From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x244.google.com (mail-qt0-x244.google.com [IPv6:2607:f8b0:400d:c0d::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3y0bGB0cqPzDqNh for ; Mon, 25 Sep 2017 04:24:17 +1000 (AEST) Received: by mail-qt0-x244.google.com with SMTP id u48so3765366qtc.4 for ; Sun, 24 Sep 2017 11:24:17 -0700 (PDT) Sender: Ram Pai From: Ram Pai To: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Cc: benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, linuxram@us.ibm.com Subject: [RFC] powerpc: add sys_pkey_modify() system call Date: Sun, 24 Sep 2017 11:23:54 -0700 Message-Id: <1506277434-13773-1-git-send-email-linuxram@us.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , sys_pkey_modify() is powerpc specific system call. It enables the ability to modify *any* attribute of a key. Since powerpc disallows modification of IAMR from user space an application is unable to change a key's execute-attribute. This system call helps accomplish the above. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/systbl.h | 1 + arch/powerpc/include/asm/unistd.h | 2 +- arch/powerpc/include/uapi/asm/unistd.h | 1 + arch/powerpc/kernel/entry_64.S | 9 +++++++++ arch/powerpc/mm/pkeys.c | 29 +++++++++++++++++++++++++++++ 5 files changed, 41 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h index b33b551..d6f667e 100644 --- a/arch/powerpc/include/asm/systbl.h +++ b/arch/powerpc/include/asm/systbl.h @@ -391,3 +391,4 @@ SYSCALL(pkey_alloc) SYSCALL(pkey_free) SYSCALL(pkey_mprotect) +PPC64ONLY(pkey_modify) diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h index daf1ba9..1e97086 100644 --- a/arch/powerpc/include/asm/unistd.h +++ b/arch/powerpc/include/asm/unistd.h @@ -12,7 +12,7 @@ #include -#define NR_syscalls 387 +#define NR_syscalls 388 #define __NR__exit __NR_exit diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h index 71ae45e..c70b6d3 100644 --- a/arch/powerpc/include/uapi/asm/unistd.h +++ b/arch/powerpc/include/uapi/asm/unistd.h @@ -397,5 +397,6 @@ #define __NR_pkey_alloc 384 #define __NR_pkey_free 385 #define __NR_pkey_mprotect 386 +#define __NR_pkey_modify 387 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */ diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 4a0fd4f..5980b9e 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -455,6 +455,15 @@ _GLOBAL(ppc_switch_endian) bl sys_switch_endian b .Lsyscall_exit +_GLOBAL(ppc_pkey_modify) + bl save_nvgprs +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + bl sys_pkey_modify +#else + bl sys_ni_syscall +#endif + b .Lsyscall_exit + _GLOBAL(ret_from_fork) bl schedule_tail REST_NVGPRS(r1) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index de2e88f..bd16bc4 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -364,3 +364,32 @@ bool arch_vma_access_permitted(struct vm_area_struct *vma, return pkey_access_permitted(pkey, write, execute); } + +unsigned int arch_usable_pkeys(void) +{ + unsigned int reserved; + + if (!pkey_inited) + return 0; + + /* Reserve one more to account for the execute-only pkey. */ + reserved = hweight32(initial_allocation_mask) + 1; + + return pkeys_total > reserved ? pkeys_total - reserved : 0; +} + +bool arch_supports_pkeys(int cap) +{ + if (cap & PKEY_DISABLE_EXECUTE) + return pkey_execute_disable_support; + return (cap & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)); +} + +long sys_pkey_modify(int pkey, unsigned long new_val) +{ + /* check for unsupported init values */ + if (new_val & ~PKEY_ACCESS_MASK) + return -EINVAL; + + return __arch_set_user_pkey_access(current, pkey, new_val); +} -- 1.7.1