[RFC v6 17/62] powerpc: implementation for arch_set_user_pkey_access()
From: Ram Pai <hidden>
Date: 2017-07-16 03:58:48
Also in:
linux-arch, linux-mm, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 till the system call is implemented. The next patch will do so. Signed-off-by: Ram Pai <redacted> --- arch/powerpc/include/asm/pkeys.h | 10 +++++++++- arch/powerpc/mm/pkeys.c | 27 +++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 7f5c21d..1943e6b 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h@@ -3,6 +3,10 @@ extern bool pkey_inited; #define arch_max_pkey() 32 +#define AMR_RD_BIT 0x1UL +#define AMR_WR_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) #define AMR_BITS_PER_PKEY 2
@@ -113,10 +117,14 @@ 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; + if (!pkey_inited) + return -1; + 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/pkeys.c b/arch/powerpc/mm/pkeys.c
index 04ee361..98d0391 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c@@ -17,6 +17,10 @@ bool pkey_inited; #define pkeyshift(pkey) ((arch_max_pkey()-pkey-1) * AMR_BITS_PER_PKEY) +static bool is_pkey_enabled(int pkey) +{ + return !!(read_uamor() & (0x3ul << pkeyshift(pkey))); +} static inline void init_amr(int pkey, u8 init_bits) {
@@ -60,3 +64,26 @@ void __arch_deactivate_pkey(int pkey) { pkey_status_change(pkey, false); } + +/* + * 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 new_amr_bits = 0x0ul; + + if (!is_pkey_enabled(pkey)) + return -1; + + /* Set the bits we need in AMR: */ + if (init_val & PKEY_DISABLE_ACCESS) + new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT; + else if (init_val & PKEY_DISABLE_WRITE) + new_amr_bits |= AMR_WR_BIT; + + init_amr(pkey, new_amr_bits); + + return 0; +}
--
1.7.1