The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=fd25c62278cea3492a14abadc190f43da5f74224
commit fd25c62278cea3492a14abadc190f43da5f74224 Author: Konstantin Belousov <[email protected]> AuthorDate: 2022-09-07 20:13:35 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2022-09-14 15:46:32 +0000 i386: check that trap() and syscall() run on the thread kstack and not on the trampoline stack. This is a useful way to ensure that we did not enabled interrupts while on user %cr3 or trampoline stack. Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week --- sys/i386/i386/mp_machdep.c | 4 ++++ sys/i386/i386/trap.c | 30 ++++++++++++++++++++++++++++++ sys/x86/include/x86_var.h | 6 ++++++ sys/x86/isa/atpic.c | 1 + sys/x86/x86/local_apic.c | 5 +++++ 5 files changed, 46 insertions(+) diff --git a/sys/i386/i386/mp_machdep.c b/sys/i386/i386/mp_machdep.c index 777aefa021b3..bf1c7faf6182 100644 --- a/sys/i386/i386/mp_machdep.c +++ b/sys/i386/i386/mp_machdep.c @@ -658,6 +658,7 @@ invltlb_handler(void) { uint32_t generation; + trap_check_kstack(); #ifdef COUNT_XINVLTLB_HITS xhits_gbl[PCPU_GET(cpuid)]++; #endif /* COUNT_XINVLTLB_HITS */ @@ -680,6 +681,7 @@ invlpg_handler(void) { uint32_t generation; + trap_check_kstack(); #ifdef COUNT_XINVLTLB_HITS xhits_pg[PCPU_GET(cpuid)]++; #endif /* COUNT_XINVLTLB_HITS */ @@ -699,6 +701,7 @@ invlrng_handler(void) vm_offset_t addr, addr2; uint32_t generation; + trap_check_kstack(); #ifdef COUNT_XINVLTLB_HITS xhits_rng[PCPU_GET(cpuid)]++; #endif /* COUNT_XINVLTLB_HITS */ @@ -724,6 +727,7 @@ invlcache_handler(void) { uint32_t generation; + trap_check_kstack(); #ifdef COUNT_IPIS (*ipi_invlcache_counts[PCPU_GET(cpuid)])++; #endif /* COUNT_IPIS */ diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c index d09ba78cd83e..a4decc4976dc 100644 --- a/sys/i386/i386/trap.c +++ b/sys/i386/i386/trap.c @@ -184,6 +184,34 @@ SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, &uprintf_signal, 0, "Print debugging information on trap signal to ctty"); + +#ifdef INVARIANTS +static __inline register_t +read_esp(void) +{ + register_t res; + + __asm __volatile("movl\t%%esp,%0" : "=r" (res)); + return (res); +} + +void +trap_check_kstack(void) +{ + struct thread *td; + vm_offset_t stk; + + td = curthread; + stk = read_esp(); + if (stk >= PMAP_TRM_MIN_ADDRESS) + panic("td %p stack %#x in trampoline", td, stk); + if (stk < td->td_kstack || stk >= td->td_kstack + + ptoa(td->td_kstack_pages)) + panic("td %p stack %#x not in kstack VA %#x %d", + td, stk, td->td_kstack, td->td_kstack_pages); +} +#endif + /* * Exception, fault, and trap interface to the FreeBSD kernel. * This common code is called from assembly language IDT gate entry @@ -227,6 +255,7 @@ trap(struct trapframe *frame) return; } #endif + trap_check_kstack(); if (type == T_RESERVED) { trap_fatal(frame, 0); @@ -1126,6 +1155,7 @@ syscall(struct trapframe *frame) /* NOT REACHED */ } #endif + trap_check_kstack(); orig_tf_eflags = frame->tf_eflags; td = curthread; diff --git a/sys/x86/include/x86_var.h b/sys/x86/include/x86_var.h index 3e8e643e1b9c..38a332e36078 100644 --- a/sys/x86/include/x86_var.h +++ b/sys/x86/include/x86_var.h @@ -175,4 +175,10 @@ uint64_t rdtsc_ordered(void); void x86_msr_op(u_int msr, u_int op, uint64_t arg1, uint64_t *res); +#if defined(__i386__) && defined(INVARIANTS) +void trap_check_kstack(void); +#else +#define trap_check_kstack() +#endif + #endif diff --git a/sys/x86/isa/atpic.c b/sys/x86/isa/atpic.c index 0c0ca6d3ea8d..03ad707abdfa 100644 --- a/sys/x86/isa/atpic.c +++ b/sys/x86/isa/atpic.c @@ -526,6 +526,7 @@ atpic_handle_intr(u_int vector, struct trapframe *frame) kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0); kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED); + trap_check_kstack(); KASSERT(vector < NUM_ISA_IRQS, ("unknown int %u\n", vector)); isrc = &atintrs[vector].at_intsrc; diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c index 42a5a9fd4c8c..609635bdad3d 100644 --- a/sys/x86/x86/local_apic.c +++ b/sys/x86/x86/local_apic.c @@ -1296,6 +1296,7 @@ lapic_handle_intr(int vector, struct trapframe *frame) kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0); kmsan_mark(&vector, sizeof(vector), KMSAN_STATE_INITED); kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED); + trap_check_kstack(); isrc = intr_lookup_source(apic_idt_to_irq(PCPU_GET(apic_id), vector)); @@ -1314,6 +1315,7 @@ lapic_handle_timer(struct trapframe *frame) kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0); kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED); + trap_check_kstack(); #if defined(SMP) && !defined(SCHED_ULE) /* @@ -1433,6 +1435,7 @@ lapic_timer_stop(struct lapic *la) void lapic_handle_cmc(void) { + trap_check_kstack(); lapic_eoi(); cmc_intr(); @@ -1495,6 +1498,8 @@ lapic_handle_error(void) { uint32_t esr; + trap_check_kstack(); + /* * Read the contents of the error status register. Write to * the register first before reading from it to force the APIC
