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Message-Id: <20230724-arm64-gcs-v2-7-dc2c1d44c2eb@kernel.org>
Date: Mon, 24 Jul 2023 13:45:54 +0100
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Jonathan Corbet <corbet@....net>,
Andrew Morton <akpm@...ux-foundation.org>,
Marc Zyngier <maz@...nel.org>,
Oliver Upton <oliver.upton@...ux.dev>,
James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Arnd Bergmann <arnd@...db.de>, Oleg Nesterov <oleg@...hat.com>,
Eric Biederman <ebiederm@...ssion.com>,
Kees Cook <keescook@...omium.org>,
Shuah Khan <shuah@...nel.org>,
"Rick P. Edgecombe" <rick.p.edgecombe@...el.com>,
Deepak Gupta <debug@...osinc.com>,
Ard Biesheuvel <ardb@...nel.org>,
Szabolcs Nagy <Szabolcs.Nagy@....com>
Cc: "H.J. Lu" <hjl.tools@...il.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org,
kvmarm@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
linux-arch@...r.kernel.org, linux-mm@...ck.org,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-riscv@...ts.infradead.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH v2 07/35] arm64/gcs: Provide copy_to_user_gcs()
In order for EL1 to write to an EL0 GCS it must use the GCSSTTR instruction
rather than a normal STTR. Provide a copy_to_user_gcs() which does this.
Since it is not possible to store anything other than a 64 bit value the
interface is presented in terms of 64 bit values, using unsigned long
rather than u64 due to sparse.
Signed-off-by: Mark Brown <broonie@...nel.org>
---
arch/arm64/include/asm/uaccess.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 22e10e79f56a..24aa804e95a7 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -445,6 +445,26 @@ static inline int gcssttr(unsigned long __user *addr, unsigned long val)
return err;
}
+static inline int copy_to_user_gcs(unsigned long __user *addr,
+ unsigned long *val,
+ int count)
+{
+ int ret = -EFAULT;
+ int i;
+
+ if (access_ok((char __user *)addr, count * sizeof(u64))) {
+ uaccess_ttbr0_enable();
+ for (i = 0; i < count; i++) {
+ ret = gcssttr(addr++, *val++);
+ if (ret != 0)
+ break;
+ }
+ uaccess_ttbr0_disable();
+ }
+
+ return ret;
+}
+
#endif /* CONFIG_ARM64_GCS */
#endif /* __ASM_UACCESS_H */
--
2.30.2
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