[PATCH v10 09/27] powerpc: ability to create execute-disabled pkeys
From: Ram Pai <hidden>
Date: 2018-01-19 01:52:35
Also in:
linux-arch, linux-kselftest, linux-mm, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
powerpc has hardware support to disable execute on a pkey. This patch enables the ability to create execute-disabled keys. Signed-off-by: Ram Pai <redacted> --- arch/powerpc/include/uapi/asm/mman.h | 6 ++++++ arch/powerpc/mm/pkeys.c | 16 ++++++++++++++++ 2 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
index e63bc37..65065ce 100644
--- a/arch/powerpc/include/uapi/asm/mman.h
+++ b/arch/powerpc/include/uapi/asm/mman.h@@ -30,4 +30,10 @@ #define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */ #define MAP_HUGETLB 0x40000 /* create a huge page mapping */ +/* Override any generic PKEY permission defines */ +#define PKEY_DISABLE_EXECUTE 0x4 +#undef PKEY_ACCESS_MASK +#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ + PKEY_DISABLE_WRITE |\ + PKEY_DISABLE_EXECUTE) #endif /* _UAPI_ASM_POWERPC_MMAN_H */
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index eca04cd..39e9814 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c@@ -29,6 +29,14 @@ int pkey_initialize(void) int os_reserved, i; /* + * We define PKEY_DISABLE_EXECUTE in addition to the arch-neutral + * generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE. + * Ensure that the bits a distinct. + */ + BUILD_BUG_ON(PKEY_DISABLE_EXECUTE & + (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)); + + /* * Disable the pkey system till everything is in place. A subsequent * patch will enable it. */
@@ -181,10 +189,18 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { u64 new_amr_bits = 0x0ul; + u64 new_iamr_bits = 0x0ul; if (!is_pkey_enabled(pkey)) return -EINVAL; + if (init_val & PKEY_DISABLE_EXECUTE) { + if (!pkey_execute_disable_supported) + return -EINVAL; + new_iamr_bits |= IAMR_EX_BIT; + } + init_iamr(pkey, new_iamr_bits); + /* Set the bits we need in AMR: */ if (init_val & PKEY_DISABLE_ACCESS) new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT;
--
1.7.1