From 3ad1a6cb0abc63d036fc866bd7c2c5983516dec5 Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Thu, 18 Mar 2021 14:33:07 +0000 Subject: bug: Remove redundant condition check in report_bug report_bug() will return early if it cannot find a bug corresponding to the provided address. The subsequent test for the bug will always be true so remove it. Fixes: 1b4cfe3c0a30d ("lib/bug.c: exclude non-BUG/WARN exceptions from report_bug()") Signed-off-by: Andrew Scull Cc: Peter Zijlstra Cc: "Steven Rostedt (VMware)" Reviewed-by: Steven Rostedt (VMware) Acked-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210318143311.839894-2-ascull@google.com --- lib/bug.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/lib/bug.c b/lib/bug.c index 8f9d537bfb2a..b92da1f6e21b 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -155,30 +155,27 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) file = NULL; line = 0; - warning = 0; - if (bug) { #ifdef CONFIG_DEBUG_BUGVERBOSE #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS - file = bug->file; + file = bug->file; #else - file = (const char *)bug + bug->file_disp; + file = (const char *)bug + bug->file_disp; #endif - line = bug->line; + line = bug->line; #endif - warning = (bug->flags & BUGFLAG_WARNING) != 0; - once = (bug->flags & BUGFLAG_ONCE) != 0; - done = (bug->flags & BUGFLAG_DONE) != 0; - - if (warning && once) { - if (done) - return BUG_TRAP_TYPE_WARN; - - /* - * Since this is the only store, concurrency is not an issue. - */ - bug->flags |= BUGFLAG_DONE; - } + warning = (bug->flags & BUGFLAG_WARNING) != 0; + once = (bug->flags & BUGFLAG_ONCE) != 0; + done = (bug->flags & BUGFLAG_DONE) != 0; + + if (warning && once) { + if (done) + return BUG_TRAP_TYPE_WARN; + + /* + * Since this is the only store, concurrency is not an issue. + */ + bug->flags |= BUGFLAG_DONE; } /* -- cgit v1.2.3 From 26dbc7e299c7ebbb6a95e2c620b21b5280b37c57 Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Thu, 18 Mar 2021 14:33:08 +0000 Subject: bug: Factor out a getter for a bug's file line There is some non-trivial config-based logic to get the file name and line number associated with a bug. Factor this out to a getter that can be resused. Signed-off-by: Andrew Scull Cc: Peter Zijlstra Cc: "Steven Rostedt (VMware)" Reviewed-by: Steven Rostedt (VMware) Acked-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210318143311.839894-3-ascull@google.com --- include/linux/bug.h | 3 +++ lib/bug.c | 27 +++++++++++++++++---------- 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/include/linux/bug.h b/include/linux/bug.h index f639bd0122f3..e3841bee4c8d 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -36,6 +36,9 @@ static inline int is_warning_bug(const struct bug_entry *bug) return bug->flags & BUGFLAG_WARNING; } +void bug_get_file_line(struct bug_entry *bug, const char **file, + unsigned int *line); + struct bug_entry *find_bug(unsigned long bugaddr); enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); diff --git a/lib/bug.c b/lib/bug.c index b92da1f6e21b..e65398082cbc 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -127,6 +127,22 @@ static inline struct bug_entry *module_find_bug(unsigned long bugaddr) } #endif +void bug_get_file_line(struct bug_entry *bug, const char **file, + unsigned int *line) +{ + *file = NULL; + *line = 0; + +#ifdef CONFIG_DEBUG_BUGVERBOSE +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + *file = bug->file; +#else + *file = (const char *)bug + bug->file_disp; +#endif + *line = bug->line; +#endif +} + struct bug_entry *find_bug(unsigned long bugaddr) { struct bug_entry *bug; @@ -153,17 +169,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) disable_trace_on_warning(); - file = NULL; - line = 0; + bug_get_file_line(bug, &file, &line); -#ifdef CONFIG_DEBUG_BUGVERBOSE -#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS - file = bug->file; -#else - file = (const char *)bug + bug->file_disp; -#endif - line = bug->line; -#endif warning = (bug->flags & BUGFLAG_WARNING) != 0; once = (bug->flags & BUGFLAG_ONCE) != 0; done = (bug->flags & BUGFLAG_DONE) != 0; -- cgit v1.2.3 From 5b8be5d875a996776708ba174fcd08c8bcd721a5 Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Thu, 18 Mar 2021 14:33:09 +0000 Subject: bug: Assign values once in bug_get_file_line() Set bug_get_file_line()'s output parameter values directly rather than first nullifying them and then conditionally setting new values. Signed-off-by: Andrew Scull Cc: Peter Zijlstra Cc: "Steven Rostedt (VMware)" Acked-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210318143311.839894-4-ascull@google.com --- lib/bug.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/bug.c b/lib/bug.c index e65398082cbc..45a0584f6541 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -130,9 +130,6 @@ static inline struct bug_entry *module_find_bug(unsigned long bugaddr) void bug_get_file_line(struct bug_entry *bug, const char **file, unsigned int *line) { - *file = NULL; - *line = 0; - #ifdef CONFIG_DEBUG_BUGVERBOSE #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS *file = bug->file; @@ -140,6 +137,9 @@ void bug_get_file_line(struct bug_entry *bug, const char **file, *file = (const char *)bug + bug->file_disp; #endif *line = bug->line; +#else + *file = NULL; + *line = 0; #endif } -- cgit v1.2.3 From f79e616f27ab6cd74deb0995a8eead3d1c9d65af Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Thu, 18 Mar 2021 14:33:10 +0000 Subject: KVM: arm64: Use BUG and BUG_ON in nVHE hyp hyp_panic() reports the address of the panic by using ELR_EL2, but this isn't a useful address when hyp_panic() is called directly. Replace such direct calls with BUG() and BUG_ON() which use BRK to trigger an exception that then goes to hyp_panic() with the correct address. Also remove the hyp_panic() declaration from the header file to avoid accidental misuse. Signed-off-by: Andrew Scull Acked-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210318143311.839894-5-ascull@google.com --- arch/arm64/include/asm/kvm_hyp.h | 1 - arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 +- arch/arm64/kvm/hyp/nvhe/hyp-smp.c | 6 ++---- 3 files changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 32ae676236b6..fe5fc814f228 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -100,7 +100,6 @@ u64 __guest_enter(struct kvm_vcpu *vcpu); bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt); -void __noreturn hyp_panic(void); #ifdef __KVM_NVHE_HYPERVISOR__ void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr, u64 elr, u64 par); diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 936328207bde..821a69601dd9 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -178,6 +178,6 @@ void handle_trap(struct kvm_cpu_context *host_ctxt) handle_host_smc(host_ctxt); break; default: - hyp_panic(); + BUG(); } } diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c index 879559057dee..9f54833af400 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c @@ -18,8 +18,7 @@ u64 __ro_after_init hyp_cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID u64 cpu_logical_map(unsigned int cpu) { - if (cpu >= ARRAY_SIZE(hyp_cpu_logical_map)) - hyp_panic(); + BUG_ON(cpu >= ARRAY_SIZE(hyp_cpu_logical_map)); return hyp_cpu_logical_map[cpu]; } @@ -30,8 +29,7 @@ unsigned long __hyp_per_cpu_offset(unsigned int cpu) unsigned long this_cpu_base; unsigned long elf_base; - if (cpu >= ARRAY_SIZE(kvm_arm_hyp_percpu_base)) - hyp_panic(); + BUG_ON(cpu >= ARRAY_SIZE(kvm_arm_hyp_percpu_base)); cpu_base_array = (unsigned long *)&kvm_arm_hyp_percpu_base; this_cpu_base = kern_hyp_va(cpu_base_array[cpu]); -- cgit v1.2.3 From aec0fae62e47050019474936248a311a0ab08705 Mon Sep 17 00:00:00 2001 From: Andrew Scull Date: Thu, 18 Mar 2021 14:33:11 +0000 Subject: KVM: arm64: Log source when panicking from nVHE hyp To aid with debugging, add details of the source of a panic from nVHE hyp. This is done by having nVHE hyp exit to nvhe_hyp_panic_handler() rather than directly to panic(). The handler will then add the extra details for debugging before panicking the kernel. If the panic was due to a BUG(), look up the metadata to log the file and line, if available, otherwise log an address that can be looked up in vmlinux. The hyp offset is also logged to allow other hyp VAs to be converted, similar to how the kernel offset is logged during a panic. __hyp_panic_string is now inlined since it no longer needs to be referenced as a symbol and the message is free to diverge between VHE and nVHE. The following is an example of the logs generated by a BUG in nVHE hyp. [ 46.754840] kvm [307]: nVHE hyp BUG at: arch/arm64/kvm/hyp/nvhe/switch.c:242! [ 46.755357] kvm [307]: Hyp Offset: 0xfffea6c58e1e0000 [ 46.755824] Kernel panic - not syncing: HYP panic: [ 46.755824] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800 [ 46.755824] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000 [ 46.755824] VCPU:0000d93a880d0000 [ 46.756960] CPU: 3 PID: 307 Comm: kvm-vcpu-0 Not tainted 5.12.0-rc3-00005-gc572b99cf65b-dirty #133 [ 46.757459] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 [ 46.758366] Call trace: [ 46.758601] dump_backtrace+0x0/0x1b0 [ 46.758856] show_stack+0x18/0x70 [ 46.759057] dump_stack+0xd0/0x12c [ 46.759236] panic+0x16c/0x334 [ 46.759426] arm64_kernel_unmapped_at_el0+0x0/0x30 [ 46.759661] kvm_arch_vcpu_ioctl_run+0x134/0x750 [ 46.759936] kvm_vcpu_ioctl+0x2f0/0x970 [ 46.760156] __arm64_sys_ioctl+0xa8/0xec [ 46.760379] el0_svc_common.constprop.0+0x60/0x120 [ 46.760627] do_el0_svc+0x24/0x90 [ 46.760766] el0_svc+0x2c/0x54 [ 46.760915] el0_sync_handler+0x1a4/0x1b0 [ 46.761146] el0_sync+0x170/0x180 [ 46.761889] SMP: stopping secondary CPUs [ 46.762786] Kernel Offset: 0x3e1cd2820000 from 0xffff800010000000 [ 46.763142] PHYS_OFFSET: 0xffffa9f680000000 [ 46.763359] CPU features: 0x00240022,61806008 [ 46.763651] Memory Limit: none [ 46.813867] ---[ end Kernel panic - not syncing: HYP panic: [ 46.813867] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800 [ 46.813867] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000 [ 46.813867] VCPU:0000d93a880d0000 ]--- Signed-off-by: Andrew Scull Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210318143311.839894-6-ascull@google.com --- arch/arm64/include/asm/kvm_mmu.h | 2 ++ arch/arm64/kernel/image-vars.h | 3 +-- arch/arm64/kvm/handle_exit.c | 45 +++++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp/include/hyp/switch.h | 2 -- arch/arm64/kvm/hyp/nvhe/host.S | 18 +++++-------- arch/arm64/kvm/hyp/nvhe/psci-relay.c | 2 -- arch/arm64/kvm/hyp/vhe/switch.c | 4 +-- 7 files changed, 56 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 90873851f677..7c17a67d2291 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -121,6 +121,8 @@ void kvm_update_va_mask(struct alt_instr *alt, void kvm_compute_layout(void); void kvm_apply_hyp_relocations(void); +#define __hyp_pa(x) (((phys_addr_t)(x)) + hyp_physvirt_offset) + static __always_inline unsigned long __kern_hyp_va(unsigned long v) { asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n" diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 5aa9ed1e9ec6..5ff2b6909387 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -70,8 +70,7 @@ KVM_NVHE_ALIAS(kvm_get_kimage_voffset); KVM_NVHE_ALIAS(kvm_vgic_global_state); /* Kernel symbols used to call panic() from nVHE hyp code (via ERET). */ -KVM_NVHE_ALIAS(__hyp_panic_string); -KVM_NVHE_ALIAS(panic); +KVM_NVHE_ALIAS(nvhe_hyp_panic_handler); /* Vectors installed by hyp-init on reset HVC. */ KVM_NVHE_ALIAS(__hyp_stub_vectors); diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index cebe39f3b1b6..6f48336b1d86 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -291,3 +291,48 @@ void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index) if (exception_index == ARM_EXCEPTION_EL1_SERROR) kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu)); } + +void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr, + u64 par, uintptr_t vcpu, + u64 far, u64 hpfar) { + u64 elr_in_kimg = __phys_to_kimg(__hyp_pa(elr)); + u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr; + u64 mode = spsr & PSR_MODE_MASK; + + /* + * The nVHE hyp symbols are not included by kallsyms to avoid issues + * with aliasing. That means that the symbols cannot be printed with the + * "%pS" format specifier, so fall back to the vmlinux address if + * there's no better option. + */ + if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) { + kvm_err("Invalid host exception to nVHE hyp!\n"); + } else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 && + (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) { + struct bug_entry *bug = find_bug(elr_in_kimg); + const char *file = NULL; + unsigned int line = 0; + + /* All hyp bugs, including warnings, are treated as fatal. */ + if (bug) + bug_get_file_line(bug, &file, &line); + + if (file) + kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line); + else + kvm_err("nVHE hyp BUG at: %016llx!\n", elr + hyp_offset); + } else { + kvm_err("nVHE hyp panic at: %016llx!\n", elr + hyp_offset); + } + + /* + * Hyp has panicked and we're going to handle that by panicking the + * kernel. The kernel offset will be revealed in the panic so we're + * also safe to reveal the hyp offset as a debugging aid for translating + * hyp VAs to vmlinux addresses. + */ + kvm_err("Hyp Offset: 0x%llx\n", hyp_offset); + + panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n", + spsr, elr, esr, far, hpfar, par, vcpu); +} diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 6c1f51f25eb3..32d0c036c050 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -30,8 +30,6 @@ #include #include -extern const char __hyp_panic_string[]; - extern struct exception_table_entry __start___kvm_ex_table; extern struct exception_table_entry __stop___kvm_ex_table; diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 5d94584840cc..2b23400e0fb3 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -79,22 +79,18 @@ SYM_FUNC_START(__hyp_do_panic) mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\ PSR_MODE_EL1h) msr spsr_el2, lr - ldr lr, =panic + ldr lr, =nvhe_hyp_panic_handler hyp_kimg_va lr, x6 msr elr_el2, lr mov x29, x0 - /* Load the format string into x0 and arguments into x1-7 */ - ldr x0, =__hyp_panic_string - hyp_kimg_va x0, x6 - - /* Load the format arguments into x1-7. */ - mov x6, x3 - get_vcpu_ptr x7, x3 - mrs x3, esr_el2 - mrs x4, far_el2 - mrs x5, hpfar_el2 + /* Load the panic arguments into x0-7 */ + mrs x0, esr_el2 + get_vcpu_ptr x4, x5 + mrs x5, far_el2 + mrs x6, hpfar_el2 + mov x7, xzr // Unused argument /* Enter the host, conditionally restoring the host context. */ cbz x29, __host_enter_without_restoring diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c index 63de71c0481e..ca630896476d 100644 --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c @@ -22,8 +22,6 @@ void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt); struct kvm_host_psci_config __ro_after_init kvm_host_psci_config; s64 __ro_after_init hyp_physvirt_offset; -#define __hyp_pa(x) ((phys_addr_t)((x)) + hyp_physvirt_offset) - #define INVALID_CPU_ID UINT_MAX struct psci_boot_args { diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index af8e940d0f03..7b8f7db5c1ed 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -27,8 +27,6 @@ #include #include -const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n"; - /* VHE specific context */ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data); DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); @@ -207,7 +205,7 @@ static void __hyp_call_panic(u64 spsr, u64 elr, u64 par) __deactivate_traps(vcpu); sysreg_restore_host_state_vhe(host_ctxt); - panic(__hyp_panic_string, + panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n", spsr, elr, read_sysreg_el2(SYS_ESR), read_sysreg_el2(SYS_FAR), read_sysreg(hpfar_el2), par, vcpu); -- cgit v1.2.3