c

@@ -66,6 +66,9 @@ static void assert_slb_presence(bool present, unsigned long ea)
 
 	WARN_ON_ONCE(mfmsr() & MSR_EE);
 
+	if (!cpu_has_feature(CPU_FTR_ARCH_206))
+		return;
+
 	asm volatile(__PPC_SLBFEE_DOT(%0, %1) : "=r"(tmp) : "r"(ea) : "cr0");
 
 	WARN_ON(present == (tmp == 0));

-- 
2.17.2

Re: [1/3] powerpc/mm/64s: Consolidate SLB assertions

From: Michael Ellerman <hidden>
Date: 2018-11-07 21:31:53

On Tue, 2018-11-06 at 12:37:07 UTC, Michael Ellerman wrote:

The code for assert_slb_exists() and assert_slb_notexists() is almost
identical, except for the polarity of the WARN_ON(). In a future patch
we'll need to modify this code, so consolidate it now into a single
function.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Series applied to powerpc fixes.

https://git.kernel.org/powerpc/c/0ae790683fc28bb718d74f87cdf753

cheers

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