| Message ID | 20220715061027.1612149-8-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM nVHE Hypervisor stack unwinder | expand |
Hi Kalesh, On Fri, Jul 15, 2022 at 7:11 AM Kalesh Singh <kaleshsingh@google.com> wrote: > > On hyp stack overflow switch to 16-byte aligned secondary stack. > This provides us stack space to better handle overflows; and is > used in a subsequent patch to dump the hypervisor stacktrace. > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Thanks, /fuad > --- > arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- > arch/arm64/kvm/hyp/nvhe/host.S | 9 ++------- > arch/arm64/kvm/hyp/nvhe/stacktrace.c | 11 +++++++++++ > 3 files changed, 14 insertions(+), 8 deletions(-) > create mode 100644 arch/arm64/kvm/hyp/nvhe/stacktrace.c > > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile > index f9fe4dc21b1f..524e7dad5739 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -14,7 +14,7 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs)) > > obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ > hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \ > - cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o > + cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o > obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ > ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o > obj-$(CONFIG_DEBUG_LIST) += list_debug.o > diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S > index ea6a397b64a6..b6c0188c4b35 100644 > --- a/arch/arm64/kvm/hyp/nvhe/host.S > +++ b/arch/arm64/kvm/hyp/nvhe/host.S > @@ -177,13 +177,8 @@ SYM_FUNC_END(__host_hvc) > b hyp_panic > > .L__hyp_sp_overflow\@: > - /* > - * Reset SP to the top of the stack, to allow handling the hyp_panic. > - * This corrupts the stack but is ok, since we won't be attempting > - * any unwinding here. > - */ > - ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 > - mov sp, x0 > + /* Switch to the overflow stack */ > + adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0 > > b hyp_panic_bad_stack > ASM_BUG() > diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c > new file mode 100644 > index 000000000000..a3d5b34e1249 > --- /dev/null > +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c > @@ -0,0 +1,11 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * KVM nVHE hypervisor stack tracing support. > + * > + * Copyright (C) 2022 Google LLC > + */ > +#include <asm/memory.h> > +#include <asm/percpu.h> > + > +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) > + __aligned(16); > -- > 2.37.0.170.g444d1eabd0-goog >
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index f9fe4dc21b1f..524e7dad5739 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -14,7 +14,7 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs)) obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \ - cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o + cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o obj-$(CONFIG_DEBUG_LIST) += list_debug.o diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index ea6a397b64a6..b6c0188c4b35 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -177,13 +177,8 @@ SYM_FUNC_END(__host_hvc) b hyp_panic .L__hyp_sp_overflow\@: - /* - * Reset SP to the top of the stack, to allow handling the hyp_panic. - * This corrupts the stack but is ok, since we won't be attempting - * any unwinding here. - */ - ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 - mov sp, x0 + /* Switch to the overflow stack */ + adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0 b hyp_panic_bad_stack ASM_BUG() diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c new file mode 100644 index 000000000000..a3d5b34e1249 --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c @@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM nVHE hypervisor stack tracing support. + * + * Copyright (C) 2022 Google LLC + */ +#include <asm/memory.h> +#include <asm/percpu.h> + +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) + __aligned(16);
On hyp stack overflow switch to 16-byte aligned secondary stack. This provides us stack space to better handle overflows; and is used in a subsequent patch to dump the hypervisor stacktrace. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/arm64/kvm/hyp/nvhe/host.S | 9 ++------- arch/arm64/kvm/hyp/nvhe/stacktrace.c | 11 +++++++++++ 3 files changed, 14 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/kvm/hyp/nvhe/stacktrace.c