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authorGeoff Levand <geoff@infradead.org>2016-04-27 17:47:03 +0100
committerWill Deacon <will.deacon@arm.com>2016-04-28 12:05:46 +0100
commitad72e59ff2bad55f6b9e7ac1fe5d824831ea2550 (patch)
treeca5eca21b84288153c2ea778da81b9a5420afd95 /arch/arm64/kvm/hyp.S
parent00a44cdaba0900c63a003e0c431f506f49376a90 (diff)
downloadlinux-ad72e59ff2bad55f6b9e7ac1fe5d824831ea2550.tar.bz2
arm64: hyp/kvm: Make hyp-stub extensible
The existing arm64 hcall implementations are limited in that they only allow for two distinct hcalls; with the x0 register either zero or not zero. Also, the API of the hyp-stub exception vector routines and the KVM exception vector routines differ; hyp-stub uses a non-zero value in x0 to implement __hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp. To allow for additional hcalls to be defined and to make the arm64 hcall API more consistent across exception vector routines, change the hcall implementations to reserve all x0 values below 0xfff for hcalls such as {s,g}et_vectors(). Define two new preprocessor macros HVC_GET_VECTORS, and HVC_SET_VECTORS to be used as hcall type specifiers and convert the existing __hyp_get_vectors() and __hyp_set_vectors() routines to use these new macros when executing an HVC call. Also, change the corresponding hyp-stub and KVM el1_sync exception vector routines to use these new macros. Signed-off-by: Geoff Levand <geoff@infradead.org> [Merged two hcall patches, moved immediate value from esr to x0, use lr as a scratch register, changed limit to 0xfff] Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kvm/hyp.S')
-rw-r--r--arch/arm64/kvm/hyp.S4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 4ee5612f43ea..7ce931565151 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -35,8 +35,8 @@
* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
* passed in x0.
*
- * A function pointer with a value of 0 has a special meaning, and is
- * used to implement __hyp_get_vectors in the same way as in
+ * A function pointer with a value less than 0xfff has a special meaning,
+ * and is used to implement __hyp_get_vectors in the same way as in
* arch/arm64/kernel/hyp_stub.S.
* HVC behaves as a 'bl' call and will clobber lr.
*/