[PATCH 08/55] arm64: KVM: Always reference __hyp_panic_string via its kernel VA
From: Marc Zyngier <hidden>
Date: 2016-07-22 17:28:25
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
__hyp_panic_string is passed via the HYP panic code to the panic function, and is being "upgraded" to a kernel address, as it is referenced by the HYP code (in a PC-relative way). This is a bit silly, and we'd be better off obtaining the kernel address and not mess with it at all. This patch implements this with a tiny bit of asm glue, by forcing the string pointer to be read from the literal pool. Signed-off-by: Marc Zyngier <redacted> Signed-off-by: Christoffer Dall <redacted> --- arch/arm64/kvm/hyp/switch.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 437cfad..81f21a2 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c@@ -299,9 +299,16 @@ static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:% static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par) { - unsigned long str_va = (unsigned long)__hyp_panic_string; + unsigned long str_va; - __hyp_do_panic(hyp_kern_va(str_va), + /* + * Force the panic string to be loaded from the literal pool, + * making sure it is a kernel address and not a PC-relative + * reference. + */ + asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va)); + + __hyp_do_panic(str_va, spsr, elr, read_sysreg(esr_el2), read_sysreg_el2(far), read_sysreg(hpfar_el2), par,
--
2.8.1