[PATCH v2 1/3] Revert "powerpc/64s: Remove PROT_SAO support"
Shawn Anastasio
shawn at anastas.io
Sat Aug 22 04:55:56 AEST 2020
This reverts commit 5c9fa16e8abd342ce04dc830c1ebb2a03abf6c05.
Since PROT_SAO can still be useful for certain classes of software,
reintroduce it. Concerns about guest migration for LPARs using SAO
will be addressed next.
Signed-off-by: Shawn Anastasio <shawn at anastas.io>
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 8 ++--
arch/powerpc/include/asm/cputable.h | 10 ++---
arch/powerpc/include/asm/mman.h | 26 ++++++++++--
arch/powerpc/include/asm/nohash/64/pgtable.h | 2 +
arch/powerpc/include/uapi/asm/mman.h | 2 +-
arch/powerpc/kernel/dt_cpu_ftrs.c | 2 +-
arch/powerpc/mm/book3s64/hash_utils.c | 2 +
include/linux/mm.h | 2 +
include/trace/events/mmflags.h | 2 +
mm/ksm.c | 4 ++
tools/testing/selftests/powerpc/mm/.gitignore | 1 +
tools/testing/selftests/powerpc/mm/Makefile | 4 +-
tools/testing/selftests/powerpc/mm/prot_sao.c | 42 +++++++++++++++++++
13 files changed, 90 insertions(+), 17 deletions(-)
create mode 100644 tools/testing/selftests/powerpc/mm/prot_sao.c
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..495fc0ccb453 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -20,13 +20,9 @@
#define _PAGE_RW (_PAGE_READ | _PAGE_WRITE)
#define _PAGE_RWX (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
#define _PAGE_PRIVILEGED 0x00008 /* kernel access only */
-
-#define _PAGE_CACHE_CTL 0x00030 /* Bits for the folowing cache modes */
- /* No bits set is normal cacheable memory */
- /* 0x00010 unused, is SAO bit on radix POWER9 */
+#define _PAGE_SAO 0x00010 /* Strong access order */
#define _PAGE_NON_IDEMPOTENT 0x00020 /* non idempotent memory */
#define _PAGE_TOLERANT 0x00030 /* tolerant memory, cache inhibited */
-
#define _PAGE_DIRTY 0x00080 /* C: page changed */
#define _PAGE_ACCESSED 0x00100 /* R: page referenced */
/*
@@ -828,6 +824,8 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
return hash__set_pte_at(mm, addr, ptep, pte, percpu);
}
+#define _PAGE_CACHE_CTL (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
+
#define pgprot_noncached pgprot_noncached
static inline pgprot_t pgprot_noncached(pgprot_t prot)
{
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index fdddb822d564..f89205eff691 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -191,7 +191,7 @@ static inline void cpu_feature_keys_init(void) { }
#define CPU_FTR_SPURR LONG_ASM_CONST(0x0000000001000000)
#define CPU_FTR_DSCR LONG_ASM_CONST(0x0000000002000000)
#define CPU_FTR_VSX LONG_ASM_CONST(0x0000000004000000)
-// Free LONG_ASM_CONST(0x0000000008000000)
+#define CPU_FTR_SAO LONG_ASM_CONST(0x0000000008000000)
#define CPU_FTR_CP_USE_DCBTZ LONG_ASM_CONST(0x0000000010000000)
#define CPU_FTR_UNALIGNED_LD_STD LONG_ASM_CONST(0x0000000020000000)
#define CPU_FTR_ASYM_SMT LONG_ASM_CONST(0x0000000040000000)
@@ -436,7 +436,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
- CPU_FTR_DSCR | CPU_FTR_ASYM_SMT | \
+ CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | \
CPU_FTR_VMX_COPY | CPU_FTR_HAS_PPR | CPU_FTR_DABRX )
@@ -445,7 +445,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
- CPU_FTR_DSCR | \
+ CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \
@@ -456,7 +456,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
- CPU_FTR_DSCR | \
+ CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
@@ -474,7 +474,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
- CPU_FTR_DSCR | \
+ CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h
index 7c07728af300..4ba303ea27f5 100644
--- a/arch/powerpc/include/asm/mman.h
+++ b/arch/powerpc/include/asm/mman.h
@@ -13,20 +13,38 @@
#include <linux/pkeys.h>
#include <asm/cpu_has_feature.h>
-#ifdef CONFIG_PPC_MEM_KEYS
static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
unsigned long pkey)
{
- return pkey_to_vmflag_bits(pkey);
+#ifdef CONFIG_PPC_MEM_KEYS
+ return (((prot & PROT_SAO) ? VM_SAO : 0) | pkey_to_vmflag_bits(pkey));
+#else
+ return ((prot & PROT_SAO) ? VM_SAO : 0);
+#endif
}
#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
{
- return __pgprot(vmflag_to_pte_pkey_bits(vm_flags));
+#ifdef CONFIG_PPC_MEM_KEYS
+ return (vm_flags & VM_SAO) ?
+ __pgprot(_PAGE_SAO | vmflag_to_pte_pkey_bits(vm_flags)) :
+ __pgprot(0 | vmflag_to_pte_pkey_bits(vm_flags));
+#else
+ return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0);
+#endif
}
#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
-#endif
+
+static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
+{
+ if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | PROT_SAO))
+ return false;
+ if ((prot & PROT_SAO) && !cpu_has_feature(CPU_FTR_SAO))
+ return false;
+ return true;
+}
+#define arch_validate_prot arch_validate_prot
#endif /* CONFIG_PPC64 */
#endif /* _ASM_POWERPC_MMAN_H */
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index 59ee9fa4ae09..6cb8aa357191 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -82,6 +82,8 @@
*/
#include <asm/nohash/pte-book3e.h>
+#define _PAGE_SAO 0
+
#define PTE_RPN_MASK (~((1UL << PTE_RPN_SHIFT) - 1))
/*
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
index 3a700351feca..c0c737215b00 100644
--- a/arch/powerpc/include/uapi/asm/mman.h
+++ b/arch/powerpc/include/uapi/asm/mman.h
@@ -11,7 +11,7 @@
#include <asm-generic/mman-common.h>
-#define PROT_SAO 0x10 /* Unsupported since v5.9 */
+#define PROT_SAO 0x10 /* Strong Access Ordering */
#define MAP_RENAME MAP_ANONYMOUS /* In SunOS terminology */
#define MAP_NORESERVE 0x40 /* don't reserve swap pages */
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 6f8c0c6b937a..231f92248140 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -657,7 +657,7 @@ static struct dt_cpu_feature_match __initdata
{"processor-control-facility-v3", feat_enable_dbell, CPU_FTR_DBELL},
{"processor-utilization-of-resources-register", feat_enable_purr, 0},
{"no-execute", feat_enable, 0},
- /* strong-access-ordering is unused */
+ {"strong-access-ordering", feat_enable, CPU_FTR_SAO},
{"cache-inhibited-large-page", feat_enable_large_ci, 0},
{"coprocessor-icswx", feat_enable, 0},
{"hypervisor-virtualization-interrupt", feat_enable_hvi, 0},
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 1da9dbba9217..c1ea93b368b6 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -232,6 +232,8 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
rflags |= HPTE_R_I;
else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_NON_IDEMPOTENT)
rflags |= (HPTE_R_I | HPTE_R_G);
+ else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO)
+ rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M);
else
/*
* Add memory coherence if cache inhibited is not set
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1983e08f5906..5abe6df4247e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -321,6 +321,8 @@ extern unsigned int kobjsize(const void *objp);
#if defined(CONFIG_X86)
# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
+#elif defined(CONFIG_PPC)
+# define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
#elif defined(CONFIG_PARISC)
# define VM_GROWSUP VM_ARCH_1
#elif defined(CONFIG_IA64)
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 939092dbcb8b..5fb752034386 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -114,6 +114,8 @@ IF_HAVE_PG_IDLE(PG_idle, "idle" )
#if defined(CONFIG_X86)
#define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" }
+#elif defined(CONFIG_PPC)
+#define __VM_ARCH_SPECIFIC_1 {VM_SAO, "sao" }
#elif defined(CONFIG_PARISC) || defined(CONFIG_IA64)
#define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP, "growsup" }
#elif !defined(CONFIG_MMU)
diff --git a/mm/ksm.c b/mm/ksm.c
index 0aa2247bddd7..90a625b02a1d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2453,6 +2453,10 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
if (vma_is_dax(vma))
return 0;
+#ifdef VM_SAO
+ if (*vm_flags & VM_SAO)
+ return 0;
+#endif
#ifdef VM_SPARC_ADI
if (*vm_flags & VM_SPARC_ADI)
return 0;
diff --git a/tools/testing/selftests/powerpc/mm/.gitignore b/tools/testing/selftests/powerpc/mm/.gitignore
index 91c775c23c66..aac4a59f9e28 100644
--- a/tools/testing/selftests/powerpc/mm/.gitignore
+++ b/tools/testing/selftests/powerpc/mm/.gitignore
@@ -2,6 +2,7 @@
hugetlb_vs_thp_test
subpage_prot
tempfile
+prot_sao
segv_errors
wild_bctr
large_vm_fork_separation
diff --git a/tools/testing/selftests/powerpc/mm/Makefile b/tools/testing/selftests/powerpc/mm/Makefile
index 250ce172e0da..defe488d6bf1 100644
--- a/tools/testing/selftests/powerpc/mm/Makefile
+++ b/tools/testing/selftests/powerpc/mm/Makefile
@@ -2,7 +2,7 @@
noarg:
$(MAKE) -C ../
-TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot segv_errors wild_bctr \
+TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao segv_errors wild_bctr \
large_vm_fork_separation bad_accesses pkey_exec_prot \
pkey_siginfo stack_expansion_signal stack_expansion_ldst
@@ -14,6 +14,8 @@ include ../../lib.mk
$(TEST_GEN_PROGS): ../harness.c ../utils.c
+$(OUTPUT)/prot_sao: ../utils.c
+
$(OUTPUT)/wild_bctr: CFLAGS += -m64
$(OUTPUT)/large_vm_fork_separation: CFLAGS += -m64
$(OUTPUT)/bad_accesses: CFLAGS += -m64
diff --git a/tools/testing/selftests/powerpc/mm/prot_sao.c b/tools/testing/selftests/powerpc/mm/prot_sao.c
new file mode 100644
index 000000000000..e2eed65b7735
--- /dev/null
+++ b/tools/testing/selftests/powerpc/mm/prot_sao.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2016, Michael Ellerman, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include <asm/cputable.h>
+
+#include "utils.h"
+
+#define SIZE (64 * 1024)
+
+int test_prot_sao(void)
+{
+ char *p;
+
+ /* 2.06 or later should support SAO */
+ SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
+
+ /*
+ * Ensure we can ask for PROT_SAO.
+ * We can't really verify that it does the right thing, but at least we
+ * confirm the kernel will accept it.
+ */
+ p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE | PROT_SAO,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+ FAIL_IF(p == MAP_FAILED);
+
+ /* Write to the mapping, to at least cause a fault */
+ memset(p, 0xaa, SIZE);
+
+ return 0;
+}
+
+int main(void)
+{
+ return test_harness(test_prot_sao, "prot-sao");
+}
--
2.28.0
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