From: ira.weiny@intel.com To: Dave Hansen <dave.hansen@linux.intel.com>, Dan Williams <dan.j.williams@intel.com> Cc: Ira Weiny <ira.weiny@intel.com>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Fenghua Yu <fenghua.yu@intel.com>, Rick Edgecombe <rick.p.edgecombe@intel.com>, x86@kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org Subject: [PATCH V7 02/18] x86/fpu: Refactor arch_set_user_pkey_access() Date: Tue, 3 Aug 2021 21:32:15 -0700 [thread overview] Message-ID: <20210804043231.2655537-3-ira.weiny@intel.com> (raw) In-Reply-To: <20210804043231.2655537-1-ira.weiny@intel.com> From: Ira Weiny <ira.weiny@intel.com> Both PKU and PKS update their register values in the same way. They can therefore share the update code. Define a helper, update_pkey_val(), which will be used to support both Protection Key User (PKU) and the new Protection Key for Supervisor (PKS) in subsequent patches. Use that helper in arch_set_user_pkey_access(). Co-developed-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ira Weiny <ira.weiny@intel.com> --- arch/x86/include/asm/pkeys.h | 2 ++ arch/x86/kernel/fpu/xstate.c | 22 ++++------------------ arch/x86/mm/pkeys.c | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index 5c7bcaa79623..597f19e4525b 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -133,4 +133,6 @@ static inline int vma_pkey(struct vm_area_struct *vma) return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT; } +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags); + #endif /*_ASM_X86_PKEYS_H */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 6af0c80ad425..4f95ab38a23c 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -915,8 +915,7 @@ EXPORT_SYMBOL_GPL(get_xsave_addr); int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { - u32 old_pkru, new_pkru_bits = 0; - int pkey_shift; + u32 pkru; /* * This check implies XSAVE support. OSPKE only gets @@ -933,22 +932,9 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, if (WARN_ON_ONCE(pkey >= arch_max_pkey())) return -EINVAL; - /* Set the bits needed in PKRU: */ - if (init_val & PKEY_DISABLE_ACCESS) - new_pkru_bits |= PKR_AD_BIT; - if (init_val & PKEY_DISABLE_WRITE) - new_pkru_bits |= PKR_WD_BIT; - - /* Shift the bits in to the correct place in PKRU for pkey: */ - pkey_shift = pkey * PKRU_BITS_PER_PKEY; - new_pkru_bits <<= pkey_shift; - - /* Get old PKRU and mask off any old bits in place: */ - old_pkru = read_pkru(); - old_pkru &= ~((PKR_AD_BIT|PKR_WD_BIT) << pkey_shift); - - /* Write old part along with new part: */ - write_pkru(old_pkru | new_pkru_bits); + pkru = read_pkru(); + pkru = update_pkey_val(pkru, pkey, init_val); + write_pkru(pkru); return 0; } diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index aa7042f272fb..ca2e20b18645 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -190,3 +190,26 @@ static __init int setup_init_pkru(char *opt) return 1; } __setup("init_pkru=", setup_init_pkru); + +/* + * Replace disable bits for @pkey with values from @flags + * + * Kernel users use the same flags as user space: + * PKEY_DISABLE_ACCESS + * PKEY_DISABLE_WRITE + */ +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags) +{ + int pkey_shift = pkey * PKR_BITS_PER_PKEY; + + /* Mask out old bit values */ + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift); + + /* Or in new values */ + if (flags & PKEY_DISABLE_ACCESS) + pk_reg |= PKR_AD_BIT << pkey_shift; + if (flags & PKEY_DISABLE_WRITE) + pk_reg |= PKR_WD_BIT << pkey_shift; + + return pk_reg; +} -- 2.28.0.rc0.12.gb6a658bd00c9
next prev parent reply other threads:[~2021-08-04 4:32 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-04 4:32 [PATCH V7 00/18] PKS/PMEM: Add Stray Write Protection ira.weiny 2021-08-04 4:32 ` [PATCH V7 01/18] x86/pkeys: Create pkeys_common.h ira.weiny 2021-08-04 4:32 ` ira.weiny [this message] 2021-11-25 14:23 ` [PATCH V7 02/18] x86/fpu: Refactor arch_set_user_pkey_access() Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 03/18] x86/pks: Add additional PKEY helper macros ira.weiny 2021-11-25 14:25 ` Thomas Gleixner 2021-11-25 16:58 ` Thomas Gleixner 2021-12-08 0:51 ` Ira Weiny 2021-12-08 15:11 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 04/18] x86/pks: Add PKS defines and Kconfig options ira.weiny 2021-08-04 4:32 ` [PATCH V7 05/18] x86/pks: Add PKS setup code ira.weiny 2021-11-25 15:15 ` Thomas Gleixner 2021-11-26 3:11 ` taoyi.ty 2021-11-26 9:57 ` Thomas Gleixner 2021-11-26 11:03 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 06/18] x86/fault: Adjust WARN_ON for PKey fault ira.weiny 2021-08-04 4:32 ` [PATCH V7 07/18] x86/pks: Preserve the PKRS MSR on context switch ira.weiny 2021-11-25 15:25 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 08/18] x86/entry: Preserve PKRS MSR across exceptions ira.weiny 2021-11-13 0:50 ` Ira Weiny 2021-11-25 11:19 ` Thomas Gleixner 2021-12-03 1:13 ` Andy Lutomirski 2021-11-25 14:12 ` Thomas Gleixner 2021-12-07 1:54 ` Ira Weiny 2021-12-07 4:45 ` Ira Weiny 2021-12-08 0:21 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 09/18] x86/pks: Add PKS kernel API ira.weiny 2021-08-04 4:32 ` [PATCH V7 10/18] x86/pks: Introduce pks_abandon_protections() ira.weiny 2021-08-04 4:32 ` [PATCH V7 11/18] x86/pks: Add PKS Test code ira.weiny 2021-08-04 4:32 ` [PATCH V7 12/18] x86/pks: Add PKS fault callbacks ira.weiny 2021-08-11 21:18 ` Edgecombe, Rick P 2021-08-17 3:21 ` Ira Weiny 2021-08-04 4:32 ` [PATCH V7 13/18] memremap_pages: Add access protection via supervisor Protection Keys (PKS) ira.weiny 2021-08-04 4:32 ` [PATCH V7 14/18] memremap_pages: Add memremap.pks_fault_mode ira.weiny 2021-08-04 4:57 ` Randy Dunlap 2021-08-07 19:32 ` Ira Weiny 2021-08-11 19:01 ` Edgecombe, Rick P 2021-08-17 3:12 ` Ira Weiny 2021-08-04 4:32 ` [PATCH V7 15/18] kmap: Add stray access protection for devmap pages ira.weiny 2021-08-04 4:32 ` [PATCH V7 16/18] dax: Stray access protection for dax_direct_access() ira.weiny 2021-08-04 4:32 ` [PATCH V7 17/18] nvdimm/pmem: Enable stray access protection ira.weiny 2021-08-04 4:32 ` [PATCH V7 18/18] devdax: " ira.weiny
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