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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-24 03:35:57 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-24 03:35:57 +0300 |
commit | 9c0e6a89b592f4c4e4d769dbc22d399ab0685159 (patch) | |
tree | 54865d08ede844e868b3403670a9a91ad24bba82 /arch/arm/kernel/traps.c | |
parent | e6aef3496a00a12e78a571f61d98300cf0a86e6a (diff) | |
parent | 234a0f202a09a6144fd3c17ac6d018bdab9780bb (diff) | |
download | linux-9c0e6a89b592f4c4e4d769dbc22d399ab0685159.tar.xz |
Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
"Updates for IRQ stacks and virtually mapped stack support, and ftrace:
- Support for IRQ and vmap'ed stacks
This covers all the work related to implementing IRQ stacks and
vmap'ed stacks for all 32-bit ARM systems that are currently
supported by the Linux kernel, including RiscPC and Footbridge. It
has been submitted for review in four different waves:
- IRQ stacks support for v7 SMP systems [0]
- vmap'ed stacks support for v7 SMP systems[1]
- extending support for both IRQ stacks and vmap'ed stacks for all
remaining configurations, including v6/v7 SMP multiplatform
kernels and uniprocessor configurations including v7-M [2]
- fixes and updates in [3]
- ftrace fixes and cleanups
Make all flavors of ftrace available on all builds, regardless of
ISA choice, unwinder choice or compiler [4]:
- use ADD not POP where possible
- fix a couple of Thumb2 related issues
- enable HAVE_FUNCTION_GRAPH_FP_TEST for robustness
- enable the graph tracer with the EABI unwinder
- avoid clobbering frame pointer registers to make Clang happy
- Fixes for the above"
[0] https://lore.kernel.org/linux-arm-kernel/20211115084732.3704393-1-ardb@kernel.org/
[1] https://lore.kernel.org/linux-arm-kernel/20211122092816.2865873-1-ardb@kernel.org/
[2] https://lore.kernel.org/linux-arm-kernel/20211206164659.1495084-1-ardb@kernel.org/
[3] https://lore.kernel.org/linux-arm-kernel/20220124174744.1054712-1-ardb@kernel.org/
[4] https://lore.kernel.org/linux-arm-kernel/20220203082204.1176734-1-ardb@kernel.org/
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (62 commits)
ARM: fix building NOMMU ARMv4/v5 kernels
ARM: unwind: only permit stack switch when unwinding call_with_stack()
ARM: Revert "unwind: dump exception stack from calling frame"
ARM: entry: fix unwinder problems caused by IRQ stacks
ARM: unwind: set frame.pc correctly for current-thread unwinding
ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y
ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses
Revert "ARM: 9144/1: forbid ftrace with clang and thumb2_kernel"
ARM: mach-bcm: disable ftrace in SMC invocation routines
ARM: cacheflush: avoid clobbering the frame pointer
ARM: kprobes: treat R7 as the frame pointer register in Thumb2 builds
ARM: ftrace: enable the graph tracer with the EABI unwinder
ARM: unwind: track location of LR value in stack frame
ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST
ARM: ftrace: avoid unnecessary literal loads
ARM: ftrace: avoid redundant loads or clobbering IP
ARM: ftrace: use trampolines to keep .init.text in branching range
ARM: ftrace: use ADD not POP to counter PUSH at entry
ARM: ftrace: ensure that ADR takes the Thumb bit into account
ARM: make get_current() and __my_cpu_offset() __always_inline
...
Diffstat (limited to 'arch/arm/kernel/traps.c')
-rw-r--r-- | arch/arm/kernel/traps.c | 93 |
1 files changed, 87 insertions, 6 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index cae4a748811f..b532039286a2 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -36,6 +36,7 @@ #include <asm/ptrace.h> #include <asm/unwind.h> #include <asm/tls.h> +#include <asm/stacktrace.h> #include <asm/system_misc.h> #include <asm/opcodes.h> @@ -61,13 +62,24 @@ static int __init user_debug_setup(char *str) __setup("user_debug=", user_debug_setup); #endif -static void dump_mem(const char *, const char *, unsigned long, unsigned long); - void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame, const char *loglvl) { unsigned long end = frame + 4 + sizeof(struct pt_regs); + if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER) && + IS_ENABLED(CONFIG_CC_IS_GCC) && + end > ALIGN(frame, THREAD_SIZE)) { + /* + * If we are walking past the end of the stack, it may be due + * to the fact that we are on an IRQ or overflow stack. In this + * case, we can load the address of the other stack from the + * frame record. + */ + frame = ((unsigned long *)frame)[-2] - 4; + end = frame + 4 + sizeof(struct pt_regs); + } + #ifndef CONFIG_KALLSYMS printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n", loglvl, where, from); @@ -111,7 +123,8 @@ void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) static int verify_stack(unsigned long sp) { if (sp < PAGE_OFFSET || - (sp > (unsigned long)high_memory && high_memory != NULL)) + (!IS_ENABLED(CONFIG_VMAP_STACK) && + sp > (unsigned long)high_memory && high_memory != NULL)) return -EFAULT; return 0; @@ -121,8 +134,8 @@ static int verify_stack(unsigned long sp) /* * Dump out the contents of some memory nicely... */ -static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top) +void dump_mem(const char *lvl, const char *str, unsigned long bottom, + unsigned long top) { unsigned long first; int i; @@ -281,7 +294,8 @@ static int __die(const char *str, int err, struct pt_regs *regs) if (!user_mode(regs) || in_interrupt()) { dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, - THREAD_SIZE + (unsigned long)task_stack_page(tsk)); + ALIGN(regs->ARM_sp - THREAD_SIZE, THREAD_ALIGN) + + THREAD_SIZE); dump_backtrace(regs, tsk, KERN_EMERG); dump_instr(KERN_EMERG, regs); } @@ -880,3 +894,70 @@ void __init early_trap_init(void *vectors_base) */ } #endif + +#ifdef CONFIG_VMAP_STACK + +DECLARE_PER_CPU(u8 *, irq_stack_ptr); + +asmlinkage DEFINE_PER_CPU(u8 *, overflow_stack_ptr); + +static int __init allocate_overflow_stacks(void) +{ + u8 *stack; + int cpu; + + for_each_possible_cpu(cpu) { + stack = (u8 *)__get_free_page(GFP_KERNEL); + if (WARN_ON(!stack)) + return -ENOMEM; + per_cpu(overflow_stack_ptr, cpu) = &stack[OVERFLOW_STACK_SIZE]; + } + return 0; +} +early_initcall(allocate_overflow_stacks); + +asmlinkage void handle_bad_stack(struct pt_regs *regs) +{ + unsigned long tsk_stk = (unsigned long)current->stack; +#ifdef CONFIG_IRQSTACKS + unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr); +#endif + unsigned long ovf_stk = (unsigned long)this_cpu_read(overflow_stack_ptr); + + console_verbose(); + pr_emerg("Insufficient stack space to handle exception!"); + + pr_emerg("Task stack: [0x%08lx..0x%08lx]\n", + tsk_stk, tsk_stk + THREAD_SIZE); +#ifdef CONFIG_IRQSTACKS + pr_emerg("IRQ stack: [0x%08lx..0x%08lx]\n", + irq_stk - THREAD_SIZE, irq_stk); +#endif + pr_emerg("Overflow stack: [0x%08lx..0x%08lx]\n", + ovf_stk - OVERFLOW_STACK_SIZE, ovf_stk); + + die("kernel stack overflow", regs, 0); +} + +#ifndef CONFIG_ARM_LPAE +/* + * Normally, we rely on the logic in do_translation_fault() to update stale PMD + * entries covering the vmalloc space in a task's page tables when it first + * accesses the region in question. Unfortunately, this is not sufficient when + * the task stack resides in the vmalloc region, as do_translation_fault() is a + * C function that needs a stack to run. + * + * So we need to ensure that these PMD entries are up to date *before* the MM + * switch. As we already have some logic in the MM switch path that takes care + * of this, let's trigger it by bumping the counter every time the core vmalloc + * code modifies a PMD entry in the vmalloc region. Use release semantics on + * the store so that other CPUs observing the counter's new value are + * guaranteed to see the updated page table entries as well. + */ +void arch_sync_kernel_mappings(unsigned long start, unsigned long end) +{ + if (start < VMALLOC_END && end > VMALLOC_START) + atomic_inc_return_release(&init_mm.context.vmalloc_seq); +} +#endif +#endif |