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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm64/kvm/hyp/nvhe/stacktrace.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/kvm/hyp/nvhe/stacktrace.c')
-rw-r--r-- | arch/arm64/kvm/hyp/nvhe/stacktrace.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c new file mode 100644 index 0000000000..ed6b58b19c --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM nVHE hypervisor stack tracing support. + * + * Copyright (C) 2022 Google LLC + */ +#include <asm/kvm_asm.h> +#include <asm/kvm_hyp.h> +#include <asm/memory.h> +#include <asm/percpu.h> + +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) + __aligned(16); + +DEFINE_PER_CPU(struct kvm_nvhe_stacktrace_info, kvm_stacktrace_info); + +/* + * hyp_prepare_backtrace - Prepare non-protected nVHE backtrace. + * + * @fp : frame pointer at which to start the unwinding. + * @pc : program counter at which to start the unwinding. + * + * Save the information needed by the host to unwind the non-protected + * nVHE hypervisor stack in EL1. + */ +static void hyp_prepare_backtrace(unsigned long fp, unsigned long pc) +{ + struct kvm_nvhe_stacktrace_info *stacktrace_info = this_cpu_ptr(&kvm_stacktrace_info); + struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params); + + stacktrace_info->stack_base = (unsigned long)(params->stack_hyp_va - PAGE_SIZE); + stacktrace_info->overflow_stack_base = (unsigned long)this_cpu_ptr(overflow_stack); + stacktrace_info->fp = fp; + stacktrace_info->pc = pc; +} + +#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE +#include <asm/stacktrace/nvhe.h> + +DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace); + +static struct stack_info stackinfo_get_overflow(void) +{ + unsigned long low = (unsigned long)this_cpu_ptr(overflow_stack); + unsigned long high = low + OVERFLOW_STACK_SIZE; + + return (struct stack_info) { + .low = low, + .high = high, + }; +} + +static struct stack_info stackinfo_get_hyp(void) +{ + struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params); + unsigned long high = params->stack_hyp_va; + unsigned long low = high - PAGE_SIZE; + + return (struct stack_info) { + .low = low, + .high = high, + }; +} + +static int unwind_next(struct unwind_state *state) +{ + return unwind_next_frame_record(state); +} + +static void notrace unwind(struct unwind_state *state, + stack_trace_consume_fn consume_entry, + void *cookie) +{ + while (1) { + int ret; + + if (!consume_entry(cookie, state->pc)) + break; + ret = unwind_next(state); + if (ret < 0) + break; + } +} + +/* + * pkvm_save_backtrace_entry - Saves a protected nVHE HYP stacktrace entry + * + * @arg : index of the entry in the stacktrace buffer + * @where : the program counter corresponding to the stack frame + * + * Save the return address of a stack frame to the shared stacktrace buffer. + * The host can access this shared buffer from EL1 to dump the backtrace. + */ +static bool pkvm_save_backtrace_entry(void *arg, unsigned long where) +{ + unsigned long *stacktrace = this_cpu_ptr(pkvm_stacktrace); + int *idx = (int *)arg; + + /* + * Need 2 free slots: 1 for current entry and 1 for the + * delimiter. + */ + if (*idx > ARRAY_SIZE(pkvm_stacktrace) - 2) + return false; + + stacktrace[*idx] = where; + stacktrace[++*idx] = 0UL; + + return true; +} + +/* + * pkvm_save_backtrace - Saves the protected nVHE HYP stacktrace + * + * @fp : frame pointer at which to start the unwinding. + * @pc : program counter at which to start the unwinding. + * + * Save the unwinded stack addresses to the shared stacktrace buffer. + * The host can access this shared buffer from EL1 to dump the backtrace. + */ +static void pkvm_save_backtrace(unsigned long fp, unsigned long pc) +{ + struct stack_info stacks[] = { + stackinfo_get_overflow(), + stackinfo_get_hyp(), + }; + struct unwind_state state = { + .stacks = stacks, + .nr_stacks = ARRAY_SIZE(stacks), + }; + int idx = 0; + + kvm_nvhe_unwind_init(&state, fp, pc); + + unwind(&state, pkvm_save_backtrace_entry, &idx); +} +#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */ +static void pkvm_save_backtrace(unsigned long fp, unsigned long pc) +{ +} +#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */ + +/* + * kvm_nvhe_prepare_backtrace - prepare to dump the nVHE backtrace + * + * @fp : frame pointer at which to start the unwinding. + * @pc : program counter at which to start the unwinding. + * + * Saves the information needed by the host to dump the nVHE hypervisor + * backtrace. + */ +void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc) +{ + if (is_protected_kvm_enabled()) + pkvm_save_backtrace(fp, pc); + else + hyp_prepare_backtrace(fp, pc); +} |