This patch provides the detailed implementation for
a user to allocate a key and enable it in the hardware.
It provides the plumbing, but it cannot be used yet
till the system call is implemented. The next patch
will do so.
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
---
arch/powerpc/include/asm/pkeys.h | 8 ++++-
arch/powerpc/mm/Makefile | 1 +
arch/powerpc/mm/pkeys.c | 66 ++++++++++++++++++++++++++++++++++++++
3 files changed, 74 insertions(+), 1 deletions(-)
create mode 100644 arch/powerpc/mm/pkeys.c
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 9345767..1495342 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -2,6 +2,10 @@
#define _ASM_PPC64_PKEYS_H
#define arch_max_pkey() 32
+#define AMR_AD_BIT 0x1UL
+#define AMR_WD_BIT 0x2UL
+#define IAMR_EX_BIT 0x1UL
+#define AMR_BITS_PER_PKEY 2
#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
VM_PKEY_BIT3 | VM_PKEY_BIT4)
/*
@@ -93,10 +97,12 @@ static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
return 0;
}
+extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
+ unsigned long init_val);
static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
unsigned long init_val)
{
- return 0;
+ return __arch_set_user_pkey_access(tsk, pkey, init_val);
}
static inline void pkey_mm_init(struct mm_struct *mm)
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 7414034..8cc2ff1 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -45,3 +45,4 @@ obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o
obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_iommu.o
obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o
obj-$(CONFIG_PPC_HTDUMP) += dump_hashpagetable.o
+obj-$(CONFIG_PPC64_MEMORY_PROTECTION_KEYS) += pkeys.o
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
new file mode 100644
index 0000000..d3ba167
--- /dev/null
+++ b/arch/powerpc/mm/pkeys.c
@@ -0,0 +1,66 @@
+/*
+ * PowerPC Memory Protection Keys management
+ * Copyright (c) 2015, Intel Corporation.
+ * Copyright (c) 2017, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+#include <linux/pkeys.h> /* PKEY_* */
+#include <uapi/asm-generic/mman-common.h>
+
+/*
+ * set the access right in AMR IAMR and UAMOR register
+ * for @pkey to that specified in @init_val.
+ */
+int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
+ unsigned long init_val)
+{
+ u64 old_amr, old_uamor, old_iamr;
+ int pkey_shift = (arch_max_pkey()-pkey-1) * AMR_BITS_PER_PKEY;
+ u64 new_amr_bits = 0x0ul;
+ u64 new_iamr_bits = 0x0ul;
+ u64 new_uamor_bits = 0x3ul;
+
+ /* Set the bits we need in AMR: */
+ if (init_val & PKEY_DISABLE_ACCESS)
+ new_amr_bits |= AMR_AD_BIT | AMR_WD_BIT;
+ if (init_val & PKEY_DISABLE_WRITE)
+ new_amr_bits |= AMR_WD_BIT;
+
+ /*
+ * By default execute is disabled.
+ * To enable execute, PKEY_ENABLE_EXECUTE
+ * needs to be specified.
+ */
+ if ((init_val & PKEY_DISABLE_EXECUTE))
+ new_iamr_bits |= IAMR_EX_BIT;
+
+ /* Shift the bits in to the correct place in AMR for pkey: */
+ new_amr_bits <<= pkey_shift;
+ new_iamr_bits <<= pkey_shift;
+ new_uamor_bits <<= pkey_shift;
+
+ /* Get old AMR and mask off any old bits in place: */
+ old_amr = read_amr();
+ old_amr &= ~((u64)(AMR_AD_BIT|AMR_WD_BIT) << pkey_shift);
+
+ old_iamr = read_iamr();
+ old_iamr &= ~(0x3ul << pkey_shift);
+
+ old_uamor = read_uamor();
+ old_uamor &= ~(0x3ul << pkey_shift);
+
+ /* Write old part along with new part: */
+ write_amr(old_amr | new_amr_bits);
+ write_iamr(old_iamr | new_iamr_bits);
+ write_uamor(old_uamor | new_uamor_bits);
+
+ return 0;
+}
--
1.7.1
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