From a5eff7259790d5314eff10563d6e59d358cce482 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 3 Apr 2019 18:41:56 +0200 Subject: x86/pkeys: Add PKRU value to init_fpstate MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The task's initial PKRU value is set partly for fpu__clear()/ copy_init_pkru_to_fpregs(). It is not part of init_fpstate.xsave and instead it is set explicitly. If the user removes the PKRU state from XSAVE in the signal handler then __fpu__restore_sig() will restore the missing bits from `init_fpstate' and initialize the PKRU value to 0. Add the `init_pkru_value' to `init_fpstate' so it is set to the init value in such a case. In theory copy_init_pkru_to_fpregs() could be removed because restoring the PKRU at return-to-userland should be enough. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Borislav Petkov Reviewed-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andi Kleen Cc: Andy Lutomirski Cc: "Chang S. Bae" Cc: Dominik Brodowski Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "Jason A. Donenfeld" Cc: Konrad Rzeszutek Wilk Cc: kvm ML Cc: Paolo Bonzini Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: x86-ml Link: https://lkml.kernel.org/r/20190403164156.19645-28-bigeasy@linutronix.de --- arch/x86/kernel/cpu/common.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/x86/kernel/cpu/common.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index cb28e98a0659..352fa19e6311 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -372,6 +372,8 @@ static bool pku_disabled; static __always_inline void setup_pku(struct cpuinfo_x86 *c) { + struct pkru_state *pk; + /* check the boot processor, plus compile options for PKU: */ if (!cpu_feature_enabled(X86_FEATURE_PKU)) return; @@ -382,6 +384,9 @@ static __always_inline void setup_pku(struct cpuinfo_x86 *c) return; cr4_set_bits(X86_CR4_PKE); + pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU); + if (pk) + pk->pkru = init_pkru_value; /* * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE * cpuid bit to be set. We need to ensure that we -- cgit v1.2.3