Re: [PATCH v12 2/3] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey
From: Dave Hansen <hidden>
Date: 2018-02-26 21:14:39
Also in:
linux-arch, linux-mm, lkml
On 02/21/2018 03:52 PM, Ram Pai wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/linux/mm.h b/include/linux/mm.h index ad207ad..d534f46 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h@@ -231,9 +231,10 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, #ifdef CONFIG_ARCH_HAS_PKEYS # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ -# define VM_PKEY_BIT1 VM_HIGH_ARCH_1 +# define VM_PKEY_BIT1 VM_HIGH_ARCH_1 /* on x86 and 5-bit value on ppc64 */ # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 +# define VM_PKEY_BIT4 VM_HIGH_ARCH_4 #endif /* CONFIG_ARCH_HAS_PKEYS */
I think I would prefer if VM_PKEY_BIT4 was unusable on x86, or #defined to 0. We don't want folks using a bit that can not be programmed into the hardware.