linux-kernel - [PATCH 11/14] arm64: KVM: Add HYP per-cpu accessors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180522150648.28297-12-marc.zyngier@arm.com>
Date:   Tue, 22 May 2018 16:06:45 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu
Cc:     Will Deacon <will.deacon@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andy Lutomirski <luto@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christoffer Dall <christoffer.dall@....com>
Subject: [PATCH 11/14] arm64: KVM: Add HYP per-cpu accessors

As we're going to require to access per-cpu variables at EL2,
let's craft the minimum set of accessors required to implement
reading a per-cpu variable, relying on tpidr_el2 to contain the
per-cpu offset.

Reviewed-by: Christoffer Dall <christoffer.dall@....com>
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 arch/arm64/include/asm/kvm_asm.h | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index f6648a3e4152..fefd8cf42c35 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -71,14 +71,37 @@ extern u32 __kvm_get_mdcr_el2(void);
 
 extern u32 __init_stage2_translation(void);
 
+/* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */
+#define __hyp_this_cpu_ptr(sym)						\
+	({								\
+		void *__ptr = hyp_symbol_addr(sym);			\
+		__ptr += read_sysreg(tpidr_el2);			\
+		(typeof(&sym))__ptr;					\
+	 })
+
+#define __hyp_this_cpu_read(sym)					\
+	({								\
+		*__hyp_this_cpu_ptr(sym);				\
+	 })
+
 #else /* __ASSEMBLY__ */
 
-.macro get_host_ctxt reg, tmp
-	adr_l	\reg, kvm_host_cpu_state
+.macro hyp_adr_this_cpu reg, sym, tmp
+	adr_l	\reg, \sym
 	mrs	\tmp, tpidr_el2
 	add	\reg, \reg, \tmp
 .endm
 
+.macro hyp_ldr_this_cpu reg, sym, tmp
+	adr_l	\reg, \sym
+	mrs	\tmp, tpidr_el2
+	ldr	\reg,  [\reg, \tmp]
+.endm
+
+.macro get_host_ctxt reg, tmp
+	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
+.endm
+
 .macro get_vcpu_ptr vcpu, ctxt
 	get_host_ctxt \ctxt, \vcpu
 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
-- 
2.14.2