From d1e420772cd1eb0afe5858619c73ce36f3e781a1 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Tue, 15 Apr 2025 19:16:58 -0700 Subject: [PATCH] x86/pkeys: Simplify PKRU update in signal frame The signal delivery logic was modified to always set the PKRU bit in xregs_state->header->xfeatures by this commit: ae6012d72fa6 ("x86/pkeys: Ensure updated PKRU value is XRSTOR'd") However, the change derives the bitmask value using XGETBV(1), rather than simply updating the buffer that already holds the value. Thus, this approach induces an unnecessary dependency on XGETBV1 for PKRU handling. Eliminate the dependency by using the established helper function. Subsequently, remove the now-unused 'mask' argument. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Aruna Ramakrishna Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Tony W Wang-oc Cc: Dave Hansen Link: https://lore.kernel.org/r/20250416021720.12305-9-chang.seok.bae@intel.com --- arch/x86/kernel/fpu/xstate.h | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h index 4231e449f0b46..a0256ef34ecb0 100644 --- a/arch/x86/kernel/fpu/xstate.h +++ b/arch/x86/kernel/fpu/xstate.h @@ -85,18 +85,15 @@ static inline int set_xfeature_in_sigframe(struct xregs_state __user *xbuf, u64 /* * Update the value of PKRU register that was already pushed onto the signal frame. */ -static inline int update_pkru_in_sigframe(struct xregs_state __user *buf, u64 mask, u32 pkru) +static inline int update_pkru_in_sigframe(struct xregs_state __user *buf, u32 pkru) { - u64 xstate_bv; int err; if (unlikely(!cpu_feature_enabled(X86_FEATURE_OSPKE))) return 0; /* Mark PKRU as in-use so that it is restored correctly. */ - xstate_bv = (mask & xfeatures_in_use()) | XFEATURE_MASK_PKRU; - - err = __put_user(xstate_bv, &buf->header.xfeatures); + err = set_xfeature_in_sigframe(buf, XFEATURE_MASK_PKRU); if (err) return err; @@ -320,7 +317,7 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf, u32 pkr clac(); if (!err) - err = update_pkru_in_sigframe(buf, mask, pkru); + err = update_pkru_in_sigframe(buf, pkru); return err; } -- 2.47.3